Thu·Dec 9, 2021Thursday·December 9, 2021

1. 01*

   Leptonic CP violation from a vector-like lepton

   A. L. Cherchiglia🇧🇷 · G. De Conto🇧🇷 · C. C. Nishi🇧🇷

   Leptonic CP violation is yet to be confirmed as an additional source of CP violation in fundamental interactions. We study the case where leptonic CP violation is spontaneous and is induced by the mixing with a heavy charged vector-like lepton (VLL). We show that the non-decoupling of this VLL is linked with the presence of CP violation and its coupling with the SM leptons are partly fixed from the SM Yukawas. Due to the large leptonic mixing angles, these couplings are typically of the same order and there is no flavor preference. Strong but not definitive constraints come from charged lepton flavor violating processes because the VLL can decouple from one or two leptonic flavors in very special points of parameter space. These special points are very sensitive to the neutrino Majorana phases.

   hep-phJHEP(2022)·11 citations
2. 02*

   Quantum Simulation of Chiral Phase Transitions

   Alexander M. Czajka🇺🇸 · Zhong-Bo Kang🇺🇸 · Henry Ma🇺🇸 · Fanyi Zhao🇺🇸

   The Nambu-Jona-Lasinio (NJL) model has been widely studied for investigating the chiral phase structure of strongly interacting matter. The study of the thermodynamics of field theories within the framework of Lattice Field Theory is limited by the sign problem, which prevents Monte Carlo evaluation of the functional integral at a finite chemical potential. Using the quantum imaginary time evolution (QITE) algorithm, we construct a quantum simulation for the $(1+1)$ dimensional NJL model at finite temperature and finite chemical potential. We observe consistency among digital quantum simulation, exact diagonalization, and analytical solution, indicating further applications of quantum computing in simulating QCD thermodynamics.

   hep-phhep-exhep-latnucl-th+1JHEP(2022)·40 citations
3. 03*

   Study of the projected sensitivity on the anomalous quartic gauge couplings via $Z\gamma \gamma$ production at the CLIC

   V. Ari🇹🇷 · E. Gurkanli🇹🇷 · M. Köksal🇹🇷 · A. Gutiérrez-Rodríguez🇲🇽 · M. A. Hernández-Ruíz🇲🇽

   Gauge boson self-couplings are completely defined by the non-Abelian gauge symmetry of the Standard Model (SM). For this reason, a direct search for these couplings is extremely significant in understanding the gauge structure of the SM. The possible deviation from the SM predictions of gauge boson self-couplings would be a sign of the presence of new physics beyond the SM. In this work, we study the sensitivities on the anomalous couplings defined by dimension-8 operators related to the $ZZ\gamma \gamma$ and $Z\gamma \gamma \gamma$ quartic vertices through the process $e^{+}{e}^{-}\to Z\gamma \gamma$ with Z-boson decaying to charged leptons at the Compact Linear Collider (CLIC). We analyze the center-of-mass energy of 3 TeV, integrated luminosities of $\mathcal{L}=1,4,5$ $\mathrm{a}{\mathrm{b}}^{-1}$, systematic uncertainties of ${\delta }_{sys}=0\%,3\%,5\%$, unpolarized and polarized electron beams and considering the Initial State Radiation and Beamstrahlung effects for extraction of expected sensitivity on the anomalous $f_{T,j}/{\Lambda }^4$ couplings at $95\%$ confidence level, which are especially sensitive to the $Z\gamma \gamma$ channel. It is clear from the results that we expect better limits on the couplings if the systematic error is improved. The best limits obtained on the anomalous quartic couplings for the process $e^{+}{e}^{-}\to Z\gamma \gamma$ with $\sqrt{s}=3$ TeV, $\mathcal{L}=5$ $\mathrm{a}{\mathrm{b}}^{-1}$, and ${\delta }_{sys}=0\%$ can be approximately improved up to about 1.1 times better than the limits obtained with ${\delta }_{sys}=5\%$. Our sensitivities on the anomalous quartic couplings can set more stringent sensitivity by two orders of magnitude concerning the best sensitivity derived from the current experimental limits. Finally, with initial electron beam polarization, the sensitivity of the anomalous quartic couplings improves by almost a factor of 1.2.

   hep-phNPB(2023)·14 citations
4. 04*

   Pandax-4T limits on $Z^{\prime }$ mass in 3-3-1LHN model

   Vinícius Oliveira🇧🇷 · C. A. de S. Pires🇧🇷

   The framework of the so-called 3-3-1LHN model may accommodate two different, but viable, scenarios of dark matter: one involving a heavy Dirac neutrino , $N_1$, or another having a scalar, $\varphi$, as dark matter candidate. In both cases the dark matter phenomenology, relic abundance and scattering cross section off of nuclei, is controlled by exchange of $Z^{\prime }$. We then investigate the impact on the parameter space $(M_{Z^{\prime }},M_{(N_1,\varphi )})$ due to the recent Pandax-4T experimental result in both scenarios. First, the Pandax-4T experiment excludes scenarios with dark matter mass below $1.9$ TeV. Concerning $Z^{\prime }$, we find the lower bound $M_{Z^{\prime }}>4.1$ TeV for the case when $N_1$ as the dark matter and $M_{Z^{\prime }}>5.7$ TeV for the other case. This implies that the 3-3-1 symmetry is spontaneously broken above $10$ TeV scale. We also comment on the contributions to the relic abundance of processes involving flavor changing neutral current mediated by $Z^{\prime }$.

