Tue·Dec 22, 2020Tuesday·December 22, 2020

1. 01*

   Flavor Non-universal Pati-Salam Unification and Neutrino Masses

   Javier Fuentes-Martin🇩🇪 · Gino Isidori🇨🇭 · Julie Pagès🇨🇭 · Ben A. Stefanek🇨🇭

   We analyze the neutrino mass spectrum and discuss the extra-dimensional interpretation of a three-site Pati-Salam model which i) unifies all families of quark and leptons, ii) provides a natural description of the Standard Model Yukawa couplings, iii) could account for the recent $B$-physics anomalies. The key feature of the model is a breaking of the Pati-Salam and electroweak gauge symmetries localized on opposite sites, communicated to the other sites in an attenuated manner via nearest-neighbor interactions. We show that in this context gauge-singlet fermions localized on each site, receiving hierarchical Majorana masses, can allow the implementation of an inverse seesaw mechanism leading to light anarchic neutrino masses consistent with data. The continuum limit of this three-site setup has a natural interpretation in terms of a warped extra dimension with three defects, where the required exponential hierarchies can be achieved from $\mathcal{O}(1)$ differences in the bulk field masses.

   hep-phPLB(2021)·58 citations
2. 02*

   Neutral Current Neutrino Interactions at FASER$\nu$

   Ahmed Ismail🇺🇸 · Felix Kling🇺🇸 · Roshan Mammen Abraham🇺🇸

   In detecting neutrinos from the Large Hadron Collider, FASER$\nu$ will record the most energetic laboratory neutrinos ever studied. While charged current neutrino scattering events can be cleanly identified by an energetic lepton exiting the interaction vertex, neutral current interactions are more difficult to detect. We explore the potential of FASER$\nu$ to observe neutrino neutral current scattering $\nu N\to \nu N$, demonstrating techniques to discriminate neutrino scattering events from neutral hadron backgrounds as well as to estimate the incoming neutrino energy given the deep inelastic scattering final state. We find that deep neural networks trained on kinematic observables allow for the measurement of the neutral current scattering cross section over neutrino energies from 100 GeV to several TeV. Such a measurement can be interpreted as a probe of neutrino non-standard interactions that is complementary to limits from other tests such as oscillations and coherent neutrino-nucleus scattering.

   hep-phPRD(2021)·55 citations
3. 03*

   Power corrections in a transverse-momentum cut for vector-boson production at NNLO: the $qg$-initiated real-virtual contribution

   Carlo Oleari🇮🇹 · Marco Rocco🇮🇹

   We consider the production of a vector boson ($Z$, $W^{\pm }$ or ${\gamma }^{\ast }$) at next-to-next-to-leading order in the strong coupling constant ${\alpha }_{\mathrm{S}}$. We impose a transverse-momentum cutoff, $q_{\mathrm{T}}^{\mathrm{cut}}$, on the vector boson produced in the $qg$-initiated channel. We then compute the power corrections in the cutoff, up to the second power, of the real-virtual interference contribution to the cumulative cross section at order ${\alpha }_{\mathrm{S}}^2$. Other terms with the same kinematics, originating from the subtraction method applied to the double-real contribution, have been also considered. The knowledge of such power corrections is a required ingredient in order to reduce the dependence on the transverse-momentum cutoff of the QCD cross sections at next-to-next-to-leading order, when the $q_{\mathrm{T}}$-subtraction method is applied. In addition, the study of the dependence of the cross section on $q_{\mathrm{T}}^{\mathrm{cut}}$ allows as well for an understanding of its behaviour in the small transverse-momentum limit, giving hints on the structure at all orders in ${\alpha }_{\mathrm{S}}$ and on the identification of universal patterns. Our result are presented in an analytic form, using the process-independent procedure described in a previous paper for the calculation of the all-order power corrections in $q_{\mathrm{T}}^{\mathrm{cut}}$.

   hep-phEPJC(2021)·20 citations
4. 04*

   Dark Energy Radiation

   Kim V. Berghaus🇺🇸 · Peter W. Graham🇺🇸 · David E. Kaplan🇺🇸 · Guy D. Moore🇩🇪 · Surjeet Rajendran🇺🇸

   We show that if dark energy evolves in time, its dynamical component could be dominated by a bath of dark radiation. Within current constraints this radiation could have up to $\sim 10^4$ times more energy density than the cosmic microwave background. We demonstrate particular models in which a rolling scalar field generates different forms of dark radiation such as hidden photons, milli-charged particles and even Standard Model neutrinos. We find the leading effect on the late-time cosmological expansion history depends on a single parameter beyond $\Lambda$CDM, namely the temperature of the dark radiation today. Cosmological observations of this modified expansion rate could provide a striking signature of this scenario. The dark radiation itself could even be directly detectable in laboratory experiments, suggesting a broader experimental program into the nature of dark energy.

   hep-phastro-ph.COhep-thPRD(2021)·66 citations
5. 05*

   Reinvestigating the $B$ $\to$ $PP$ decays by including the contributions from ${\varphi }_{B2}$

   Yueling Yang🇨🇳 · Lan Lang🇨🇳 · Xule Zhao🇨🇳 · Jinshu Huang🇨🇳 · Junfeng Sun🇨🇳

   Considering the $B$ mesonic distribution amplitude ${\varphi }_{B2}$, we reinvestigated the $B$ $\to$ $PP$ (where $P$ $=$ $\pi$ and $K$) decays with the perturbative QCD (pQCD) approach based on the $k_T$ factorization for three scenarios. It is found that the contributions of ${\varphi }_{B2}$ to formfactors $F_0^{B\to P}(0)$ and branching ratios are comparable with those from the NLO corrections. The $B$ $\to$ $K\pi$ decays could be well explained by considering the ${\varphi }_{B2}$. Hence, when the nonleptonic $B$ decays are studied withe the pQCD approach, the ${\varphi }_{B2}$ should be taken into account seriously.

   hep-phPRD(2021)·16 citations
6. 06*

   Rise of the DIS structure function F_L at small x caused by double-logarithmic contributions

   B.I. Ermolaev🇷🇺 · S.I. Troyan🇷🇺

   We present calculation of F_L in the double-logarithmic approximation and demonstrate that the synergic effect of the factor 1/x from the \alpha_s^2-order and the steep x-dependence of the totally resummed double logarithmic contributions of higher orders ensures the power-like rise of F_L at small x and arbitrary Q^2.

   hep-phhep-exJHEP(2021)·1 citation
7. 07*

   Pentagon integrals to arbitrary order in the dimensional regulator

   Nikolaos Syrrakos🇬🇷

   We analytically calculate one-loop five-point Master Integrals, \textit{pentagon integrals}, with up to one off-shell leg to arbitrary order in the dimensional regulator in $d=4-2ϵ$ space-time dimensions. A pure basis of Master Integrals is constructed for the pentagon family with one off-shell leg, satisfying a single-variable canonical differential equation in the Simplified Differential Equations approach. The relevant boundary terms are given in closed form, including a hypergeometric function which can be expanded to arbitrary order in the dimensional regulator using the \texttt{Mathematica} package \texttt{HypExp}. Thus one can obtain solutions of the canonical differential equation in terms of Goncharov Polylogartihms of arbitrary transcendental weight. As a special limit of the one-mass pentagon family, we obtain a fully analytic result for the massless pentagon family in terms of pure and universally transcendental functions. For both families we provide explicit solutions in terms of Goncharov Polylogartihms up to weight four.

   hep-phJHEP(2021)·28 citations
8. 08*

   Analytical Investigation of Meson Spectrum via Exact Quantization Rule Approach

   Etido P. Inyang🇳🇬 · Ephraim P. Inyang · Eddy S. William🇳🇬 · Etebong E. Ibekwe🇳🇬 · Ita O.Akpan🇳🇬

   We solved the radial Schr"odinger equation analytically using the Exact Quantization Rule approach to obtain the energy eigenvalues with the Extended Cornell potential ECP. The present results are applied for calculating the mass spectra of heavy mesons such as charmonium cc and bottomonium bb, and heavylight mesons such as bottom-charm bc and charm-Strange cs for different quantum states. Two special cases were considered when some of the potential parameters were set to zero, resulting into Coulomb potential, and Cornell potential, respectively. The present potential provides excellent results in comparison with experimental data with a maximum error of 0.0065 GeV and work of other researchers.

   hep-phquant-ph10 citations
9. 09*

   Interaction rates in cosmology: heavy particle production and scattering

   Mudit Rai🇺🇸 · Daniel Boyanovsky🇺🇸

   We study transition rates and cross sections from first principles in a spatially flat radiation dominated cosmology. We consider a model of scalar particles to study scattering and heavy particle production from pair annihilation, drawing more general conclusions. The S-matrix formulation is ill suited to study these ubiquitous processes in a rapidly expanding cosmology. We introduce a physically motivated adiabatic expansion that relies on wavelengths much smaller than the particle horizon at a given time. The leading order in this expansion dominates the transition rates and cross sections. Several important and general results are direct consequences of the cosmological redshift and a finite particle horizon: i) a violation of local Lorentz invariance, ii) freeze-out of the production cross section at a finite time, iii) sub-threshold production of heavier particles as a consequence of the uncertainty in the local energy from a finite particle horizon, a manifestation of the \emph{antizeno} effect. If heavy dark matter is produced via annihilation of a lighter species, sub-threshold production yields an enhanced abundance. We discuss several possible consequences of these effects.

