Thu·Nov 24, 2022Thursday·November 24, 2022

1. 01*

   Measuring neutrino dynamics in NMSSM with a right-handed sneutrino LSP at the ILC

   Yi Liu🇬🇧 · Stefano Moretti🇬🇧 · Harri Waltari🇸🇪

   We study the possibility of measuring neutrino Yukawa couplings in the Next-to-Minimal Supersymmetric Standard Model with right-handed neutrinos (NMSSMr) when the lightest Supersymmetric partner (a right-handed sneutrino) is the Dark Matter (DM) candidate, by exploiting a `dijet + dilepton + Missing Transverse Energy' (MET) signature. We show that, unlike the miminal realisation of Supersymmetry (SUSY), i.e., the MSSM, for which the DM candidate is a much heavier (fermionic) state (a neutralino), this non-minimal SUSY model offers one with a much lighter (bosonic) state (a sneutrino) as DM, which can be produced at future $e^{+}{e}^{-}$ colliders with energies up to about 500 GeV. The emerging signal, from chargino pair production and subsequent decay, is extremely pure so it allows for the possibility of extracting the Yukawa parameters of the (s)neutrino sector. These results should then motivate searches for light DM signals at such accelerators, where a DM candidate with mass at the Electro-Weak (EW) scale can then be accessed.

   hep-phPoS(2022)·1 citation
2. 02*

   Higgs-like particle decays into $\gamma Z$ and $\gamma \gamma$ : Fingerprints of some non-supersymmetric models

   R.Benbrik🇲🇦 · M. Boukidi🇲🇦 · M. Ouchemhou🇲🇦 · L. Rahili🇲🇦 · O. Tibssirte🇲🇦

   Recently, ATLAS and CMS experiments at the LHC put on light the relevant results in the measurement precision of the Higgs and BSM. In such a report, where the resonance direct search was made in the $\gamma Z$ channel, a mass adjustment distribution for the reconstructed $Z$ boson and photon was established. Thus, simultaneously with the signal-from-background separation, the number of events has been perfectly described, and an excess signal approximately twice that expected by the Standard Model (SM) has been noticed, which is equivalent to a significance of 2.2 standard deviations. In this study, we examine how any possible new physics models can explain this excess, such as the CP-conserving Two-Higgs doublet model (2HDMs), the Inert doublet model (IDM), and the Higgs triplet model (HTM). While considering the available theoretical and most recent experimental constraints, the phenomenological implications of existing extensions beyond the SM are discussed, and prospects for precision studies of these processes are described. We have found that the excess could be explained in the BSM framework studied, depending on the charged and double-charged Higgs boson masses.

   hep-phNPB(2023)·12 citations
3. 03*

   Event characterization of dark bosons via exotic Higgs decays with final states of displaced dimuons in high luminosity era of the LHC

   Tamer Elkafrawy🇺🇸 · Marcus Hohlmann🇺🇸 · Teruki Kamon🇺🇸 · Paul Padley🇺🇸

   We investigate the potential reach of a search for a long-lived/prompt dark vector boson $Z_D$, also called dark $Z$, and a prompt dark Higgs boson $h_D$ through exotic decays of the observed Higgs boson $h$ into either $Z_D{Z}_D$, $h_D{h}_D$, or $Z{Z}_D$ with $Z$ being the hypercharge gauge boson. The $Z_D$ production through the Higgs portal is completed via one of two mechanisms, kinetic mixing of $Z_D$ with $Z$ and the mixing of $h_D$ with $h$. All production modes of $h$ are considered, while the branching fractions are calculated in Monte Carlo simulation using the {\textsc{MadGraph5}}\_aMC@NLO v2.7.2 framework. We focus on a final state of multiple dimuons, displaced up to \mbox{7500 mm}, where the muons can be reconstructed without vertex constraint using data from ATLAS and CMS detectors to be collected in Run~3. Integrated luminosities of 137, 300, and 3000 fb${}^{-1}$ for Run~2, Run~3, and high luminosity run (HL-LHC), respectively, are used for estimating the expected search sensitivity of the Large Hadron Collider to each of the decay modes.

   hep-phhep-exPoS(2022)·0 citations
4. 04*

   Schwinger mechanism for gluons from lattice QCD

   A. C. Aguilar🇧🇷 · F. De Soto🇪🇸 · M. N. Ferreira🇪🇸 · J. Papavassiliou🇪🇸 · F. Pinto-Gómez🇪🇸 · C. D. Roberts🇨🇳 · J. Rodríguez-Quintero🇪🇸

   Continuum and lattice analyses have revealed the existence of a mass-scale in the gluon two-point Schwinger function. It has long been conjectured that this expresses the action of a Schwinger mechanism for gauge boson mass generation in quantum chromodynamics (QCD). For such to be true, it is necessary and sufficient that a dynamically-generated, massless, colour-carrying, scalar gluon+gluon correlation emerge as a feature of the dressed three-gluon vertex. Working with results on elementary Schwinger functions obtained via the numerical simulation of lattice-regularised QCD, we establish with an extremely high level of confidence that just such a feature appears; hence, confirm the conjectured origin of the gluon mass scale.