   hep-phastro-ph.HEPRD(2022)·12 citations
5. 05*

   Probing non-thermal light DM with structure formation and $N_{\mathrm{eff}}$

   Sven Baumholzer🇩🇪 · Pedro Schwaller🇩🇪

   In many models of dark matter (DM), several production mechanisms contribute to its final abundance, often leading to a non-thermal momentum distribution. This makes it more difficult to assess whether such a model is consistent with structure formation observations. We simulate the matter power spectrum for DM scenarios characterized by at least two temperatures and derive the suppression of structures at small scales and the expected number of Milky Way dwarf galaxies from it. This, together with the known bound on the number of relativistic particle species, $N_{\mathrm{eff}}$, allows us to obtain constraints on the parameter space of non-thermally produced DM. We propose a simple parametrization for non-thermal DM distributions and present a fitting procedure that can be used to adapt our results to other models.

   hep-phastro-ph.COJCAP(2022)·3 citations
6. 06*

   Probing light vector mediators with coherent scattering at future facilities

   Enrico Bertuzzo🇧🇷 · Giovanni Grilli di Cortona🇮🇹 · Lucas Magno D. Ramos🇧🇷

   Future experiments dedicated to the detection of Coherent Elastic Neutrino-Nucleus Scattering may be powerful tools in probing light new physics. In this paper we study the sensitivity on light $Z^{\prime }$ mediators of two proposed experiments: a directional low pressure Time Projection Chamber detector, $\nu$BDX-DRIFT, that will utilize neutrinos produced at the Long Baseline Neutrino Facility, and several possible experiments to be installed at the European Spallation Source. We compare the results obtained with existing limits from fixed-target, accelerator, solar neutrino and reactor experiments. Furthermore, we show that these experiments have the potential to test unexplored regions that, in some case, could explain the anomalous magnetic moment of the muon or peculiar spectral features in the cosmic neutrino spectrum observed by IceCube.

   hep-phJHEP(2022)·27 citations
7. 07*

   FastGPL: a C++ library for fast evaluation of generalized polylogarithms

   Yuxuan Wang🇨🇳 · Li Lin Yang🇨🇳 · Bin Zhou🇨🇳

   We present FastGPL, a C++ library for the fast evaluation of generalized polylogarithms which appear in many multi-loop Feynman integrals. We implement the iterative algorithm proposed by Vollinga and Weinzierl in a two-step approach, i.e., we generate concise expressions using an external program and hard-code them into the numeric library. This allows efficient and accurate numeric evaluations of generalized polylogarithms suitable for Monte Carlo integration and event generation. Floating-point arithmetics are carefully taken care of to avoid loss of accuracy. As an application and demonstration, we calculate the two-loop corrections for Higgs boson production in the vector boson fusion channel at electron-positron colliders. FastGPL is expected to be useful for event generators at the next-to-next-to-leading order accuracy.

   hep-ph24 citations
8. 08*

   Radiative decay of the ${\Xi }_c(2923)$ in a hadronic molecule picture

   Feng Yang🇨🇳 · Hong Qiang Zhu🇨🇳 · Yin Huang🇨🇳

   In the present work, we study the radiative decay of newly observed ${\Xi }_c(2923{)}^0$ based on the successful explanation that ${\Xi }_c(2923{)}^0$ is an $S$-wave $D\Lambda -D\Sigma$ molecular state in our previous study~\cite{Zhu:2020jke}. The radiative decay width of $D\Lambda -D\Sigma$ molecular state into ${\Xi }_c^0\gamma$ final state through hadronic loops are evaluated using effective Lagrangians. We find that decay width ${\Xi }_c(2923{)}^0\to {\Xi }_c^0\gamma$ and ${\Xi }_c(2923{)}^0\to {\Xi }_c^{{}^{\prime }0}\gamma$ is evaluated to be approximately 1.23-11.66 KeV and 0.30-3.71 KeV, respectively. These are different from the results~\cite{Wang:2020gkn,Bijker:2020tns} that obtained by assuming ${\Xi }_c(2923{)}^0$ may be conventional charmed baryon. If measurements are in future experimental, these differences will be very useful to help us to test various interpretations of ${\Xi }_c(2923{)}^0$.

   hep-phhep-exnucl-th1 citation
9. 09*

   Next-to-next-to-leading order event generation for $VH$ production with $H\to b\bar{b}$ decay

