Thu·Mar 3, 2022Thursday·March 3, 2022

1. 01*

   Rapidity evolution of the entanglement entropy in quarkonium: parton and string duality

   Yizhuang Liu🇵🇱 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸

   We investigate the quantum entanglement in rapidity space of the soft gluon wave function of a quarkonium, in theories with non-trivial rapidity evolutions. We found that the rapidity evolution drastically changes the behavior of the entanglement entropy, at any given order in perturbation theory. At large $N_c$, the reduced density matrices that "resum" the leading rapidity-logs can be explicitly constructed, and shown to satisfy Balitsky-Kovchegov (BK)-like evolution equations. We study their entanglement entropy in a simplified $1+1$ toy model, and in 3D QCD. The entanglement entropy in these cases, after re-summation, is shown to saturate the Kolmogorov-Sinai bound of 1. Remarkably, in 3D QCD the essential growth rate of the entanglement entropy is found to vanish at large rapidities, a result of kinematical "quenching" in transverse space. The one-body reduction of the entangled density matrix obeys a BFKL evolution equation, which can be recast as an evolution in an emergent AdS space, at large impact-parameter and large rapidity. This observation allows the extension of the perturbative wee parton evolution at low-x, to a dual non-perturbative evolution of string bits in curved AdS${}_5$ space, with manifest entanglement entropy in the confining regime.

   hep-phhep-thnucl-thquant-phPRD(2022)·34 citations
2. 02*

   Proton and pion distribution functions in counterpoint

   Ya Lu🇨🇳 · Lei Chang🇨🇳 · Khépani Raya🇪🇸 · Craig D. Roberts🇨🇳 · José Rodríguez-Quintero🇪🇸

   Working with proton and pion valence distribution functions (DFs) determined consistently at the same, unique hadron scale and exploiting the possibility that there is an effective charge which defines an evolution scheme for DFs that is all-orders exact, we obtain a unified body of predictions for all proton and pion DFs - valence, glue, and four-flavour-separated sea. Whilst the hadron light-front momentum fractions carried by identifiable parton classes are the same for the proton and pion at any scale, the pointwise behaviour of the DFs is strongly hadron-dependent. All calculated distributions comply with quantum chromodynamics constraints on low- and high-$x$ scaling behaviour and, owing to emergent hadron mass, pion DFs are the most dilated. These results aid in elucidating the sources of similarities and differences between proton and pion structure.

   hep-phhep-exhep-latnucl-ex+1PLB(2022)·58 citations
3. 03*

   Possible studies on generalized parton distributions and gravitational form factors in neutrino reactions

   S. Kumano🇯🇵 · R. Petti🇺🇸

   Spacelike and timelike generalized parton distributions (GPDs) have been investigated in charged-lepton scattering and electron-positron collisions via deeply virtual Compton scattering and two-photon processes, respectively. Furthermore, we expect that hadron-accelerator-facility measurements will be performed in future. The GPDs will play a crucial role in clarifying the origins of hadron spins and masses in terms of quarks and gluons. It is also possible to probe internal pressure within hadrons for understanding their stability. Gravitational form factors of hadrons used to be considered as a purely academic subject because gravitational interactions are too weak to be measured in microscopic systems. However, due to the development of hadron-tomography field, it became possible to extract the gravitational form factors from the actual GPD measurements without relying on direct gravitational interactions. Neutrino reactions can also be used for GPD studies in future, for example, by using the Long-Baseline Neutrino Facility at Fermilab. The neutrino GPD measurements are valuable especially for finding the flavor dependence of the GPDs in a complementary way to the charged-lepton experiments. We give an overview of the GPDs and discuss possible neutrino GPD measurements using the single-pion production processes $\nu +N\to {\ell }^{-}+N^{\prime }+\pi$ and $\bar{\nu }+N\to {\ell }^{+}+N^{\prime }+\pi$.

   hep-phhep-exhep-latnucl-ex+1PoS(2022)·4 citations
4. 04*

   The structure of cosmic strings of a $U(1)$ gauge field for the conservation of $B-L$