   hep-phhep-exhep-latnucl-ex+1PLB(2023)·37 citations
5. 05*

   Subleading power corrections to heavy quarkonium production in QCD factorization approach

   Kyle Lee🇺🇸 · Jian-Wei Qiu🇺🇸 · George Sterman🇺🇸 · Kazuhiro Watanabe🇫🇷

   We report the current understanding of heavy quarkonium production at high transverse momentum ($p_T$) in hadronic collisions in terms of QCD factorization. In this presentation, we highlight the role of subleading power corrections to heavy quarkonium production, which are essential to describe the $p_T$ spectrum of quarkonium at a relatively lower $p_T$. We also introduce prescription to match QCD factorization to fixed-order NRQCD factorization calculations for quarkonium production at low $p_T$.

   hep-phnucl-thEPJ Web Conf.(2022)·5 citations
6. 06*

   SMEFT deviations

   Federico Camponovo🇮🇹 · Giampiero Passarino (Turin U. and INFN Turin)🇮🇹

   This work is based on a bottom{-}up approach to the standard{-}model effective field theory (SMEFT), resulting in an equiprobable space of Wilson coefficients. The randomly generated Wilson coefficients of the SMEFT (in the Warsaw basis) are treated as pseudo-data and, for each observable, the corresponding probability density function is computed. The goal has been to understand how large are the deviations from the SM once the SMEFT scale and the range of the Wilson coefficients are selected. Correlations between different observables are also discussed.

   hep-phEPJC(2023)·3 citations
7. 07*

   Heavy-flavor baryons

   Eberhard Klempt🇩🇪 · Sebastian Neubert🇩🇪

   This is a contribution to the review "50 Years of Quantum Chromdynamics" edited by F. Gross and E. Klempt [arXiv:2212.11107], to be published in EPJC. The contribution reviews the properties of baryons with one heavy flavor: the lifetimes of ground states and the spectrum of excited states. The importance of symmetries to understand the excitation spectrum is underlined. An overview of searches for pentaquarks is given.

   hep-ph2 citations
8. 08*

   Glueballs, a fulfilled promise of QCD?

   Eberhard Klempt🇩🇪

   This is a contribution to the review "50 Years of Quantum Chromdynamics" edited by F. Gross and E. Klempt [arXiv:2212.11107], to be published in EPJC. The contribution remembers the early searches and explains how to find a glueball, based on its properties. The results of a coupled-channel analysis are presented that provides evidence for the scalar glueball and first hints for the tensor glueball. Data on radiative decays of $\psi (2S)$ and ${\rm Y}(1S)$ show scalar intensity that is likely due to glueball production.

   hep-ph8 citations
9. 09*

   Light-quark baryons

   Volker Burkert🇺🇸 · Eberhard Klempt🇩🇪 · Ulrike Thoma🇩🇪

   This is a contribution to the review "50 Years of Quantum Chromdynamics" edited by F. Gross and E. Klempt [arXiv:2212.11107], to be published in EPJC. The contribution reviews the new baryon resonances derived from photoproduction experiments. Implications of the new results for the interpretation of baryons are discussed.

   hep-phnucl-ex5 citations
10. 10*

    New Physics Opportunities in Triangle Singularity

    Yu Gao🇨🇳 · Yu Jia🇨🇳 · Yugen Lin🇨🇳 · Jia-Yue Zhang🇨🇳

    We show that loop-induced processes involving new physics particles can readily satisfy Landau Equation and trigger triangular singularities at high energy colliders, leading to fully visible Standard Model final states. Four-particle vertices in new physics allow triangular singularity diagrams to evade large virtuality suppression. In addition, a $t$-channel triangular singularity can also occur in particle scattering processes that may extend to low momentum exchange. We discuss several typical scenarios in supersymmetric and extended Higgs models, then identify the singular component in the loop-integral amplitude at specific external momentum points.

    hep-phMod.Phys.Lett.A(2024)·1 citation
11. 11*

    Nonleptonic decays of ${\Xi }_{cc}\to {\Xi }_c\pi$ with ${\Xi }_c-{\Xi }_c^{\prime }$ mixing

