Mon·Jul 25, 2022Monday·July 25, 2022

1. 01*

   Phenomenological implications of sterile neutrinos in the $\mu \nu$SSM and dark matter

   Paulina Knees🇦🇷 · Daniel E. Lopez-Fogliani🇦🇷 · C. Munoz🇪🇸

   We analyze the role of sterile neutrinos in the framework of the $\mu \nu$SSM, where the presence of right-handed neutrinos provides a simultaneous solution to $\mu$- and $\nu$-problems in supersymmetry. We adopt a minimalistic approach, reproducing light neutrino masses and mixing angles at tree level using just two right-handed neutrinos as part of the seesaw mechanism. A third right-handed neutrino does not contribute significantly to the mass of the three active ones, behaving as a sterile neutrino with a mass in the range keV$-$MeV. Furthermore, a sterile neutrino of about $10$ keV can be a good candidate for dark matter with a lifetime larger than the age of the Universe. In particular, the three-body decay to active neutrinos gives the dominant contribution to its lifetime. The one-loop decay to gamma and active neutrino is subdominant, but relevant for observations such as astrophysical X-rays. We find regions of the parameter space of the $\mu \nu$SSM, with different values of the sterile neutrino mass, fulfilling not only these constraints but also collider constraints from the Higgs sector.

   hep-phastro-ph.HEAstropart.Phys.(2023)·4 citations
2. 02*

   Collider Events on a Quantum Computer

   Gösta Gustafson🇸🇪 · Stefan Prestel🇸🇪 · Michael Spannowsky🇬🇧 · Simon Williams🇬🇧

   High-quality simulated data is crucial for particle physics discoveries. Therefore, parton shower algorithms are a major building block of the data synthesis in event generator programs. However, the core algorithms used to generate parton showers have barely changed since the 1980s. With quantum computers' rapid and continuous development, dedicated algorithms are required to exploit the potential that quantum computers provide to address problems in high-energy physics. This paper presents a novel approach to synthesising parton showers using the Discrete QCD method. The algorithm benefits from an elegant quantum walk implementation which can be embedded into the classical toolchain. We use the ibm_algiers device to sample parton shower configurations and generate data that we compare against measurements taken at the ALEPH, DELPHI and OPAL experiments. This is the first time a Noisy Intermediate-Scale Quantum (NISQ) device has been used to simulate realistic high-energy particle collision events.

   hep-phhep-exquant-phJHEP(2022)·33 citations
3. 03*

   Two-loop three-gluon vertex from the Curci-Ferrari model and its leading infrared behavior to all loop orders

   Nahuel Barrios🇺🇾 · Marcela Peláez🇺🇾 · Urko Reinosa🇫🇷

   We evaluate the three-gluon vertex with one vanishing external momentum within the Curci-Ferrari (CF) model at two-loop order and compare our results to Landau-gauge lattice simulations of the same vertex function for the SU(2) and SU(3) gauge groups in four dimensions. The parameters of the model being adjusted by fitting the two-point functions to lattice data, our evaluation of the three-gluon vertex arises as a pure prediction. We find that two-loop corrections systematically improve the agreement between the model and the lattice data as compared to earlier one-loop calculations, with a better agreement in the SU(3) case, as already seen in previous studies [1,2]. We also analyze the renormalization scheme dependence of our calculation. In all cases, this dependence diminishes when two-loop corrections are included, which is consistent with the perturbative CF paradigm. In addition, we study the low momentum regime of the three-gluon vertex in relation with the possibility of zero-crossing. Within the CF model, we show that the leading infrared behavior of the exact vertex is given by the same linear logarithm that arises at one-loop order, multiplied by the all orders cubic ghost dressing function at zero-momentum (we provide similar exact results for other vertex functions). We argue that this property remains true within the FP framework under the assumption that the resummed gluon propagator features a decoupling behavior. This shows that the zero-crossing is a property of the exact three-gluon vertex function. Within the CF model, we find however that the scale of the zero-crossing is considerably reduced when going from one- to two-loop order. This seems consistent with some recent lattice simulations [3]. Our analysis also allows us to support recent claims about the dominance of the tree-level tensor component [4].

   hep-phhep-lathep-thPRD(2022)·30 citations
4. 04*

   Drell-Yan Tails Beyond the Standard Model

   Lukas Allwicher🇨🇭 · Darius A. Faroughy🇨🇭 · Florentin Jaffredo🇫🇷 · Olcyr Sumensari🇫🇷 · Felix Wilsch🇨🇭

