Mon·Jun 1, 2020Monday·June 1, 2020

1. 01*

   Observation of Odderon Effects at LHC energies -- A Real Extended Bialas-Bzdak Model Study

   T. Csorgo🇭🇺 · I. Szanyi🇭🇺

   The unitarily extended Bialas-Bzdak model of elastic proton-proton scattering is applied, without modifications, to describe the differential cross-section of elastic proton-antiproton collisions in the TeV energy range, and to extrapolate these differential cross-sections to LHC energies. In this model-dependent study we find that the differential cross-sections of elastic proton-proton collision data at 2.76 and 7 TeV energies differ significantly from the differential cross-section of elastic proton-antiproton collisions extrapolated to these energies. The elastic proton-proton differential cross-sections, extrapolated to 1.96 TeV energy with the help of this extended Bialas-Bzdak model do not differ significantly from that of elastic proton-antiproton collisions, within the theoretical errors of the extrapolation. Taken together these results provide a model-dependent, but statistically significant evidence for a crossing-odd component of the elastic scattering amplitude at the at least 7.08 sigma level. From the reconstructed Odderon and Pomeron amplitudes, we determine the $\sqrt{s}$ dependence of the corresponding total and differential cross-sections.

   hep-phEPJC(2021)·22 citations
2. 02*

   The Drell-Yan process with pions and polarized nucleons

   S. Bastami🇺🇸 · L. Gamberg🇺🇸 · B. Parsamyan🇮🇹 · B. Pasquini🇮🇹 · A. Prokudin🇺🇸 · P. Schweitzer🇺🇸

   The Drell-Yan process provides important information on the internal structure of hadrons including transverse momentum dependent parton distribution functions (TMDs). In this work we present calculations for all leading twist structure functions describing the pion induced Drell-Yan process. The non-perturbative input for the TMDs is taken from the light-front constituent quark model, the spectator model, and available parametrizations of TMDs extracted from the experimental data. TMD evolution is implemented at Next-to-Leading Logarithmic precision for the first time for all asymmetries. Our results are compatible with the first experimental information, help to interpret the data from ongoing experiments, and will allow one to quantitatively assess the models in future when more precise data will become available.

   hep-phhep-exnucl-thJHEP(2021)·25 citations
3. 03*

   Unitarization Technics in Hadron Physics with Historical Remarks

   J. A. Oller🇪🇸

   We review a series of unitarization techniques that have been used during the last decades, many of them in connection with the advent and development of current algebra and later of Chiral Perturbation Theory. Several methods are discussed like the generalized effective-range expansion, K-matrix approach, Inverse Amplitude Method, Padé approximants and the N/D method. More details are given for the latter though. We also consider how to implement them in order to correct by final-state interactions. In connection with this some other methods are also introduced like the expansion of the inverse of the form factor, the Omnés solution, generalization to coupled channels and the Khuri-Treiman formalism, among others.

   hep-phnucl-thSymmetry(2020)·51 citations
4. 04*

   Chiral Phase Transition in an Expanding Quark System

   Ziyue Wang🇨🇳 · Shuzhe Shi🇨🇦 · Pengfei Zhuang🇨🇳

   We investigate the influence of chiral symmetry which varies along the space-time evolution of the system by considering the chiral phase transition in an non-equilibrium expanding quark-antiquark system. The chiral symmetry is described by the mean field order parameter, whose values is the solution of a self-consistent equation, and affects the space-time evolution of the system through the force term in the Vlasov equation. The Vlasov equation and the gap equation are solved concurrently and continuously for a longitudinal boost-invariant and transversely rotation-invariant system. This numerical framework enables us to carefully investigate how the phase transition and collision affect the evolution of the system. It is observed that the chiral phase transition gives rise to a kink in the flow velocity, which is caused by the force term in the Vlasov equation. The kink is enhanced by larger susceptibility and tends to be smoothed out by non-equilibrium effect. The spatial phase boundary appears as a "wall" for the quarks, as the quarks with low momentum are bounced back, while those with high momentum go through the wall but are slowed down.

