Tue·Dec 13, 2022Tuesday·December 13, 2022

1. 01*

   Remarks on propagating waves in non-linear vacuum electrodynamics

   M. Ángeles Pérez-García🇪🇸 · A. Pérez Martínez🇪🇸 · E. Rodríguez Querts🇨🇺

   Using the quadratic expansion in the photon fields of Euler-Heisenberg (EH) non-linear electrodynamics (NLED) Lagrangian model we study relevant vacuum properties in a scenario involving the propagation of a photon probe in the presence of a background constant and static magnetic field, ${\mathbf{B}}_{\mathbf{e}}$. We compute the gauge invariant, symmetric and conserved energy-momentum tensor (EMT) and angular momentum tensor (AMT) for arbitrary magnetic field strength using the Hilbert method under the soft-photon approximation. We discuss how the presence of magneto-electric terms in the EH Lagrangian is a source of anisotropy, induce the non-zero trace in the EMT and leads to differences between EMT calculated by the Hilbert or Noether method. From the Hilbert EMT we analyze some quantities of interest such as the energy density, pressures, Poynting vector, and angular momentum vector, comparing and discussing the differences with respect to the improved Noether method. The magnetized vacuum properties are also studied showing that a photon effective magnetic moment can be defined for different polarization modes. The calculations are done in terms of derivatives of the two scalar invariants of electrodynamics, hence, extension to other NLED Lagrangian is straightforward. We discuss further physical implications and experimental strategies to test magnetization, photon pressure, and effective magnetic moment.

   hep-phhep-thphysics.opticsEPJC(2023)·7 citations
2. 02*

   Mesons on the light front

   Meijian Li🇪🇸

   This lecture note is written for 'Courses on Light-Cone Techniques applied to QCD', Nov 21-25, 2022, IGFAE. It is intended to provide basic knowledge and selective perspectives on the application of light-front Hamiltonian approach to mesons in two 1.5-hour lectures.

   hep-phnucl-th3 citations
3. 03*

   Probing anomalous $ZZ\gamma$ and $Z\gamma \gamma$ Couplings at the $e^{+}{e}^{-}$ Colliders using Optimal Observable Technique

   Sahabub Jahedi🇮🇳 · Jayita Lahiri🇩🇪

   We study the anomalous $ZZ\gamma$ and $Z\gamma \gamma$ couplings that can be probed via $Z\gamma$ production at the $e^{+}{e}^{-}$ colliders. We take Standard Model Effective Field Theory (SMEFT) approach to examine these anomalous neutral triple gauge couplings in a model independent way. There are four independent dimension-8 operators that generate these gauge interactions, one of them is CP-conserving and rest three are CP-violating. We adopt optimal observable technique to extract the sensitivity at which these anomalous couplings can be probed at future $e^{+}{e}^{-}$ colliders and then compare the results with the latest experimental limit obtained at the LHC. We also study the impact and advantage of beam polarization in these precision measurements. Statistical limit (95\% C.L.) on individual anomalous couplings as well as the correlation between various couplings have been discussed in detail.

   hep-phJHEP(2023)·29 citations
4. 04*

   Inflation caused by a potential valley with CP violation

   Daijiro Suematsu🇯🇵

   We propose an inflation scenario caused by an inflaton identified with a potential valley which brings about $CP$ violation in the standard model (SM). If singlet scalars have nonminimal couplings with the Ricci scalar in a suitable way, favorable inflation could be derived through the potential valley composed of such scalars. We study dynamics of the scalars during and after the inflation, which suggests that it could be described as a single field inflation approximately. If these scalars make suitable ingredients of the SM couple with vectorlike fermions and right-handed neutrinos, a CKM phase could be induced and also leptogenesis could occur successfully even at a rather low reheating temperature.

   hep-phJCAP(2023)·5 citations
5. 05*

   QCD cusp anomalous dimension: current status

   Andrey Grozin🇷🇺

   Calculation results for the HQET field anomalous dimension and the QCD cusp anomalous dimension, as well as their properties, are reviewed. The HQET field anomalous dimension ${\gamma }_h$ is known up to 4 loops. The cusp anomalous dimension $\Gamma (\phi )$ is known up to 3 loops, and its small-angle and large-angle asymptotics -- up to 4 loops. Some (but not all) color structures at 4 loops are known with the full $\phi$ dependence. Some simple contributions are known at higher loops. For the $\phi \to \infty$ asymptotics of $\Gamma (\phi )$ (the light-like cusp anomalous dimension) and the ${\phi }^2$ term of the small-$\phi$ expansion (the Bremsstrahlung function), the $\mathcal{N}=4$ SYM results are equal to the highest-weight parts of the QCD results. There is an interesting conjecture about the structure of $\Gamma (\phi )$ which holds up to 3 loops; at 4 loops it holds for some color structures and breaks down for other ones. In cases when it holds it related highly non-trivial functions of $\phi$, and it cannot be accidental; however, the reasons of this conjecture and its failures are not understood. The cusp anomalous dimension at Euclidean angle $\varphi \to \pi$ is related to the static quark-antiquark potential due to conformal symmetry; in QCD this relation is broken by an anomalous term proportional to the $\beta$ function. Some new results are also presented. Using the recent 4-loop result for ${\gamma }_h$, here we obtain analytical expressions for some terms in the 4-loop on-shell renormalization constant of the massive quark field $Z_Q^{\text{os}}$ which were previously known only numerically. We also present 2 new contribution to ${\gamma }_h$, $\Gamma (\phi )$ at 5 loops and to the quark-antiquark potential at 4 loops.

   hep-phInt.J.Mod.Phys.A(2023)·10 citations
6. 06*

   Probing Minimal Grand Unification through Gravitational Waves, Proton Decay, and Fermion Masses