   hep-phastro-ph.COgr-qchep-thClass.Quant.Grav.(2021)·8 citations
10. 10*

    Light Higgs searches in $t\bar{t}\varphi$ production at the LHC

    Duarte Azevedo🇵🇹 · Rodrigo Capucha🇵🇹 · Emanuel Gouveia🇵🇹 · António Onofre🇵🇹 · Rui Santos🇵🇹

    In this paper we propose a new reconstruction method to explore the low mass region in the associated production of top-quark pairs ($t\bar{t}$) with a generic scalar boson ($\varphi$) at the LHC. The new method of mass reconstruction shows an improved resolution of at least a factor of two in the low mass region when compared to previous methods, without the loss of sensitivity of previous analyses. It turns out that it also leads to an improvement of the mass reconstruction of the 125 GeV Higgs for the same production process. We use an effective Lagrangian to describe a scalar with a generic Yukawa coupling to the top quarks. A full phenomenological analysis was performed, using Standard Model background and signal events generated with MadGraph5\_aMC@NLO and reconstructed using a kinematic fit. The use of CP-sensitive variables allows then to maximize the distinction between CP-even and CP-odd components of the Yukawa couplings. Confidence Levels (CLs) for the exclusion of $\varphi$ bosons with mixed CP (both CP-even and CP-odd components) were determined as a function of the top Yukawa couplings to the $\varphi$ boson. The mass range analysed starts slightly above the ${\rm Y}$ mass up to 40 GeV, although the analysis can be used for an arbitrary mass. %We focus on dileptonic final states of the $t\bar{t}\varphi$ system, with $\varphi \to b\bar{b}$. If no new light scalar is found, exclusion limits at 95\% CL for the absolute value of the CP-even and CP-odd Yukawa are derived. %couplings are expected to be, approximately, as low as 0.10 and 0.50, respectively, at the end of the High Luminosity phase of the LHC (HL-LHC). Finally, we analyse how these limits constrain the parameter space of the complex two-Higgs doublet model (C2HDM).

    hep-phhep-exJHEP(2021)·17 citations
11. 11*

    Total yield of electron-positron pairs produced from vacuum in strong electromagnetic fields: validity of the locally constant field approximation

    D. G. Sevostyanov🇷🇺 · I. A. Aleksandrov🇷🇺 · G. Plunien🇩🇪 · V. M. Shabaev🇷🇺

    The widely-used locally constant field approximation (LCFA) can be utilized in order to derive a simple closed-form expression for the total number of particles produced in the presence of a strong electromagnetic field of a general spatio-temporal configuration. A usual justification for this approximate approach is the requirement that the external field vary slowly in space and time. In this investigation, we examine the validity of the LCFA by comparing its predictions to the results obtained by means of exact nonperturbative numerical techniques. To benchmark the LCFA in the regime of small field amplitudes and low frequencies, we employ a semiclassical approach. As a reference, we consider a standing electromagnetic wave oscillating both in time and space as well as two spatially uniform field configurations: Sauter pulse and oscillating electric field. Performing a thorough numerical analysis, we identify the domain of the field parameters where the approximation is well justified. In particular, it is demonstrated that the Keldysh parameter is not a relevant quantity governing the accuracy of the LCFA.

    hep-phhep-thPRD(2021)·20 citations
12. 12*

    Inflaton Oscillations and Post-Inflationary Reheating

    Marcos A. G. Garcia🇪🇸 · Kunio Kaneta🇰🇷 · Yann Mambrini🇫🇷 · Keith A. Olive🇺🇸

    We analyze in detail the perturbative decay of the inflaton oscillating about a generic form of its potential $V(\varphi )={\varphi }^k$, taking into account the effects of non-instantaneous reheating. We show that evolution of the temperature as a function of the cosmological scale factor depends on the spin statistics of the final state decay products when $k>2$. We also include the inflaton-induced mass of the final states leading to either kinematic suppression or enhancement if the final states are fermionic or bosonic respectively. We compute the maximum temperature reached after inflation, the subsequent evolution of the temperature and the final reheat temperature. We apply our results to the computation of the dark matter abundance through thermal scattering during reheating. We also provide an example based on supersymmetry for the coupling of the inflaton to matter.

    hep-phastro-ph.COJCAP(2021)·207 citations
13. 13*

    A decaying neutralino as dark matter and its gamma ray spectrum

    Amin Aboubrahim🇩🇪 · Tarek Ibrahim🇪🇬 · Michael Klasen🇩🇪 · Pran Nath🇺🇸

    It is shown that a decaying neutralino in a supergravity unified framework is a viable candidate for dark matter. Such a situation arises in the presence of a hidden sector with ultraweak couplings to the visible sector where the neutralino can decay into the hidden sector's lightest supersymmetric particle (LSP) with a lifetime larger than the lifetime of the universe. We present a concrete model where the MSSM/SUGRA is extended to include a hidden sector comprised of $U(1{)}_{X_1}\times U(1{)}_{X_2}$ gauge sector and the LSP of the hidden sector is a neutralino which is lighter than the LSP neutralino of the visible sector. We compute the loop suppressed radiative decay of the visible sector neutralino into the neutralino of the hidden sector and show that the decay can occur with a lifetime larger than the age of the universe. The decaying neutralino can be probed by indirect detection experiments, specifically by its signature decay into the hidden sector neutralino and an energetic gamma ray photon. Such a gamma ray can be searched for with improved sensitivity at Fermi-LAT and by future experiments such as the Square Kilometer Array (SKA) and the Cherenkov Telescope Array (CTA). We present several benchmarks which have a natural suppression of the hadronic channels from dark matter annihilation and decays and consistent with measurements of the antiproton background.

    hep-phastro-ph.HEEPJC(2021)·7 citations
14. 14*

    Resolving XENON Excess With Decaying Cold Dark Matter

    Shuai Xu🇨🇳 · Sibo Zheng🇨🇳

    We propose a decaying cold dark matter model to explain the excess of electron recoil observed at the XENON1T experiment. In this scenario, the daughter dark matter from the parent dark matter decay easily obtains velocity large enough to saturate the peak of the electron recoil energy around 2.5 keV, and the observed signal rate can be fulfilled by the parent dark matter with a mass of order 10-200 MeV and a lifetime larger than the age of Universe. We verify that this model is consistent with experimental limits from dark matter detections, Cosmic Microwave Background and Large Scale Structure experiments.

    hep-phastro-ph.COhep-exEPJC(2021)·11 citations
15. 15*

    Probing the $L_{\mu }-L_{\tau }$ gauge boson at electron colliders

    Yu Zhang🇨🇳 · Zhuo Yu🇨🇳 · Qiang Yang🇨🇳 · Mao Song🇨🇳 · Gang Li🇨🇳 · Ran Ding🇨🇳

    We investigate the minimal $U(1{)}_{L_{\mu }-L_{\tau }}$ model with extra heavy vector-like leptons or charged scalars. By studying the kinetic mixing between $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge boson $Z^{\prime }$ and standard model photon, which is absent at tree level and will arise at one loop level due to $\mu$, $\tau$ and new heavy charged leptons or scalars, the interesting behavior is shown. It can provide possibility for visible signatures of new heavy particles. We propose to search for $Z^{\prime }$ at electron collider experiments, such as Belle II, BESIII and future Super Tau Charm Factory (STCF), using the monophoton final state. The parameter space of $Z^{\prime }$ is probed, and scanned by its gauge coupling constant $g_{Z^{\prime }}$ and mass $m_{Z^{\prime }}$. We find that electron colliders have sensitivity to the previously unexplored parameter space for $Z^{\prime }$ with MeV-GeV mass. Future STCF experiments with $\sqrt{s}=2-7$ GeV can exclude the anomalous muon magnetic moment favored area when $m_{Z^{\prime }}<5$ GeV with the luminosity of 30 ab${}^{-1}$. For $m_{Z^{\prime }}<2m_{\mu }$, $g_{Z^{\prime }}$ can be down to $4.2\times 10^{-5}$ at 2 GeV STCF.

    hep-phPRD(2021)·17 citations
16. 16*

    Dark matter in the fully flipped 3-3-1-1 model

    Duong Van Loi🇻🇳 · Cao H. Nam🇻🇳 · Phung Van Dong🇻🇳

    We present the features of the fully flipped 3-3-1-1 model and show that this model leads to dark matter candidates naturally. We study two dark matter scenarios corresponding to the triplet fermion and singlet scalar candidates, and we determine the viable parameter regimes constrained from the observed relic density and direct detection experiments.

    hep-phEPJC(2021)·14 citations
17. 17*

    Adequacy of Effective Born for electroweak effects and TauSpinner algorithms for LEP, Tevatron, HL-LHC and FCC simulated samples