    Chia-Wei Liu🇨🇳 · Chao-Qiang Geng🇨🇳

    Aiming on testing the ${\Xi }_c-{\Xi }_c^{\prime }$ mixing, we study the decays of ${\Xi }_{cc}\to {\Xi }_c\pi$ with ${\Xi }_{cc}=({\Xi }_{cc}^{++},{\Xi }_{cc}^{+})$, ${\Xi }_c=({\Xi }_c^{(\prime )+},{\Xi }_c^{(\prime )0})$ and $\pi =({\pi }^{+},{\pi }^0)$. The soft-meson limit is considered along with the pole model, and the baryon matrix elements are evaluated by the bag model with and without removing the center-of-mass motion (CMM). We find that the four-quark operator matrix elements are about twice larger once the unwanted CMM is removed. We obtain that $\mathcal{R}=\mathcal{B}({\Xi }_{cc}^{+}\to {\Xi }_c^{\prime +}{\pi }^{+})/\mathcal{B}({\Xi }_{cc}^{+}\to {\Xi }_c^{+}{\pi }^{+})=0.87_{-0.11}^{+0.17}$ and $1.45$ with and without removing the CMM, where the former is close to the lower bound and the later is well consistent with $\mathcal{R}=1.41\pm 0.17\pm 0.10$ measured at LHCb. In addition, we show that after including the mixing, the up-down asymmetry of $\alpha ({\Xi }_{cc}^{+}\to {\Xi }_c^{(\prime )0}{\pi }^{+})$ flips sign. Explicitly, we obtain that $\alpha ({\Xi }_{cc}^{+}\to {\Xi }_c^{\prime +}{\pi }^0)=0.52$ and $\alpha ({\Xi }_{cc}^{+}\to {\Xi }_c^0{\pi }^{+})=0.31$ with and without the CMM corrections, respectively, which are all negative if the mixing is absence. As a bonus, a positive value of $\alpha ({\Xi }_{cc}^{+}\to {\Xi }_c^{\prime 0}{\pi }^{+})$ in experiments can also serve as the evidence of the $W$-exchange contributions.

    hep-phhep-exPRD(2023)·10 citations
12. 12*

    Dark matter and radiative neutrino masses in conversion-driven scotogenesis

    Julian Heeck🇺🇸 · Jan Heisig🇺🇸 · Anil Thapa🇺🇸

    The scotogenic model generates Majorana neutrino masses radiatively, with dark matter particles running in the loop. We explore the parameter space in which the relic density of fermionic dark matter is generated via a conversion-driven freeze-out mechanism. The necessity for small Yukawa couplings to initiate chemical decoupling for conversion processes naturally reproduces small neutrino masses as long as the active neutrinos are hierarchical. The model can also resolve the recently reported deviation in the $W$-boson mass while satisfying constraints from direct detection, charged lepton flavor violation as well as collider bounds. Parts of the parameter space lead to long-lived particle signatures to be probed at the LHC.

    hep-phPRD(2023)·14 citations
13. 13*

    Round table on Standard Model Anomalies

    Ashutosh Kotwal🇺🇸 · Joaquim Matias🇪🇸 · Andrea Mauri🇬🇧 · Tom Tong🇩🇪 · Lukas Varnhorst🇩🇪

    This contribution to the XVth Quark Confinement and the Hadron Spectrum conference covers a description, both theoretical and experimental, of the present status of a set of very different anomalies. The discussion ranges from the long standing $b\to sll$ anomalies, $(g-2)$ and the new $M_W$ anomaly.

    hep-phhep-exhep-lat1 citation
14. 14*

    Axion Free-kick Misalignment Mechanism

    Ling-Xiao Xu🇮🇹 · Seokhoon Yun🇮🇹

    We propose an alternative scenario for the axion misalignment mechanism based on the nontrivial interplay between the axion and a light dilaton in the early universe. Dark matter abundance is still sourced by the initial misalignment of the axion field, whose motion along the potential kicks the dilaton field away from its minimum, and dilaton starts to oscillate later with a delayed onset time for oscillation and a relatively large misalignment value due to the kick; eventually the dilaton dominates over the axion in their energy densities, and the dilaton is identified as dark matter. The kick effect due to axion motion is the most significant if the initial field value of dilaton is near its minimum; therefore, we call this scenario axion free-kick misalignment mechanism, where axion plays the role similar to a football player. Dark matter abundance can be obtained with a lower axion decay constant compared to the conventional misalignment mechanism.

    hep-phastro-ph.COPRD(2023)·2 citations
15. 15*

    Oriented Event Shapes for massive Quarks

    A. Bris🇪🇸 · N.G. Gracia🇪🇸 · V. Mateu🇪🇸

    In this work we present the computation of so-called oriented event-shape distributions for massive quarks up to $\mathcal{O}({\alpha }_s)$, along with the total oriented cross section in which one does not look at the geometric properties of the momentum distribution for particles in the final state. We consider the vector and axial-vector currents, and for the former, we find a non-vanishing result at $\mathcal{O}({\alpha }_s^0)$ that translates into a significant enhancement as compared to the massless approximation. Our results are an important ingredient for analyses that aim to determine the strong coupling with high accuracy.

    hep-phEPJ Web Conf.(2022)·0 citations
16. 16*

    Bubble wall velocity during electroweak phase transition in the inert doublet model

    Siyu Jiang🇨🇳 · Fa Peng Huang🇨🇳 · Xiao Wang🇨🇳

    The bubble wall velocity is essential for the spectra of phase-transition gravitational waves, electroweak baryogenesis and the dynamical dark matter mechanism. We perform detailed calculations of the bubble wall velocity in the well-motivated inert doublet model using the microphysical approach with some recent new methods.

    hep-phPRD(2023)·50 citations
17. 17*

    Observable $\mathrm{\Delta }{\mathrm{N}}_{\mathrm{eff}}$ in Dirac Scotogenic Model