   Shaikh Saad🇨🇭

   Motivated by the direct discovery of gravitational waves (GWs) from black holes and neutron stars, there is a growing interest in investigating GWs from other sources. Among them, GWs from cosmic strings are particularly fascinating since they naturally appear in a large class of grand unified theories (GUTs). Remarkably, a series of pulsar-timing arrays (PTAs) might have already observed GWs in the nHz regime, hinting towards forming a cosmic string network in the early universe, which could originate from phase transition associated with the seesaw scale emerging from GUT. In this work, we show that if these observations from PTAs are confirmed, GWs from cosmic strings, when combined with fermion masses, gauge coupling unification, and proton decay constraints, the parameter space of the minimal SO(10) GUT becomes exceedingly restrictive. The proposed minimal model is highly predictive and will be fully tested in a number of upcoming gravitational wave observatories.

   hep-phJHEP(2023)·27 citations
7. 07*

   Electroweak Effects in Neutral Current Drell-Yan Processes within SANC System

   A. Arbuzov🇷🇺 · S. Bondarenko🇷🇺 · Ya. Dydyshka🇷🇺 · L. Kalinovskaya🇷🇺 · R. Sadykov🇷🇺 · V. Yermolchyk🇷🇺 · Yu. Yermolchyk🇷🇺

   The complete one-loop electroweak radiative corrections to the neutral current Drell-Yan process $pp\to {\ell }^{+}{\ell }^{-}X$ are presented for the case of longitudinal polarization of initial particles. The calculations are based on the SANC computer system. The paper contains a brief description of the SANC approach and a discussion of the sources of theoretical uncertainties in electroweak effects.

   hep-phPhys.Part.Nucl.(2023)·2 citations
8. 08*

   On different approaches to freeze-in and freeze-out leptogenesis with quasi-degenerate neutrinos

   J. Racker🇦🇷

   We compare two approaches for determining the generation of lepton asymmetry during production and decay of quasi-degenerate neutrinos, namely the density matrix formalism and a recent proposal which does not involve any counting of neutrino number densities and is based on plugging the resummed propagator in a quantum field theory model for neutrino oscillations. We show numerically and analytically that they are almost equivalent except in the limit of very large mass splittings. The comparison, performed in a simple scalar toy model, helps to understand several issues that have been discussed in the literature.

   hep-phEPJC(2023)·3 citations
9. 09*

   ee$\in$MC: Higher Orders of Radiative Emissions for $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}(n\gamma )$ and $e^{+}{e}^{-}\to {\tau }^{+}{\tau }^{-}(n\gamma )$ Events

   Ian M. Nugent🇨🇦

   The radiative emissions in the ee$\in$MC generator are extended to include the Initial/Final-State radiative diagrams, with Initial-State/Final-State interference, for the NLO and NNLO calculations and the Initial-State radiative diagrams associated with the NNNLO calculation for $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}(n\gamma )$ and $e^{+}{e}^{-}\to {\tau }^{+}{\tau }^{-}(n\gamma )$ Events. The NNNLO Initial-State radiative diagrams represent the largest contribution to the perturbative Feynman series in the emission of 4 hard-photons. From the convergence of the total cross-section for $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}(n\gamma )$ and $e^{+}{e}^{-}\to {\tau }^{+}{\tau }^{-}(n\gamma )$, we estimate an uncertainty on the theoretical error corresponding to the truncation of the perturbative Feynman series as a function of the soft-photon cut-off applied in the exponentiation using the technique described in [1]. We discuss how this estimation procedure of the theoretical error associated with the truncation of the perturbative Feynman series can be extended to most experimentally measurable physical observables and the potential pitfalls of this strategy.

   hep-phhep-ex2 citations
10. 10*

    Exposing new scalars hiding behind the Higgs boson

    Qing-Hong Cao🇨🇳 · Kun Cheng🇨🇳 · Yandong Liu🇨🇳 · Xin-Kai Wen🇨🇳 · Changlong Xu🇨🇳 · Hao Zhang🇨🇳

    It is possible that there is another scalar hiding behind the known 125 GeV Higgs boson. If the hidden scalar exhibits a CP property different from the Higgs boson, it can be exposed in the di-Higgs production at the high-luminosity large hadron collider and future colliders.

    hep-phhep-exPRD(2023)·0 citations
11. 11*

    Building the Standard Model Historical and Qualitative Aspects

    Jan O.Eeg🇳🇴

    Without going to the details, I give a short, qualitative and historical description of the development of the Standard Model, from quantum electrodynamics, further through quantum chromodynamics, then to weak interactions with parity- and CP-violation, ending up with electroweak symmetry breaking and the Higgs boson. The presentation is based on my own experiences from the late 1960's up to the discovery of the Higgs boson. It is mainly meant for students at master level, and at some points it is presented somewhat different from standard textbook presentations.

    hep-ph0 citations
12. 12*

    Hadronic contributions to the muon $g-2$ in holographic QCD

    Josef Leutgeb🇦🇹 · Jonas Mager🇦🇹 · Anton Rebhan🇦🇹

    We discuss the recent progress made in using bottom-up holographic QCD models in calculating hadronic contributions to the anomalous magnetic moment of the muon, in particular the hadronic light-by-light scattering contribution, where holographic QCD naturally satisfies the Melnikov-Vainshtein constraint by an infinite series of axial vector meson contributions.

    hep-phEPJ Web Conf.(2023)·0 citations
13. 13*

    Deep Inelastic Scattering with Application to Nuclear Targets: Lectures at the 1985 Los Alamos School on Relativistic Dynamics and Quark Nuclear Physics