    E. Richter-Was🇵🇱 · Z. Was🇵🇱

    Matching and comparing measurements of past and future experiments calls for consistency checks of calculations used for their interpretation. New schemes of the field theory may optimize precision, but obscure comparisons with earlier results. Over years concepts of Improved Born, Effective Born, effective couplings, and sin^2theta_W^eff mixing angle for electroweak interactions, have evolved. We use four DIZET electroweak library versions; of today and of the last 30 years, wich were used for phenomenology of practically all HEP accelerator experiments. Versions differ by incremented with time updates of corrections. We rely on the codes archived with the KKMC Monte Carlo program for e^+e^- to f bar f n(gamma). Versions became recently available for the TauSpinner reweighting of simulated and stored events. Documentation of TauSpinner upgrade, to version 2.1.0, and of its arrangement for semi-automated electroweak (EW) effects benchmark plots are provided. Details which can be used to complete simulated sample with EW effects, are given. Focus is placed on numerical results and on approximations introduced in Improved Born to obtain Effective Born, to match with QCD corrections. The tau lepton polarization P_tau, forward backward asymmetry A_FB and parton level cross section sigma^tot are used to monitor electroweak effects and effective sin^2theta_W^eff limitations. Results include: (i) feasibility of Effective Born approximation and sin^2theta_W^eff, (ii) differences between versions of electroweak libraries and (iii) parametric ambiguities due to e.g. m_t or Delta alpha_h^(5)(s). Example results allow to evaluate adequacy of Effective Born with respect to Improved Born.

    hep-phEur.Phys.J.Plus(2022)·11 citations
18. 18*

    Nuclear Fusion Inside Dark Matter

    Javier F. Acevedo🇨🇦 · Joseph Bramante🇨🇦 · Alan Goodman🇨🇦

    A new dynamic is identified between dark matter and nuclei. Nuclei accelerated to MeV energies by the internal potential of composite dark matter can undergo nuclear fusion. This effect arises in simple models of composite dark matter made of heavy fermions bound by a light scalar field. Cosmologies and detection prospects are explored for composites that catalyze nuclear reactions in underground detectors and stars, including bremsstrahlung radiation from nuclei scattering against electrons in hot plasma formed in the composite interior. If discovered and collected, this kind of composite dark matter could in principle serve as a ready-made, compact nuclear fusion generator.

    hep-phastro-ph.COastro-ph.HEhep-exPRD(2021)·44 citations
19. 19*

    Chiral effective Lagrangian for doubly charmed baryons up to $\mathcal{O}(q^4)$

    Peng-Cheng Qiu🇨🇳 · De-Liang Yao🇨🇳

    The chiral effective meson-baryon Lagrangian for the description of interactions between the doubly charmed baryons and Goldstone bosons is constructed up to the order of $q^4$. The numbers of linearly independent invariant monomials of $\mathcal{O}(q^2)$, $\mathcal{O}(q^3)$ and $\mathcal{O}(q^4)$ are 8, 32 and 218, in order. The obtained Lagrangian can be used to study the chiral dynamics and relevant phenomenology of the doubly charmed baryons at complete one-loop level in future. For completeness, the non-relativistic reduction of the Lagrangian is also discussed.

    hep-phPRD(2021)·16 citations
20. 20*

    Muon $g-2$, dark matter, and neutrino mass explanations in a modular $A_4$ symmetry

    Parada T. P. Hutauruk🇰🇷 · Dong Woo Kang🇰🇷 · Jongkuk Kim🇰🇷 · Hiroshi Okada🇰🇷

    We study a successful model to explain the muon anomalous magnetic moment originating from Yukawa-type interactions {in a supersymmetric theory}. Thanks to a modular $A_4$ flavor symmetry, any lepton flavor violations that spoil the model are forbidden. We also investigate a predictive radiative seesaw model including a dark matter (DM) candidate. At first, we construct the minimum model to satisfy the neutrino oscillation data and obtain several predictions such as Dirac CP and Majorana phases, the neutrino masses through ${\chi }^2$ analysis. However, the minimum model would not provide our promising DM candidate. Thus, we minimally extend the model and find a good DM candidate. In the extended framework, we show the allowed regions to satisfy the muon anomalous magnetic moment and the observed relic density of dark matter in addition to predictions of the lepton sector.

    hep-phPhys.Dark Univ.(2024)·28 citations
21. 21*

    On symmetry breaking in the B-L extended spectral Standard Model

    Fabien Besnard🇫🇷

    We apply Connes-Chamseddine spectral action to the $U(1{)}_{\mathrm{B}-\mathrm{L}}$- extension of the Standard Model. We show that in order for the scalar potential to reach its minimum for a non-zero value of the new complex scalar field, thus triggering the breaking of B-L symmetry, a constraint on the quartic coupling constants must be satisfied at unification scale. We then explore the renormalization flow of this model in two opposite scenarios for the neutrino sector, and show that this constraint is not compatible with the pole masses of the top quark and SM Higgs boson. We also show that the model suffers from a mass-splitting problem similar to the doublet-triplet splitting problem of Grand Unified Theories. We discuss potential implications for the Noncommutative Geometry program.

    hep-phhep-thJ.Phys.A(2022)·1 citation
22. 22*

    A technique to study the elastic and inelastic interaction of quarkonium with hadrons using femtoscopic correlations

    Marzieh Bahmani🇵🇱 · Daniel Kikoła🇵🇱 · Leszek Kosarzewski🇨🇿

    We present a method for the measurement of parameters of elastic and inelastic interactions of charmonium with hadrons. In this technique, we use femtoscopic analysis of charmonium-hadron correlations at low relative momentum and the Lednicky-Lyuboshitz analytical model to extract the interaction parameters. We argue that such a study is already feasible in the LHCb experiment at the LHC, and we discuss the prospects for studies in the STAR at RHIC and other experiments at the LHC.

    hep-phhep-exnucl-exEPJC(2021)·2 citations
23. 23*

    Origin of the VEVs hierarchy

    Gauhar Abbas🇮🇳

    We present an origin of the VEVs hierarchy in a non-minimal technicolour framework which is capable of explaining the flavour spectrum of the standard model along with neutrino masses and mixing, and simultaneously satisfying crucial experimental bounds. The technicolour scale in this framework can be lower such that a standard model-like Higgs boson emerges from within the model. We also derive lower bound on the mass of the vector technicolour state using the latest experimental bound on the $S$-parameter.

    hep-phInt.J.Mod.Phys.A(2022)·13 citations
24. 24*

    Role of IR-Improvement in LHC/FCC Physics

    B.F.L. Ward (1)🇺🇸 · B. Shakerin (1)🇺🇸 · S.A. Yost (2) ((1) Baylor University, Waco, TX, USA, (2) The Citadel, Charleston, SC, USA)🇺🇸

    One may use amplitude-based resummation in QED $\otimes$ QCD to achieve IR-improvement of unintegrable singularities in the infrared regime to arbitrary precision in principle. We illustrate such improvement in specific examples in precision LHC/FCC physics.

    hep-phPoS(2021)·0 citations
25. 25*

    SMEFTsim 3.0 -- a practical guide

    Ilaria Brivio🇩🇪

    The SMEFTsim package is designed to enable automated computations in the Standard Model Effective Field Theory (SMEFT), where the SM Lagrangian is extended with a complete basis of dimension six operators. It contains a set of models written in FeynRules and pre-exported to the UFO format, for usage within Monte Carlo event generators. The models differ in the flavor assumptions and in the input parameters chosen for the electroweak sector. The present document provides a self-contained, pedagogical reference that collects all the theoretical and technical aspects relevant to the use of SMEFTsim and it documents the release of version 3.0. Compared to the previous release, the description of Higgs production via gluon-fusion in the SM has been significantly improved, two flavor assumptions for studies in the top quark sector have been added, and a new feature has been implemented, that allows the treatment of linearized SMEFT corrections to the propagators of unstable particles.

    hep-phhep-exJHEP(2021)·237 citations
26. 26*

    Vector dark matter from a gauged $SU(2)$ symmetry

    Takaaki Nomura🇨🇳 · Hiroshi Okada🇰🇷 · Seokhoon Yun🇮🇹

    We propose a scenario of dark sector described by a hidden $SU(2)$ gauge symmetry which is broken by a vacuum expectation value(VEV) of a scalar multiplet. We discuss a general mass relation among $SU(2)$ gauge bosons after spontaneous symmetry breaking which is determined by weight of gauge group representation associated with a scalar multiplet developing VEV. Then a model with quintet and triplet scalar fields is discussed in which hidden gauge boson can be dark matter(DM) stabilized by remnant discrete $Z_2$ symmetry and resonant dark matter annihilation is realized by mass relation between DM and mediator. We estimate relic density and spin independent DM-nucleon scattering cross section searching for allowed parameter region.