   Silvia Zanoli🇩🇪 · Mauro Chiesa🇮🇹 · Emanuele Re🇫🇷 · Marius Wiesemann🇩🇪 · Giulia Zanderighi🇩🇪

   We consider the Higgsstrahlung process in hadronic collisions and present the computation of next-to-next-to-leading order predictions matched to parton showers for both production and $H\to b\bar{b}$ decay employing the MiNNLO${}_{\mathrm{PS}}$ method. We present predictions for $ZH$ and $W^{\pm }H$ production including spin correlations and off-shell effects by calculating the full processes $pp\to {\ell }^{+}{\ell }^{-}H\to {\ell }^{+}{\ell }^{-}b\bar{b}$, $pp\to {\nu }_{\ell }{\bar{\nu }}_{\ell }H\to {\nu }_{\ell }{\bar{\nu }}_{\ell }b\bar{b}$ and $pp\to {\ell }^{\pm }{\nu }_{\ell }H\to {\ell }^{\pm }{\nu }_{\ell }b\bar{b}$ in the narrow-width approximation for the Higgs boson. For the $W^{\pm }H$ process, NNLO+PS accuracy in production and decay is achieved for the first time. Our calculations are validated against earlier simulations in the NNLOPS approach that includes NNLO corrections via multi-differential reweighting. The new MiNNLO${}_{\mathrm{PS}}$ generators for these processes, which evaluate NNLO corrections on-the-fly in the event generation, will supersede those earlier calculations. Our predictions are in good agreement with recent measurements of the Higgsstrahlung cross sections.

   hep-phhep-exJHEP(2022)·42 citations
10. 10*

    Multiplicity dependence freeze-out scenarios in pp collisions at $\sqrt{s}$ = 7 TeV

    Susil Kumar Panda🇮🇳 · Sandeep Chatterjee🇮🇳 · Ajay Kumar Dash🇮🇳 · Bedangadas Mohanty🇮🇳 · Rita Paikaray🇮🇳 · Subhasis Samanta🇵🇱 · Ranbir Singh🇮🇳

    The data on transverse momentum integrated hadron yields in different multiplicity classes of p+p collisions at $\sqrt{s}=7$ TeV have been analyzed to extract the chemical freeze-out parameters using a thermal model. The chemical freeze-out parameters have been extracted for three different freeze-out schemes: i. unified freeze-out for all hadrons in complete thermal equilibrium (1CFO), ii. unified freeze-out for all hadrons with an additional parameter ${\gamma }_S$ which accounts for possible out-of-equilibrium production of strange hadrons (1CFO$+{\gamma }_S$), and iii. separate freeze-out for hadrons with and without strangeness content (2CFO). It has been observed that 1CFO$+{\gamma }_S$ scheme gives the best description of the hadronic yields at midrapidity when multiplicity ($⟨d{N}_{ch}/d\eta ⟩$) of the collision is less than 10. This indicates that the strangeness is out of equilibrium in most of the multiplicity classes of p+p collisions. All the three parameters of this CFO scheme, temperature ($T$), radius of the fireball ($R$) and strangeness suppression factor (${\gamma }_S$) increase with the increase of $⟨d{N}_{ch}/d\eta ⟩$. Further, we have compared applicability of different CFO schemes considering two more colliding system p+Pb at $\text{sNN}$ = 5.02 and Pb+Pb at $\text{sNN}$ = 2.76 TeV along with p+p collisions at $\sqrt{s}=7$ TeV. We observe a freeze-out volume (or multiplicity) dependence of CFO schemes regardless of colliding ions. The 1CFO+${\gamma }_S$, 1CFO and 2CFO schemes provide best description of the data when the dimension less quantity $V{T}^3$ approximately satisfies the conditions $V{T}^3<50$, $50<V{T}^3<100$ and $V{T}^3>100$ respectively or the corresponding multiplicity satisfies the conditions $⟨d{N}_{ch}/d\eta ⟩<30$, $30<d{N}_{ch}/d\eta <60$ and $⟨d{N}_{ch}/d\eta ⟩>100$ respectively.

    hep-phhep-exPRC(2021)·3 citations
11. 11*

    NNLO Positivity Bounds on Chiral Perturbation Theory for a General Number of Flavours

    Benjamin Alvarez🇫🇷 · Johan Bijnens🇸🇪 · Mattias Sjö🇸🇪

    We present positivity bounds, derived from the principles of analyticity, unitarity and crossing symmetry, that constrain the low-energy constants of chiral perturbation theory. Bounds are produced for 2, 3 or more flavours in meson-meson scattering with equal meson masses, up to and including next-to-next-to-leading order (NNLO), using the second and higher derivatives of the amplitude. We enhance the bounds by using the most general isospin combinations posible (or higher-flavour counterparts thereof) and by analytically integrating the low-energy range of the discontinuities. In addition, we present a powerful and general mathematical framework for efficiently managing large numbers of positivity bounds.