   We investigate the high-$p_T$ tails of the $pp\to \ell \nu$ and $pp\to \ell \ell$ Drell-Yan processes as probes of New Physics in semileptonic interactions with an arbitrary flavor structure. For this purpose, we provide a general decomposition of the $2\to 2$ scattering amplitudes in terms of form-factors that we match to specific scenarios, such as the Standard Model Effective Field Theory (SMEFT), including all relevant operators up to dimension-$8$, as well as ultraviolet scenarios giving rise to tree-level exchange of new bosonic mediators with masses at the TeV scale. By using the latest LHC run-II data in the monolepton ($e\nu$, $\mu \nu$, $\tau \nu$) and dilepton ($ee$, $\mu \mu$, $\tau \tau$, $e\mu$, $e\tau$, $\mu \tau$) production channels, we derive constraints on the SMEFT Wilson coefficients for semileptonic four-fermion and dipole operators with the most general flavor structure, as well as on all possible leptoquark models. For the SMEFT, we discuss the range of validity of the EFT description, the relevance of $\mathcal{O}(1/{\Lambda }^2)$ and $\mathcal{O}(1/{\Lambda }^4)$ truncations, the impact of $d=8$ operators and the effects of different quark-flavor alignments. Finally, as a highlight, we extract for several New Physics scenarios the combined limits from high-$p_T$ processes, electroweak pole measurements and low-energy flavor data for the $b\to c\tau \nu$ transition, showing the complementarity between these different observables. Our results are compiled in {\tt HighPT}, a package in {\tt Mathematica} which provides a simple way for users to extract the Drell-Yan tails likelihoods for semileptonic effective operators and for leptoquark models.

   hep-phJHEP(2023)·129 citations
5. 05*

   Lepton Flavour Universality in $\tau$ decays

   Lukas Allwicher🇨🇭 · Nudžeim Selimović🇨🇭

   The evidence for Lepton Flavour Universality (LFU) violation in semileptonic $B$-decays has been rising over the past few years. Relying on generic effective field theory (EFT) results, it has been shown that models addressing the $B$-anomalies necessarily lead, at one-loop, to deviations from LFU in $\tau$ decays at the few per-mil level. Once a (renormalizable) UV model is specified, the leading-log EFT result receives finite corrections from the matching at the UV scale. We discuss such corrections in a motivated class of models for the B-anomalies, based on an extended $SU(4)\times SU(3)\times SU(2)\times U(1)$ gauge sector. In this scenario, we obtain precise predictions for the effective $W$-boson and $Z$-boson couplings to leptons in terms of the masses and couplings of the new heavy fields. We confirm a few per-mil deviation from universality, within reach of future high-precision experiments.

   hep-phNuovo Cim.C(2022)·0 citations
6. 06*

   Charged Higgs in 3-3-1 Model Through $e^{-}{e}^{+}$ Collisions

   J. E. Cieza Montalvo🇧🇷 · K. I. Cuba Quispe🇵🇪 · R. J. Gil Ramírez🇵🇪 · C. A. Morgan Cruz🇵🇪 · J. F. Rabanal Muñoz🇵🇪 · G. H. Ramírez Ulloa🇵🇪 · A. I. Rivasplata Mendoza🇵🇪 · M. D. Tonasse🇧🇷

   In this work we present an analysis of production and signature of charged Higgs bosons $H_2^{\pm }$ in the version of the 3-3-1 model containing heavy leptons at the CLIC (Cern Linear Collider). The production rate is found to be significant for the direct production of $e^{-}{e}^{+}\to H_2^{+}{H}_2^{-}$. We also studied the possibility to identify it using their respective branching ratios.

   hep-ph0 citations
7. 07*

   Effective-theory description of heavy-flavored hadrons and their properties in a hot medium

   Glòria Montaña🇪🇸

   This dissertation investigates exotic hadrons with heavy-quark content that may be understood as being generated dynamically from the hadron-hadron interaction. This interaction is derived from a suitable effective Lagrangian and properly unitarized in a full coupled-channel basis. In particular, we discuss the possible interpretation of some of the {\Omega}c* excited states recently discovered at LHCb as being meson-baryon molecular states. We also discuss the dynamical generation of excited open-charm mesons from the scattering of pseudoscalar and vector charmed mesons off light mesons. We show that a double-pole structure is predicted for the D0*(2300) state, as well as for the D1(2430), while the Ds0*(2317) and the Ds1(2460) may be interpreted as molecular bound states. Extensions of these calculations to the bottom sector are also presented. Furthermore, we investigate the thermal modification of the open heavy-flavor mesons in a hot medium. By means of an extension to finite temperature of the unitarized effective interactions with the light mesons, we obtain the in-medium spectral properties of the D, D*, Ds, and Ds* ground-state mesons. We also analyze the temperature dependence of the masses and the decay widths of the dynamically generated states. Additionally, we provide results for the bottomed mesons by exploiting the heavy-quark spin-flavor symmetry of the Lagrangian. We employ the temperature-dependent spectral functions to compute charm Euclidean correlators. We also present calculations of off-shell transport coefficients in the hadronic phase implementing in-medium scattering amplitudes and the thermal dependence of the heavy-meson spectral properties.

   hep-phnucl-th5 citations
8. 08*

   HighPT: A Tool for high-$p_T$ Drell-Yan Tails Beyond the Standard Model

   Lukas Allwicher🇨🇭 · Darius. A. Faroughy🇨🇭 · Florentin Jaffredo🇫🇷 · Olcyr Sumensari🇫🇷 · Felix Wilsch🇨🇭