    hep-phJHEP(2021)·23 citations
27. 27*

    \boldmath{${\rm Y}$} and \boldmath{${\eta }_b$} mass shifts in nuclear matter

    G. N. Zeminiani🇧🇷 · J. J. Cobos-Martinez🇲🇽 · K. Tsushima🇧🇷

    We estimate the ${\rm Y}$, ${\eta }_b$ and $B^{\ast }$ meson mass shifts in symmetric nuclear matter. The interest is, whether the strengths of the bottomonium-(nuclear matter) and charmonium-(nuclear matter) interactions are similar or different. This is because, each ($J/\Psi ,{\rm Y}$) and (${\eta }_c,{\eta }_b$) meson group is usually assumed to have very similar properties based on the heavy charm and bottom quark masses. The estimate for the ${\rm Y}$ is made using an SU(5) effective Lagrangian and the anomalous coupling one, by studying the $BB$, $B{B}^{\ast }$, and $B^{\ast }{B}^{\ast }$ meson loop contributions for the self-energy. As for the ${\eta }_b$, we include the $B{B}^{\ast }$ and $B^{\ast }{B}^{\ast }$ meson loop contributions in the self-energy. The in-medium masses of the $B$ and $B^{\ast }$ mesons appearing in the self-energy are calculated by the quark-meson coupling model. An analysis on the $BB$, $B{B}^{\ast }$, and $B^{\ast }{B}^{\ast }$ meson loops in the ${\rm Y}$ mass shift is made by comparing with the corresponding $DD,D{D}^{\ast }$, and $D^{\ast }{D}^{\ast }$ meson loops for the $J/\Psi$ mass shift. Our prediction for the ${\eta }_b$ mass shift is made including only the lowest order $B{B}^{\ast }$ meson loop. The ${\rm Y}$ mass shift, with including only the $BB$ loop, is predicted to be -16 to -22 MeV at the nuclear matter saturation density using the ${\rm Y}BB$ coupling constant determined by the vector meson dominance model with the experimental data, while the ${\eta }_b$ mass shift is predicted to be -75 to -82 MeV with the SU(5) universal coupling constant determined by the ${\rm Y}BB$ coupling constant. Our results show an appreciable difference between the bottomonium-(nuclear matter) and charmonium-(nuclear matter) interaction strengths. We also study the ${\rm Y}$ and ${\eta }_b$ mass shifts in a heavy quark (heavy meson) symmetry limit.

    hep-phhep-exhep-latnucl-ex+1EPJA(2021)·24 citations
28. 28*

    Constraining new physics from Higgs measurements with Lilith-2

    Marius Bertrand🇫🇷 · Sabine Kraml🇫🇷 · Tran Quang Loc🇬🇧 · Dao Thi Nhung🇻🇳 · Le Duc Ninh🇻🇳

    Lilith is a public Python library for constraining new physics from Higgs signal strength measurements. Version 2.0 of Lilith comes with an extensive XML database which includes the ATLAS and CMS Run 2 Higgs results for 36/fb, in addition the the Run 1 results. Both the code and the database were extended from the ordinary Gaussian approximation employed in Lilith-1.1 to using variable Gaussian and Poisson likelihoods. Moreover, Lilith-2 can make use of correlation matrices of arbitrary dimension. We will report on these novelties and ongoing developments. The importance of how correlations and uncertainties are treated will be demonstrated by means of detailed validations of the implemented experimental results. Moreover, we show the effects for global fits of reduced Higgs couplings, 2HDMs of Type I and Type II, and invisible Higgs decays. The program is publicly available on GitHub and can be used to constrain a wide class of new physics scenarios.

    hep-phPoS(2021)·11 citations
29. 29*

    Overview of the Path to 0.01$\%$ Theoretical Luminosity Precision for the FCCee and Its Possible Synergistic Effects for Other FCC Precision Theory Requirements

    B.F.L. Ward (1)🇺🇸 · S. Jadach (2)🇵🇱 · W. Placzek (3)🇵🇱 · M. Skrzypek (2)🇵🇱 · S.A. Yost (4) ((1) Baylor University, Waco, TX, USA, (2) Institute of Nuclear Physics Polish Academy of Sciences, Krakow, PL, (3) Institute of Applied Computer Science, Jagiellonian University, Krakow, PL, (4) The Citadel, Charleston, SC, USA)🇺🇸

    To exploit properly the precision physics program at the FCC-ee, the theoretical precision tag on the respective luminosity will need to be improved from the 0.054$\%$ (0.061$\%$) results at LEP to 0.01$\%$, where the former (latter) LEP result has (does not have) the pairs correction. We present an overview of the roads one may take to reach the required 0.01$\%$ precision tag at the FCC-ee and we discuss possible synergistic effects of the walk along these roads for other FCC precision theory requirements.

    hep-phPoS(2021)·1 citation
30. 30*

    Decay properties of the $d^{\ast }(2380)$ hexaquark multiplet

    M. Bashkanov🇬🇧 · G. Clash🇬🇧 · M. Mocanu🇬🇧 · M. Nicol🇬🇧 · D.P. Watts🇬🇧

    The recently discovered $d^{\ast }(2380)$ hexaquark is expected to be the lightest member of an extended SU(3) antidecuplet of hexaquark states. The experimental search for the other heavier and strange partners of the $d^{\ast }(2380)$ in the antidecuplet is a challenging task. Evaluating the most appropriate methodologies necessitates some understanding of the underlying properties of the decuplet states such as mass, width and decay branches. In this paper we provide estimates of these key properties for all decuplet states, extrapolating from information and insights garnered for the $d^{\ast }(2380)$. The predictions form a basis for the design of future discovery experiments.

    hep-phnucl-ex3 citations
31. 31*

    Reweighted nuclear PDFs using Heavy-Flavor Production Data at the LHC: nCTEQ15_rwHF & EPPS16_rwHF

    Aleksander Kusina🇵🇱 · Jean-Philippe Lansberg🇫🇷 · Ingo Schienbein🇫🇷 · Hua-Sheng Shao🇫🇷

    We present the reweighting of two sets of nuclear PDFs, nCTEQ15 and EPPS16, using a selection of experimental data on heavy-flavor meson [D0, J/psi, J/psi from B and Upsilon(1S)] production in proton-lead collisions at the LHC which were not used in the original determination of these nuclear PDFs. The reweighted PDFs exhibit significantly smaller uncertainties thanks to these new heavy-flavor constraints. We present a comparison with another selection of data from the LHC and RHIC which were not included in our reweighting procedure. The comparison is overall very good and serves as a validation of these reweighted nuclear PDF sets, which we dub nCTEQ15_rwHF & EPPS16_rwHF. This indicates that the LHC and forward RHIC heavy-flavor data can be described within the standard collinear factorization framework with the same (universal) small-x gluon distribution. We discuss how we believe such reweighted PDFs should be used as well as the limitations of our procedure.

    hep-phhep-exnucl-exnucl-thPRD(2021)·38 citations
32. 32*

    Resonant third-generation leptoquark signatures at the Large Hadron Collider

    Ulrich Haisch🇩🇪 · Giacomo Polesello🇮🇹

    Given the hints of lepton-flavour non-universality in $B$-meson decays, leptoquarks (LQs) are enjoying a renaissance. We propose novel Large Hadron Collider (LHC) searches for such hypothetical states that do not rely on strong production only, but can also receive important contributions from quark-lepton annihilation. For the cases of a resonant signal involving a bottom quark and a tau lepton ($b+\tau$), a top quark and missing transverse energy ($E_T^{\mathrm{miss}}$) and light-flavour jets plus $E_T^{\mathrm{miss}}$, we develop realistic analysis strategies and provide detailed evaluations of the achievable sensitivities for the corresponding LQ signatures at future LHC runs. Our analyses allow us to derive a series of stringent constraints on the masses and couplings of third-generation singlet vector LQs, showing that at LHC Run III and the high-luminosity LHC the proposed search channels can probe interesting parts of the LQ parameter space addressing the $B$-physics anomalies. In view of the reach of the proposed $b+\tau$ signature, we recommend that dedicated resonance searches for this final state should be added to the exotics search canon of both ATLAS and CMS.

    hep-phhep-exJHEP(2021)·39 citations
33. 33*

    Testing the $R_{D^{(\ast )}}$ Anomaly at the LHeC

    Georges Azuelos🇨🇦 · Oliver Fischer🇬🇧 · Sudip Jana🇩🇪

    B-Physics anomalies have recently raised renewed interest in leptoquarks (LQ), predicted in several theoretical frameworks. Under simplifying but conservative assumptions, we show that the current limits from LHC searches together with the requirement to explain the observed value for $R_{D^{(\ast )}}$ constrain the $R_2$ leptoquark mass to be in the range of $800\le m_{R_2}\le 1000$ GeV. We study the search for $R_2$ at the LHeC via its resonance in the $b\tau$ final state by performing a cut-and-count analysis of the signal and the dominant Standard Model backgrounds. We find that the LHeC has an excellent discovery potential for $R_2$ even for couplings to the first generation as small as $\mathcal{O}(10^{-2})$.

    hep-phhep-exEPJC(2021)·3 citations
34. 34*

    SU(2)${}_R$ and its Axion in Cosmology: A common Origin for Inflation, Cold Sterile Neutrinos, and Baryogenesis

    Azadeh Maleknejad🇨🇭

    We introduce an axion-inflation model embedded in the Left-Right symmetric extension of the SM in which $W_R$ is coupled to the axion. This model merges three milestones of modern cosmology, i.e., inflation, cold dark matter, and baryon asymmetry. Thus, it can naturally explain the observed coincidences among cosmological parameters, i.e., ${\eta }_B\approx P_{\zeta }$ and ${\Omega }_{DM}\simeq 5{\Omega }_B$. The source of asymmetry is spontaneous CP violation in the physics of inflation, and the lightest right-handed neutrino is the cold dark matter candidate with mass $m_{N_1}\sim 1GeV$. The introduced mechanism does not rely on the largeness of the unconstrained CP-violating phases in the neutrino sector nor fine-tuned masses for the heaviest right-handed neutrinos. It has two unknown fundamental scales, i.e. scale of inflation ${\Lambda }_{\inf }=\sqrt{H{M}_{Pl}}$ and left-right symmetry breaking ${\Lambda }_F$. Sufficient matter asymmetry demands ${\Lambda }_{\inf }\approx {\Lambda }_F$. The baryon asymmetry and dark matter today are remnants of a pure quantum effect (chiral anomaly) in inflation, which, thanks to flavor effects, are memorized by cosmic evolution.

