Fri·Jan 27, 2023Friday·January 27, 2023

1. 01*

   Flavor Leptogenesis During Reheating Era

   Arghyajit Datta🇮🇳 · Rishav Roshan🇰🇷 · Arunansu Sil🇮🇳

   Recently, it has been shown that the presence of a non-instantaneous era of reheating can significantly alter the charged lepton(s) equilibration temperature(s) which plays important role in flavor leptogenesis. In this work, we extend the analysis to a more general situation where RHNs are also produced from the decay of the inflaton. The presence of these RHNs along with the thermally generated ones (above its mass equivalent temperature only) redistributes different components of the energy density of the Universe during this reheating era, thereby affecting the charged lepton equilibration temperature (in addition to the Hubble effect) as well as the final reheating temperature $T_{\mathrm{RH}}$. Taking both the effects into account, we find that the decay of the lightest RHN in the set-up not only provides a platform to study flavor leptogenesis during reheating, but also an interesting framework of $quasi$-thermal leptogenesis emerges.

   hep-phastro-ph.COPRD(2023)·23 citations
2. 02*

   Discrete dark matter mechanism as the source of neutrino mass scales

   Cesar Bonilla🇨🇱 · Johannes Herms🇩🇪 · Omar Medina🇪🇸 · Eduardo Peinado🇲🇽

   The hierarchy in scale between atmospheric and solar neutrino mass splittings is investigated through two distinct neutrino mass mechanisms, from tree- and one-loop-level contributions. We demonstrate that the minimal discrete dark matter mechanism contains the ingredients for explaining this hierarchy. This scenario is characterized by adding new RH neutrinos and scalar $SU(2)$-doublets to the Standard Model as triplet representations of an $A_4$ flavor symmetry. The $A_4$ symmetry breaking, which occurs at the electroweak scale, leads to a residual ${\mathbb{Z}}_2$ symmetry responsible for the dark matter stability and dictates the neutrino phenomenology. Finally, we show that to reproduce the neutrino mixing angles correctly it is necessary to violate CP in the scalar potential.

   hep-phhep-thJHEP(2023)·17 citations
3. 03*

   Two-loop helicity amplitudes for $H+$jet production to higher orders in the dimensional regulator

   Thomas Gehrmann🇨🇭 · Petr Jakubčík🇨🇭 · Cesare Carlo Mella🇩🇪 · Nikolaos Syrrakos🇩🇪 · Lorenzo Tancredi🇩🇪

   In view of the forthcoming High-Luminosity phase of the LHC, next-to-next-to-next-to-leading (N${}^3$LO) calculations for the most phenomenologically relevant processes become necessary. In this work, we take the first step towards this goal for H$+$jet production by computing the one- and two-loop helicity amplitudes for the two contributing processes, $H\to ggg$, $H\to q\bar{q}g$, in an effective theory with infinite top quark mass, to higher orders in the dimensional regulator. We decompose the amplitude in scalar form factors related to the helicity amplitudes and in a new basis of tensorial structures. The form factors receive contributions from Feynman integrals which were reduced to a novel canonical basis of master integrals. We derive and solve a set of differential equations for these integrals in terms of Multiple Polylogarithms (MPLs) of two variables up to transcendental weight six.

   hep-phJHEP(2023)·31 citations
4. 04*

   A comparative study of hadron-hadron and heavy-ion collision using the $q$-Weibull distribution function

   Rohit Gupta🇮🇳 · Satyajit Jena🇮🇳

   Recent results on multiplicity dependent transverse momentum spectra data in different high multiplicity $pp$ collision have opened a window to search for QGP like medium in hadron-hadron collision. In this work we have performed a comparative study of charged hadron spectra in $pp$, $pPb$ and $PbPb$ collision using the $q$ parameter obtained from the $q$-Weibull distribution function. We observed a disparity in the trend of $q$ parameter in high $p_T$ range.