    hep-phJHEP(2022)·12 citations
12. 12*

    Hadron masses from a Kaluza-Klein like Model

    Manfred M. Vieten🇩🇪

    The purpose of this paper is to calculate the masses of hadrons without orbital momentum. It is hypothized the Kaluza-Klein like model does deliver results in particle physics complementing those of the Standard Model of particle physics. For this paper a Kaluza-Klein like model was developed based on the structure of the Standard Model. The model consists of 10 dimensions which are: one time, three usual macroscopic space and six compactified dimensions. Excitations - disturbances traveling with the speed of light on the 10D-spacetime - are introduced. An excitation on a compactified dimension can induce a mass in 4D-spacetime; it is accompanied by an integer, the excitation number, and has a well-defined spin. The model's parameters are determined using electron's g-factor and the measured masses of the charged leptons, the proton, the neutron, the mesons ${\pi }^{+},\varphi ,\psi ,{\rm Y}$. So far, exact formulas for calculating hadron masses were not derived. The approximate formulas, however, are reported and applied to about one hundred composite particles, which are compiled within four separate tables. The comparison between the measured masses of 64 hadrons and the approximations shows relative errors below $0.05$ for 55\% and below $0.1$ in 81\% of all cases. Pearson's correlation coefficient of masses measured versus calculated is $r=0.998$. The results of another 36 hadron masses, not yet experimentally determined, are stated. For a better assessment of the presented model's validity, and in addition to the paper's original purpose, the strong, electric, and weak forces were calculated. These forces together with other derived parameters are discussed and compared with measurements or values from the standard model of particle physics.

    hep-ph0 citations
13. 13*

    Tetraquarks: relativistic corrections and other issues

    Jean-Marc Richard🇫🇷 · Alfredo Valcarce🇪🇸 · Javier Vijande🇪🇸

    We discuss the effect of relativistic kinematics on the binding energy of multiquark states. For a given potential, the use of relativistic kinematics lowers the energy by a larger amount for the threshold made of two mesons than for a tetraquark, so that its binding is weakened. Some other issues associated with exotic hadrons are also briefly discussed.

    hep-phnucl-thRev.Mex.Fis.Suppl.(2022)·2 citations
14. 14*

    Gravity-Higgs portal for dark matter decay

    Xudong Sun🇨🇳

    Dark matter can decay via gravity portals and contribute a minor decay (MD) width. This paper proposes that nonminimal coupling between the Higgs field and gravity can lead to additional gravity-Higgs portals for gravitational dark matter to decay and contribute additional decay (AD) width. For scalar dark matter candidates with a mass less than 5 TeV, the decay branching ratios are almost independent of whether dark matter decay through gravity portals or gravity-Higgs portals; therefore, it is almost impossible to distinguish gravity portals from gravity-Higgs portals by observing decay products. For fermionic singlet dark matter candidates, their MD products are diverse, while their AD products are monotonous, only neutrinos and Higgs bosons. As for both dark matter candidates, gravity-Higgs portals prefer to dominate the decay at around several hundred GeV. Besides, for both TeV dark matter candidates, there is still a vast parameter space alive.

    hep-phEPJC(2026)·7 citations
15. 15*

    Singlet-octet-glueball mixing of scalar mesons

    Eberhard Klempt🇩🇪 · Andrey V. Sarantsev🇩🇪

    The mixing angles between scalar isoscalar resonances and a scalar glueball are determined from their decays into two pseudoscalar mesons. For $f_0(1370)$ and $f_0(1500)$, at most a small glueball component is admitted by the data. The decay modes of $f_0(1710)$, $f_0(1770)$, $f_0(2020)$, and $f_0(2100)$ require significant glueball fractions. Above this mass, the errors in the decay frequencies become too large to extract a glueball component. The summation of all observed glueball fractions up to 2100\,MeV yields (78\er18)\%. The glueball fractions as function of the mass are consistent with a scalar glueball at 1965\,MeV and a width of 370\,MeV as suggested by a measurement of the yield of scalar isoscalar mesons in radiative $J/\psi$ decays.

    hep-phPLB(2022)·49 citations
16. 16*

    Dark matter and flavor anomalies in the light of vector-like fermions and scalar leptoquark

    Suchismita Sahoo🇮🇳 · Shivaramakrishna Singirala🇮🇳 · Rukmani Mohanta🇮🇳

    We make a comprehensive study of vector-like fermionic dark matter and flavor anomalies in a simple extension of standard model. The model is added with doublet vector-like fermions of quark and lepton types, and also a $S_1(\bar{\text{3}},\text{1},1/3)$ scalar leptoquark. An additional lepton type singlet fermion is included, whose admixture with vector-like lepton doublet plays the role of dark matter and is examined in relic density and direct detection perspective. Electroweak precision observables are computed to put constraint on model parameter space. We constrain the new couplings from the branching ratios and angular observables associated with $b\to sll({\nu }_l{\bar{\nu }}_l)$, $b\to s\gamma$ decays and also from the recent measurement on muon anomalous magnetic moment. We then estimate the branching ratios of the rare lepton flavor vioalting $B_{(s)}$ decay modes such as $B_{(s)}\to l_i^{\mp }{l}_j^{\pm }$, $B_{(s)}\to (K^{(\ast )},\varphi )l_i^{\mp }{l}_j^{\pm }$.