   hep-phnucl-thPRC(2021)·3 citations
5. 05*

   Impact of off-shell dynamics on the transport properties and the dynamical evolution of Charm Quarks at RHIC and LHC temperatures

   Maria Lucia Sambataro (1 and 2)🇮🇹 · Salvatore Plumari (1 and 2)🇮🇹 · Vincenzo Greco (1 and 2) ((1) Department of Physics and Astronomy 'E. Majorana', University of Catania, (2) Laboratori Nazionali del Sud, INFN-LNS)🇮🇹

   We evaluate drag and diffusion transport coefficients comparing a quasi-particle approximation with on-shell constituents of the QGP medium and a dynamical quasi-particles model with off-shell bulk medium at finite temperature T. We study the effects of the width $\gamma$ of the particles of the bulk medium on the charm quark transport properties exploring the range where $\gamma <M_{q,g}$. We find that off-shell effects are in general quite moderate and can induce a reduction of the drag coefficient at low momenta that disappear already at moderate momenta, $p\gtrsim 2-3\mathrm{GeV}$. We also observe a moderate reduction of the breaking of the Fluctuation-Dissipation theorem (FDT) at finite momenta. Moreover, we have performed a first study of the dynamical evolution of HQ elastic energy loss in a bulk medium at fixed temperature extending the Boltzmann (BM) collision integral to include off-shell dynamics. A comparison among the Langevin dynamics, the BM collisional integral with on-shell and the BM extension to off-shell dynamics shows that the evolution of charm energy when off-shell effects are included remain quite similar to the case of the on-shell BM collision integral.

   hep-phnucl-thEPJC(2020)·22 citations
6. 06*

   HL-LHC and ILC sensitivities in the hunt for heavy Higgs bosons

   H. Bahl🇩🇪 · P. Bechtle🇩🇪 · S. Heinemeyer🇪🇸 · S. Liebler🇩🇪 · T. Stefaniak🇩🇪 · G. Weiglein🇩🇪

   The prediction of additional Higgs bosons is one of the key features of physics beyond the Standard Model (SM) that gives rise to an extended Higgs sector. We assess the sensitivity of the Large Hadron Collider (LHC) in the high luminosity (HL) run alone and in combination with a possible future International Linear Collider (ILC) to probe heavy neutral Higgs bosons. We employ the Minimal Supersymmetric Standard Model (MSSM) as a framework and assume the light CP-even MSSM Higgs boson to be the Higgs boson observed at 125 GeV. We discuss the constraints on the MSSM parameter space arising from the precision measurements of the rates of the detected signal at 125 GeV and from direct searches for new heavy Higgs bosons in the ${\tau }^{+}{\tau }^{-}$, $b\bar{b}$ and di-Higgs ($hh$) final states. A new benchmark scenario for heavy Higgs searches in the $b\bar{b}$ channel is proposed in this context. For the future Higgs rate measurements at the HL-LHC and ILC two different scenarios are investigated, namely the case where the future rate measurements agree with the SM prediction and the case where the rates agree with the predictions of possible realizations of the MSSM Higgs sector in nature.

   hep-phEPJC(2020)·42 citations
7. 07*

   Helicity-dependent extension of the McLerran-Venugopalan model

   Florian Cougoulic🇺🇸 · Yuri V. Kovchegov🇺🇸

   We construct a generalization of the McLerran-Venugopalan (MV) model including helicity effects for a longitudinally polarized target (a proton or a large nucleus). The extended MV model can serve as the initial condition for the helicity generalization of the JIMWLK evolution equation constructed in our previous paper, as well as for calculation of helicity-dependent observables in the quasi-classical approximation to QCD.

   hep-phhep-exnucl-exnucl-thNPA(2020)·55 citations
8. 08*

   Effects of Longitudinal Short-Distance Constraints on the Hadronic Light-by-Light Contribution to the Muon $g-2$

