Tue·Oct 20, 2020Tuesday·October 20, 2020

1. 01*

   Revisiting QCD corrections to the forward-backward charge asymmetry of heavy quarks in electron-positron collisions at the Z pole: really a problem?

   Juan Alcaraz Maestre (CIEMAT-Madrid)🇪🇸

   We review in some detail the QCD corrections to the measurement of the forward-backward charge asymmetry of heavy quarks in the ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to \mathrm{Q}\overline{\mathrm{Q}}(\mathrm{g})$ process at the Z pole. We show that the size of these corrections can be reduced by an order of magnitude by using simple cuts on jet acollinearity. Such a reduction is expected to lead to systematic uncertainties at the $\Delta {\mathrm{A}}_{\mathrm{FB}}^{0,\mathrm{Q}}\approx 10^{-4}$ level, opening up the path to high precision electroweak measurements with heavy flavors at future high luminosity ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ colliders like the FCC-ee.

   hep-phhep-ex10 citations
2. 02*

   Searches for new sources of CP violation using molecules as quantum sensors

   N. R. Hutzler🇺🇸 · A. Borschevsky🇳🇱 · D. Budker🇩🇪 · D. DeMille🇺🇸 · V. V. Flambaum🇦🇺 · G. Gabrielse🇺🇸 · R. F. Garcia Ruiz🇺🇸 · A. M. Jayich🇺🇸 · L. A. Orozco🇺🇸 · M. Ramsey-Musolf🇺🇸 · M. Reece🇺🇸 · M. S. Safronova🇺🇸 and 3 other authors

   We discuss how molecule-based searches offer complementary probes to study the violation of fundamental symmetries. These experiments have the potential to probe not only the electron EDM, but also hadronic CPV phenomena. Future experimental developments will offer generic sensitivity to probe flavor neutral sources of both leptonic and hadronic CPV at scales of $\ge$ 100 TeV, and flavor changing CPV at scales of $\ge$ 1000 TeV.

   hep-phhep-exnucl-exSnowmass LOI 2020·18 citations
3. 03*

   Weak-basis invariants and CP conservation in the leptonic sector with Majorana neutrinos

   Bingrong Yu🇨🇳 · Shun Zhou🇨🇳

   In this talk, we present a recent investigation of the sufficient and necessary conditions for CP conservation in the leptonic sector with massive Majorana neutrinos in terms of CP-odd weak-basis invariants. The number of weak-basis invariants to guarantee CP conservation in the leptonic sector is clarified and a new set of invariants are advocated for the description of CP conservation, given the physical parameters in their experimentally allowed regions.

   hep-phPoS(2021)·5 citations
4. 04*

   Searching for charged lepton flavor violation at $ep$ colliders

   Stefan Antusch🇨🇭 · A. Hammad🇨🇭 · Ahmed Rashed🇺🇸

   We investigate the sensitivity of electron-proton ($ep$) colliders for charged lepton flavor violation (cLFV) in an effective theory approach, considering a general effective Lagrangian for the conversion of an electron into a muon or a tau via the effective coupling to a neutral gauge boson or a neutral scalar field. For the photon, the $Z$ boson and the Higgs particle of the Standard Model, we present the sensitivities of the LHeC for the coefficients of the effective operators, calculated from an analysis at the reconstructed level. As an example model where such flavor changing neutral current (FCNC) operators are generated at loop level, we consider the extension of the Standard Model by sterile neutrinos. We show that the LHeC could already probe the LFV conversion of an electron into a muon beyond the current experimental bounds, and could reach more than an order of magnitude higher sensitivity than the present limits for LFV conversion of an electron into a tau. We discuss that the high sensitivities are possible because the converted charged lepton is dominantly emitted in the backward direction, enabling an efficient separation of the signal from the background.

   hep-phJHEP(2021)·14 citations
5. 05*

   Generalized Crewther relation and a novel demonstration of the scheme independence of commensurate scale relations up to all orders

   Xu-Dong Huang🇨🇳 · Xing-Gang Wu🇨🇳 · Qing Yu🇨🇳 · Xu-Chang Zheng🇨🇳 · Jun Zeng🇨🇳 · Jian-Ming Shen🇨🇳

   In the paper, we make a detailed study on the generalized Crewther Relation (GCR) between the Adler function ($D$) and the Gross-Llewellyn Smith sum rules coefficient ($C^{\mathrm{GLS}}$) by using the newly suggested single-scale approach of the principle of maximum conformality (PMC). The resultant GCR is scheme-independent, whose residual scale dependence due to unknown higher-order terms are highly suppressed. Thus a precise test of QCD theory without renormalization scheme and scale ambiguities can be achieved by comparing with the data. Moreover, a demonstration of the scheme independence of commensurate scale relation up to all orders has been presented. And as the first time, the Pade approximation approach has been adopted for estimating the unknown $5_{\mathrm{th}}$-loop contributions from the known four-loop perturbative series.