   Victor Muñoz-Vitelly🇲🇽 · José Antonio García-Hernández🇲🇽 · Wolfgang Bietenholz🇲🇽

   We consider an extension of the Standard Model, where the difference between the baryon number $B$ and the lepton number $L$ is gauged with an Abelian gauge field, in order to explain the exact conservation of $B-L$. To avoid a gauge anomaly, we add a right-handed neutrino ${\nu }_{\mathrm{R}}$ to each fermion generation. Here it is not sterile, so the usual Majorana term is excluded by gauge invariance. We provide a mass term for ${\nu }_{\mathrm{R}}$ by adding a non-standard 1-component Higgs field, thus arriving at a consistent extension of the Standard Model, where the conservation of $B-L$ is natural, with a modest number of additional fields. We study the possible formation of cosmic strings by solving the coupled field equations of the two Higgs fields and the non-standard U(1) gauge field. Numerical methods provide the corresponding string profiles, depending on the Higgs winding numbers, such that the appropriate boundary conditions in the string center and far from it are fulfilled.

   hep-phRev.Mex.Fis.Suppl.(2022)·2 citations
5. 05*

   Emergent Hadron Mass in Strong Dynamics

   Daniele Binosi🇮🇹

   Emergent Hadron Mass (EHM) is a mechanism capable of explaining both the unnaturally small (pion) and large (proton) masses of hadrons and if not the origin of confinement, then intimately connected with it. Even though the modern formulation of EHM has only recently been completed, it is rapidly becoming a fundamental focus for modern and future experimental efforts aimed at understanding the strong force within the Standard Model. Using Dyson-Schwinger equations for the gluon, ghost and quark propagators, I will introduce the main EHM concepts and illustrate how far this framework can take us in understanding strong interaction phenomenology.

   hep-phhep-lathep-thFew Body Syst.(2022)·76 citations
6. 06*

   Feasibility of tau g-2 measurements in ultra-peripheral collisions of heavy ions

   Nazar Burmasov🇷🇺 · Evgeny Kryshen · Paul Buehler🇦🇹 · Roman Lavicka🇦🇹

   The anomalous magnetic moment of the tau lepton, a_tau = (g_tau - 2)/2, is a sensitive probe of new physics but is extremely difficult to measure precisely in contrast to electron and muon moments. The best experimental limits were set by the DELPHI collaboration more than 15 years ago in studies of the ditau production in the e+e -> e+e+tau+tau process. Ultra-peripheral collisions (UPCs) of heavy ions at the LHC may provide a unique opportunity to improve the a_tau constraints in the studies of Pb+Pb -> Pb+Pb+tau+tau process. We review recent proposals to study ditau production via semi-leptonic tau decays in Pb-Pb UPC with the available ATLAS and CMS data and discuss the feasibility to explore this process down to low transverse momenta of decay leptons with the ALICE and LHCb experiments.

   hep-phSciPost Phys.Proc.(2025)·6 citations
7. 07*

   QED and Lasers: A Tutorial

   T. Heinzl🇬🇧

   This is a write-up of a short tutorial talk on high-intensity QED, video-presented at the 2021 annual Christmas meeting of the Central Laser Facility at Rutherford-Appleton Lab, UK. The first half consists of a largely historical introduction to (quantum) electrodynamics focussing on a few key concepts. This well-established theory is then compared to its strong-field generalisation when a high-intensity laser is present. Some supplementary material and a fair amount of references have been added.

   hep-phphysics.plasm-ph5 citations
8. 08*

   Estimating Elliptic Flow Coefficient in Heavy Ion Collisions using Deep Learning

   Neelkamal Mallick🇮🇳 · Suraj Prasad🇮🇳 · Aditya Nath Mishra🇭🇺 · Raghunath Sahoo🇮🇳 · Gergely Gábor Barnaföldi🇭🇺