    hep-phastro-ph.COgr-qchep-thPRD(2021)·36 citations
35. 35*

    Two Paths Towards Precision at a Very High Energy Lepton Collider

    Dario Buttazzo🇮🇹 · Roberto Franceschini🇮🇹 · Andrea Wulzer🇨🇭

    We illustrate the potential of a very high energy lepton collider (from 10 to 30 TeV center of mass energy) to explore new physics indirectly in the vector boson fusion double Higgs production process and in direct diboson production at high energy. Double Higgs production is found to be sensitive to the anomalous Higgs trilinear coupling at the percent level, and to the Higgs compositeness $\xi$ parameter at the per mille or sub-per mille level thanks to the measurement of the cross-section in the di-Higgs high invariant mass tail. High energy diboson (and tri-boson) production is sensitive to Higgs-lepton contact interaction operators at a scale of several tens or hundred TeV, corresponding to a reach on the Higgs compositeness scale well above the one of any other future collider project currently under discussion. This result follows from the unique capability of the very high energy lepton collider to measure Electroweak cross-sections at 10 TeV energy or more, where the effect of new physics at even higher energy is amplified. The general lesson is that the standard path towards precision physics, based on measurements of high-statistics processes such as single and double Higgs production, is accompanied at the very high energy lepton collider by a second strategy based on measurements at the highest available energy.

    hep-phhep-exJHEP(2021)·86 citations
36. 36*

    nCTEQ15HIX -- Extending nPDF Analyses into the High-$x$, Low $Q^2$ Region

    E.P. Segarra🇺🇸 · T. Ježo🇩🇪 · A. Accardi🇺🇸 · P. Duwentäster🇩🇪 · O. Hen🇺🇸 · T.J. Hobbs🇺🇸 · C. Keppel🇺🇸 · M. Klasen🇩🇪 · K. Kovařík🇩🇪 · A. Kusina🇵🇱 · J.G. Morfín🇺🇸 · K.F. Muzakka🇩🇪 and 3 other authors

    We use the nCTEQ analysis framework to investigate nuclear Parton Distribution Functions (nPDFs) in the region of large x and intermediate-to-low $Q$, with special attention to recent JLab Deep Inelastic Scattering data on nuclear targets. This data lies in a region which is often excluded by $W$ and $Q$ cuts in global nPDF analyses. As we relax these cuts, we enter a new kinematic region, which requires new phenomenology. In particular, we study the impact of i) target mass corrections, ii) higher twist corrections, iii) deuteron corrections, and iv) the shape of the nuclear PDF parametrization at large-$x$ close to one. Using the above tools, we produce a new nPDF set (named nCTEQ15HIX) which yields a good description of the new JLab data in this challenging kinematic region, and displays reduced uncertainties at large $x$, in particular for up and down quark flavors.

    hep-phnucl-thPRD(2021)·49 citations
37. 37*

    Neutrino parameters in the Planck-scale lepton number breaking scenario with extended scalar sectors

    Cesar Bonilla🇨🇱 · Johannes Herms🇩🇪 · Alejandro Ibarra🇩🇪 · Patrick Strobl🇩🇪

    Two-loop effects on the right-handed neutrino masses can have an impact on the low-energy phenomenology, especially when the right-handed neutrino mass spectrum is very hierarchical at the cut-off scale. In this case, the physical masses of the lighter right-handed neutrinos can be dominated by quantum effects induced by the heavier ones. Further, if the heaviest right-handed neutrino mass is at around the Planck scale, two-loop effects on the right-handed neutrino masses generate, through the seesaw mechanism, an active neutrino mass which is in the ballpark of the experimental values. In this paper we investigate extensions of the Planck-scale lepton number breaking scenario by additional Higgs doublets (inert or not). We find that under reasonable assumptions these models lead simultaneously to an overall neutrino mass scale and to a neutrino mass hierarchy in qualitative agreement with observations.

    hep-phPRD(2021)·3 citations
38. 38*

    Kilobyte Cosmic Birefringence from ALP Domain Walls

    Fuminobu Takahashi🇯🇵 · Wen Yin🇯🇵

    ALP domain walls without strings may be formed in the early Universe. We point out that such ALP domain walls lead to both isotropic and anisotropic birefringence of cosmic microwave background (CMB) polarization, which reflects spatial configuration of the domain walls at the recombination. The polarization plane of the CMB photon coming from each domain is either not rotated at all or rotated by a fixed angle. For domain walls following the scaling solution, the cosmic birefringence of CMB is characterized by $2^N$, i.e. $N$-bit, of information with $N=\mathcal{O}(10^{3-4})$ being equal to the number of domains at the last scattering surface, and thus the name, $kilobytecosmicbirefringence$. The magnitude of the isotropic birefringence is consistent with the recently reported value, while the anisotropic one is determined by the structure of domains at the last scattering surface. The predicted cosmic birefringence is universal over a wide range of the ALP mass and coupling to photons. The detection of both signals will be a smoking-gun evidence for the ALP domain walls without strings.

    hep-phastro-ph.COhep-exJCAP(2021)·92 citations
39. 39*

    Testing the dark SU(N) Yang-Mills theory Confined Landscape: From the Lattice to Gravitational Waves

    Wei-Chih Huang🇩🇰 · Manuel Reichert🇬🇧 · Francesco Sannino🇩🇰 · Zhi-Wei Wang🇩🇰

    We pave the way for future gravitational-wave detection experiments, such as the Big Bang Observer and DECIGO, to constrain dark sectors made of SU(N) Yang-Mills confined theories. We go beyond the state-of-the-art by combining first principle lattice results and effective field theory approaches to infer essential information about the non-perturbative dark deconfinement phase transition driving the generation of gravitational-waves in the early universe, such as the order, duration and energy budget of the phase transition which are essential in establishing the strength of the resulting gravitational-wave signal.

    hep-phastro-ph.HEgr-qchep-lat+1PRD(2021)·131 citations
40. 40*

    Depicting the Landscape of Generic Effective Field Theories

    Hao-Lin Li🇨🇳 · Jing Shu🇨🇳 · Ming-Lei Xiao🇨🇳 · Jiang-Hao Yu🇨🇳

    We describe a general framework to depict the space of Lorentz invariant effective field theories, which we call the landscape, given any kind of gauge symmetry and field content. Various operator bases in the landscape can be systematically constructed, with the help of amplitude-operator correspondence, to emphasize different aspects: operator independence (y-basis), flavor relation (p-basis) and conserved quantum number (j-basis). The transformation matrices among the bases encode model-independent properties of the operators, such as implications on their UV origin. We illustrate this salient feature in examining the dimension 9 operators relevant for neutron-antineutron oscillation.

    hep-phhep-th21 citations
41. 41*

    On the shape of nucleons at high energies

    M. L. Nekrasov🇷🇺

    A scenario of evolution of the shape of nucleons with increasing energy is described in the framework of extended parton model, which consistently takes into account the transverse motion of the partons. At the energy $E$ up to LHC, the nucleons have the form of a spheroid which expands as $\sqrt{\ln E}$ in the transverse directions and grows linearly in $E$ in the longitudinal direction. With a further increase in the energy a mode of correlated behavior of the partons is established, which stops the longitudinal growth. Simultaneously, the expansion in the transverse directions changes to $\ln E$, and a hollow mostly free of partons is formed inside the nucleons along the central axis in the direction of their motion. Numerical estimates of the corresponding parameters are obtained.

    hep-phhep-thParticles(2021)·6 citations
42. 42*

    Complementary Probes of Two-component Dark Matter

    J. Hernandez-Sanchez🇲🇽 · V. Keus🇫🇮 · S. Moretti🇬🇧 · D. Rojas-Ciofalo🇬🇧 · D. Sokolowska🇵🇱

    We study a $Z_2\times Z_2^{\prime }$ symmetric 3-Higgs Doublet Model (3HDM), wherein two of the doublets are inert and one is active (thus denoted in literature as I(2+1)HDM), yielding a two-component Dark Matter (DM) sector. The two DM candidates emerge as the lightest scalar component of a different inert doublet, each with a different odd discrete parity, and cooperate to achieve the correct relic density. When a sufficient mass difference exists between the two DM candidates, it is possible to test the presence of both in present and/or forthcoming facilities, as the corresponding masses are typically at the electroweak scale. Specifically, the light DM component can be probed by the nuclear recoil energy in direct detection experiments while the heavy DM component appears through the photon flux in indirect detection experiments. In fact, the DM mass sensitivity that the two experimental set-ups can achieve should be adequate to establish the presence of two different DM signals. This result has been obtained in the presence of a thorough theoretical analysis of the stability conditions of the vacuum structure emerging from our I(2+1)HDM construct, ensuring that the model configurations adopted are physical, and of up-to-date constraints coming from data collected by both space and ground experiments, ensuring that the coupling and mass spectra investigated are viable phenomenologically.