    Debasish Borah🇮🇳 · Pritam Das🇮🇳 · Dibyendu Nanda🇰🇷

    We study the possibility of probing the radiative Dirac seesaw model with dark sector particles going inside the loop, popularly referred to as the Dirac scotogenic model via measurements of effective relativistic degrees of freedom $\mathrm{\Delta }{\mathrm{N}}_{\mathrm{eff}}$ at cosmic microwave background (CMB) experiments. The loop suppression and additional free parameters involved in neutrino mass generation allow large ($\sim \mathcal{O}(1))$ coupling of light Dirac neutrinos with the dark sector particles. Such large Yukawa coupling not only dictates the relic abundance of heavy fermion singlet dark matter but also can lead to the thermalisation of the right chiral part of Dirac neutrinos, generating additional relativistic degrees of freedom $\mathrm{\Delta }{\mathrm{N}}_{\mathrm{eff}}$. We find that the parameter space consistent with dark matter phenomenology and neutrino mass bounds can also be probed at future cosmic microwave background experiments like CMB-S4 via precision measurements of $\mathrm{\Delta }{\mathrm{N}}_{\mathrm{eff}}$. The same parameter space, while leading to loop-suppressed direct detection cross-section of dark matter outside future sensitivities, can also have other interesting and complementary observational prospects via charged lepton flavour violation and collider signatures.

    hep-phastro-ph.COEPJC(2024)·18 citations
18. 18*

    Multi-Petawatt Physics Prioritization (MP3) Workshop Report

    A. Di Piazza🇩🇪 · L. Willingale🇺🇸 · J. D. Zuegel🇺🇸

    This Multi-Petawatt Physics Prioritization (MP3) Workshop Report captures the outcomes from a community-initiated workshop held April 20-22, 2022 at Sorbonne University in Paris, France. The MP3 workshop aimed at developing science questions to guide research and future experiments in four areas identified by corresponding MP3 working groups: high-field physics and quantum electrodynamics (HFP/QED), laboratory astrophysics and planetary physics (LAPP), laser-driven nuclear physics (LDNP), and particle acceleration and advanced light sources (PAALS).

    hep-phastro-ph.HEnucl-exphysics.acc-ph+124 citations
19. 19*

    Phase transition amplification of proton number fluctuations in nuclear collisions from a transport model approach

    O. Savchuk🇺🇸 · R. V. Poberezhnyuk🇺🇦 · A. Motornenko🇩🇪 · J. Steinheimer🇩🇪 · M. I. Gorenstein🇺🇦 · V. Vovchenko🇺🇸

    The time evolution of particle number fluctuations in nuclear collisions at intermediate energies ($E_{\mathrm{lab}}=1.23-10A$ GeV) is studied by means of the UrQMD-3.5 transport model. The transport description incorporates baryonic interactions through a density-dependent potential. This allows for an implementation of a first order phase transition including a mechanically unstable region at large baryon density. The scaled variance of the baryon and proton number distributions is calculated in the central cubic spatial volume of the collisions at different times. A significant enhancement of fluctuations associated with the unstable region is observed. This enhancement persists to late times reflecting a memory effect for the fluctuations. The presence of the phase transition has a much smaller influence on the observable event-by-event fluctuations of protons in momentum space.

    hep-phnucl-thPRC(2023)·14 citations
20. 20*

    Transverse-momentum-dependent factorization at next-to-leading power

    Leonard Gamberg🇺🇸 · Zhong-Bo Kang🇺🇸 · Ding Yu Shao🇨🇳 · John Terry🇺🇸 · Fanyi Zhao🇺🇸

    We study transverse momentum dependent factorization and resummation at sub-leading power in Drell-Yan and semi-inclusive deep inelastic scattering. In these processes the sub-leading power contributions to the cross section enter as a kinematic power correction to the leptonic tensor, and the kinematic, intrinsic, and dynamic sub-leading contributions to the hadronic tensor. By consistently treating the power counting of the interactions, we demonstrate renormalization group consistency. We calculate the anomalous dimensions of the kinematic and intrinsic sub-leading correlation functions at one loop and find that the evolution equations give rise to anomalous dimension matrices which mix leading and sub-leading power distribution functions. Additionally we calculate the hard and soft functions associated with each of these contributions. We find that these hard and soft contributions differ from those at the leading power. Finally, we calculate the rapidity anomalous dimension for the dynamic sub-leading distributions and find that it is the same as the leading power anomalous dimension. We then comment on the implications for the soft function associated with this contribution. Using this information, we establish the factorization formalism at sub-leading power for these processes at the one-loop level.

    hep-phnucl-exnucl-th30 citations
21. 21*

    Asymmetric Reheating via Inverse Symmetry Breaking

    Aurora Ireland🇺🇸 · Seth Koren🇺🇸

    Asymmetric reheating is a generic requirement for models of dark sectors with light species, but its implementation is usually in tension with unique phenomenologies otherwise possible in compelling theories containing dark copies of the Standard Model. We present a simple module to implement asymmetric reheating during a ${\mathbb{Z}}_2$-breaking phase above some critical temperature. This reinvigorates the possibility of an exactly degenerate mirror sector and the striking phenomenology of composite particles oscillating into their mirror counterparts.