    hep-ph11 citations
17. 17*

    Deriving experimental constraints on the scalar form factor in the second-class $\tau \to \eta \pi \nu$ mode

    B. Moussallam🇫🇷

    The rare second-class decay mode of the $\tau$ into $\eta \pi \nu$ could be observed for the first time at Belle II. It is important to try to derive a reliable evaluation of the branching fraction and of the energy distribution of this mode within the standard-model. Many predictions exist already in the literature which can differ by one to two orders of magnitude. Here, an approach based on a systematic use of the property of analyticity of form factors and scattering amplitudes in QCD is discussed. In particular, we will show that the scalar form factor in the $\tau$ decay can be related to photon-photon scattering and radiative $\varphi$ decay amplitudes for which precise experimental measurements have been performed by the Belle and KLOE collaborations.

    hep-phSciPost Phys.Proc.(2025)·6 citations
18. 18*

    Radiation reaction and limiting acceleration

    Will Price🇺🇸 · Martin Formanek🇺🇸 · Johann Rafelski🇺🇸

    We investigate the strong acceleration properties of the radiation reaction force and identify a new and promising limiting acceleration feature in the Eliezer-Ford-O'Connell model; in the strong field regime, for many field configurations, we find an upper limit to acceleration resulting in a bound to the rate of radiation emission. If this model applies, strongly accelerated particles are losing energy at a much slower pace than predicted by the usual radiation reaction benchmark, the Landau-Lifshitz equation, which certainly cannot be used in this regime. We explore examples involving various "constant" electromagnetic field configurations and study particle motion in a light plane wave as well as in a material medium.

    hep-phPRD(2022)·9 citations
19. 19*

    BICEP/Keck Constraints on Attractor Models of Inflation and Reheating

    John Ellis🇬🇧 · Marcos A. G. Garcia🇲🇽 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸 · Sarunas Verner🇺🇸

    Recent BICEP/Keck data on the cosmic microwave background, in combination with previous WMAP and Planck data, impose strong new constraints on the tilt in the scalar perturbation spectrum, $n_s$, as well as the tensor-to-scalar ratio, $r$. These constrain the number of e-folds of inflation, $N_{\ast }$, the magnitude of the inflaton coupling to matter, $y$, and the reheating temperature, $T_{\mathrm{reh}}$, which we evaluate in attractor models of inflation as formulated in no-scale supergravity. The 68% C.L. region of $(n_s,r)$ favours large values of $N_{\ast },y$ and $T_{\mathrm{reh}}$ that are constrained by the production of gravitinos and supersymmetric dark matter.

    hep-phastro-ph.COPRD(2022)·82 citations
20. 20*

    Lepton-Flavor-Violating ALPs at the Electron-Ion Collider: A Golden Opportunity

    Hooman Davoudiasl🇺🇸 · Roman Marcarelli🇺🇸 · Ethan T. Neil🇺🇸

    Axion-like particles (ALPs) arise in a variety of theoretical contexts and can, in general, mediate flavor violating interactions and parity non-conservation. We consider lepton flavor violating ALPs with GeV scale or larger masses which may, for example, arise in composite dark sector models. We show that a future Electron-Ion Collider (EIC) can uncover or constrain such ALPs via processes of the type $e{A}_Z\to \tau A_{Z}a$, where $A_Z$ is a nucleus of charge $Z$ and $a$ is an ALP in the range $m_{\tau }\le m_a\lesssim 20$ GeV. The production of the ALP can have a large $Z^2$ enhancement from low $Q^2$ electromagnetic scattering of the electron from a heavy ion. Using the gold nucleus ($Z=79$) as an example, we show that the EIC can explore $e-\tau$ flavor violation, mediated by GeV-scale ALPs, well beyond current limits. Importantly, the EIC reach for this interaction is not sensitive to the lepton-flavor conserving ALP couplings, whose possible smallness can render searches using $\tau$ decays ineffective. We also discuss how the EIC electron beam polarization can provide a powerful tool for investigating parity violating ALPs.

    hep-phhep-exnucl-exJHEP(2023)·46 citations
21. 21*

    Dedicated Triggers for Displaced Jets using Timing Information from Electromagnetic Calorimeter at HL-LHC

    Biplob Bhattacherjee🇮🇳 · Tapasi Ghosh🇮🇳 · Rhitaja Sengupta🇮🇳 · Prabhat Solanki🇮🇳

    In this paper, we study the prospect of ECAL barrel timing to develop triggers dedicated to long-lived particles decaying to jets, at the level-1 of HL-LHC. We construct over 20 timing based variables, and identify three of them which have better performances and are robust against increasing PU. We estimate the QCD prompt jet background rates accurately using the "stitching" procedure for varying thresholds defining our triggers, and compute the signal efficiencies for different LLP scenarios for a permissible background rate. The trigger efficiencies can go up to $\mathcal{O}(80\%)$ for the most optimal trigger for pair-produced heavy LLPs having high decay lengths, which degrades with decreasing mass and decay length of the LLP. We also discuss the prospect of including the information of displaced L1 tracks to our triggers, which further improves the results, especially for LLPs characterised by lower decay lengths.