    hep-ph35 citations
43. 43*

    Nucleon decay in the R-parity violating MSSM

    Nidal Chamoun🇸🇾 · Florian Domingo🇩🇪 · Herbert K. Dreiner🇩🇪

    We present a reanalysis of nucleon decay in the context of the R-parity violating MSSM, updating bounds on R-parity violating parameters against recent experimental and lattice results. We pay particular attention to the derivation of these constraints and specifically to the hadronic matrix elements, which usually stand as the limiting factor in order to derive reliable bounds, except for these few channels that have been studied on the lattice.

    hep-phPRD(2021)·27 citations
44. 44*

    A fully differential SMEFT analysis of the golden channel using the method of moments

    Shankha Banerjee🇨🇭 · Rick S. Gupta🇬🇧 · Oscar Ochoa-Valeriano🇬🇧 · Michael Spannowsky🇬🇧 · Elena Venturini🇩🇪

    The Method of Moments is a powerful framework to disentangle the relative contributions of amplitudes of a specific process to its various phase space regions. We apply this method to carry out a fully differential analysis of the Higgs decay channel $h\to 4\ell$ and constrain gauge-Higgs coupling modifications parametrised by dimension-six effective operators. We find that this analysis approach provides very good constraints and minimises degeneracies in the parameter space of the effective theory. By combining the decay $h\to 4\ell$ with Higgs-associated production processes, $Wh$ and $Zh$, we obtain the strongest reported bounds on anomalous gauge-Higgs couplings.

    hep-phhep-exJHEP(2021)·23 citations
45. 45*

    Supernova Constraints on Dark Flavored Sectors

    Jorge Martin Camalich🇪🇸 · Jorge Terol-Calvo🇪🇸 · Laura Tolos🇪🇸 · Robert Ziegler🇩🇪

    Proto-neutron stars forming a few seconds after core-collapse supernovae are hot and dense environments where hyperons can be efficiently produced by weak processes. By making use of various state-of-the-art supernova simulations combined with the proper extensions of the equations of state including $\Lambda$ hyperons, we calculate the cooling of the star induced by the emission of dark bosons $X^0$ through the decay $\Lambda \to n{X}^0$. Comparing this novel energy-loss process to the neutrino cooling of SN 1987A allows us to set stringent constraints on massless dark photons and axions with flavor-violating couplings to quarks. We find that this new supernova bound can be orders of magnitude stronger than other limits in dark-sector models.

    hep-phastro-ph.HEPRD(2021)·39 citations
46. 46*

    Primordial nucleosynthesis with varying fundamental constants: Degeneracies with cosmological parameters

    C. J. A. P. Martins🇵🇹

    The success of primordial nucleosynthesis as a cornerstone of the hot Big Bang model has been limited by the long-standing lithium problem. Recent work presented a self-consistent perturbative analysis of the effects of variations in nature's fundamental constants on primordial nucleosynthesis for a broad class of grand unified theory models, showing that such models provide a possible solution to the lithium problem, provided the value of the fine-structure constant $\alpha$ at the nucleosynthesis epoch is larger than the current laboratory one by a few parts per million of relative variation. Here we extend the earlier analysis, focusing on how this preferred value of $\alpha$ is affected if relevant cosmological parameters are also allowed to vary--specifically focusing on the baryon-to-photon ratio, the number of neutrinos, and the neutron lifetime. We rephrase the lithium problem in terms of the values of these parameters that would be needed to solve it within this class of grand unified theories, thus obtaining values that would disagree with the results of other experiments by several standard deviations. Using these experimental results as priors in the analysis, we find that a larger value of $\alpha$ is still preferred, confirming our previous results. By excluding lithium from the analysis, we also obtain upper limits on possible variations of $\alpha$ at the primordial nucleosynthesis epoch. At the two-sigma level, these are $|\Delta \alpha /\alpha |<50$ ppm without nuclear physics, cosmology, or atomic clocks priors, or alternatively $|\Delta \alpha /\alpha |<5$ ppm if these priors are used. While the simplest solution to the lithium problem is likely to be found within observational astrophysics, our work shows that varying fundamental constants remain a viable alternative.

    ↳ astro-ph.COhep-phAstron.Astrophys.(2021)·17 citations
47. 47*

    Constraining alternatives to a cosmological constant: generalized couplings and scale invariance

    C. B. D. Fernandes🇵🇹 · C. J. A. P. Martins🇵🇹 · B. A. R. Rocha🇵🇹

    We present a comparative analysis of observational low-redshift background constraints on three candidate models for explaining the low-redshift acceleration of the universe. The generalized coupling model by Feng and Carloni and the scale invariant model by Maeder (both of which can be interpreted as bimetric theories) are compared to the traditional parametrization of Chevallier, Polarski and Linder. In principle the generalized coupling model, which in vacuum is equivalent to General Relativity, contains two types of vacuum energy: the usual cosmological constant plus a second contribution due to the matter fields. We show that the former is necessary for the model to agree with low-redshift observations, while there is no statistically significant evidence for the presence of the second. On the other hand the scale invariant model effectively has a time-dependent cosmological constant. In this case we show that a matter density ${\Omega }_m\sim 0.3$ is a relatively poor fit to the data, and the best-fit model would require a fluid with a much smaller density and a significantly positive equation of state parameter.

    ↳ astro-ph.COgr-qchep-phPhys.Dark Univ.(2021)·9 citations
48. 48*

    Extraction of the specific shear viscosity of quark-gluon plasma from two-particle transverse momentum correlations

    Victor Gonzalez🇺🇸 · Sumit Basu🇸🇪 · Pedro Ladron de Guevara🇪🇸 · Ana Marin🇩🇪 · Jinjin Pan🇺🇸 · Claude A. Pruneau🇺🇸

    The specific shear viscosity, $\eta /s$, of the quark-gluon plasma formed in ultrarelativistic heavy-ion collisions at RHIC and LHC is estimated based on the progressive longitudinal broadening of transverse momentum two-particle correlators, $G_2$, reported as a function of collision centrality by the STAR and ALICE experiments. Estimates are computed as a function of collision centrality using the Gavin ansatz which relates the $G_2$ longitudinal broadening to the specific shear viscosity. Freeze out times required for the use of the ansatz are computed using a linear fit of freeze out times reported as a function of the cubic root of the charged particle pseudorapidity density $(\mathrm{d}{N}_{\mathrm{ch}}/\mathrm{d}\eta {)}^{1/3}$. Estimates of $\eta /s$ based on ALICE data exhibit little to no dependence on collision centrality at LHC energy, while estimates obtained from STAR data hint that $\eta /s$ might be a function of collision centrality at top RHIC energy.

    ↳ nucl-exhep-exhep-phEPJC(2021)·15 citations
49. 49*

    Probing the reheating phase through primordial magnetic field and CMB

    Md Riajul Haque🇮🇳 · Debaprasad Maity🇮🇳 · Sourav Pal🇮🇳

    Inflationary magnetogenesis has long been assumed to be the most promising mechanism for producing large-scale magnetic fields in our universe. However, generically, such models are plagued with either backreaction or strong coupling problems within the standard framework. This paper has shown that the reheating phase can play a crucial role in alleviating those problems along with CMB. Assuming the electrical conductivity to be negligible during the entire period of reheating, the classic Faraday electromagnetic induction changes the magnetic field's dynamics drastically. Our detailed analysis reveals that this physical phenomenon not only converts a large class of magnetogenesis model observationally viable without any theoretical problem but also can uniquely fix the perturbative average inflaton equation of state, ${\omega }_{\varphi }=(p+2)/(p+2)$ during reheating given a specific value of the large scale magnetic field. This observation hints the inflaton to assume the potential of form $V(\varphi )\sim {\varphi }^p$ near its minimum with $p\gtrsim 3.5$ if one considers the limit of the present-day strength of the large scale magnetic field to be ${\mathcal{P}}_{B0}^{\frac{1}{2}}\gtrsim 10^{-18}$ G. Our analysis opens up a new avenue towards constraining the inflationary and magnetogenesis model together via reheating.

    ↳ hep-thgr-qchep-phPRD(2021)·23 citations
50. 50*

    Tensor amplitudes for partial wave analysis of $\psi \to \Delta \bar{\Delta }$ within helicity frame

    Xiang Dong🇨🇳 · Kexin Su🇨🇳 · Hao Cai🇨🇳 · Kai Zhu🇨🇳 · Yonggui Gao🇨🇳

    We have derived the tensor amplitudes for partial wave analysis of $\psi \to \Delta \bar{\Delta }$, $\Delta \to p\pi$ within the helicity frame, as well as the amplitudes for the other decay sequences with same final states. These formulae are practical for the experiments measuring $\psi$ decaying into $p\bar{p}{\pi }^{+}{\pi }^{-}$ final states, such as BESIII with its recently collected huge $J/\psi$ and $\psi (2S)$ data samples.