   HighPT is a Mathematica package for the analysis of high-energy data of semileptonic transitions at hadron colliders. It allows to compute high-$p_T$ tail observables for semileptonic processes, i.e. Drell-Yan cross sections, for dilepton and monolepton final states at the LHC. These observables can be calculated at tree level within the Standard Model Effective Field Theory, including the relevant operators up to dimension eight to ensure a consistent description of the cross section including terms of $\mathcal{O}({\Lambda }^{-4})$ in the cutoff scale $\Lambda$. For New Physics models with new mediators that can be resolved at LHC energies, HighPT can also account for the full propagation effects of these new bosonic states at tree level. Using the available data from the high-$p_T$ tails in the relevant LHC run-II searches by the ATLAS and CMS collaborations, HighPT can also construct the corresponding likelihoods for all possible flavors of the leptonic final states. As an illustration, we derive and compare constraints on Wilson coefficients at different orders in the Effective Field Theory expansion, and we investigate lepton flavor violation for the $S_3$ leptoquark model. The HighPT code is publicly available at https://github.com/HighPT/HighPT.

   hep-phComput.Phys.Commun.(2023)·106 citations
9. 09*

   Benchmarks for a Global Extraction of Information from Deeply Virtual Exclusive Scattering

   Manal Almaeen🇺🇸 · Jake Grigsby🇺🇸 · Joshua Hoskins🇺🇸 · Brandon Kriesten🇺🇸 · Yaohang Li🇺🇸 · Huey-Wen Lin🇺🇸 · Simonetta Liuti🇺🇸

   We develop a framework to establish benchmarks for machine learning and deep neural networks analyses of exclusive scattering cross sections (FemtoNet). Within this framework we present an extraction of Compton form factors for deeply virtual Compton scattering from an unpolarized proton target. Critical to this effort is a study of the effects of physics constraint built into machine learning (ML) algorithms. We use the Bethe-Heitler process, which is the QED radiative background to deeply virtual Compton scattering, to test our ML models and, in particular, their ability to generalize information extracted from data. We then use these techniques on the full cross section and compare the results to analytic model calculations. We propose a quantification technique, the random targets method, to begin understanding the separation of aleatoric and epistemic uncertainties as they are manifest in exclusive scattering analyses. We propose a set of both physics driven and machine learning based benchmarks providing a stepping stone towards applying explainable machine learning techniques with controllable uncertainties in a wide range of deeply virtual exclusive processes.

   hep-ph24 citations
10. 10*

    Spatial densities of momentum and forces in spin-one hadrons

    Adam Freese🇺🇸 · Wim Cosyn🇺🇸

    Densities associated with the energy-momentum tensor are calculated for spin-one targets. These calculations are done in a light front formalism, which accounts for relativistic effects due to boosts and allows for arbitrary spatial localization of the target. These densities include the distribution of momentum, angular momentum, and pressures over a two-dimensional plane transverse to the light front. Results are obtained for both longitudinally and transversely polarized targets, and the formalism is tailored to allow the possibility of massless targets. The momentum density and pressure distributions are calculated for a deuteron target in a light cone convolution model, with which the properties of this model (such as helicity dependence of the densities) is illustrated.

    hep-phnucl-thPRD(2022)·23 citations
11. 11*

    Spatial densities of the photon on the light front

    Adam Freese🇺🇸 · Wim Cosyn🇺🇸

    The light front densities of momentum, angular momentum, and intrinsic pressure are calculated for the photon, both in the free case and at leading order in quantum electrodynamics. In the latter case, we moreover decompose the form factors into photon and electron contributions. Circularly and linearly polarized photons are both considered, with the latter containing significant azimuthal modulations in both the momentum density and in intrinsic stresses. We find that the D-term of the photon is positive instead of negative, and accordingly the intrinsic radial pressure of the photon is negative. Despite this, the radiation pressure exerted by the photon is positive. We illustrate through explicit calculation how the intrinsic pressure associated with the D-term and the radiation pressure exerted by the photon are different quantities.

    hep-phnucl-thPRD(2022)·14 citations
12. 12*

    Search for the Higgs boson pair production in the $b\bar{b}{\mu }^{+}{\mu }^{-}$ final state at the LHC

    Botao Guo🇨🇳 · Xiaohu Sun🇨🇳 · Licheng Zhang🇨🇳 · Zhe Li🇨🇳 · Yong Ban🇨🇳

    The Higgs boson pair production via gluon-gluon fusion and vector boson fusion in the $b\bar{b}{\mu }^{+}{\mu }^{-}$ final state at the LHC is studied to probe the Higgs self-coupling ${\kappa }_{\lambda }$ and the four-boson HHVV coupling ${\kappa }_{2V}$ for the first time. A cut-based analysis and a machine learning analysis using boosted decision trees are performed with categorizations and optimizations depending on the variations of these couplings. The expected sensitivities are extracted with different integrated luminosities assumed up to the full HL-LHC runs. The expected upper limit at 95\% confidence level on the HH production is calculated as 47 (28) times the Standard Model cross-section using the cut-based method (boosted decision trees) for the gluon-gluon fusion production, and 928 for the vector boson fusion production, assuming an integrated luminosity of 3000 fb${}^{-1}$. The expected constraints on the couplings at 95\% confidence level are calculated to be $-13.8<{\kappa }_{\lambda }<19.1$ ($-10.0<{\kappa }_{\lambda }<15.5$) and $-3.4<{\kappa }_{2V}<5.5$ using the cut-based method (boosted decision trees), respectively, assuming an integrated luminosity of 3000 fb${}^{-1}$.