   Jan Lüdtke🇦🇹 · Massimiliano Procura🇦🇹

   We present a model-independent method to estimate the effects of short-distance constraints (SDCs) on the hadronic light-by-light contribution to the muon anomalous magnetic moment $a_{\mu }^{\text{HLbL}}$. The relevant loop integral is evaluated using multi-parameter families of interpolation functions, which satisfy by construction all constraints derived from general principles and smoothly connect the low-energy region with those where either two or all three independent photon virtualities become large. In agreement with other recent model-based analyses, we find that the SDCs and thus the infinite towers of heavy intermediate states that are responsible for saturating them have a rather small effect on $a_{\mu }^{\text{HLbL}}$. Taking as input the known ground-state pseudoscalar pole contributions, we obtain that the longitudinal SDCs increase $a_{\mu }^{\text{HLbL}}$ by $(9.1\pm 5.0)\times 10^{-11}$, where the isovector channel is responsible for $(2.6\pm 1.5)\times 10^{-11}$. More precise estimates can be obtained with our method as soon as further accurate, model-independent information about important low-energy contributions from hadronic states with masses up to 1-2 GeV become available.

   hep-phnucl-thEPJC(2020)·69 citations
9. 09*

   Resummation of non-global logarithms in cross sections with massive particles

   Marcel Balsiger🇨🇭 · Thomas Becher🇨🇭 · Andrea Ferroglia🇺🇸

   A factorization formalism for jet processes involving massive colored particles such as the top quark is developed, extending earlier results for the massless case. The factorization of soft emissions from the underlying hard process is implemented in an effective field theory framework, which forms the basis for the resummation of large logarithms. The renormalization group evolution giving rise to non-global logarithms is implemented into a parton shower code in the large-$N_c$ limit. After a comparison of the massive and massless radiations patterns, the cross section for $t\bar{t}$ production with a veto on additional central jet activity is computed, taking into account radiation both from the production and the decay of the top quarks. The resummation of the leading logarithms leads to an improved description of ATLAS measurements at $\sqrt{s}=7\mathrm{TeV}$.

   hep-phJHEP(2020)·23 citations
10. 10*

    Light-nuclei production and search for the QCD critical point

    Edward Shuryak🇺🇸 · Juan M. Torres-Rincon🇩🇪

    We discuss the potential of light-nuclei measurement in heavy-ion collisions at intermediate energies for the search of the hypothetical QCD critical end-point. A previous proposal based on neutron density fluctuations has brought appealing experimental evidences of a maximum in a ratio involving tritons, protons and deuterons, ${\mathcal{O}}_{tpd}$. However these results are difficult to reconcile with the state-of-the-art statistical thermal model predictions. Based on the idea that the QCD critical point can lead to a substantial attraction among nucleons, we propose new ratios involving ${}^4$He in which the maximum would be more evident. We argue that the experimental extraction is feasible by presenting actual measurements at low and high collision energies. We also illustrate the possible behavior of these ratios at intermediate energies applying the semiclassical method based on flucton paths using preliminary STAR data for ${\mathcal{O}}_{tpd}$.

    ↳ nucl-thhep-phnucl-exEPJA(2020)·31 citations
11. 11*

    Few-body systems consisting of mesons

    A. Martinez Torres🇧🇷 · K. P. Khemchandani🇧🇷 · L. Roca🇪🇸 · E. Oset🇪🇸

    We present a work which is meant to inspire the few-body practitioners to venture into the study of new, more exotic, systems and to hadron physicists, working mostly on two-body problems, to move in the direction of studying related few-body systems. For this purpose we devote the discussions in the introduction to show how the input two-body amplitudes can be easily obtained using techniques of the chiral unitary theory, or its extensions to the heavy quark sector. We then briefly explain how these amplitudes can be used to solve the Faddeev equations or a simpler version obtained by treating the three-body scattering as that of a particle on a fixed center. Further, we give some examples of the results obtained by studying systems involving mesons. We have also addressed the field of many meson systems, which is currently almost unexplored, but for which we envisage a bright future. Finally, we give a complete list of works dealing with unconventional few-body systems involving one or several mesons, summarizing in this way the findings on the topic, and providing a motivation for those willing to investigate such systems.