    Robert L. Jaffe🇺🇸

    This paper is essentially a verbatim reconstruction of lectures that I gave at the Los Alamos School on Relativistic Dynamics and Quark Nuclear Physics in 1985. They were published in the school proceedings, but the book is not widely available. The Los Alamos School took place at the height of the first wave of interest in the quark substructure of nuclei, stimulated by the 1983 discovery of the EMC Effect. Interest in this subject has been increasing for years and the prospect of a dedicated Electron Ion Collider within the decade guarantees even greater attention to quarks and gluons in nuclei among both theorists and experimentalists. Recently, to my surprise, I learned that copies of my old lectures have been circulating and been found useful by the relatively few people who know about them. The are, of course, dated: experiments have far outstripped what was available 37 years ago and theory has progressed too. However, the rest frame derivation of the parton model, the derivation and discussion of the convolution formalism for nucleons, nucleon correlations, and other, virtual, constituents of nuclei, and sections on scaling violation and the operator product expansion have aged pretty well and seem to still be useful. With the help and encouragement of Richard Milner, I have recreated the LaTeX files necessary to post the 1985 Lectures on the arXiv, making them available to the nuclear and particle physics community. Apart from correcting some typographical errors, I have made no attempt to edit, improve, or update these lectures. I hope readers will nevertheless find them useful.

    hep-phhep-thnucl-exnucl-thPublished in M. B. Johnson and A. Pickles…·9 citations
14. 14*

    Formal Theory: Status and Outlook

    Fernando Quevedo🇬🇧

    A very brief overview is presented on some of the current most active areas of research in formal aspects of High Energy Physics and Cosmology. Including the recent breakthrough on the black hole information paradox, developments on amplitudes, the bootstrap and swampland programmes as well as progress towards realistic UV complete models of particle physics and cosmology. Perspectives on future contact with observations are discussed, emphasising the long term prospect for ultra high frequency gravitational waves to test early universe physics beyond the Standard Model.

    hep-phgr-qchep-exhep-thPoS(2022)·1 citation
15. 15*

    Halo-independent bounds on the non-relativistic effective theory of WIMP-nucleon scattering from direct detection and neutrino observations

    Sunghyun Kang🇰🇷 · Arpan Kar🇰🇷 · Stefano Scopel (Sogang U. and CQUeST)🇰🇷

    We combine experimental constraints from direct detection searches and from neutrino telescopes looking for WIMP annihilations in the Sun to derive halo-independent bounds on each of the 28 WIMP-proton and WIMP-neutron couplings of the effective non-relativistic Hamiltonian that drives the scattering process off nuclei of a WIMP of spin 1/2. The method assumes that the velocity distribution is normalized to one and homogeneous at the the solar system scale, as well as equilibrium between WIMP capture and annihilation in the Sun, and requires to fix the WIMP annihilation channels (we assume $b\bar{b}$). We consider a single non-vanishing coupling at a time, and find that for most of the couplings the degree of relaxation of the halo-independent bounds compared to those obtained by assuming the Standard Halo Model is with few exceptions relatively moderate in the low and high WIMP mass regimes, where it can be as small as a factor of $\simeq 2$, while in the intermediate mass range between 10 GeV and 200 GeV it can be as large as $\sim 10^3$. An exception to this general pattern, with more moderate values of the bound relaxation, is observed in the case of spin-dependent WIMP-proton couplings with no or a comparatively small momentum suppression, for which WIMP capture is strongly enhanced because it is driven by scattering events off ${}^{1}H$, which is the most abundant target in the Sun. Within this class of operators the relaxation is particularly small for interactions that are driven by only the velocity-dependent term, for which the solar capture signal is enhanced compared to the direct detection one, thanks to the highest speed of scattering WIMPs within the Sun due to the larger gravitational acceleration.

    hep-phastro-ph.COJCAP(2023)·10 citations
16. 16*

    Azimuthal asymmetries of muon pair production in ultraperipheral heavy ion collisions

    Ding Yu Shao🇨🇳 · Cheng Zhang🇨🇳 · Jian Zhou🇨🇳 · Yajin Zhou🇨🇳

    In this paper we study azimuthal asymmetries of the muon pair production in ultraperipheral heavy ion collisions within the joint impact parameter and transverse momentum dependent framework. The final state QED radiation effects are resummed to all orders in perturbation theory, where the complete muon mass corrections are also taken into account. We further make numerical estimations for azimuthal asymmetries in the different kinematic regions accessible at RHIC and LHC with the derived resummation formula. We find that the lepton mass effects can give sizable corrections to the asymmetries at relatively large pair transverse momentum at RHIC energy.

    hep-phPRD(2023)·25 citations
17. 17*

    Finite size effect on the thermodynamics of a hot and magnetized hadron resonance gas

    Debasis Atta🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Snigdha Ghosh🇮🇳

    The thermodynamic properties of a non-interacting ideal Hadron Resonance Gas (HRG) of finite volume have been studied in the presence of an external magnetic field. The inclusion of background magnetic field in the calculation of thermodynamic potential is done by the modification of the dispersion relations of the charged hadrons in terms of Landau quantization. The generalized Matsubara prescription has been employed to take into account the finite size effects in which a periodic (anti-periodic) boundary conditions is considered for the mesons (baryons). We find significant effects of the magnetic field as well as system size on the temperature dependence of energy density, longitudinal and transverse pressure especially in low temperature regions. The HRG is found to exhibit diamagnetism (paramagnetism) in the low (high) temperature region whereas the finite size effect is seen to strengthen the diamagnetic behavior of the medium.

    hep-phnucl-thMod.Phys.Lett.A(2022)·3 citations
18. 18*

    Comparing the MARTINI and CUJET models for jet-quenching: Medium modification of jets and jet substructure

    Shuzhe Shi🇺🇸 · Rouzbeh Modarresi Yazdi🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦

    Jets produced by the initial hard scattering in heavy ion collision events lose energy due to interactions with the color-deconfined medium formed around them: the quark-gluon plasma (QGP). Jet-medium interactions constitute an important theoretical and experimental field for studies of QGP, and various models with different assumptions have been proposed to describe them. A fair and direct comparison of these models requires that all other aspects of the simulation be fixed, which is achieved in this work by relying on the JETSCAPE framework. We employ JETSCAPE to directly and comprehensively compare two successful energy loss models: CUJET and MARTINI. We compare the models with the results of measurements of jet spectra and substructure observables. With the strong coupling tuned separately, we find that the two models broadly agree with each other in nuclear modification factors for charged hadrons and jets with cone size $R=0.4$. Systematic differences are reported in fragmentation functions, jet shape, and cone size dependent jet $R_{\mathrm{AA}}$.

    hep-phnucl-thPRC(2023)·16 citations
19. 19*

    Precision comparisons between theory and data in $t\bar{t}$-production at the LHC

    Rene Poncelet🇬🇧

    NNLO QCD corrections to the production and decay of top-quark pairs allow performing precision phenomenology in inclusive and fiducial phase spaces. State-of-the-art predictions for top-quark pair production and their comparison to recent collider data are discussed.

    hep-ph0 citations
20. 20*

    Quantum Coherence of Critical Unstable Two-Level Systems

    Dimitrios Karamitros🇬🇧 · Thomas McKelvey🇬🇧 · Apostolos Pilaftsis🇬🇧

    We study in detail the dynamics of unstable two-level quantum systems by adopting the Bloch-sphere formalism of qubits. By employing the Bloch-vector representation for such unstable qubit systems, we identify a novel class of critical scenarios in which the so-called energy-level and decay-width vectors, $\mathbf{E}$ and $\mathbf{\Gamma }$, are orthogonal to one another, and the parameter $r=|\mathbf{\Gamma }|/(2|\mathbf{E}|)$ is less than 1. Most remarkably, we find that critical unstable qubit systems exhibit atypical behaviours like coherence--decoherence oscillations when analysed in an appropriately defined co-decaying frame of the system. In the same frame, a unit Bloch vector $\mathbf{b}$ describing a pure critical qubit will sweep out unequal areas during equal intervals of time, while rotating about the vector $\mathbf{E}$. These phenomena emerge beyond the usual oscillatory pattern due to the energy-level difference of the two-level quantum system. Interestingly enough, we observe that these new features will persist even for quasi-critical scenarios, in which the vectors $\mathbf{E}$ and $\mathbf{\Gamma }$ are not perfectly orthogonal to each other. Applications of our results to quantum information and to unstable meson--antimeson and other systems are discussed.

    hep-phhep-thquant-phPRD(2023)·10 citations
21. 21*

    Search for new particles at the ILC

    Mikael Berggren (DESY, for the ICFA-IDT-WG3 BSM group)🇩🇪

    The LHC experiments have searched for and excluded many proposed Beyond the Standard Model (BSM) theories. However, there are many scenarios where LHC has little or no sensitivity. Electron-positron colliders offers a different avenue for searches for such phenomena.In this talk, we will review the expectations for searches for number of BSM models at the International Linear Collider (ILC). We will discuss new Higgs-like scalars, indirect BSM via Standard Model Effective Field Theory (SMEFT) fits, mono-photons, and SUSY in strongly or moderately compressed models.

    hep-phhep-exPoS·0 citations
22. 22*

    The Heisenberg-Wigner formalism for transverse fields

    Christian Kohlfürst🇩🇪

    We discuss the Heisenberg-Wigner phase-space formalism in quantum electrodynamics as well as scalar quantum electrodynamics with respect to transverse fields. In regard to the special characteristics of such field types we derive modified transport equations such that particle momenta perpendicular to the propagation direction of the waves show up as external parameters only. In case of spatially oscillating fields we further demonstrate how to transform momentum derivative operators of infinite order into simple coupling terms.

    hep-phhep-th11 citations
23. 23*

    Natural cancellation of powerlike divergences in the SM by dark matter through gauged Higgs portal

    S.S. Afonin🇷🇺 · A.A. Andrianov🇷🇺 · V.A. Andrianov🇷🇺 · D. Espriu🇪🇸

    We discuss the connection between the vacuum energy problem and the number of dark matter sectors and its relation to the cancellation of quadratic divergences both in the cosmological constant and simultaneously in the polarization tensor renormalizing the Higgs meson mass. In the absence of global supersymmetry, the cancellations of quartic and quadratic divergences call for a dark Higgs scalar sector. We estimate the number of hidden(dark) gauged Higgs field sectors to be equal to five. The masses of dark bosons may be of the order of the Standard Model boson masses. Then the following picture of the Standard Model emerges: 6 leptons and 6 quarks are accompanied by 6 boson sectors, only one of the latter is realized in the conventional Standard Model.

    hep-phgr-qchep-th1 citation
24. 24*

    Sensitivity of Future Tritium Decay Experiments to New Physics

    James A. L. Canning🇬🇧 · Frank F. Deppisch🇬🇧 · Wenna Pei🇬🇧

    Tritium beta-decay is the most promising approach to measure the absolute masses of active light neutrinos in the laboratory and in a model-independent fashion. The development of Cyclotron Radiation Emission Spectroscopy techniques and the use of atomic tritium has the potential to improve the current limits by an order of magnitude in future experiments. In this paper, we analyse the potential sensitivity of such future searches to keV-mass sterile neutrinos and exotic interactions of either the active or sterile neutrinos. We calculate the relevant decay distributions in both energy and angle of the emitted electron with respect to a potential polarisation of the tritium, including the interference with the Standard Model case as well as incorporating relevant final state corrections for atomic tritium. We present projected sensitivities on the active-sterile neutrino mixing and effective coupling constants of exotic currents, demonstrating the potential to probe New Physics in tritium experiments.

    hep-phJHEP(2023)·8 citations
25. 25*

    From Cosmic Inflation and Matter Creation to Dark Matter -- Journey of the Inflaton?