    hep-phPRD(2023)·7 citations
13. 13*

    Indirect constraints on lepton-flavour-violating quarkonium decays

    Lorenzo Calibbi🇨🇳 · Tong Li🇨🇳 · Xabier Marcano🇪🇸 · Michael A. Schmidt🇦🇺

    Within an effective-field-theory framework, we present a model-independent analysis of the potential of discovering new physics by searching for lepton flavour violation in heavy quarkonium decays and, more in general, we study the phenomenology of lepton-flavour-violating (LFV) 2 quark - 2 lepton ($2q2\ell$) operators with two charm or bottom fields. We compute the constraints from LFV muon and tau decays on the new-physics operators that can induce LFV processes involving $c\bar{c}$ and $b\bar{b}$ systems, thus providing a comprehensive list of indirect upper limits on processes such as $J/\psi \to \ell {\ell }^{\prime }$, ${\rm Y}(nS)\to \ell {\ell }^{\prime }$, ${\rm Y}(nS)\to \ell {\ell }^{\prime }\gamma$ etc., which can be sought at BESIII, Belle II, and the proposed super tau-charm factory. We show that such indirect constraints are so stringent that they prevent the detection of quarkonium decays into $e\mu$. In the case of decays of quarkonia into $\ell \tau$ ($\ell =e,\mu$), we find that an improvement by 2-3 orders of magnitude on the current sensitivities is in general required in order to discover or further constrain new physics. However, we show that cancellations among different contributions to the LFV tau decay rates are possible, such that ${\rm Y}(nS)\to \ell \tau$ can saturate the present experimental bounds. We also find that, interestingly, searches for LFV $Z$ decays, $Z\to \ell \tau$, at future $e^{+}{e}^{-}$ colliders are complementary probes of $2q2\ell$ operators with third generation quarks.

    hep-phhep-exPRD(2022)·20 citations
14. 14*

    Towards matching effective theories efficiently

    Felix Wilsch🇨🇭

    Separation of scales in quantum field theories is essential when studying the low-energy phenomenology of a given UV model. To this end, it is necessary to construct an effective field theory containing only the light degrees of freedom and matching it to the full theory, ensuring that both describe the same low-energy dynamics. Performing this matching beyond the leading order is crucial, as a great number of observables, like FCNC, only appear at the loop level in the Standard Model and in many new physics scenarios. One possibility to obtain the low-energy theory is by integrating out the heavy particles from the full theory using path integral techniques. We review this functional matching procedure at the one-loop level and discuss common challenges involved in determining the matching conditions for effective theories. Due to the great diversity of beyond the Standard Model theories and the complexity of the matching computations, an automation of this procedure is desirable. On this matter, we present the ongoing effort to develop the Mathematica package Matchete facilitating the fully automatic matching for a broad range of theories. When completed, this will significantly simplify the analysis of the low-energy phenomenology of beyond the Standard Model physics. These proceedings are based on arXiv:2012.08506 and work in progress.

    hep-phNuovo Cim.C(2022)·2 citations
15. 15*

    Determining neutrino mass hierarchy in an extended Left-Right model

    Prativa Pritimita🇮🇳 · Urjit A. Yajnik🇮🇳 · Nitali Dash🇮🇳 · Sudhanwa Patra🇮🇳

    We derive the lower bound on absolute scale of lightest neutrino mass for normal hierarchy and inverted hierarchy pattern of light neutrinos by studying the new physics contributions to charged lepton flavour violating decays and neutrinoless double beta decay in the framework of a TeV scale left-right symmetric model. Neutrino mass is generated in the model via type-II seesaw dominance with the help of a heavy sterile neutrino. This scenario allows large light-heavy neutrino mixing and the mixing facilitates new channels for neutrinoless double beta decay and lepton flavour violating decays. We express all the model parameters in terms of oscillation parameters in order to constrain light neutrino mass scale and extract information on neutrino mass hierarchy.

    hep-ph0 citations
16. 16*

    Evidence of $A_{CP}(D^0\to {\pi }^{+}{\pi }^{-})$ implies observable $CP$ violation in the $D^0\to {\pi }^0{\pi }^0$ decay

    Di Wang🇨🇳

    Inspired by the recent measurement of $CP$ asymmetry in the individual mode on LHCb, we study $CP$ asymmetry of the $D\to \pi \pi$ system in the isospin and topological analysis. The ratio between penguin and tree amplitudes $P/(T+C)$ in the $D\to \pi \pi$ system is found to be greater than two in most values of the relative strong phase. And $D^0\to {\pi }^0{\pi }^0$ is a potential mode to reveal the $CP$ asymmetry of the order of $10^{-3}$, which would be observed by Belle II in the future. The large $CP$ asymmetry in the $D\to \pi \pi$ system might be understood in the $t$-channel final-state interaction.