    hep-phhep-exJHEP(2022)·12 citations
22. 22*

    Neutrino masses and magnetic moments of electron and muon in the Zee Model

    Rahool Kumar Barman🇺🇸 · Ritu Dcruz🇺🇸 · Anil Thapa🇺🇸

    We explore parameter space in the Zee Model to resolve the long-standing tension of the electron and muon anomalous magnetic moment (AMM). The model comprises a second Higgs doublet and a charged singlet at electroweak scale and generates Majorana neutrino masses at one-loop level; the neutral partner of the $SU(2{)}_L$ doublet contributes to the AMM of electron and muon via one loop and two-loop corrections. We propose two minimal flavor structures that can explain these anomalies while fitting the neutrino oscillation data. We find that the neutral Higgs resides in the mass range of roughly 10-300 GeV or 1-30 GeV, depending on the flavor structures. The model is consistent with constraints from colliders, electroweak precision data, and lepton flavor violation. To be comprehensive, we examine the constraints from the electric dipole moment (EDM) and find a region of parameter space that gives a sizable contribution to muon EDM while simultaneously giving corrections to muon AMM. In addition to the light scalar, the two charged scalars with masses as low as 100 GeV can induce nonstandard interactions ${\epsilon }_{ee}$ as large as $8\%$, potentially hinting at new physics. We also investigate the projected capability of future lepton colliders to probe the currently allowed parameter space consistent with both electron and muon AMMs via direct searches in the ${\ell }^{+}{\ell }^{-}\to {\ell }^{+}{\ell }^{-}(H\to {\ell }^{+}{\ell }^{-})$ channel.

    hep-phJHEP(2022)·21 citations
23. 23*

    Natural F-theory constructions of Standard Model structure from $E_7$ flux breaking

    Shing Yan Li🇺🇸 · Washington Taylor🇺🇸

    We describe a broad class of 4D F-theory models in which an $E_7$ gauge group is broken through fluxes to the Standard Model gauge group. These models are ubiquitous in the 4D F-theory landscape and can arise from flux breaking of most models with $E_7$ factors. While in many cases the $E_7$ breaking leads to exotic matter, there are large families of models in which the Standard Model gauge group and chiral matter representations are obtained through an intermediate $\mathrm{SU}(5)$ group. The number of generations of matter appearing in these models can easily be small. We demonstrate the possibility of getting three generations of chiral matter as the preferred matter content.

    ↳ hep-thhep-phPRD(2022)·11 citations
24. 24*

    $x$-dependence reconstruction of pion and kaon PDFs from Mellin moments

    Constantia Alexandrou🇨🇾 · Simone Bacchio🇨🇾 · Ian Cloët🇺🇸 · Martha Constantinou🇺🇸 · Kyriakos Hadjiyiannakou🇨🇾 · Giannis Koutsou🇨🇾 · Colin Lauer🇺🇸

    We present a calculation of the connected-diagram contributions to the first three non-trivial Mellin moments for the pion and kaon, extracted using local operators with up to 3 covariant derivatives. We use one ensemble of gauge configurations with two degenerate light, a strange and a charm quark ($N_f$=2+1+1) of maximally twisted mass fermions with clover improvement. The ensemble has a pion mass $\sim$260 MeV, and a kaon mass $\sim$530 MeV. We reconstruct the $x$-dependence of the PDFs via fits to our results, and find that our lattice data favor a $(1-x{)}^2$-behavior in the large-$x$ region for both the pion and kaon PDFs. We integrate the reconstructed PDFs to extract the higher moments, $⟨x^n⟩$, with $4\le n\le 6$. Finally, we compare the pion and kaon PDFs, as well as the ratios of their Mellin moments, to address the effect of SU(3) flavor symmetry breaking.

    ↳ hep-lathep-phnucl-thPoS(2022)·2 citations
25. 25*

    Pion and kaon form factors using twisted-mass fermions

    Constantia Alexandrou🇨🇾 · Simone Bacchio🇨🇾 · Ian Cloët🇺🇸 · Martha Constantinou🇺🇸 · Joseph Delmar🇺🇸 · Kyriakos Hadjiyiannakou🇨🇾 · Giannis Koutsou🇨🇾 · Colin Lauer🇺🇸 · Alejandro Vaquero Avilés-Casco🇺🇸

    We present a calculation of the scalar, vector and tensor pion and kaon form factors using one ensemble of two degenerate light, a strange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with clover improvement. The quark masses are chosen so that they produce a pion mass of about 265 MeV, and a kaon mass of 530 MeV. The lattice spacing of the ensemble is 0.093 fm and the lattice has a spatial extent of 3 fm. We use a rest frame, as well as a boosted frame to obtain the form factors for a wider and denser set of four-vector momentum transfer squared, $Q^2$. To assess and eliminate excited-states contamination, we analyze several values of the source-sink time separation within the range of 1.12 - 2.23 fm (1.12 - 1.67 fm) for the rest (boosted) frame. The $Q^2$ dependence of the form factors is parametrized using a monopole fit, which leads to the extraction of the corresponding radius, and the tensor anomalous magnetic moment for the tensor form factor. The results for these parametrizations are compared for the pion and kaon to assess the level of the SU(3) flavor symmetry breaking.