    hep-phastro-ph.COPRD(2024)·12 citations
22. 22*

    A study of the relativistic corrections to polarized tritium $\beta$-decay

    Gianluca Cavoto🇮🇹 · Angelo Esposito🇮🇹 · Guglielmo Papiri🇮🇹 · Antonio Davide Polosa🇮🇹

    Forthcoming experiments like Project8 and Ptolemy aim at investigating with high precision the end-point of the tritium $\beta$-decay spectrum sensitive to the neutrino mass. In light of this, using the standard parametrization in terms of nuclear polar form factors, we analyze the complete relativistic expression for the spectrum of the $\beta$-electron emitted by a tritium nucleus. Given the small parameters in the problem, we systematically discuss the approximations that can be made, and present the first two corrections to the standard lowest order formula. We particularly discuss the case of an initially polarized target, and the consequences on the spectrum as a function of the neutrino mass. We show that, while it induces an angular anisotropy that can be measured by future experiments, such anisotropy cannot be used as an additional handle to constrain the neutrino mass.

    hep-phnucl-thPRC(2023)·3 citations
23. 23*

    CaloMan: Fast generation of calorimeter showers with density estimation on learned manifolds

    Jesse C. Cresswell · Brendan Leigh Ross · Gabriel Loaiza-Ganem · Humberto Reyes-Gonzalez🇮🇹 · Marco Letizia🇮🇹 · Anthony L. Caterini

    Precision measurements and new physics searches at the Large Hadron Collider require efficient simulations of particle propagation and interactions within the detectors. The most computationally expensive simulations involve calorimeter showers. Advances in deep generative modelling - particularly in the realm of high-dimensional data - have opened the possibility of generating realistic calorimeter showers orders of magnitude more quickly than physics-based simulation. However, the high-dimensional representation of showers belies the relative simplicity and structure of the underlying physical laws. This phenomenon is yet another example of the manifold hypothesis from machine learning, which states that high-dimensional data is supported on low-dimensional manifolds. We thus propose modelling calorimeter showers first by learning their manifold structure, and then estimating the density of data across this manifold. Learning manifold structure reduces the dimensionality of the data, which enables fast training and generation when compared with competing methods.

    hep-phcs.LGhep-exphysics.data-an+152 citations
24. 24*

    A Study of Warm Dark Matter, the Missing Satellites Problem, and the UV Luminosity Cut-Off

    Bruce Hoeneisen🇪🇨

    In the warm dark matter scenario, the Press-Schechter formalism is valid only for galaxy masses greater than the "velocity dispersion cut-off". In this work we extend the predictions to masses below the velocity dispersion cut-off, and thereby address the "Missing Satellites Problem", and the rest-frame ultra-violet luminosity cut-off required to not exceed the measured reionization optical depth. We find agreement between predictions and observations of these two phenomena. As a by-product, we obtain the empirical Tully-Fisher relation from first principles.

    ↳ astro-ph.GAastro-ph.COhep-ph0 citations
25. 25*

    Special point "trains" in the M-R diagram of hybrid stars

    David Blaschke🇵🇱 · Alexander Ayriyan🇦🇲 · Mateusz Cierniak🇵🇱 · Ana Gabriela Grunfeld🇦🇷 · Oleksii Ivanytskyi🇵🇱 · Mahboubeh Shahrbaf🇵🇱

    We present a systematic investigation of the possible locations for the special point (SP), a unique feature of hybrid neutron stars in the mass-radius diagram. The study is performed within the two-phase approach where the high-density (quark matter) phase is described by the covariant nonlocal Nambu--Jona-Lasinio (nlNJL) model equation of state (EOS) which is shown to be equivalent to a constant-sound-speed (CSS) EOS. For the nuclear matter phase around saturation density different relativistic density functional EOSs are used: DD2p00, its excluded-volume modification DD2p40 and the hypernuclear EOS DD2Y-T. In the present contribution we apply the Maxwell construction scheme for the deconfinement transition and demonstrate that a simultaneous variation of the vector and diquark coupling constants results in the occurrence of SP "trains" which are invariant against changing the nuclear matter EOS. We propose that the SP train corresponding to a variation of the diquark coupling at constant vector coupling is special since it serves as a lower bound for the line of maximum masses and accessible radii of massive hybrid stars.