    B. S. Balakrishna

    A scenario of the inflaton evolution from cosmic inflation and matter creation to dark matter/dark energy today is presented. To start with, a model of the inflationary phase of the inflaton is introduced. The inflaton rolls down a hilltop potential along with matter creation being dragged down by the presence of matter. Presence of matter provides a mechanism to stop universe's acceleration and hence the inflationary phase. The model predictions for the standard metrics are fully consistent with the current CMB limits. The potential could in principle be extended to complete a potential hill subsequent to inflation. The evolution of the inflaton from the inflationary phase to radiation/matter dominated eras and to current times can be inferred qualitatively following the evolution of its equation of state parameter. Existence of solutions to its dynamics, tracking matter as it evolves to current times, provides a plausible reasoning for the relative order of magnitudes of the cosmological parameters, in particular to the relative abundance of dark matter today.

    hep-phastro-ph.COgr-qchep-th0 citations
26. 26*

    Efficiently Moving Instead of Reweighting Collider Events with Machine Learning

    Radha Mastandrea🇺🇸 · Benjamin Nachman🇺🇸

    There are many cases in collider physics and elsewhere where a calibration dataset is used to predict the known physics and / or noise of a target region of phase space. This calibration dataset usually cannot be used out-of-the-box but must be tweaked, often with conditional importance weights, to be maximally realistic. Using resonant anomaly detection as an example, we compare a number of alternative approaches based on transporting events with normalizing flows instead of reweighting them. We find that the accuracy of the morphed calibration dataset depends on the degree to which the transport task is set up to carry out optimal transport, which motivates future research into this area.

    hep-phhep-exphysics.data-an11 citations
27. 27*

    Probing the muon (g-2) anomaly at the LHC in final states with two muons and two taus

    Yoav Afik🇨🇭 · P. S. Bhupal Dev🇺🇸 · Amarjit Soni🇺🇸 · Fang Xu🇺🇸

    The longstanding muon $(g-2)$ anomaly, as well as the persistent hints of lepton flavor universality violation in $B$-meson decays, could be signaling new physics beyond the Standard Model (SM). A minimal $R$-parity-violating supersymmetric framework with light third-generation sfermions (dubbed as 'RPV3') provides a compelling solution to these flavor anomalies, while simultaneously addressing other pressing issues of the SM. We propose a new RPV3 scenario for the solution of the muon $(g-2)$ anomaly, which leads to an interesting LHC signal of ${\mu }^{+}{\mu }^{-}{\tau }^{+}{\tau }^{-}$ final state. We analyze the Run-2 LHC multilepton data to derive stringent constraints on the sneutrino mass and the relevant RPV coupling in this scenario. We then propose dedicated selection strategies to improve the bound even with the existing dataset. We also show that the high-luminosity LHC will completely cover the remaining muon $(g-2)$-preferred parameter space, thus providing a robust, independent test of the muon $(g-2)$ anomaly.

    hep-phhep-exPLB(2023)·9 citations
28. 28*

    Electroweak-flavour and quark-lepton unification: a family non-universal path

    Joe Davighi🇨🇭 · Gino Isidori🇨🇭 · Marko Pesut🇨🇭

    We present a family-non-universal extension of the Standard Model where the the first two families feature both quark-lepton and electroweak-flavour unification, via the $SU(4)\times Sp(4{)}_L\times Sp(4{)}_R$ gauge group, whereas quark-lepton unification for the third family is realised à la Pati-Salam. Via staggered symmetry breaking steps, this construction offers a natural explanation for the observed hierarchical pattern of fermion masses and mixings, while providing a natural suppression for flavour-changing processes involving the first two generations. The last-but-one step in the symmetry-breaking chain is a non-universal 4321 model, characterised by a vector leptoquark naturally coupled mainly to the third generation. The stability of the Higgs sector points to a 4321$\to$SM symmetry-breaking scale around the TeV, with interesting phenomenological consequences in $B$ physics and collider processes that differ from those of other known 4321 completions.

    hep-phhep-thJHEP(2023)·40 citations
29. 29*

    MadNIS -- Neural Multi-Channel Importance Sampling

    Theo Heimel🇩🇪 · Ramon Winterhalder🇧🇪 · Anja Butter🇩🇪 · Joshua Isaacson🇺🇸 · Claudius Krause🇩🇪 · Fabio Maltoni🇧🇪 · Olivier Mattelaer🇧🇪 · Tilman Plehn🇩🇪

    Theory predictions for the LHC require precise numerical phase-space integration and generation of unweighted events. We combine machine-learned multi-channel weights with a normalizing flow for importance sampling, to improve classical methods for numerical integration. We develop an efficient bi-directional setup based on an invertible network, combining online and buffered training for potentially expensive integrands. We illustrate our method for the Drell-Yan process with an additional narrow resonance.

    hep-phhep-exphysics.comp-phSciPost Phys.(2023)·103 citations
30. 30*

    Resonant Lepton-Gluon Collisions at the Large Hadron Collider

    Eduardo da Silva Almeida🇧🇷 · Alexandre Alves🇧🇷 · Oscar J. P. Éboli🇧🇷 · F. S. Queiroz🇧🇷

    We study the lepton-induced resonant production of color-adjoint leptons (leptogluons) at the LHC employing the lepton parton density function of the proton. We demonstrate that this production mechanism can be useful to extend the LHC ability to search for leptogluons beyond purely quark/gluon initiated production processes up to ~ 3.5 TeV leptogluon masses and O(1) TeV compositeness scales. Discerning leptogluons from scalar and vector leptoquarks is also possible in this channel, given a data sample containing the order of 100 signal events. We argue that the resonant channel can be combined with leptogluon pair and associated leptogluon-lepton productions to boost exclusion limits and discovery prospects at the LHC.

    hep-phPRD(2023)·6 citations
31. 31*

    Collective dynamics of polarized spin-half fermions in relativistic heavy-ion collisions