    ↳ hep-lathep-phnucl-thPoS(2022)·1 citation
26. 26*

    String Cosmology and the Breakdown of Local Effective Field Theory

    Robert Brandenberger🇨🇦

    Most current cosmological models of the very early universe are based on local point particle effective field theories coupled to gravity. I will discuss some conceptual limitations of this approach and argue that an improved description of the early universe needs to go beyond this framework. I will outline a couple of ideas based on superstring theory.

    ↳ hep-thastro-ph.COgr-qchep-phNuovo Cim.C(2022)·23 citations
27. 27*

    Thermal properties of hot and dense medium in interacting hadron resonance gas model

    S. Sahoo🇮🇳 · D. K. Mishra🇮🇳 · P. K. Sahu🇮🇳

    The meson exchange interaction based on relativistic mean-field (RMF) theory has been introduced in the hadron resonance gas (HRG) model, called interacting HRG (iHRG) model. This model can be used to explain the experimental data both at finite temperature ($T$) with finite chemical potential (${\mu }_B$) and finite temperature at vanishing chemical potential. The nuclear matter equation of state also can be explained at zero temperature with finite baryon density (finite chemical potential) due to the presence of attractive and repulsive interactions between the hadrons in the iHRG model. Similarly, the lattice equation of state is well described at ${\mu }_B$ = 0 and finite temperature by the iHRG model. In the present study, we have calculated the thermodynamical quantities as a function of temperature and chemical potential using both HRG and iHRG models. Also, we have presented the isothermal compressibility ($k_T$), specific heat ($C_V$), and speed of sound ($c_s^2$) as a function of ${\mu }_B$, $T$, and center of mass energies. The effect of kinematic acceptance on these quantities are also presented as a function of $\mu$ and $T$. Results from this study on $k_T$ are compared with results from other heavy-ion transport models and experimental data up to LHC energies.

    ↳ nucl-thhep-phnucl-exNPA(2022)·4 citations
28. 28*

    Geometrization of light bending and its application to SdSw spacetime

    Zhen Zhang🇨🇳

    The mysterious dark energy remains one of the greatest puzzles of modern science. Current detections for it are mostly indirect. The spacetime effects of dark energy can be locally described by the SdSw metric. Understanding these local effects exactly is an essential step towards the direct probe of dark energy. From first principles, we prove that dark energy can exert a repulsive dark force on astrophysical scales, different from the Newtonian attraction of both visible and dark matter. One way of measuring local effects of dark energy is through the gravitational deflection of light. We geometrize the bending of light in any curved static spacetime. First of all, we define a generalized deflection angle, referred to as the Gaussian deflection angle, in a mathematically strict and conceptually clean way. Basing on the Gauss-Bonnet theorem, we then prove that the Gaussian deflection angle is equivalent to the surface integral of the Gaussian curvature over a chosen lensing patch. As an application of the geometrization, we study the problem of whether dark energy affects the bending of light and provide a strict solution to this problem in the SdSw spacetime. According to this solution, we propose a method to overcome the difficulty of measuring local dark energy effects. Exactly speaking, we find that the lensing effect of dark energy can be enhanced by 14 orders of magnitude when properly choosing the lensing patch in certain cases. It means that we can probe the existence and nature of dark energy directly in our Solar System. This points to an exciting direction to help unraveling the great mystery of dark energy.