    hep-phEPJC(2023)·13 citations
17. 17*

    Axion-Photon Interaction from Nonminimal Dimension-5 Lorentz-Violating Operators

    A. J. G. Carvalho🇧🇷 · A. G. Dias🇧🇷 · A. F. Ferrari🇧🇷 · T. Mariz🇧🇷 · J. R. Nascimento🇧🇷 · A. Yu. Petrov🇧🇷

    In this paper, we discuss various possible schemes for the perturbative generation of the axion-photon interaction term in different Lorentz-breaking extensions of QED, involving operators with mass dimensions up to 5. We demonstrate explicitly that there are only a few schemes allowing to generate a finite axion-photon interaction term from one-loop radiative corrections, and within all these schemes, the generated term turns out to be ambiguous.

    hep-phhep-thPRD(2023)·7 citations
18. 18*

    Transport properties of the QCD medium

    Jacopo Ghiglieri🇫🇷

    I present an overview of recent developments in the microscopic description of the quark-gluon plasma. I will concentrate on medium-induced emission and transverse momentum broadening. These are two key ingredients of the theory of jet modifications in the QCD medium and of the kinetic theory used for transport and thermalisation. The main focus is on progress towards a better understanding of theory and of its uncertainties.

    hep-phnucl-thActa Phys.Polon.Supp.(2023)·1 citation
19. 19*

    The $P_{\psi s}^{\Lambda }(4338)$ pentaquark and its partners in the molecular picture

    Mao-Jun Yan🇨🇳 · Fang-Zheng Peng🇨🇳 · Mario Sánchez Sánchez🇫🇷 · Manuel Pavon Valderrama🇨🇳

    The LHCb collaboration has detected a new hidden-charm pentaquark with the quantum numbers of a $\Lambda$ baryon: the $P_{\psi s}^{\Lambda }(4338)$. This pentaquark will be interpreted as a ${\bar{D}}_s{\Lambda }_c$-$\bar{D}{\Xi }_c$ resonance within a contact-range theory. Here we briefly comment on the relation of the new $P_{\psi s}^{\Lambda }(4338)$ with the $P_{\psi s}^{\Lambda }(4459)$. We find that the $P_{\psi s}^{\Lambda }(4338)$ and $P_{\psi s}^{\Lambda }(4459)$ both accept a common description in terms of the same parameters, which predicts the existence of a few additional $P_{\psi }^N$, $P_{\psi s}^{\Lambda }$, $P_{\psi s}^{\Sigma }$ and $P_{\psi ss}^{\Xi }$ molecular pentaquarks composed of a charmed antimeson and an antitriplet charmed baryon. The most robust of these predicted pentaquarks is a $P_{\psi s}^{\Lambda }$ with a mass in the $(4235-4255)\mathrm{MeV}$ range, while other two interesting ones are a $P_{\psi }^N(4150)$ and a $P_{\psi }^{\Sigma }(4335)$, the latter basically at the same mass as the $P_{\psi }^{\Lambda }(4338)$, with which it might mix owing to isospin symmetry breaking effects.

    hep-phhep-exnucl-thPRD(2023)·47 citations
20. 20*

    Imprints of ultralight axions on the gravitational wave and pulsar timing measurement

    Ning Xie🇨🇳 · Fa Peng Huang🇨🇳

    The axion or axion-like particle motivated from a natural solution of strong CP problem or string theory is a promising dark matter candidate. We study the new observational effects of ultralight axion-like particles by the space-borne gravitational wave detector and the radio telescope. Taking the neutron star-black hole binary as an example, we demonstrate that the gravitational waveform could be obviously modified by the slow depletion of the axion cloud around the black hole formed through the superradiance process. We compare these new effects on the binary with the well-studied effects from dynamical friction with dark matter and dipole radiation in model-independent ways. Finally, we discuss the constraints from LIGO/Virgo and study the detectability of the ultralight axion particles at LISA and TianQin.