    Rajeev Singh🇵🇱

    Relativistic hydrodynamics has been quite successful in describing the properties of strongly-interacting matter produced in heavy-ion collision experiments. Recently, there has been a significant advancement in this field to explain the spin polarization of hadrons emitted in these processes. Although current models have successfully explained some of the experimental data based on spin-vorticity coupling, they still lack a clear understanding of differential measurements. This is an indication that the spin needs to be treated as an independent degree of freedom whose dynamics is not entirely bound to flow circulation. In particular, if the spin is a macroscopic property of the system, in equilibrium its dynamics should follow hydrodynamic laws. In this thesis, we develop a framework of relativistic perfect-fluid hydrodynamics which includes spin degrees of freedom from kinetic theory, and use it for modeling the dynamics of matter produced in relativistic heavy-ion collisions. Following experimental observations, we assume that the polarization effects are small and derive conservation laws for net-baryon current, energy-momentum tensor, and spin tensor based on the de Groot-van Leeuwen-van Weert pseudogauge. Subsequently, we present various properties of the spin polarization tensor and its components, analyze the propagation properties of the spin polarization components, and derive the spin-wave velocity for arbitrary statistics. We find that only the transverse spin components propagate, analogously to the EM waves. Finally, we study the spacetime evolution of spin polarization for the systems respecting certain spacetime symmetries and calculate the mean spin polarization per particle, which can be compared to the experimental data. We find that, for some observables, our spin polarization results agree qualitatively with the experimental findings and other model calculations.

    hep-phnucl-thInt.J.Mod.Phys.A(2023)·12 citations
32. 32*

    Nuclear matter from the ladder resummation in terms of the experimental nucleon-nucleon scattering amplitudes

    J. M. Alarcón🇪🇸 · J. A. Oller🇪🇸

    Infinite nuclear matter is studied by resuming the series of ladder diagrams based on the results developed by us in Ann. Phys. 437, 168741 (2022). The master formula for the energy density is explicitly solved for the case of contact interactions, within a pionless description of the nucleon-nucleon interactions. Renormalized results are obtained which are directly expressed in terms of the nucleon-nucleon phase shifts and mixing angles in partial-wave amplitudes up to an including $G$ waves, with convergence reached under the inclusion of higher partial waves. The energy per particle, density and sound velocity resulting from the ladder series are given for symmetric and neutron matter. This resummation of the ladder diagrams provides a rigorous result that may be used as low-density reference for other parameterizations of $\bar{\mathcal{E}}$ for higher densities.

    ↳ nucl-thcond-mat.quant-gashep-phPRC(2023)·11 citations
33. 33*

    Non-equilibrium dynamics of Axion-like particles: the quantum master equation

    Shuyang Cao🇺🇸 · Daniel Boyanovsky🇺🇸

    We study the non-equilibrium dynamics of Axion-like particles (ALP) coupled to Standard Model degrees of freedom in thermal equilibrium. The Quantum Master Equation (QME) for the (ALP) reduced density matrix is derived to leading order in the coupling of the (ALP) to the thermal bath, but to \emph{all} orders of the bath couplings to degrees of freedom within or beyond the Standard Model other than the (ALP). The (QME) describes the damped oscillation dynamics of an initial misaligned (ALP) condensate, thermalization with the bath, decoherence and entropy production within a unifying framework. The (ALP) energy density $\mathcal{E}(t)$ features two components: a ``cold'' component from the misaligned condensate and a ``hot'' component from thermalization with the bath, with $\mathcal{E}(t)={\mathcal{E}}_c{e}^{-\gamma (T)t}+{\mathcal{E}}_h(1-e^{-\gamma (T)t})$ thus providing a ``mixed dark matter'' scenario. Relaxation of the (ALP) condensate, thermalization, decoherence and entropy production occur on similar time scales. An explicit example with (ALP)-photon coupling, valid post recombination yields a relaxation rate $\gamma (T)$ with a substantial enhancement from thermal emission and absorption. A misaligned condensate is decaying at least since recombination and on the same time scale thermalizing with the cosmic microwave background (CMB). Possible consequences for birefringence of the (CMB) and (ALP) contribution to the effective number of ultrarelativistic species and galaxy formation are discussed.

    ↳ astro-ph.COcond-mat.otherhep-phhep-th+1PRD(2023)·33 citations
34. 34*

    First Direct Measurement of the Absolute Branching Fraction of ${\Sigma }^{+}\to \Lambda e^{+}{\nu }_e$

    BESIII Collaboration: M. Ablikim · M. N. Achasov · P. Adlarson · R. Aliberti · A. Amoroso · M. R. An · Q. An · Y. Bai · O. Bakina · R. Baldini Ferroli · I. Balossino · Y. Ban and 591 other authors

    The first direct measurement of the absolute branching fraction of ${\Sigma }^{+}\to \Lambda e^{+}{\nu }_e$ is reported based on an $e^{+}{e}^{-}$ annihilation sample of $(10087\pm 44)\times 10^6$ $J/\psi$ events collected with the BESIII detector at $\sqrt{s}=3.097$ GeV. The branching fraction is determined to be $\mathcal{B}({\Sigma }^{+}\to \Lambda e^{+}{\nu }_e)=[2.93\pm 0.74(\mathrm{stat})\pm 0.13(\mathrm{syst})]\times 10^{-5}$, which is the most precise measurement obtained in a single experiment to date and also the first result obtained at a collider experiment. Combining this result with the world average of $\mathcal{B}({\Sigma }^{-}\to \Lambda e^{-}{\bar{\nu }}_e)$ and the lifetimes of ${\Sigma }^{\pm }$, the ratio, $\frac{\Gamma ({\Sigma }^{-}\to \Lambda e^{-}{\bar{\nu }}_e)}{\Gamma ({\Sigma }^{+}\to \Lambda e^{+}{\nu }_e)}$, is determined to be $1.06\pm 0.28$, which is within 1.8 standard deviations of the value expected in the absence of second-class currents that are forbidden in the Standard Model.