    ↳ nucl-thastro-ph.HEhep-phEPJ Web Conf.(2022)·3 citations
26. 26*

    Analytic construction of sphaleron-like solution invoking higher dimensional gauge theory

    Yuki Adachi🇯🇵 · C. S. Lim🇯🇵 · Nobuhito Maru🇯🇵

    We perform analytic construction of a sphaleron-like solution in the 4-dimensional (4D) space-time invoking the framework of 5D SU(2) gauge theory. By the sphaleron-like solution we mean a static finite energy solution to the equation of motion, which carries the Chern-Simons number $N_{\text{CS}}=\frac{1}{2}$. Since we are interested in the static solution in the low-energy effective theory, we focus on the part of the action which contains only the gauge fields in the 4D space (not space-time), $(A_i,A_y)(i=1,2,3)$ and keep only the Kaluza-Klein zero modes of these fields. Interestingly, the self-duality condition in this 4D space is known to be nothing but the BPS condition for the 't Hooft-Polyakov monopole, once the extra-space component $A_y$ is identified with the adjoint scalar, needed for the monopole solution. Thus, the sphaleron-like solution is based on the BPS monopole embedded in the higher dimensional space-time, which may be interpreted as a self-dual gauge field. By use of the lesson we learn in the case of the instanton in ordinary 4D space-time, we achieve the sphaleron-like configuration of $A_i$, which carries $N_{\text{CS}}=\frac{1}{2}$. As a characteristic feature of this construction invoking higher dimensional gauge theory, in clear contrast to the case of the ordinary BPS monopole, the VEV of the adjoint scalar is topologically fixed, and therefore the mass of the sphaleron-like solution is determined to be $M_{\text{sp}}=\frac{4\pi }{g_4^2}\frac{1}{R}$ ($g_4$: 4D gauge coupling constant, $R$: the radius of the circle as the extra space). We also argue that the sphaleron-like solution may be regarded as a saddle point of the energy in the space of static field configurations.

    ↳ hep-thhep-ph0 citations
27. 27*

    Early deconfinement of asymptotically conformal color-superconducting quark matter in neutron stars

    Oleksii Ivanytskyi🇵🇱 · David Blaschke🇵🇱 · Tobias Fischer🇵🇱 · Andreas Bauswein🇩🇪

    We present a relativistic density functional approach to color superconducting quark matter that mimics quark confinement by a fast growth of the quasiparticle selfenergy in the confining region. The approach is shown to be equivalent to a chiral model of quark matter with medium dependent couplings. While the (pseudo)scalar sector of the model is fitted to the vacuum phenomenology of quantum chromodynamics, the strength of interaction in the vector and diquark channels is varied in order to provide the best agreement with the observational constraints on the mass-radius relation and tidal deformability of neutron stars modelled with our approach. In order to recover the conformal behavior of quark matter at asymptotically high densities we introduce a medium dependence of the vector and diquark couplings motivated by the nonperturbative gluon exchange. Our analysis signals that the onset of deconfinement to color superconducting quark matter is likely to occur in neutron stars with masses below 1.0 $M_{\odot }$.

    ↳ nucl-thastro-ph.HEhep-phEPJ Web Conf.(2022)·2 citations
28. 28*

    One-loop tensor power spectrum from an excited scalar field during inflation

    Atsuhisa Ota🇨🇳 · Misao Sasaki🇯🇵 · Yi Wang🇨🇳

    We present a consistent one-loop calculation for the inflationary tensor power spectrum in the presence of an excited spectator scalar field using the in-in formalism. We find that the super-horizon primordial power spectrum of the tensor mode can be scale-invariantly enhanced or reduced by the loop effects of a subhorizon scalar field. Our calculation also includes the scalar-induced gravitational wave spectrum classically computed in the previous literature, which is significant only near the scales where the scalar field is amplified. The super-horizon enhancement is a higher-order effect of the interaction Hamiltonian, which can be understood as a Bogoliubov transformation introduced by nonlinear interactions. On the other hand, the scale-invariant reduction of the tensor power spectrum may occur due to the fourth-order scalar-scalar-tensor-tensor coupling. This phenomenon can be understood as the evolution of an anisotropic Bianchi type-I background in the separate universe approach. Our result suggests that large-scale measurements may indirectly test the dramatic effects of small-scale cosmological perturbations through loop corrections. This possibility opens a new ground in probing the small-scale physics of the primordial Universe through gravitational wave detectors of cosmological scales.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2023)·36 citations
29. 29*

    Interpretability of an Interaction Network for identifying $H\to b\bar{b}$ jets

    Avik Roy🇺🇸 · Mark S. Neubauer🇺🇸

    Multivariate techniques and machine learning models have found numerous applications in High Energy Physics (HEP) research over many years. In recent times, AI models based on deep neural networks are becoming increasingly popular for many of these applications. However, neural networks are regarded as black boxes -- because of their high degree of complexity it is often quite difficult to quantitatively explain the output of a neural network by establishing a tractable input-output relationship and information propagation through the deep network layers. As explainable AI (xAI) methods are becoming more popular in recent years, we explore interpretability of AI models by examining an Interaction Network (IN) model designed to identify boosted $H\to b\bar{b}$ jets amid QCD background. We explore different quantitative methods to demonstrate how the classifier network makes its decision based on the inputs and how this information can be harnessed to reoptimize the model-making it simpler yet equally effective. We additionally illustrate the activity of hidden layers within the IN model as Neural Activation Pattern (NAP) diagrams. Our experiments suggest NAP diagrams reveal important information about how information is conveyed across the hidden layers of deep model. These insights can be useful to effective model reoptimization and hyperparameter tuning.