   hep-phPLB(2025)·1 citation
5. 05*

   QCD's equation of state from Dyson-Schwinger equations

   Philipp Isserstedt🇩🇪 · Christian S. Fischer🇩🇪 · Thorsten Steinert🇩🇪

   In this contribution, we summarize a truncation-independent method to compute the equation of state within nonperturbative functional approaches. After demonstrating its viability, the method is applied to solutions obtained from a set of truncated Dyson-Schwinger equations for the quark and gluon propagators of (2+1)-flavor QCD to obtain thermodynamic quantities across the phase diagram of strong-interaction matter.

   hep-phPoS(2023)·1 citation
6. 06*

   Critical Endpoint of QCD and Baryon Number Fluctuations in a Finite Volume

   Julian Bernhardt🇩🇪 · Christian S. Fischer🇩🇪 · Philipp Isserstedt🇩🇪

   We summarize recent results on the volume dependence of the location of the critical endpoint in the QCD phase diagram. To this end, we employ a sophisticated combination of Lattice Yang--Mills theory and a (truncated) version of Dyson--Schwinger equations in Landau gauge for $2+1$ quark flavours. We study this system at small and intermediate volumes and determine the dependence of the location of the critical endpoint on the boundary conditions and the volume of a three-dimensional cube with edge length $L$. We also discuss recent results on baryon number fluctuations in this setup.

   hep-phPoS(2023)·1 citation
7. 07*

   Four-quark states from functional methods

   Joshua Hoffer🇩🇪 · Christian S. Fischer🇩🇪

   The discovery of four-quark states attracted a lot of attention from the theoretical as well as the experimental side. To study their properties from QCD we use a functional framework which combines (truncated) Dyson-Schwinger and Bethe-Salpeter equations in Landau gauge. This approach allows us to extract qualitative results for mass spectra, decay widths and wavefunctions of candidates for bound as well as resonant four-quark states. Furthermore, we can investigate the possible internal structure of such states. We report on recent developments and results using this functional framework and give an overview about the current status as well as future developments.

   hep-phPoS(2023)·0 citations
8. 08*

   Covariant Light-Front Approach for $B_c$ Decays into Charmonium: Implications on Form Factors and Branching Ratios

   Zhi-Qing Zhang🇨🇳 · Zhi-Jie Sun🇨🇳 · Yan-Chao Zhao🇨🇳 · You-Ya Yang🇨🇳 · Zi-Yu Zhang🇨🇳

   In this work, we investigate the form factors of $B_c$ decays into $J/\Psi ,\psi (2S,3S)$, ${\eta }_c,{\eta }_c(2S,3S),{\chi }_{c0},{\chi }_{c1},h_c$ and $X(3872)$ mesons in the covariant light-front quark model (CLFQM). For the purpose of the branching ratio calculation, the form factors of $B_c\to D^{(\ast )},D_s^{(\ast )}$ transitions are also included. In order to obtain the form factors for the physical transition processes, we need extend these form factors from the space-like region to the time-like region. The $q^2$-dependence for each transition form factor is also plotted. Then, under the factorization method, we calculate the branching ratios of 80 $B_c$ decay channels with a charmonium involved in each mode. Most of our predictions are comparable with the results given by most of other approaches. As to the decays with the radially excited state S-wave charmonia, such as $\psi (2S,3S)$ and ${\eta }_c(2S,3S)$, involved, there are two sets of parameters for their light-front wave functions, corresponding to scenario I (SI) and scenario II (SII), are adopted to calculate the branching ratios. Comparing with the future experimental data, one can discriminate which parameters are more favored.