   Machine Learning (ML) techniques have been employed for the high energy physics (HEP) community since the early 80s to deal with a broad spectrum of problems. This work explores the prospects of using Deep Learning techniques to estimate elliptic flow ($v_2$) in heavy-ion collisions at the RHIC and LHC energies. A novel method is developed to process the input observables from particle kinematic information. The proposed DNN model is trained with Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV minimum bias events simulated with AMPT model. The predictions from the ML technique are compared to both simulation and experiment. The Deep Learning model seems to preserve the centrality and energy dependence of $v_2$ for the LHC and RHIC energies. The DNN model is also quite successful in predicting the $p_{\mathrm{T}}$ dependence of $v_2$. When subjected to event simulation with additional noise, the proposed DNN model still keeps the robustness and prediction accuracy intact up to a reasonable extent.

   hep-phhep-exhep-thnucl-ex+1PRD(2022)·34 citations
9. 09*

   Modifying the Dyson Series for Unstable Particles and Resonances

   Peter Matak🇸🇰

   In this work, we introduce a modification of the Dyson series based on the perturbative unitarity as a starting point. The presented approach systematically avoids singularities and double-counting related to the presence of unstable particles as intermediate states and, at the same time, it does not rely on a specific choice of the renormalization scheme.

   hep-phPRD(2022)·6 citations
10. 10*

    Determination of coupling patterns by parallel searches for ${\mu }^{-}\to e^{+}$ and ${\mu }^{-}\to e^{-}$ in muonic atoms

    Joe Sato🇯🇵 · Kohei Sugawara🇯🇵 · Yuichi Uesaka🇯🇵 · Masato Yamanaka🇯🇵

    We investigate a possibility that the ${\mu }^{-}\to e^{+}$ conversion is discovered prior to the ${\mu }^{-}\to e^{-}$ conversion, and its implications to the new physics search. We focus on the specific model including the mixing of the $SU(2{)}_L$ doublet- and singlet-type scalar leptoquarks, which induces not only the lepton flavor violation but also the lepton number violation. Such a structure is motivated by R-parity violating (RPV) supersymmetric models, where a sbottom mediates the conversion processes. We formulate the ${\mu }^{-}\to e^{+}$ rate in analogy with the muon capture in a muonic atom, and numerically evaluate it using several target nuclei. The lepton flavor universality test of pion decay directly limits the ${\mu }^{-}\to e^{+}$ rate, and the maximally allowed ${\mu }^{-}\to e^{+}$ branching ratio is $\sim 10^{-18}$ under the various bounds on RPV parameters. We show that either ${\mu }^{-}\to e^{-}$ or ${\mu }^{-}\to e^{+}$ signals can be discovered in near future experiments. This indicates that parallel searches for these conversions will give us significant information on the pattern of coupling constants.

    hep-phPLB(2023)·2 citations
11. 11*

    Constraining heavy axion-like particles by energy deposition in Globular Cluster stars

    Giuseppe Lucente🇮🇹 · Oscar Straniero🇮🇹 · Pierluca Carenza🇸🇪 · Maurizio Giannotti🇺🇸 · Alessandro Mirizzi🇮🇹

    Heavy axion-like particles (ALPs), with masses up to a few 100 keV and coupled with photons can be efficiently produced in stellar plasmas, contributing to a significant energy-loss. This argument has been applied to helium burning stars in Globular Clusters (GCs) to obtain stringent bounds on the ALP-photon coupling $g_{a\gamma }$. However, for sufficiently large values of the ALP mass and coupling to photons, one should expect a significant fraction of ALPs to decay inside the star. These ALPs do not contribute to the energy loss but rather lead to an efficient energy transfer inside the star. We present a new ballistic recipe that covers both the energy-loss and energy-transfer regimes and we perform the first dedicated simulation of GC stars including the ALP energy transfer. This argument allows us to constrain ALPs with $m_a\lesssim 0.4$ MeV and $g_{a\gamma }\simeq 10^{-5}$ GeV${}^{-1}$, probing a section of the ALP parameter space informally known as "cosmological triangle". This region is particularly interesting since it has been excluded only using standard cosmological arguments that can be evaded in nonstandard scenarios.