    ↳ hep-exhep-phstat.MLPoS·3 citations
30. 30*

    Isospin-breaking corrections to light-meson leptonic decays from lattice simulations at physical quark masses

    Peter Boyle🇺🇸 · Matteo Di Carlo🇬🇧 · Felix Erben🇬🇧 · Vera Gülpers🇬🇧 · Maxwell T. Hansen🇬🇧 · Tim Harris🇬🇧 · Nils Hermansson-Truedsson🇨🇭 · Raoul Hodgson🇬🇧 · Andreas Jüttner🇬🇧 · Fionn Ó hÓgáin🇬🇧 · Antonin Portelli🇬🇧 · James Richings🇬🇧 · Andrew Zhen Ning Yong🇬🇧

    The decreasing uncertainties in theoretical predictions and experimental measurements of several hadronic observables related to weak processes, which in many cases are now smaller than $\mathrm{O}(1\%)$, require theoretical calculations to include subleading corrections that were neglected so far. Precise determinations of leptonic and semi-leptonic decay rates, including QED and strong isospin-breaking effects, can play a central role in solving the current tensions in the first-row unitarity of the CKM matrix. In this work we present the first RBC/UKQCD lattice calculation of the isospin-breaking corrections to the ratio of leptonic decay rates of kaons and pions into muons and neutrinos. The calculation is performed with $N_{\mathrm{f}}=2+1$ dynamical quarks close to the physical point and domain wall fermions in the Möbius formulation are employed. Long-distance QED interactions are included according to the $\mathrm{QE}{\mathrm{D}}_{\mathrm{L}}$ prescription and the crucial role of finite-volume electromagnetic corrections in the determination of leptonic decay rates, which produce a large systematic uncertainty, is extensively discussed. Finally, we study the different sources of uncertainty on $|V_{\mathrm{us}}|/|V_{\mathrm{ud}}|$ and observe that, if finite-volume systematics can be reduced, the error from isospin-breaking corrections is potentially sub-dominant in the final precision of the ratio of the CKM matrix elements.

    ↳ hep-lathep-phJHEP(2023)·48 citations
31. 31*

    Gravitational radiation from binary systems in $f(R)$ gravity: A semi-classical approach

    Ashish Narang🇮🇳 · Subhendra Mohanty🇮🇳 · Soumya Jana🇮🇳

    The rate of energy loss and orbital period decay of quasi-stable compact binary systems are derived in $f(R)$ theory of gravity using the method of a single vertex graviton emission process from a classical source. After linearising the $f(R)$ action written in an equivalent scalar-tensor format in the Einstein frame, we identify the appropriate interaction terms between the massless spin-2 tensor mode, massive scalar mode, and the energy momentum tensor. The definition of the scalar field is related to the $f(R)$ models. Then using the interaction vertex we compute the rate of energy loss due to spin-2 quadrupole radiation, which comes out to be the same as the Peter-Mathews formula with a multiplication factor, and also the energy loss due to the scalar dipole radiation. The total energy loss is the sum of these two contributions. Our derivation is most general as it is applicable for both arbitrary eccentricity of the binary orbits and arbitrary mass of the scalar field. Using the derived theoretical formula for the period decay of the binary systems, we compare the predictions of $f(R)$ gravity and general relativity for the observations of four binary systems, i.e. Hulse-Taylor Binary, PSR J1141-6545, PSR J1738+0333, and PSR J0348+0432. Thus we put bound on three well-known $f(R)$ dark energy models, namely the Hu-Sawicki, the Starobinsky, and the Tsujikawa model. We get the best constraint on $f^{\prime }(R_0)-1$ (where $R_0$ is the scalar curvature of the Universe at the present epoch) from the Tsujikawa model, i.e $|f^{\prime }(R_0)-1|<2.09\times 10^{-4}$. This bound is stronger than those from most of the astrophysical observations and even some cosmological observations.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2023)·10 citations
32. 32*

    Searching for double-peak and doubly broken gravitational-wave spectra from Advanced LIGO-Virgo's first three observing runs

    Wang-Wei Yu🇨🇳 · Shao-Jiang Wang🇨🇳

    The current LIGO-Virgo observing run has been pushing the sensitivity limit to touch the stochastic gravitational-wave backgrounds (SGWBs). However, no significant detection has been reported to date for any single dominated source of SGWBs with a single broken-power-law (BPL) spectrum. Nevertheless, it could equally well escape from existing Bayesian searches from, for example, two comparable dominated sources with two separate BPL spectra (double-peak case) or a single source with its power-law behavior in the spectrum broken twice (doubly broken case). In this paper, we put constraints on these two cases but specifically for the model with cosmological first-order phase transitions from Advanced LIGO-Virgo's first three observing runs. We found strong negative evidence for the double-peak case and hence place 95\% C.L. upper limits ${\Omega }_{\mathrm{BPL},1}<5.8\times 10^{-8}$ and ${\Omega }_{\mathrm{BPL},2}<4.4\times 10^{-8}$ on the two BPL spectra amplitudes with respect to the unresolved compact binary coalescence (CBC) amplitude ${\Omega }_{\mathrm{CBC}}<5.6\times 10^{-9}$. We further found weak negative evidence for the doubly broken case and hence place 95\% C.L. upper limit ${\Omega }_{\mathrm{DB}}<1.2\times 10^{-7}$ on the overall amplitude of the doubly broken spectrum with respect to ${\Omega }_{\mathrm{CBC}}<6.0\times 10^{-9}$. In particular, the results from the double-peak case have marginally ruled out the strong super-cooling first-order phase transitions at LIGO-Virgo band.