   hep-phEPJC(2023)·35 citations
9. 09*

   Dark Photon Bremsstrahlung and Ultra-High-Energy Cosmic Ray

   Predee Tantirangsri🇹🇭 · Daris Samart🇹🇭 · Chakrit Pongkitivanichkul🇹🇭

   A dark photon is a hypothetical particle that is similar to a photon with a small mass and interacts very weakly with ordinary matter through a kinetic mixing with the ordinary photon. In this paper, we propose a new way to probe the existence of dark photons through the Bremsstrahlung effect on ultra-high-energy cosmic rays (UHECRs). Using the standard soft photon calculation, we demonstrate that the dark photon Bremsstrahlung process could lead to significant energy loss for protons in the ultralight dark photon scenario, and that this effect could be tested against observational data of UHECRs. We also provide exclusion limits which can be compared with existing limits on ultralight dark photons.

   hep-phastro-ph.HEPhys.Dark Univ.(2024)·4 citations
10. 10*

    Radiation from polarized vacuum in a laser-particle collision

    M. Jirka🇨🇿 · P. Sasorov🇨🇿 · S. V. Bulanov🇨🇿

    The probability of photon emission of a charged particle traversing a strong field becomes modified if vacuum polarization is considered. This feature is important for fundamental quantum electrodynamics processes present in extreme astrophysical environments and can be studied in a collision of a charged particle with a strong laser field. We show that for today's available 700 GeV (6.5 TeV) protons and the field provided by the next generation of lasers, the emission spectra peak is enhanced due to vacuum polarization effect by 30% (suppressed by 65%) in comparison to the traditionally considered Compton process. This striking phenomenon offers a novel path to the laboratory-based manifestation of vacuum polarization.

    hep-phastro-ph.HEhep-thphysics.plasm-phPRA(2023)·3 citations
11. 11*

    Photo- and electro-production of narrow exotic states: from light quarks to charm and up to bottom

    Xu Cao🇨🇳

    Accessing a full image of the inner content of hadrons represents a central endeavour of modern particle physics, with the main scientific motivation to investigate the strong interaction binding the visible matter. On the one hand, the structure of known exotic candidates is a fundamental open issue addressed widely by scientists. On the other hand, looking for new states of exotic nature is a central component for theoretical and experimental efforts from electron-positron machine and electron accelerator with fixed target to heavy ion and electron-ion colliders. In this article we present a succinct short overview of the attempt to search for exotic narrow $N^{\ast }$ and $Z$ states containing light quarks only or also charm, and its connotation for bottom regions (the latter two are also known as $P_c$ ($Z_c$) and $P_b$ ($Z_b$) states, respectively in {the literature}). We address the effort of searching for exotic narrow $N^{\ast }$ and $Z$ states in light quark sector. We focus on recent progress in searching for signal of $P_c$ and $Z_c$ states photoproduction and its implication into the $P_b$ and $Z_b$ photoproduction and their decay properties. We also discuss future perspectives for the field in electron-ion colliders, a good place to disentangle the nature of some of these states and investigate some other enlightening topics including QCD trace anomaly and quarkonium-nucleon scattering length.

    hep-phFront.Phys.(2023)·17 citations
12. 12*

    Gravitational Wave from Graviton Bremsstrahlung during Reheating

    Basabendu Barman🇵🇱 · Nicolás Bernal🇦🇪 · Yong Xu🇩🇪 · Óscar Zapata🇨🇴

    We revisit graviton production via Bremsstrahlung from the decay of the inflaton during inflationary reheating. Using two complementary computational techniques, we first show that such 3-body differential decay rates differ from previously reported results in the literature. We then compute the stochastic gravitational wave (GW) background that forms during the period of reheating, when the inflaton perturbatively decays with the radiative emission of gravitons. By computing the number of relativistic degrees of freedom in terms of $\Delta N_{\text{eff}}$, we constrain the resulting GW energy density from BBN and CMB. Finally, we project current and future GW detector sensitivities in probing such a stochastic GW background, which typically peaks in the GHz to THz ballpark, opening up the opportunity to be detected with microwave cavities and space-based GW detectors.

    hep-phastro-ph.COhep-thJCAP(2023)·70 citations
13. 13*

    An EFT hunter's guide to two-to-two scattering: HEFT and SMEFT on-shell amplitudes