    ↳ nucl-thhep-phFew Body Syst.(2020)·49 citations
12. 12*

    Abelian-Higgs cosmic string evolution with multiple GPUs

    J. R. C. C. C. Correia🇵🇹 · C. J. A. P. Martins🇵🇹

    Topological defects form at cosmological phase transitions by the Kibble mechanism. Cosmic strings and superstrings can lead to particularly interesting astrophysical and cosmological consequences, but this study is is currently limited by the availability of accurate numerical simulations, which in turn is bottlenecked by hardware resources and computation time. Aiming to eliminate this bottleneck, in recent work we introduced and validated a GPU-accelerated evolution code for local Abelian-Higgs strings networks. While this leads to significant gains in speed, it is still limited by the physical memory available on a graphical accelerator. Here we report on a further step towards our main goal, by implementing and validating a multiple GPU extension of the earlier code, and further demonstrate its good scalability, both in terms of strong and weak scaling. A $8192^3$ production run, using $4096$ GPUs, runs in $33.2$ minutes of wall clock time on the Piz Daint supercomputer.

    ↳ physics.comp-phastro-ph.COhep-phAstron.Comput.(2021)·25 citations
13. 13*

    Measurement of Exclusive ${\pi }^{+}{\pi }^{-}$ and ${\rho }^0$ Meson Photoproduction at HERA

    H1 collaboration

    Exclusive photoproduction of ${\rho }^0(770)$ mesons is studied using the H1 detector at the $ep$ collider HERA. A sample of about 900000 events is used to measure single- and double-differential cross sections for the reaction $\gamma p\to {\pi }^{+}{\pi }^{-}Y$. Reactions where the proton stays intact ($m_Y=m_p$) are statistically separated from those where the proton dissociates to a low-mass hadronic system ($m_p<m_Y<10$ GeV). The double-differential cross sections are measured as a function of the invariant mass $m_{\pi \pi }$ of the decay pions and the squared $4$-momentum transfer $t$ at the proton vertex. The measurements are presented in various bins of the photon-proton collision energy $W_{\gamma p}$. The phase space restrictions are $0.5<m_{\pi \pi }<2.2$ GeV, $|t|<1.5$ GeV${}^2$, and $20<W_{\gamma p}<80$ GeV. Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the $m_{\pi \pi }$ dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the ${\rho }^0(770)$ meson mass and width at $m_{\rho }=770.8{}_{-2.7}^{+2.6}$ (tot) MeV and ${\Gamma }_{\rho }=151.3{}_{-3.6}^{+2.7}$ (tot) MeV, respectively. The model is used to extract the ${\rho }^0(770)$ contribution to the ${\pi }^{+}{\pi }^{-}$ cross sections and measure it as a function of $t$ and $W_{\gamma p}$. In a Regge asymptotic limit in which one Regge trajectory $\alpha (t)$ dominates, the intercept $\alpha (t=0)=1.0654{}_{-0.0067}^{+0.0098}$ (tot) and the slope ${\alpha }^{\prime }(t=0)=0.233{}_{-0.074}^{+0.067}$ (tot) GeV${}^{-2}$ of the $t$ dependence are extracted for the case $m_Y=m_p$.

    ↳ hep-exhep-phEPJC(2020)·36 citations
14. 14*

    No short hair behaviors of ultra-compact stars

    Yan Peng🇨🇳

    In the black hole spacetime, a no short hair theorem was proved, which states that the effective radius of black hole hairs must extend beyond the null circular orbit. In the present paper, in the horizonless gravity, we find a similar no short hair behavior that the effective radius of matter fields must also extend beyond the null circular orbit of ultra-compact stars.

    ↳ gr-qchep-phhep-thEPJC(2021)·5 citations
15. 15*

    Chandrasekhar limit for rotating quark stars

    Ashadul Halder🇮🇳 · Shibaji Banerjee🇮🇳 · Sanjay K. Ghosh🇮🇳 · Sibaji Raha🇮🇳

    The limiting mass is a significant characteristic for compact exotic stars. In the case of quark stars, the limiting mass can be expressed in terms of fundamental constants and the Bag constant. In the present work, using bag model description, the maximum mass of a rotating quark star is found to depend on the rotational frequency apart from other fundamental parameters. The analytical results obtained agree with the results of several relevant numerical estimates as well as observational evidences.