    hep-phastro-ph.SRPRL(2022)·34 citations
12. 12*

    Creating Simple, Interpretable Anomaly Detectors for New Physics in Jet Substructure

    Layne Bradshaw🇺🇸 · Spencer Chang🇺🇸 · Bryan Ostdiek🇺🇸

    Anomaly detection with convolutional autoencoders is a popular method to search for new physics in a model-agnostic manner. These techniques are powerful, but they are still a "black box," since we do not know what high-level physical observables determine how anomalous an event is. To address this, we adapt a recently proposed technique by Faucett et al., which maps out the physical observables learned by a neural network classifier, to the case of anomaly detection. We propose two different strategies that use a small number of high-level observables to mimic the decisions made by the autoencoder on background events, one designed to directly learn the output of the autoencoder, and the other designed to learn the difference between the autoencoder's outputs on a pair of events. Despite the underlying differences in their approach, we find that both strategies have similar ordering performance as the autoencoder and independently use the same six high-level observables. From there, we compare the performance of these networks as anomaly detectors. We find that both strategies perform similarly to the autoencoder across a variety of signals, giving a nontrivial demonstration that learning to order background events transfers to ordering a variety of signal events.

    hep-phhep-exphysics.data-anPRD(2022)·33 citations
13. 13*

    Comments on "Direct measurement of the ionization quenching factor of nuclear recoils in germanium in the keV energy range"

    J.I. Collar🇺🇸 · C.M. Lewis🇺🇸

    We examine a recent measurement of the quenching factor (QF) in germanium at 80 K, noticing a number of inconsistencies capable of affecting a claimed agreement with Lindhard's ion-stopping formalism in the sub-keV nuclear recoil energy regime. Namely, an underestimated uncertainty in the energy scale and a missing correction for a large instrumental non-linearity in this scale able to severely distort the QF behavior at low energy, favoring reduced values. The discussion is expanded to inspect the impact of QF model selection on a study of neutrino electromagnetic properties using CE$\nu$NS data that supports a non-zero electric charge at the 3.5 $\sigma$ level.

    ↳ physics.ins-dethep-exhep-phnucl-ex4 citations
14. 14*

    Berry phase in the phase space worldline representation: the axial anomaly and classical kinetic theory

    Patrick Copinger🇹🇼 · Shi Pu🇨🇳

    The Berry phase is analyzed for Weyl and Dirac fermions in a phase space representation of the worldline formalism. Kinetic theories are constructed for both at a classical level. Whereas the Weyl fermion case reduces in dimension, resembling a theory in quantum mechanics, the Dirac fermion case takes on a manifestly Lorentz covariant form. To achieve a classical kinetic theory for the non-Abelian Dirac fermion Berry phase a spinor construction of Barut and Zanghi is utilized. The axial anomaly is also studied at a quantum level. It is found that under an adiabatic approximation, which is necessary for facilitating a classical kinetic theory, the index of the Dirac operator for massless fermions vanishes. Even so, similarities of an axial rotation to an exact non-covariant Berry phase transform are drawn by application of the Fujikawa method to the Barut and Zanghi spinors on the worldline.