    ↳ hep-thhep-exhep-phUniverse(2024)·2 citations
51. 51*

    Explicit Soft Supersymmetry Breaking in the Heterotic M-Theory $B-L$ MSSM

    Anthony Ashmore🇺🇸 · Sebastian Dumitru🇺🇸 · Burt A. Ovrut🇺🇸

    The strongly coupled heterotic M-theory vacuum for both the observable and hidden sectors of the $B-L$ MSSM theory is reviewed, including a discussion of the "bundle" constraints that both the observable sector $SU(4)$ vector bundle and the a hidden sector bundle induced from a line bundle must satisfy. Gaugino condensation is then introduced within this context, and the hidden sector bundles that exhibit gaugino condensation are presented. The condensation scale is computed, singling out one line bundle whose associated condensation scale is low enough to be compatible with the energy scales available at the LHC. The corresponding region of Kähler moduli space where all bundle constraints are satisfied is presented. The generic form of the moduli dependent $F$-terms due to a gaugino superpotential - which spontaneously break $N=1$ supersymmetry in this sector - is presented and then given explicitly for the unique line bundle associated with the low condensation scale. The moduli dependent coefficients for each of the gaugino and scalar field soft supersymmetry breaking terms are computed leading to a low-energy effective Lagrangian for the observable sector matter fields. We then show that at a large number of points in Kähler moduli space that satisfy all "bundle" constraints, these coefficients are initial conditions for the renormalization group equations which, at low energy, lead to completely realistic physics satisfying all phenomenological constraints. Finally, we show that a substantial number of these initial points also satisfy a final constraint arising from the quadratic Higgs-Higgs conjugate soft supersymmetry breaking term.

    ↳ hep-thhep-phJHEP(2021)·9 citations
52. 52*

    Polarised Beams at Future $e^{+}{e}^{-}$ Colliders

    Jenny List🇩🇪

    Beam polarisation is an integral part of the physics case of future Linear Colliders. In this contribution, important examples from Higgs coupling measurements, top and electroweak physics at high energies, the Z pole program as well as from searches for production of new particles will be reviewed. The full exploitation of its advantages requires the polarisation to be known at the permille-level. The a polarimetry concept based on the combination of Compton polarimeters, spin-tracking simulations and a global analysis of collision data which has been developed for the ILC to achieve the required precision will be presented.

    ↳ hep-exhep-phphysics.acc-phPoS(2021)·8 citations
53. 53*

    A Bit Rate Bound on Superluminal Communication

    Xi Tong🇨🇳 · Yi Wang🇨🇳 · Yuhang Zhu🇨🇳

    We study semi-classical communication in positivity-violating k-essence scalar field theories, with superluminal modes propagating on a rolling background. The self-interactions due to the non-linear nature of these theories pose a constraint on the rate of superluminal information transfer. We derive a novel bit rate bound on superluminal communication within a conceptual model, to which a general class of k-essence theories naturally reduces. Our result implies the possibility that, even if these positivity-violating k-essence theories may not possess a maximal information propagation speed, there is nevertheless an upper bound on the rate of information transfer.

    ↳ hep-thgr-qchep-phquant-phPRD(2021)·0 citations
54. 54*

    Polarization of $\Lambda (1405)$ in the $\gamma p\to K^{+}\pi \Sigma$ reaction

    Ke Wang🇨🇳 · Bo-Chao Liu🇨🇳

    In this paper, we study the polarization of the $\Lambda (1405)$ in the $\gamma p\to K^{+}\pi \Sigma$ reaction within an effective Lagrangian approach and isobar model. In our model, the $\Lambda (1405)$ is excited through the t-channel $K/K^{\ast }$ exchanges and u-channel hyperon exchange. Compared to previous studies, we also include the contribution from a contact term, which is necessary for our model to interpret the polarization of the $\Lambda (1405)$. In addition, we also discuss the possibility to verify the proposed two-pole structure of the $\Lambda (1405)$ using the polarization data. We find that the polarization of the $\Lambda (1405)$ or the polarization of the final $\Sigma$ in this reaction is sensitive to the invariant mass $M_{\pi \Sigma }$. Thus the measurement of the dependence of the $\Lambda (1405)$ polarization on the $M_{\pi \Sigma }$ can offer valuable information about the pole structure of the $\Lambda (1405)$.

    ↳ nucl-thhep-exhep-phPLB(2021)·1 citation
55. 55*

    Kinematic Edge Detection Using Finite Impulse Response Filters

    Mikael Berggren🇩🇪 · Stefano Caiazza🇩🇪 · Madalina Chera🇩🇪 · Jenny List🇩🇪

    Various physics observables can be determined from the localisation of distinct edge-like features in distributions of measurement values. In this paper, we address the observation that neither differentiating nor fitting the measured distributions is robust against significant fluctuations in the experimental data. We propose the application of Finite Impulse Response (FIR) filters instead. To demonstrate the method, we consider the typical case in particle physics in which the precise localisation of kinematic edges, often blurred by e.g.\ background contributions and detector effects, is crucial for determining particle masses. We show that even for binned data, typical for high energy physics, the optimal FIR filter kernel can be approximated by the {\em first derivative of a Gaussian} (FDOG). We study two highly complementary supersymmetric scenarios that, if realised in nature, could be observed at a future high-energy $e^{+}{e}^{-}$ collider such as the International Linear Collider (ILC) or the Compact Linear Collider (CLIC). The first scenario considers the production of ${\tilde{e}}^{\pm }-$pairs while the second focuses on the ${\tilde{\chi }}_1^{\pm }$ and ${\tilde{\chi }}_2^0$-pair production. We demonstrate that the FIR filter method for edge extraction is superior to previously employed methods in terms of robustness and precision.

    ↳ hep-exhep-phNucl.Instrum.Meth.A(2021)·5 citations
56. 56*

    Relativistic viscous effects on the primordial gravitational waves spectrum

    Nahuel Mirón-Granese🇦🇷

    We study the impact of the viscous effects of the primordial plasma on the evolution of the primordial gravitational waves (pGW) spectrum from Inflation until today, considering a self-consistent interaction that incorporates the back-reaction of the GW into the plasma. We use a relativistic causal hydrodynamic framework with a positive entropy production based on a Second-Order Theory (SOT) in which the viscous properties of the fluid are effectively described by a new set of independent variables. We study how the spin-2 modes typical of SOTs capture the simplest GW-fluid viscous interaction to first order. We consider that all non-ideal properties of the primordial plasma are due to an extra effectively massless self-interacting scalar field whose state becomes a many-particles one after Reheating and for which an effective fluid description is suitable. We numerically solve the evolution equations and explicitly compute the current GW spectrum obtaining two contributions. On the one hand we have the viscous evolution of the pGW: For the collision-dominated regime the GW source becomes negligible while in the collisionless limit there exists an absorption of the pGW energy due to the damping effect produced by the free-streaming spin-2 modes of the fluid and driven by the expansion of the Universe. The latter effect is characterized by a relative amplitude decrease of about 1 to 10 \% with respect to the GW free evolution spectrum. On the other hand we get the GW production due to the decay of the initial spin-2 fluctuations of the fluid that is negligible compared with the above-mentioned contribution. This SOT framework captures the same qualitative effects on the evolution of GW coupled to matter reported in previous works in which a kinetic theory approach has been used.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2021)·14 citations
57. 57*

    Update of the Three-fluid Hydrodynamics-based Event Simulator: light-nuclei production in heavy-ion collisions

    M. Kozhevnikova🇷🇺 · Yu. B. Ivanov🇷🇺 · Iu. Karpenko🇨🇿 · D. Blaschke🇷🇺 · O. Rogachevsky🇷🇺

    We present an update of the event generator based on the three-fluid dynamics (3FD), complemented by Ultra-relativistic Quantum Molecular Dynamics (UrQMD) for the late stage of the nuclear collision~-- the three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD final State interactions (THESEUS). Two modifications are introduced. The THESEUS table of hadronic resonances is made consistent with that of the underlying 3FD model. The main modification is that the generator is extended to simulate the light-nuclei production in relativistic heavy-ion collisions, on the equal basis with hadrons. These modifications are illustrated by applications to the description of available experimental data. The first run of the updated generator revealed a good reproduction of the NA49 data on the light nuclei. The reproduction is achieved without any extra parameters, while the coalescence approach in 3FD requires special tuning of the coalescence coefficients for each light nucleus separately.

    ↳ nucl-thhep-phnucl-exPRC(2021)·15 citations
58. 58*

    Dark matter local density determination: recent observations and future prospects

    Pablo F. de Salas🇸🇪 · Axel Widmark🇩🇰

    This report summarises progress made in estimating the local density of dark matter (${\rho }_{\mathrm{DM},\odot }$), a quantity that is especially important for dark matter direct detection experiments. We outline and compare the most common methods to estimate ${\rho }_{\mathrm{DM},\odot }$ and the results from recent studies, including those that have benefited from the observations of the ESA/Gaia satellite. The result of most local analyses coincide within a range of ${\rho }_{\mathrm{DM},\odot }\simeq \text{0.4–0.6}GeV/c{\mathrm{m}}^3=\text{0.011–0.016}{\mathrm{M}}_{\odot }/p{\mathrm{c}}^3$, while a slightly lower range of ${\rho }_{\mathrm{DM},\odot }\simeq \text{0.3–0.5}GeV/c{\mathrm{m}}^3=\text{0.008–0.013}{\mathrm{M}}_{\odot }/p{\mathrm{c}}^3$ is preferred by most global studies. In light of recent discoveries, we discuss the importance of going beyond the approximations of what we define as the Ideal Galaxy (a steady-state Galaxy with axisymmetric shape and a mirror symmetry across the mid-plane) in order to improve the precision of ${\rho }_{\mathrm{DM},\odot }$ measurements. In particular, we review the growing evidence for local disequilibrium and broken symmetries in the present configuration of the Milky Way, as well as uncertainties associated with the Galactic distribution of baryons. Finally, we comment on new ideas that have been proposed to further constrain the value of ${\rho }_{\mathrm{DM},\odot }$, most of which would benefit from Gaia's final data release.