    ↳ astro-ph.HEhep-phPRC(2021)·5 citations
16. 16*

    Equivalence of inflationary models between the metric and Palatini formulation of scalar-tensor theories

    Laur Järv🇪🇪 · Alexandros Karam🇪🇪 · Aleksander Kozak🇵🇱 · Angelos Lykkas🇬🇷 · Antonio Racioppi🇪🇪 · Margus Saal🇪🇪

    With a scalar field non-minimally coupled to curvature, the underlying geometry and variational principle of gravity - metric or Palatini - becomes important and makes a difference, as the field dynamics and observational predictions generally depend on this choice. In the present paper we describe a classification principle which encompasses both metric and Palatini models of inflation, employing the fact that inflationary observables can be neatly expressed in terms of certain quantities which remain invariant under conformal transformations and scalar field redefinitions. This allows us to elucidate the specific conditions when a model yields equivalent phenomenology in the metric and Palatini formalisms, and also to outline a method how to systematically construct different models in both formulations that produce the same observables.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·63 citations
17. 17*

    Lattice-QCD Calculations of TMD Soft Function Through Large-Momentum Effective Theory

    Qi-An Zhang🇨🇳 · Jun Hua🇨🇳 · Yikai Huo🇨🇳 · Xiangdong Ji🇺🇸 · Yizhuang Liu🇨🇳 · Yu-Sheng Liu🇨🇳 · Maximilian Schlemmer🇩🇪 · Andreas Schäfer🇩🇪 · Peng Sun🇨🇳 · Wei Wang🇨🇳 · Yi-Bo Yang (Lattice Parton Collaboration)🇨🇳

    The transverse-momentum-dependent (TMD) soft function is a key ingredient in QCD factorization of Drell-Yan and other processes with relatively small transverse momentum. We present a lattice QCD study of this function at moderately large rapidity on a 2+1 flavor CLS dynamic ensemble with $a=0.098$ fm. We extract the rapidity-independent (or intrinsic) part of the soft function through a large-momentum-transfer pseudo-scalar meson form factor and its quasi-TMD wave function using leading-order factorization in large-momentum effective theory. We also investigate the rapidity-dependent part of the soft function---the Collins-Soper evolution kernel---based on the large-momentum evolution of the quasi-TMD wave function.

    ↳ hep-lathep-phPRL(2020)·142 citations
18. 18*

    Constraints on dark matter-nucleon effective couplings in the presence of kinematically distinct halo substructures using the DEAP-3600 detector

    P. Adhikari🇨🇦 · R. Ajaj🇨🇦 · C. E. Bina🇨🇦 · W. Bonivento🇮🇹 · M. G. Boulay🇨🇦 · M. Cadeddu🇮🇹 · B. Cai🇨🇦 · M. Cárdenas-Montes🇪🇸 · S. Cavuoti🇮🇹 · Y. Chen🇨🇦 · B. T. Cleveland🇨🇦 · J. M. Corning🇨🇦 and 72 other authors

    DEAP-3600 is a single-phase liquid argon detector aiming to directly detect Weakly Interacting Massive Particles (WIMPs), located at SNOLAB (Sudbury, Canada). After analyzing data taken during the first year of operation, a null result was used to place an upper bound on the WIMP-nucleon spin-independent, isoscalar cross section. This study reinterprets this result within a Non-Relativistic Effective Field Theory framework, and further examines how various possible substructures in the local dark matter halo may affect these constraints. Such substructures are hinted at by kinematic structures in the local stellar distribution observed by the Gaia satellite and other recent astronomical surveys. These include the Gaia Sausage (or Enceladus), as well as a number of distinct streams identified in recent studies. Limits are presented for the coupling strength of the effective contact interaction operators ${\mathcal{O}}_1$, ${\mathcal{O}}_3$, ${\mathcal{O}}_5$, ${\mathcal{O}}_8$, and ${\mathcal{O}}_{11}$, considering isoscalar, isovector, and xenonphobic scenarios, as well as the specific operators corresponding to millicharge, magnetic dipole, electric dipole, and anapole interactions. The effects of halo substructures on each of these operators are explored as well, showing that the ${\mathcal{O}}_5$ and ${\mathcal{O}}_8$ operators are particularly sensitive to the velocity distribution, even at dark matter masses above 100 GeV/$c^2$.