    hep-phastro-ph.COastro-ph.HESCPMA(2024)·19 citations
21. 21*

    Higgs boson induced reheating and ultraviolet frozen-in dark matter

    Aqeel Ahmed🇩🇪 · Bohdan Grzadkowski🇵🇱 · Anna Socha🇵🇱

    A reheating phase in the early universe is an essential part of all inflationary models during which not only the Standard Model (SM) quanta are produced but it can also shed light on the production of dark matter. In this work, we explore a class of reheating models where the reheating is induced by a cubic interaction of the inflaton $\varphi$ to the SM Higgs boson $\text{h}$ of the form $g_{h\varphi }{M}_{\mathrm{Pl}}\varphi |\text{h}{|}^2$ adopting the $\alpha$-attractor T-model of inflation. Assuming inflaton as a background field such interaction implies a $\varphi$-dependent mass term of the Higgs boson and a non-trivial phase-space suppression of the reheating efficiency. As a consequence, the reheating is prolonged and the maximal temperature of the SM thermal bath is reduced. In particular, due to oscillations of the inflaton field the $\varphi$-dependent Higgs boson mass results in periodic transitions between phases of broken and unbroken electroweak gauge symmetry. The consequences of these rapid phase transitions have been studied in detail. A purely gravitational reheating mechanism in the presence of the inflaton background, i.e., for $g_{h\varphi }=0$, has also been investigated. It turned out that even though it may account for the total production of SM radiation in the absence of $g_{h\varphi }$, its contribution to the reheating is subdominant for the range of $g_{h\varphi }$ considered in this work. As a dark matter candidate, a massive Abelian vector boson, $X_{\mu }$, has been considered. Various production mechanisms of $X_{\mu }$ have been discussed including (i) purely gravitational production from the inflaton background, (ii) gravitational freeze-in from the SM quanta, (iii) inflaton decay through a dim-5 effective operator, and (iv) Higgs portal freeze-in and Higgs decay through a dim-6 effective operator. Parameters that properly describe the observed relic abundance have been determined.

    hep-phJHEP(2023)·49 citations
22. 22*

    NLO QCD and EW corrections to off-shell $\mathrm{tZj}$ production at the LHC

    Ansgar Denner🇩🇪 · Giovanni Pelliccioli🇩🇪 · Christopher Schwan🇩🇪

    The production of a single top quark in association with a $\mathrm{Z}$ boson ($\mathrm{tZj}$ production) at the LHC is a relevant probe of the electroweak sector of the Standard Model as well as a window to possible new-physics effects. The growing experimental interest in performing differential measurements for this process demands an improved theoretical modelling in realistic fiducial regions. In this article we present an NLO-accurate $\mathrm{tZj}$ calculation that includes complete off-shell effects and spin correlations, combining QCD and electroweak radiative corrections to the LO signal. Integrated and differential cross-sections are shown for a fiducial setup characterized by three charged leptons, two jets, and missing energy.

    hep-phJHEP(2022)·10 citations
23. 23*

    Reviving keV sterile Neutrino Dark Matter

    Carlos Jaramillo🇩🇪

    We propose a new production mechanism for keV sterile neutrino dark matter which relies neither on the oscillations between sterile and active neutrinos nor on the decay of additional heavier particles. The dark matter neutrinos are instead produced by thermal freeze-out, much like a typical WIMP. The challenge consists in balancing a large Yukawa coupling so that the sterile neutrinos thermalize in the early universe on the one hand, and a small enough Yukawa coupling such that they are stable on cosmological scales on the other. We solve this problem by implementing varying Yukawa couplings. We achieve this by using a three-sterile neutrino seesaw extension to the SM and embedding it in a Froggatt-Nielsen model with a single flavon. Because the vev of the flavon changes during the electroweak phase transition, the effective Yukawa couplings of the fermions have different values before and after the phase transition, thus allowing for successful dark matter genesis. Additionally, the hierarchy in the flavour structure is alleviated and the origin of the light neutrino masses are explained by the interplay of the seesaw and Froggatt-Nielsen mechanisms.

    hep-phJCAP(2022)·18 citations
24. 24*

    Purely virtual extension of quantum field theory for gauge invariant fields: Yang-Mills theory

    Damiano Anselmi🇮🇹

    We extend quantum field theory by including purely virtual "cloud" sectors, to define physical off-shell correlation functions of gauge invariant quark and gluon fields, without affecting the $S$ matrix amplitudes. The extension is made of certain cloud bosons, plus their anticommuting partners. Both are quantized as purely virtual, to ensure that they do not propagate ghosts. The extended theory is renormalizable and unitary. In particular, the off-shell, diagrammatic version of the optical theorem holds. We calculate the one-loop two-point functions of dressed quarks and gluons, and show that their absorptive parts are gauge independent, cloud independent and positive (while they are generically unphysical if the cloud sectors are not purely virtual). A gauge/cloud duality simplifies the computations and shows that the gauge choice is just a particular cloud. It is possible to dress every field insertion with a different cloud. We compare the purely virtual extension to previous approaches to similar problems.

    hep-phhep-thEPJC(2023)·4 citations
25. 25*

    Anomalies of non-Abelian finite groups via cobordism

    Joe Davighi🇨🇭 · Ben Gripaios🇬🇧 · Nakarin Lohitsiri🇬🇧

    We use cobordism theory to analyse anomalies of finite non-abelian symmetries in 4 spacetime dimensions. By applying the method of `anomaly interplay', which uses functoriality of cobordism and naturality of the $\eta$-invariant to relate anomalies in a group of interest to anomalies in other (finite or compact Lie) groups, we derive the anomaly for every representation in many examples motivated by flavour physics, including $S_3$, $A_4$, $Q_8$, and $\mathrm{SL}(2,{\mathbb{F}}_3)$. In the case of finite abelian groups, it is well known that anomalies can be `truncated' in a way that has no effect on low-energy physics, by means of a group extension. We extend this idea to non-abelian symmetries. We show, for example, that a system with $A_4$ symmetry can be rendered anomaly-free, with only one-third as many fermions as naïvely required, by passing to a larger symmetry. As another example, we find that a well-known model of quark and lepton masses utilising the $\mathrm{SL}(2,{\mathbb{F}}_3)$ symmetry is anomalous, but that the anomaly can be cancelled by enlarging the symmetry to a $\mathbb{Z}/3$ extension of $\mathrm{SL}(2,{\mathbb{F}}_3)$.