    Hongkai Liu🇮🇱 · Teng Ma🇮🇱 · Yael Shadmi🇮🇱 · Michael Waterbury🇮🇱

    We derive the contact terms contributing to the four-point amplitudes of the standard-model particles, keeping terms with up to quartic energy growth. Imposing just the unbroken low-energy symmetry, and treating the electroweak gauge bosons and the Higgs as independent degrees of freedom, we obtain the most general four-point contact-term amplitudes, corresponding to the HEFT framework. The contact terms are spanned by a basis of Stripped Contact Terms (SCTs), which carry the polarization information, multiplied by polynomials in the Mandelstam invariants. For terms with quadratic energy growth, we also derive the low-energy SMEFT predictions, via on-shell Higgsing of the massless SMEFT contact terms. We discuss several aspects of bottom-up versus top-down on-shell derivations of the HEFT and SMEFT amplitudes, highlighting in particular the simple counting of HEFT dimensions in the on-shell approach and the transparent relation between perturbative unitarity and gauge-invariance in the little-group covariant massive spinor formalism. Our results provide a formulation of EFT analyses directly in terms of observable quantities. For terms with quadratic energy growth, we also provide the mapping to the Warsaw basis.

    hep-phhep-thJHEP(2023)·40 citations
14. 14*

    Dark Radiation from Neutrino Mixing after Big Bang Nucleosynthesis

    Daniel Aloni🇺🇸 · Melissa Joseph🇺🇸 · Martin Schmaltz🇺🇸 · Neal Weiner🇺🇸

    A light ($m_{\nu d}\lesssim$ MeV) dark fermion mixing with the Standard Model neutrinos can naturally equilibrate with the neutrinos via oscillations and scattering. In the presence of dark sector interactions, production of dark fermions is generically suppressed above BBN, but then enhanced at later times. Over much of the parameter space, we find that the dark sector equilibrates, even for mixing angles ${\theta }_0$ as small as $10^{-13}$, and equilibration occurs at $T_{\mathrm{equil}}\simeq m_{\nu d}{\left({\theta }_0^2{M}_{Pl}/m_{\nu d}\right)}^{1/5}$ which is naturally at most a few orders of magnitude above the dark fermion mass. The implications of this are twofold: one, that light states are often only constrained by the CMB and LSS without leaving an imprint on BBN, and two, that sectors which equilibrate before recombination will typically have a mass threshold before recombination, as well. This can result in dark radiation abruptly transitioning from non-interacting to interacting, or vice-versa, a ''step'' in the amount of dark radiation, and dark matter with similar transitions in its interactions, all of which can leave important signals in the CMB and LSS, and may be relevant for cosmological tensions in observables such as $H_0$ or $S_8$. Minimal models leave an unambiguous imprint on the CMB above the sensitivity of upcoming experiments.

    ↳ astro-ph.COhep-phPRL(2023)·38 citations
15. 15*

    Demonstrating quantum computing with the quark model

    R. M. Woloshyn🇨🇦

    The use of quantum computing to solve a problem in quantum mechanics is illustrated, step by step, by calculating energies and transition amplitudes in a nonrelativistic quark model. The quantum computations feature the use of variational quantum imaginary time evolution implemented using automatic differentiation to determine ground and excited states of charmonium. The calculation of transition amplitudes is illustrated utilizing the Hadamard test. Examples of readout and gate error mitigation are included.