    ↳ astro-ph.GAhep-phRept.Prog.Phys.(2021)·219 citations
59. 59*

    Variations on the Maiani-Testa approach and the inverse problem

    Mattia Bruno🇨🇭 · Maxwell T. Hansen🇬🇧

    We discuss a method to construct hadronic scattering and decay amplitudes from Euclidean correlators, by combining the approach of a regulated inverse Laplace transform with the work of Maiani and Testa. Revisiting the original result, we observe that the key observation, i.e. that only threshold scattering information can be extracted at large separations, can be understood by interpreting the correlator as a spectral function, $\rho (\omega )$, convoluted with the Euclidean kernel, $e^{-\omega t}$, which is sharply peaked at threshold. We therefore consider a modification in which a smooth step function, equal to one above a target energy, is inserted in the spectral decomposition. This can be achieved either through Backus-Gilbert-like methods or more directly using the variational approach. The result is a shifted resolution function, such that the large $t$ limit projects onto scattering or decay amplitudes above threshold. The utility of this method is highlighted through large $t$ expansions of both three- and four-point functions that include leading terms proportional to the real and imaginary parts (separately) of the target observable. This work also presents new results relevant for the un-modified correlator at threshold, including expressions for extracting the $N\pi$ scattering length from four-point functions and a new strategy to organize the large $t$ expansion that exhibits better convergence than the expansion in powers of $1/t$.

    ↳ hep-lathep-phhep-thJHEP(2021)·48 citations
60. 60*

    Low-lying electron energy levels in three-particle electron-muon ions $(\mu eLi)$, $(\mu eBe)$, $(\mu eB)$

    A.E. Dorokhov🇷🇺 · V.I. Korobov🇷🇺 · A.P. Martynenko🇷🇺 · F.A. Martynenko🇷🇺

    The electron Lamb shift $(2P-2S)$ and the energy interval $(2S-1S)$ in muon-electron ions of lithium, beryllium, and boron have been calculated within the framework of the perturbation theory method for the fine structure constant and the electron-muon mass ratio. The corrections of the first and second orders of the perturbation theory, which include the effects of vacuum polarization, nuclear structure and recoil, are taken into account. The obtained analytical results in perturbation theory are compared with the results of calculations within the variational approach. The obtained values for the Lamb shift $(2P-2S)$ and the interval $(2S-1S)$ can be used for comparison with future experimental data and verification of quantum electrodynamics.

    ↳ physics.atom-phhep-phquant-phPRA(2021)·5 citations
61. 61*

    Gravitational Waves from an Axion-Dark Photon System: A Lattice Study

    Wolfram Ratzinger🇩🇪 · Pedro Schwaller🇩🇪 · Ben A. Stefanek🇨🇭

    In this work, we present a lattice study of an axion - dark photon system in the early Universe and show that the stochastic gravitational wave (GW) background produced by this system may be probed by future GW experiments across a vast range of frequencies. The numerical simulation on the lattice allows us to take into account non-linear backreaction effects and enables us to accurately predict the final relic abundance of the axion or axion-like particle (ALP) as well as its inhomogeneities, and gives a more precise prediction of the GW spectrum. Importantly, we find that the GW spectrum has more power at high momenta due to $2\to 1$ processes. Furthermore, we find the degree of polarization of the peak of the GW spectrum depends on the ALP-dark photon coupling and that the polarization can be washed out or even flipped for large values thereof. In line with recent results in the literature, we find the ALP relic abundance may be suppressed by two orders of magnitude and discuss possible extensions of the model that expand the viable parameter space. Finally, we discuss the possibility to probe ultralight ALP dark matter via spectral distortions of the CMB.

    ↳ astro-ph.COhep-phSciPost Phys.(2021)·37 citations
62. 62*

    A large-$N$ tensor model with four supercharges

    Davide Lettera🇮🇹 · Alessandro Vichi🇮🇹

    We study a supersymmetric tensor model with four supercharges and $O(N{)}^3$ global symmetry. The model is based on a chiral scalar superfield with three indices and quartic tetrahedral interaction in the superpotential, which is relevant below three dimensions. In the large-$N$ limit the model is dominated by melonic diagrams. We solve the Dyson-Schwinger equations in superspace for generic $d$ and extract the dimension of the chiral field and the dimensions of bilinear operators transforming in various representations of $O(N{)}^3$. We find that all operator dimensions are real and above the unitarity bound for $1<d<3$. Our results also agree with perturbative results in $3-\epsilon$ expansion. Finally, we extract the large spin behaviour of bilinear operators and discuss the connection with lightcone bootstrap.

    ↳ hep-thhep-phJHEP(2022)·12 citations
63. 63*

    Towards complete leading-order predictions for neutrinoless double $\beta$ decay

    Vincenzo Cirigliano🇺🇸 · Wouter Dekens🇺🇸 · Jordy de Vries🇺🇸 · Martin Hoferichter🇨🇭 · Emanuele Mereghetti🇺🇸

    The amplitude for the neutrinoless double $\beta$ ($0\nu \beta \beta$) decay of the two-neutron system, $nn\to pp{e}^{-}{e}^{-}$, constitutes a key building block for nuclear-structure calculations of heavy nuclei employed in large-scale $0\nu \beta \beta$ searches. Assuming that the $0\nu \beta \beta$ process is mediated by a light-Majorana-neutrino exchange, a systematic analysis in chiral effective field theory shows that already at leading order a contact operator is required to ensure renormalizability. In this work, we develop a method to estimate the numerical value of its coefficient in analogy to the Cottingham formula and validate the result by reproducing the charge-independence-breaking contribution to the nucleon-nucleon scattering lengths. Our central result, while derived in the $\overline{\text{MS}}$ scheme, is given in terms of the renormalized amplitude ${\mathcal{A}}_{\nu }(|\mathbf{p}|,|{\mathbf{p}}^{\prime }|)$, matching to which will allow one to determine the contact-term contribution in regularization schemes employed in nuclear-structure calculations. Our results thus greatly reduce a crucial uncertainty in the interpretation of searches for $0\nu \beta \beta$ decay.

    ↳ nucl-thhep-exhep-lathep-ph+1PRL(2021)·103 citations
64. 64*

    The Quantum Mechanics Swampland

    Aditya Parikh🇺🇸

    We investigate non-relativistic quantum mechanical potentials between fermions generated by various classes of QFT operators and evaluate their singularity structure. These potentials can be generated either by four-fermion operators or by the exchange of a scalar or vector mediator coupled via renormalizable or non-renormalizable operators. In the non-relativistic regime, solving the Schrödinger equation with these potentials provides an accurate description of the scattering process. This procedure requires providing a set of boundary conditions. We first recapitulate the procedure for setting the boundary conditions by matching the first Born approximation in quantum mechanics to the tree-level QFT approximation. Using this procedure, we show that the potentials are nonsingular, despite the presence of terms proportional to $r^{-3}$ and ${\nabla }_i{\nabla }_j{\delta }^3(\vec{r})$. This surprising feature leads us to propose the \emph{Quantum Mechanics Swampland}, in which the Landscape consists of non-relativistic quantum mechanical potentials that can be UV completed to a QFT, and the Swampland consists of pathological potentials which cannot. We identify preliminary criteria for distinguishing potentials which reside in the Landscape from those that reside in the Swampland. We also consider extensions to potentials in higher dimensions and find that Coulomb potentials are nonsingular in an arbitrary number of spacetime dimensions.

    ↳ hep-thhep-phquant-phPRD(2021)·8 citations
65. 65*

    A closer look at the $pp$-chain reaction in the Sun: Constraining the coupling of light mediators to protons

    Anna M. Suliga🇩🇰 · Shashank Shalgar (Niels Bohr Institute)🇩🇰 · George M. Fuller (University of California, San Diego)🇺🇸

    The $pp$-chain of nuclear reactions is the primary route for energy production in the Sun. The first step in that reaction sequence converts two protons to a deuterium nucleus with the emission of a positron and electron neutrino. This reaction is extremely slow because it is a weak interaction, and significantly, it involves quantum tunneling through the Coulomb barrier. Though the reaction rate can be calculated with high confidence in the Standard Model, it has not been measured at solar energies. If there exist interactions that are engendered by non-standard mediators then the rate of this reaction in the Sun could be altered. We probe such non-standard interactions by comparing calculations of solar evolution to the current solar system age in the presence and absence of the non-standard mediators. These reveal ranges of non-standard mediator mass and couplings that are inconsistent with measured properties of the Sun, including solar neutrino results. Our constraints on these non-standard parameters, in many cases overlapping those derived via other considerations, could be extended further with better confidence in the value of the metalicity of the Sun and the solar neutrino CNO flux. Intriguingly, our work reveals a degeneracy between the solar metalicity and the presence of the invoked non-standard mediators.

    ↳ astro-ph.HEhep-phJCAP(2021)·11 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.