    ↳ astro-ph.COastro-ph.GAhep-exhep-phPRD(2020)·56 citations
19. 19*

    Running the gamut of high energy nuclear collisions

    Bjoern Schenke🇺🇸 · Chun Shen🇺🇸 · Prithwish Tribedy🇺🇸

    We present calculations of bulk properties and multiparticle correlations in a large variety of collision systems within a hybrid formalism consisting of IP-Glasma initial conditions, MUSIC viscous relativistic hydrodynamics, and UrQMD microscopic hadronic transport. In particular, we study heavy ion collisions at the Large Hadron Collider (LHC), including Pb+Pb, Xe+Xe, and O+O collisions, and Au+Au, U+U, Ru+Ru, Zr+Zr, and O+O collisions at the Relativistic Heavy Ion Collider (RHIC). We further study asymmetric systems, including p+Au, d+Au, ${}^3$He+Au, and p+Pb collisions at various energies as well as p+p collisions at 0.5 and 13 TeV. We describe experimental observables in all heavy ion systems well with one fixed set of parameters, validating the energy and system dependence of the framework. Many observables in the smaller systems are also well described, although they test the limits of the model. Calculations of O+O collisions provide predictions for potential future runs at RHIC and LHC.

    ↳ nucl-thhep-phnucl-exPRC(2020)·225 citations
20. 20*

    Probing short-range correlations in the deuteron via incoherent diffractive $J/\psi$ production with spectator tagging at the EIC

    Zhoudunming Tu🇺🇸 · Alexander Jentsch🇺🇸 · Mark Baker🇺🇸 · Liang Zheng🇨🇳 · Jeong-Hun Lee🇺🇸 · Raju Venugopalan🇺🇸 · Or Hen🇺🇸 · Douglas Higinbotham🇺🇸 · Elke-Caroline Aschenauer🇺🇸 · Thomas Ullrich🇺🇸

    Understanding the role of Quantum Chromodynamics in generating nuclear forces is important for uncovering the mechanism of short-ranged nuclear interactions and their manifestation in short range correlations (SRC). The future Electron-Ion-Collider (EIC) at Brookhaven National Laboratory in the US will provide an unprecedented opportunity to systematically investigate the underlying physics of SRC for energies and kinematic regions that are otherwise impossible to reach. We study SRCs in electron-deuteron scattering events using the Monte Carlo event generator BeAGLE. Specifically, we investigate the sensitivity of observables to high internal nucleon momentum in incoherent diffractive $J/\psi$ vector meson production. In a plane wave impulse approximation, the initial state deuteron wavefunction can be accessed directly from the four-momentum of the spectator nucleon. We use realistic physics simulations and far-forward detector simulations of the EIC to fully reveal the physics potential of this exclusive process. In particular, we provide the luminosity and detector requirements necessary to study SRCs in the deuteron at an EIC.

    ↳ nucl-exhep-exhep-phnucl-thPLB(2020)·40 citations
21. 21*

    Black Hole Metamorphosis and Stabilization by Memory Burden

    Gia Dvali🇩🇪 · Lukas Eisemann🇩🇪 · Marco Michel🇩🇪 · Sebastian Zell🇨🇭

    Systems of enhanced memory capacity are subjected to a universal effect of memory burden, which suppresses their decay. In this paper, we study a prototype model to show that memory burden can be overcome by rewriting stored quantum information from one set of degrees of freedom to another one. However, due to a suppressed rate of rewriting, the evolution becomes extremely slow compared to the initial stage. Applied to black holes, this predicts a metamorphosis, including a drastic deviation from Hawking evaporation, at the latest after losing half of the mass. This raises a tantalizing question about the fate of a black hole. As two likely options, it can either become extremely long lived or decay via a new classical instability into gravitational lumps. The first option would open up a new window for small primordial black holes as viable dark matter candidates.

    ↳ hep-thastro-ph.COgr-qchep-ph+1PRD(2020)·177 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.