    ↳ quant-phhep-lathep-phnucl-th0 citations
16. 16*

    Explorations in Scalar Fermion Theories: $\beta$-functions, Supersymmetry and Fixed Points

    Ian Jack🇬🇧 · Hugh Osborn🇬🇧 · Tom Steudtner🇩🇪

    Results for $\beta$-functions and anomalous dimensions in general scalar fermion theories are presented to three loops. Various constraints on the individual coefficients for each diagram following from supersymmetry are analysed. The results are used to discuss potential fixed points in the $\epsilon$-expansion for scalar fermion theories, with arbitrary numbers of scalar fields, and where there are just two scalar couplings and one Yukawa coupling. For different examples the fixed points follow a similar pattern as the numbers of fermions is varied. For diagrams with subdivergences there are extensive consistency constraints arising from the existence of a perturbative $a$-function and these are analysed in detail. Further arbitrary scheme variations which preserve the form of $\beta$ functions and anomalous dimensions in terms of 1PI diagrams are also discussed. The existence of linear and quadratic scheme invariants is demonstrated and the consistency condition are shown to be expressible in terms of these invariants.

    ↳ hep-thhep-phJHEP(2024)·26 citations
17. 17*

    Relativistic hybrid stars with sequential first-order phase transitions in light of multimessenger constraints

    Jia Jie Li (SWU, Chongqing)🇨🇳 · Armen Sedrakian (FIAS, Frankfurt and Wroclaw U.)🇩🇪 · Mark Alford (Washington U., St. Louis)🇺🇸

    In this work, we consider the properties of compact stars in which quark matter has low- and high-density phases that are separated by a first-order phase transition. Thus, unlike the commonly considered case of a single phase transition from hadronic to quark matter, our models of hybrid stars contain sequential phase transitions from hadronic matter to low- and then to high-density quark matter phases. We extend our previous study of the parameter space of hybrid stars with a single phase transition to those with sequential phase transitions, taking into account the constraints on the mass and radius of neutron stars from the NICER experiment, the experimental inferences of the neutron skin thickness of the lead nucleus by the PREX-II experiment, and constraints on the tidal deformability from the gravitational-wave event GW170817. We determine the range of the masses for which both twin and triplet configurations, i.e., identical-mass stars with two and three different values of radii, arise.

    ↳ astro-ph.HEhep-phnucl-thApJ(2023)·26 citations
18. 18*

    Gravitational wave energy-momentum tensor and radiated power in a strongly curved background

    Yuchen Du🇺🇸 · Diana Vaman🇺🇸 · Kent Yagi🇺🇸

    Allowing for the possibility of extra dimensions, there are two paradigms: either the extra dimensions are hidden from observations by being compact and small as in Kaluza-Klein scenarios, or the extra dimensions are large/non-compact and undetectable due to a large warping as in the Randall-Sundrum scenario. In the latter case, the five-dimensional background has a large curvature, and Isaacson's construction of the gravitational energy-momentum tensor, which relies on the assumption that the wavelength of the metric fluctuations is much smaller than the curvature length of the background spacetime, cannot be used. In this paper, we construct the gravitational energy-momentum tensor in a strongly curved background such as Randall-Sundrum. We perform a scalar-vector-tensor decomposition of the metric fluctuations with respect to the $SO(1,3)$ background isometry and construct the covariantly-conserved gravitational energy-momentum tensor out of the gauge-invariant metric fluctuations. We give a formula for the power radiated by gravitational waves and verify it in known cases. In using the gauge-invariant metric fluctuations to construct the gravitational energy-momentum tensor we follow previous work done in cosmology. Our framework has applicability beyond the Randall-Sundrum model.

    ↳ gr-qchep-phhep-thPRD(2024)·2 citations
19. 19*

    Proof to count bound state nodes in supersymmetric quantum mechanics

    A. Aynbund🇷🇺 · V. V. Kiselev🇷🇺

    A normalizable static supersymmetric bound ground state annihilated by the super-generators has got zero number of internal nodes in the framework of one-dimensional supersymmetric quantum mechanics. The super-generator transformations between excited super-partner bound states as combined with the standard technique of Wronskian provides an elegant and self-sufficient way to derive the equality of internal nodes amount to the number of consequent excitation.

    ↳ hep-thhep-phMod.Phys.Lett.A(2025)·0 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.