    ↳ hep-thhep-phmath.ATJHEP(2022)·28 citations
26. 26*

    Kink Solutions With Power Law Tails

    Avinash Khare🇮🇳 · Avadh Saxena🇺🇸

    We present a comprehensive review about the various facets of kink solutions with a power law tail which have received considerable attention during the last few years. This area of research is in its early stages and while several aspects have become clear by now, there are a number of issues which have only been partially understood or not understood at all. We first discuss the aspects which are reasonably well known and then address in some detail the issues which are only partially or not understood at all. We present a wide class of higher (than sixth) order field theory models admitting implicit kink as well as mirror kink solutions where the two tails facing each other have a power law or a power-tower type fall off while the other two ends not facing each other could have either an exponential or a power law tail. The models admitting implicit kink solutions where the two ends facing each other have an exponential tail while the other two ends have a power law tail are also discussed. Moreover, we present several field theory models which admit explicit kink solutions with a power law fall off. We note that in all the polynomial models while the potential $V(\varphi )$ is continuous, its derivative is discontinuous. We also discuss one of the most important and only partially understood issues of the kink-kink and the kink-antikink forces in case the tails facing each other have a power law fall off. Finally, we briefly discuss the kink-antikink collisions at finite velocity and present some open questions.

    ↳ nlin.PShep-phFront.in Phys.(2022)·11 citations
27. 27*

    A universe born in a metastable false vacuum state needs not die

    K. Urbanowski🇵🇱

    We try to find conditions, the fulfillment of which allows a universe born in a metastable false vacuum state to survive and not to collapse. The conditions found are in the form of inequalities linking the depending on time $t$ instantaneous decay rate $\Gamma (t)$ of the false vacuum state and the Hubble parameter $H(t)$. Properties of the decay rate of a quantum metastable states are discussed and then the possible solutions of the conditions found are analyzed and discussed. Within the model considered it is shown that a universe born in the metastable vacuum state has a very high chance of surviving until very late times if the lifetime, ${\tau }_0^F$, of the metastable false vacuum state is much shorter, than the duration of the inflation process. Our analysis shows that the instability of the electroweak vacuum does not have to result in the tragic fate of our Universe leading to its death.

    ↳ gr-qcastro-ph.HEhep-phquant-phEPJC(2023)·3 citations
28. 28*

    The European Muon Collaboration effect from short-range correlated nucleons in a $x$-rescaling model

    Rong Wang🇨🇳 · Na-Na Ma🇨🇳 · Tao-Feng Wang🇨🇳

    In this paper, we examine the hypothesis that the nuclear EMC effect comes merely from the N-N SRC pairs inside the nucleus and that the properties of N-N SRC pair are universal among the various nuclei, using the conventional $x$-rescaling model for the EMC effect. With the previously determined effective mass of the short-range correlated nucleon and the number of N-N SRC pairs estimated, we calculate the EMC effect of various nuclei within the $x$-rescaling approach. From our calculations, the nuclear EMC effect due to the mass deficits of the SRC nucleons is not enough to reproduce the observed EMC effect in experiments. We speculate that the internal structure of the mean-field single nucleon is also obviously modified, or there are more origins of the EMC effect beyond the N-N SRC configuration (such as the $\alpha$ cluster), or the universality of N-N SRC pair is violated noticeably from light to heavy nuclei.

    ↳ nucl-thhep-phCPC(2023)·12 citations
29. 29*

    High precision in CKM unitarity tests in $b$ and $c$ decays

    Alexander Lenz🇩🇪 · Stephane Monteil🇫🇷

    This article surveys the important questions attached to unitarity tests of the Cabibbo-Kobayashi-Maskawa matrix, with a focus on the direct determinations of the magnitude of CKM matrix elements. The current CKM anomalies are discussed and the clear-cut prospects at LHCb and Belle II envisaged. The anticipated precision on $CP$-conserving and $CP$-violating observables at the projected upgrades of the LHCb and Belle~II experiments is examined from the point of view of the search for New Physics in $B$-meson mixing, addressing the bottlenecks in precision for the interpretation of the measurements for future experiments and highlighting the related theoretical and experimental challenges. The vibrant prospects at future $e^{+}{e}^{-}$ colliders running at the $Z^0$ pole and $W^{+}{W}^{-}$ are eventually discussed.