    ↳ hep-thcond-mat.str-elhep-phPRD(2022)·12 citations
15. 15*

    Shell-model calculation of ${}^{100}$Mo double-$\beta$ decay

    L. Coraggio🇮🇹 · N. Itaco🇮🇹 · G. De Gregorio🇮🇹 · A. Gargano🇮🇹 · R. Mancino🇮🇹 · F. Nowacki🇫🇷

    For the first time, the calculation of the nuclear matrix element of the double-$\beta$ decay of ${}^{100}$Mo, with and without the emission of two neutrinos, is performed in the framework of the nuclear shell model. This task is accomplished starting from a realistic nucleon-nucleon potential, then the effective shell-model Hamiltonian and decay operators are derived within the many-body perturbation theory. The exotic features which characterize the structure of Mo isotopes -- such as shape coexistence and triaxiality softness -- push the shell-model computational problem beyond its present limits, making it necessary to truncate the model space. This has been done with the goal to preserve as much as possible the role of the rejected degrees of freedom in an effective approach that has been introduced and tested in previous studies. This procedure is grounded on the analysis of the effective single-particle energies of a large-scale shell-model Hamiltonian, that leads to a truncation of the number of the orbitals belonging to the model space. Then, the original Hamiltonian generates a new one by way of a unitary transformation onto the reduced model space, to retain effectively the role of the excluded single-particle orbitals. The predictivity of our calculation of the nuclear matrix element for the neutrinoless double-$\beta$ decay of ${}^{100}$Mo is supported by the comparison with experiment of the calculated spectra, electromagnetic transition strengths, Gamow-Teller transition strengths and the two-neutrino double-beta nuclear matrix elements.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2022)·54 citations
16. 16*

    Holographic Confinement of the Solitary Quark

    Saulo Diles🇧🇷 · Miguel Angel Martín Contreras🇨🇱 · Alfredo Vega🇨🇱

    Single quarks moving in the vacuum of confining gauge theories are stopped by a drag force. The holographic description relates the confining scale in the bulk geometry with a range of physical values for the drag force in the vacuum. The vacuum drag force acting on the isolated quark directly manifests quark confinement since it prevents the quark from walking freely in the vacuum. However, analytical expressions for the drag force as a function of the quark velocity were lacking. In the present work, we propose that the vacuum drag force is given by the regularized zero-temperature limit of the corresponding thermal drag force. Within this approach, we obtain the desired analytic expressions in two different holographic models: the quadratic dilaton and the D-instanton. In both cases, we find well-behaved functions belonging to their physical range of values.

    ↳ hep-thhep-phRev.Mex.Fis.Suppl.(2022)·0 citations
17. 17*

    Finite System Size Correction to NLO Scattering in ${\varphi }^4$ Theory

    W. A. Horowitz🇿🇦 · J. F. Du Plessis🇿🇦

    We compute $2\to 2$ scattering in massive ${\varphi }^4$ theory on ${\mathbb{R}}^{1,m}\times T^n$ to NLO. We perform the calculations using "denominator regularization" instead of the usual dimensional regularization, which allows for asymmetric configurations of the $T^n$. We give a transparent derivation of and equation for the analytic continuation of the generalized Epstein zeta function. We show that the Optical Theorem is satisfied and generalize a conjecture by Hardy on square counting functions. We comment on the implications.

    ↳ hep-thhep-phnucl-thPRD(2022)·17 citations
18. 18*

    Scalar-Mediated Quantum Forces Between Macroscopic Bodies and Interferometry

    Philippe Brax🇫🇷 · Sylvain Fichet🇧🇷

    We study the quantum force between classical objects mediated by massive scalar fields bilinearly coupled to matter. The existence of such fields is motivated by dark matter, dark energy, and by the possibility of a hidden sector beyond the Standard Model. We introduce the quantum work felt by an arbitrary (either rigid or deformable) classical body in the presence of the scalar and show that it is finite upon requiring conservation of matter. As an example, we explicitly show that the quantum pressure inside a Dirichlet sphere is finite -- up to renormalizable divergences. Inside the bodies the scalar acquires an effective mass, leading to a behaviour for the quantum force which, in the case of rigid bodies, is reminiscent of the transition between the Casimir and Casimir-Polder forces. With this method we compute the scalar-induced quantum force in simple planar geometries. In plane-point geometry we show how to compute the contribution of the quantum force to the phase shift observable in atom interferometers. We show that atom interferometry is likely to become a competitive search method for light particles bilinearly coupled to matter, provided that the interferometer arms have lengths below ~10 cm.

    ↳ hep-thhep-phquant-phPhys.Dark Univ.(2023)·14 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.