    ↳ gr-qcastro-ph.COhep-phhep-thClass.Quant.Grav.(2022)·56 citations
29. 29*

    Primordial black hole dark matter in the presence of p-wave WIMP annihilation

    Kenji Kadota🇨🇳 · Hiroyuki Tashiro🇯🇵

    We study the allowed primordial black hole (PBH) dark matter abundance in the mixed dark matter scenarios consisting of PBHs and self-annihilating weakly interacting massive particles (WIMPs) with a velocity dependent annihilation cross section. We first briefly illustrate how the WIMP dark matter halo profile changes for the velocity suppressed p-wave annihilation scenarios, compared with the familiar s-wave annihilation scenarios, and then discuss the PBH mass dependent upper bound on the allowed PBH dark matter abundance. The WIMPs can accrete onto a PBH to form an ultracompact minihalo with a spiky density profile. Such a spike is moderated in the central region of a halo because the WIMPs are annihilated away and this moderation is less effective for a smaller annihilation cross section. The WIMP core density becomes larger while the core radius becomes smaller for a velocity suppressed p-wave annihilation cross section than those for the s-wave annihilation scenarios. The annihilation cross section is dependent on the velocity which varies across the halo, and, in addition to the change of the WIMP density profile, another interesting feature is the PBH mass dependent bound on PBH dark matter abundance. This is in stark contrast to the s-wave annihilation scenarios where the PBH abundance bound is independent of the PBH mass. The allowed PBH dark matter fraction (with respect to the total dark matter abundance) is of order $f_{PBH}\lesssim \mathcal{O}(10^{-7})(M_{\odot }/M_{PBH}{)}^{(-6+2{\gamma }_{sp})/(3{\gamma }_{sp}+3)}$ for the thermal relic p-wave dark matter with the mass $100$ GeV where ${\gamma }_{sp}$ is the slope index of the spike profile, to be compared with $f_{PBH}\lesssim \mathcal{O}(10^{-9})$ for the corresponding thermal relic s-wave dark matter scenarios.

    ↳ astro-ph.COhep-phJCAP(2022)·20 citations
30. 30*

    Patterns of flavour symmetry breaking in hadron matrix elements involving u, d and s quarks

    J.M. Bickerton🇦🇺 · A.N. Cooke🇬🇧 · R. Horsley🇬🇧 · Y. Nakamura🇯🇵 · H. Perlt🇩🇪 · D. Pleiter🇸🇪 · P.E.L. Rakow🇬🇧 · G. Schierholz🇩🇪 · H. Stüben · R.D. Young🇦🇺 · J.M. Zanotti🇦🇺

    Using an SU(3)-flavour symmetry breaking expansion between the strange and light quark masses, we determine how this constrains the extrapolation of baryon octet matrix elements and form factors. In particular we can construct certain combinations, which fan out from the symmetric point (when all the quark masses are degenerate) to the point where the light and strange quarks take their physical values. As a further example we consider the vector amplitude at zero momentum transfer for flavour changing currents.

    ↳ hep-lathep-phPoS(2022)·3 citations
31. 31*

    PQ Axiverse

    Mehmet Demirtas🇺🇸 · Naomi Gendler🇺🇸 · Cody Long🇺🇸 · Liam McAllister🇺🇸 · Jakob Moritz🇺🇸

    We show that the strong CP problem is solved in a large class of compactifications of string theory. The Peccei-Quinn mechanism solves the strong CP problem if the CP-breaking effects of the ultraviolet completion of gravity and of QCD are small compared to the CP-preserving axion potential generated by low-energy QCD instantons. We characterize both classes of effects. To understand quantum gravitational effects, we consider an ensemble of flux compactifications of type IIB string theory on orientifolds of Calabi-Yau hypersurfaces in the geometric regime, taking a simple model of QCD on D7-branes. We show that the D-brane instanton contribution to the neutron electric dipole moment falls exponentially in $N^4$, with $N$ the number of axions. In particular, this contribution is negligible in all models in our ensemble with $N>17$. We interpret this result as a consequence of large $N$ effects in the geometry that create hierarchies in instanton actions and also suppress the ultraviolet cutoff. We also compute the CP breaking due to high-energy instantons in QCD. In the absence of vectorlike pairs, we find contributions to the neutron electric dipole moment that are not excluded, but that could be accessible to future experiments if the scale of supersymmetry breaking is sufficiently low. The existence of vectorlike pairs can lead to a larger dipole moment. Finally, we show that a significant fraction of models are allowed by standard cosmological and astrophysical constraints.

    ↳ hep-thhep-phJHEP(2023)·136 citations
32. 32*

    Rare Events Are Nonperturbative: Primordial Black Holes From Heavy-Tailed Distributions

    Sina Hooshangi🇮🇷 · Mohammad Hossein Namjoo🇮🇷 · Mahdiyar Noorbala🇮🇷

    In recent years it has been noted that the perturbative treatment of the statistics of fluctuations may fail to make correct predictions for the abundance of primordial black holes (PBHs). Moreover, it has been shown in some explicit single-field examples that the nonperturbative effects may lead to an exponential tail for the probability distribution function (PDF) of fluctuations responsible for PBH formation -- in contrast to the PDF being Gaussian, as suggested by perturbation theory. In this paper, we advocate that the so-called $\delta N$ formalism can be considered as a simple, yet effective, tool for the nonperturbative estimate of the tail of the PDF. We discuss the criteria a model needs to satisfy so that the results of the classical $\delta N$ formalism can be trusted and most possible complications due to the quantum nature of fluctuations can be avoided. As a proof of concept, we then apply this method to a simple example and show that the tail of the PDF can be even {\it heavier} than exponential, leading to a significant enhancement of the PBH formation probability, compared with the predictions of the perturbation theory. Our results, along with other related findings, motivate the invention of new, nonperturbative methods for the problem and open up new ideas on generating PBHs with notable abundance.

    ↳ astro-ph.COgr-qchep-phhep-thPLB(2022)·52 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.