    ↳ gr-qcastro-ph.COhep-phPRD(2023)·7 citations
33. 33*

    Frequency space derivation of linear and non-linear memory gravitational wave signals from eccentric binary orbits

    Arpan Hait🇮🇳 · Subhendra Mohanty🇮🇳 · Suraj Prakash🇮🇳

    The memory effect in gravitational wave (GW) signals is the phenomenon, wherein the relative position of two inertial GW detectors undergoes a permanent displacement owing to the passage of GWs through them. Measurement of the memory signal is an important target for future observations as it establishes a connection between observations with field-theoretic results like the soft-graviton theorems. Theoretically, the memory signal is predicted at the leading order quadrupole formula for sources like binaries in hyperbolic orbits. This can be in the realm of observations by Advanced LIGO, Einstein-Telescope, or LISA for black-holes with masses $\sim$ $O(10^3{M}_{\odot }$) scattered by the super-massive black-hole at the galactic center. Apart from the direct memory component there is a non-linear memory signal in the secondary GW emitted from the primary GW chirp-signals emitted by coalescing binaries. In this paper, we compute the gravitational wave signals and their energy spectrum using the field-theoretic method by computing the scattering amplitudes for eccentric elliptical and hyperbolic binary orbits. The field theoretic calculation gives us the gravitational waveforms of linear and non-linear memory signals directly in the frequency space. The frequency domain templates are useful for extracting signals from the data. We compare our results with other calculations of linear and non-linear memory signals in literature and point out novel features we find in our calculations like the presence of $\log (\omega )$ terms in the linear memory from hyperbolic orbits.

    ↳ gr-qchep-phPRD(2024)·26 citations
34. 34*

    Spin polarization and alignment in heavy-ion collisions

    Subhash Singha🇨🇳

    We report the measurements of global spin polarization of hyperons ($P_{\Lambda }$) from FAIR, RHIC and LHC energies. The $P_{\Lambda }$ continue to follow an increasing trend at $\sqrt{s_{\mathrm{N}N}}$ < 7.7 GeV indicating that enormous vorticity prevail even in hadronic dominant region. New measurements of local spin polarization ($P_{z,2}$) from isobar collisions follow the same pattern observed in previous RHIC and LHC energies. An observable motivated by predicted baryonic Spin Hall Effect, the net local polarization ($P_{z,2}^{\mathrm{net}}$), shows negative value in Au+Au collisions at $\sqrt{s_{\mathrm{N}N}}$ = 19.6 and 27 GeV. The first $P_z$ measurement with respect to third order harmonic in 200 GeV RHIC isobar collisions show a non-zero sine modulation, indicating the presence of complex vortical structure in the medium. Surprising new patterns of spin alignment (${\rho }_{00}$) for various vector mesons ($K^{\ast 0}$, $K^{\ast \pm }$, $\varphi$ and $J/\psi$) emerged at both RHIC and LHC energies. The large deviation in ${\rho }_{00}$ of several species poses challenge to the theory.

    ↳ nucl-exhep-exhep-phnucl-thEPJ Web Conf.(2023)·2 citations
35. 35*

    Maximum mass of relativistic self-gravitating Bose-Einstein condensates with repulsive or attractive $|\phi {|}^4$ self-interaction

    Pierre-Henri Chavanis🇫🇷

    We derive an approximate analytical expression of the maximum mass of relativistic self-gravitating Bose-Einstein condensates with repulsive or attractive $|\phi {|}^4$ self-interaction. This expression interpolates between the general relativistic maximum mass of noninteracting bosons stars, the general relativistic maximum mass of bosons stars with a repulsive self-interaction in the Thomas-Fermi limit, and the Newtonian maximum mass of dilute axion stars with an attractive self-interaction [P.H. Chavanis, Phys. Rev. D {\bf 84}, 043531 (2011)]. We obtain the general structure of our formula from simple considerations and determine the numerical coefficients in order to recover the exact asymptotic expressions of the maximum mass in particular limits. As a result, our formula should provide a relevant approximation of the maximum mass of relativistic boson stars for any value (positive and negative) of the self-interaction parameter. We discuss the evolution of the system above the maximum mass and consider application of our results to dark matter halos and inflaton clusters. We also make a short review of boson stars and Bose-Einstein condensate dark matter halos, and point out analogies with models of extended elementary particles.

    ↳ gr-qcastro-ph.COhep-phPRD(2023)·31 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.