    ↳ hep-exhep-phPRD(2023)·0 citations
35. 35*

    Dynamical solution of the strong CP problem within QCD ?

    Gerrit Schierholz🇩🇪

    The strong CP problem is inseparably connected with the topology of gauge fields and the mechanism of color confinement, which requires nonperturbative tools to solve it. In this talk I present results of a recent lattice investigation of QCD with the $\theta$ term in collaboration with Yoshifumi Nakamura. The tool we are using to address the nonperturbative properties of the theory is the gradient flow, which is a particular realization of momentum space RG transformations. The novel result is that within QCD the vacuum angle $\theta$ is renormalized, together with the strong coupling constant, and flows to $\theta =0$ in the infrared limit. This means that CP is conserved by the strong interactions.

    ↳ hep-lathep-phhep-thnucl-thEPJ Web Conf.(2022)·8 citations
36. 36*

    How and How Much is $g_A$ {\it Fundamentally} Quenched in Nuclei?

    Mannque Rho🇫🇷

    The superallowed Gamow-Teller transition in the doubly-magic-shell nucleus ${}^{100}$Sn and the high resolution spectral shape analysis in the fourth-forbidden nonunique transition in ${}^{115}$In indicate as much as $\sim 40\%$ {\it fundamental} quenching in the axial-current coupling constant $g_A$ in nuclei. This can be attributed to an effect of the trace anomaly in QCD "emerging" in nuclear medium. If confirmed, this would signal a major revamping to do in nuclear interactions consistent with chiral-scale symmetry in nuclear medium and a big impact on $0\nu$ and $\nu \nu$ double $\beta$ decays for BSM. I present an argument that such a big anomaly-induced quenching is incompatible with how hidden scale symmetry manifests in nuclear medium, A possible means to resolve this issue is discussed in terms of hidden scale symmetry permeating in baryonic matter from normal nuclear matter to massive compact-star matter.

    ↳ nucl-thhep-ph1 citation
37. 37*

    Unitarity and unstable-particle scattering amplitudes

    Katsuki Aoki🇯🇵

    Unitarity is the fundamental property of the S-matrix while its usage for a scattering of unstable particles has been subtle as unstable particles do not appear in the asymptotic states. Defining unstable-particle amplitudes as residues of a higher-point amplitude at an appropriate complex pole, we find unitarity equations for the 2-to-2 unstable-particle amplitudes from unitarity and analyticity of stable-particle scattering amplitudes. The unstable-particle unitarity equations take a form analogous to those of the stable-particle amplitudes when the in and out states are chosen to be complex-conjugate positions. In particular, as in the optical theorem, we find a positivity constraint on a discontinuity of the amplitudes in a positive region of the momentum transfer variable.

    ↳ hep-thhep-phPRD(2023)·6 citations
38. 38*

    Spectral evolution responsible for the transition from positive lags to negative lags in Gamma-ray Bursts

    Wen-Qiang Liang · Rui-Jing Lu · Cheng-Feng Peng · Wen-Hao Chen🇺🇸

    It was well known that most of gamma-ray bursts (GRBs) are dominated by positive spectral lags, while a small fraction of GRBs show negative lags. However, Wei et al. firstly identified a well-defined transition from positive lags to negative lags in GRB 160625B, and then got robust limits on possible violation of Lorentz Invariance (LIV) based on the observation. Recently, such a transition has been found in three different emission episodes in \thisgrb by Gunapati et al., which provides us a great opportunity to investigate whether the transition results from LIV-induced observed spectral lags. Our analysis shows that the LIV model can not be compatible with the current observations, whereas, only the spectral evolution induced spectral lags could responsible for the transition. So, spectral evolution can also explain the positive to negative lag in GRB 190530A.

    ↳ astro-ph.HEhep-phApJ(2023)·3 citations
39. 39*

    Pairwise Helicity in Higher Dimensions

    Yale Fan🇺🇸

    Studies of scattering amplitudes for electric and magnetic charges have identified previously overlooked multiparticle representations of the Poincaré group in four dimensions. Such representations associate nontrivial quantum numbers (known as pairwise helicities) with asymptotically separated pairs of particles, and thus cannot be described as tensor products of one-particle states. We extend this construction to sources and spacetimes of higher dimension. We first establish the dynamical origin of pairwise helicity in $p$-form electrodynamics coupled to mutually nonlocal branes. We then interpret this pairwise helicity as a quantum number under an $SO(2)$ pairwise little group associated with pairs of distinct branes. We further characterize the "higher" little groups that could in principle be used to induce multiparticle or multi-brane representations of the Lorentz group.

    ↳ hep-thhep-phInt.J.Mod.Phys.A(2023)·2 citations
40. 40*

    Inhomogeneous phases in the 3+1-dimensional Nambu-Jona-Lasinio model and their dependence on the regularization scheme

    Laurin Pannullo🇩🇪 · Marc Wagner🇩🇪 · Marc Winstel🇩🇪

    In this work we study the $3+1$-dimensional Nambu-Jona-Lasinio (NJL) model in the mean field-approximation. We carry out calculations using five different regularization schemes (two continuum and three lattice regularization schemes) with particular focus on inhomogeneous phases and condensates. The regularization schemes lead to drastically different inhomogeneous regions. We provide evidence that inhomogeneous condensates appear for all regularization schemes almost exclusively at values of the chemical potential and with wave numbers, which are of the order of or even larger than the corresponding regulators. This can be interpreted as indication that inhomogeneous phases in the $3+1$-dimensional NJL model are rather artifacts of the regularization and not a consequence of the NJL Lagrangian and its symmetries.