    ↳ hep-exhep-ph6 citations
30. 30*

    Ab initio calculation of the $\beta$ decay spectrum of ${}^6$He

    Garrett B. King🇺🇸 · Alessandro Baroni🇺🇸 · Vincenzo Cirigliano🇺🇸 · Stefano Gandolfi🇺🇸 · Leendert Hayen🇺🇸 · Emanuele Mereghetti🇺🇸 · Saori Pastore🇺🇸 · Maria Piarulli🇺🇸

    We calculate the $\beta$ spectrum in the decay of ${}^6$He using Quantum Monte Carlo methods with nuclear interactions derived from chiral Effective Field Theory and consistent weak vector and axial currents. We work at second order in the multipole expansion, retaining terms suppressed by $\mathcal{O}(q^2/m_{\pi }^2)$, where $q$ denotes low-energy scales such as the reaction's $\mathcal{Q}$-value or the electron energy, and $m_{\pi }$ the pion mass. We go beyond the impulse approximation by including the effects of two-body vector and axial currents. We estimate the theoretical error on the spectrum by using four potential models in the Norfolk family of local two- and three-nucleon interactions, which have different cut-off, fit two-nucleon data up to different energies and use different observables to determine the couplings in the three-body force. We find the theoretical uncertainty on the $\beta$ spectrum, normalized by the total rate, to be well below the permille level, and to receive contributions of comparable size from first and second order corrections in the multipole expansion. We consider corrections to the $\beta$ decay spectrum induced by beyond-the-Standard Model charged-current interactions in the Standard Model Effective Field Theory, with and without sterile neutrinos, and discuss the sensitivity of the next generation of experiments to these interactions.

    ↳ nucl-thhep-phnucl-exPRC(2023)·36 citations
31. 31*

    Gravitational Equivalence Theorem and Double-Copy for Kaluza-Klein Graviton Scattering Amplitudes

    Yan-Feng Hang🇨🇳 · Hong-Jian He🇨🇳

    We analyze the structure of scattering amplitudes of the Kaluza-Klein (KK) gravitons and of the KK gravitational Goldstone bosons in the compactified 5d General Relativity (GR). Using a general $R_{\xi }$ gauge-fixing, we study the geometric Higgs mechanism for the massive spin-2 KK gravitons. We newly propose and prove a Gravitational Equivalence Theorem (GRET) to connect the scattering amplitudes of longitudinal KK gravitons to that of the KK gravitational Goldstone bosons, which formulates the geometric gravitational Higgs mechanism at the scattering $S$-matrix level. We demonstrate that the GRET provides a general energy-cancellation mechanism guaranteeing the $N$-point longitudinal KK graviton scattering amplitudes to have their leading energy dependence cancelled down by a large power factor of $E^{2N}$ ($N\ge 4$) up to any loop order. We propose an extended double-copy approach to construct the massive KK graviton (Goldstone) amplitudes from the KK gauge boson (Goldstone) amplitudes. With these we establish a new correspondence between the two types of energy cancellations in the four-point longitudinal KK amplitudes at tree level: $E^4\to E^0$ in the KK gauge theory and $E^{10}\to E^2$ in the KK GR theory.

    ↳ hep-thgr-qchep-phResearch(2022)·11 citations
32. 32*

    The Inflated Chern-Simons Number in Spectator Chromo-Natural Inflation

    Hengameh Bagherian🇺🇸 · Matthew Reece🇺🇸 · Weishuang Linda Xu🇺🇸

    The chromo-natural inflation (CNI) scenario predicts a potentially detectable chiral gravitational wave signal, generated by a Chern-Simons coupling between a rolling scalar axion field and an SU(2) gauge field with an isotropy-preserving classical background during inflation. However, the generation of this signal requires a very large integer Chern-Simons level, which can be challenging to explain or embed in a UV-complete model. We show that this challenge persists in the phenomenologically viable spectator field CNI (S-CNI) model. Furthermore, we show that a clockwork scenario giving rise to a large integer as a product of small integers can never produce a Chern-Simons level large enough to have successful S-CNI phenomenology. We briefly discuss other constraints on the model, both in effective field theory based on partial-wave unitarity bounds and in quantum gravity based on the Weak Gravity Conjecture, which may be relevant for further explorations of alternative UV completions.

    ↳ hep-thastro-ph.COhep-phJHEP(2023)·20 citations
33. 33*

    Purely virtual extension of quantum field theory for gauge invariant fields: quantum gravity

    Damiano Anselmi🇮🇹

    Quantum gravity is extended to include purely virtual "cloud sectors", which allow us to define a complete set of point-dependent observables, including a gauge invariant metric and gauge invariant matter fields, and calculate their off-shell correlation functions perturbatively. The ordinary on-shell correlation functions and the $S$ matrix elements are unaffected. Each extra sector is made of a cloud field, its anticommuting partner, a "cloud-fixing" function and a cloud Faddeev-Popov determinant. The additional fields are purely virtual, to ensure that no ghosts propagate. The extension is unitary. In particular, the off-shell, diagrammatic version of the optical theorem holds. The one-loop two-point functions of dressed scalars, vectors and gravitons are calculated. Their absorptive parts are positive, cloud independent and gauge independent, while they are unphysical if non purely virtual clouds are used. We illustrate the differences between our approach to the problem of finding a complete set of observables in quantum gravity and other approaches available in the literature.

    ↳ hep-thgr-qchep-phEPJC(2023)·4 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.