    ↳ hep-lathep-phPoS(2023)·20 citations
41. 41*

    Inverse Compton emission from heavy WIMP annihilations in the Galactic Centre

    Julia I. Djuvsland🇳🇴 · Jim Hinton🇩🇪 · Brian Reville🇩🇪

    A thermal relic WIMP remains a prime candidate for the nature of Dark Matter, particularly for the more poorly constrained case of a heavy ($\gtrsim$ 1 TeV) WIMP. The highest fluxes from WIMP annihilations are expected in the region of the Galactic Centre (GC) where current and near future gamma-ray observatories can be exploited to place tight limits on the WIMP paradigm. It is regularly noted that the annihilation flux of gammas will be accompanied by charged secondary particles which can produce 'delayed' inverse Compton (IC) gamma-ray emission, but this component is often neglected in indirect Dark Matter searches. In this work the inverse Compton emission is studied for the specific conditions of heavy WIMP annihilation in the GC. Using models for the magnetic and radiation fields of the region, and taking into consideration the transport of secondary particles, we find that for TeV WIMPs the IC component cannot be neglected in the GC, with the particles produced cooling within the region rather than propagating out in to the Galaxy. This effect changes the predicted spectral shape substantially and thus boosts the detection prospects for heavy WIMPs.

    ↳ astro-ph.HEhep-phPhys.Dark Univ.(2023)·6 citations
42. 42*

    Horizon thermodynamics and cosmological equations: A holographic-like connection between thermostatistical quantities on a cosmological horizon and in the bulk

    Nobuyoshi Komatsu🇯🇵

    Horizon thermodynamics is expected to be related to the effective energy based on the energy density calculated from the Friedmann equation for a Friedmann--Robertson--Walker (FRW) universe. In the present study, the effective energy and thermostatistical quantities on a cosmological horizon are examined to clarify the holographic-like connection between them, with a focus on a de Sitter universe. To this end, the Helmholtz free energy on the horizon is derived from horizon thermodynamics. The free energy is found to be equivalent to the effective energy calculated from the Friedmann equation. This consistency is interpreted as a kind of holographic-like connection. To examine this connection, Padmanabhan's holographic equipartition law, which is related to the origin of spacetime dynamics, is applied to a de Sitter universe. It is found that the law should lead to a holographic-like connection. The holographic-like connection is considered to be a bridge between thermostatistical quantities on the horizon and in the bulk. For example, cosmological equations for a flat FRW universe can be derived from horizon thermodynamics by accepting the connection as a viable scenario. In addition, a thermal entropy equivalent to the Bekenstein--Hawking entropy is obtained from the Friedmann equation using the concept of a canonical ensemble in statistical physics. The present study provides new insight into the discussion of horizon thermodynamics and cosmological equations.

    ↳ gr-qcastro-ph.COhep-phEPJC(2023)·9 citations
43. 43*

    Left-Right Symmetry Breaking and Gravitational Waves : A Tale of Two Phase Transitions

    Z. A. Borboruah🇮🇳 · U. A. Yajnik🇮🇳

    We study possible ways gravitational waves (GW) are sourced in a theory with minimal left-right symmetry breaking. Generically first order phase transitions (FOPT) lead to gravitational waves sourced by bubble dynamics, while second order phase transitions (SOPT) do not. However, due the presence of two degenerate fields, we obtain domain walls in the putative SOPT case, giving rise to GW via disintegrating domain walls, testable at experiments such as IPTA, DECIGO, and LISA. On the other hand, for the case of FOPT, we get the usual signal from spontaneously created bubbles, but there also arises a late forming domain wall structure separating the two types of vacua. The disintegration of these walls provides an additional source of GW. Thus the parameter range signalling FOPT case gives rise to two distinct peaks in the spectrum of GW. This is verifiable for the low symmetry breaking scales $10^4-10^6$ GeV, but a high scale such as $\sim 10^{10}$ GeV remains beyond the reach of currently planned experiments. Finally, we point out that a version of the left-right symmetric model which separates the scale of parity breaking from that of gauge symmetry breaking is also subject to domain wall formation and amenable to GW observations.

    ↳ astro-ph.COhep-phhep-thPRD(2024)·17 citations
44. 44*

    String-scale Gauge Coupling Relations in the Supersymmetric Pati-Salam Models from Intersecting D6-branes

    Tianjun Li🇨🇳 · Rui Sun🇰🇷 · Lina Wu🇨🇳

    We have constructed all the three-family $\mathcal{N}=1$ supersymmetric Pati-Salam models from intersecting D6-branes, and obtained 33 independent models in total. But how to realize the string-scale gauge coupling relations in these models is a big challenge. We first discuss how to decouple the exotic particles in these models. In addition, we consider the adjoint chiral mulitplets for $SU(4{)}_C$ and $SU(2{)}_L$ gauge symmetries, the Standard Model (SM) vector-like particles from D6-brane intersections, as well as the vector-like particles from the $\mathcal{N}=2$ subsector. We show that the gauge coupling relations at string scale can be achieved via two-loop renormalization group equation running for all these supersymmetric Pati-Salam models. Therefore, we propose a concrete way to obtain the string-scale gauge coupling realtions for the generic intersecting D-brane models.

    ↳ hep-thhep-phJHEP(2023)·9 citations
45. 45*

    Nonperturbative Anomalous Thresholds

    Miguel Correia🇨🇭

    Feynman diagrams (notably the triangle diagram) involving heavy enough particles contain branch cuts on the physical sheet - anomalous thresholds - which, unlike normal thresholds and bound-state poles, do not correspond to any asymptotic $n$-particle state. ``Who ordered that?" We show that anomalous thresholds arise as a consequence of established S-matrix principles and two reasonable assumptions: unitarity below the physical region and analyticity in the mass. We find explicit nonperturbative formulas for the anomalous threshold singularity and test them against the Coleman-Thun poles of the exactly solvable $E_8$ integrable model.

    ↳ hep-thhep-phPRD(2024)·24 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.