   hep-phCPC(2021)·12 citations
6. 06*

   Quark Gluon Plasma (QGP) evolution under loop corrections

   K K Gupta🇮🇳 · Agam K Jha🇮🇳 · S. Somorendro Singh🇮🇳

   We review free energy evolution of QGP (Quark-gluon plasma) under zero-loop, one loop and two loop corrections in the mean field potential. The free energies of QGP under the comparison of zero-loop and loop corrections of the interacting potential among the quarks, anti-quarks and gluons are shown. We observe that the formation of stable QGP droplet is dependent on the loop corrections with the different parametrization values of fluid. With the increase in the parametrization value, stability of droplet formation increases with smaller size of droplet. This indicates that the formation of QGP droplet can be signified more importantly by the parametrization value like the Reynold number in fluid dynamics. It means that there may be different phenomenological parameter to define the stable QGP droplet when QGP fluid is studied under loop corrections.

   hep-ph0 citations
7. 07*

   Analysis of the triply-heavy baryon states with the QCD sum rules

   Zhi-Gang Wang🇨🇳

   In this article, we restudy the mass spectrum of the ground state triply-heavy baryon states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 6 in a consistent way and preforming a novel analysis. It is the first time to take into account the three-gluon condensates in the QCD sum rules for the triply-heavy baryon states.

   hep-phAAPPS Bull.(2021)·34 citations
8. 08*

   Fully-heavy tetraquark spectra and production at hadron colliders

   Ruilin Zhu🇨🇳

   Motivated by the observation of exotic structure around 6900MeV in the $J/\psi$-pair mass spectrum using proton-proton collision data by the LHCb collaboration, we study the spectra of fully-heavy tetraquarks within Bethe-Salpeter equation and Regge trajectory relation. The $X(6900)$ may be explained as a radially excited state with quark content $cc\bar{c}\bar{c}$ and spin-parity $0^{++}(3S)$ or $2^{++}(3S)$ or an orbitally excited $2P$ state. New $cc\bar{c}\bar{c}$ structures around 6.0GeV, 6.5GeV, and 7.1GeV are predicted together. Other $bb\bar{b}\bar{b}$ and $bc\bar{b}\bar{c}$ structures which may be experimentally prominent are discussed. On the other hand, the fully-heavy S-wave tetraquark productions at hadron colliders are investigated and their cross-sections are obtained.

   hep-phhep-exnucl-exNPB(2021)·120 citations
9. 09*

   Split Left-Right Symmetry and Scotogenic Quark and Lepton Masses

   Ernest Ma (UC Riverside)🇺🇸

   A model of split left-right symmetry is proposed, where the first family of quarks and leptons transforms under $SU(2{)}_R$ but the heavier two families do not. The Higgs scalar sector consists only of an $SU(2{)}_L$ doublet and an $SU(2{)}_R$ doublet. The $u,d$ quarks and the electron, as well as the neutrinos, are massless at tree level, but become massive radiatively through their interactions with a simple dark sector. Verifiable consequences include $Z^{\prime }$ and Higgs properties, neutrino mixing and rare decays, etc.

   hep-phPLB(2020)·6 citations
10. 10*

    Weak Decays of Doubly Heavy Baryons: ${\mathcal{B}}_{cc}\to \mathcal{B}{D}^{(\ast )}$

    Run-Hui Li🇨🇳 · Juan-Juan Hou🇨🇳 · Bei He🇨🇳 · Ya-Ru Wang🇨🇳

    The discovery of ${\Xi }_{cc}^{++}$ has inspired new interest in studying doubly heavy baryons. In this study, the weak decays of a doubly charmed baryon ${\mathcal{B}}_{cc}$ to a light baryon $\mathcal{B}$ and a charm meson $D^{(\ast )}$ (either a pseudoscalar or a vector one) are calculated. Following our previous work, we calculate the short distance contributions under the factorization hypothesis, whereas the long distance contributions are modeled as the final state interactions which are calculated with the one particle exchange model. We find that the ${\mathcal{B}}_{cc}\to \mathcal{B}{D}^{\ast }$ decays' branching ratios are obviously larger, as they receive contributions of more polarization states. Among the decays that we investigate, the following have the largest branching fractions: $\mathcal{B}\mathcal{R}({\Xi }_{cc}^{++}\to {\Sigma }^{+}{D}^{\ast +})\in [0.46\%,3.33\%]$ estimated with ${\tau }_{{\Xi }_{cc}^{++}}=256$ fs; $\mathcal{B}\mathcal{R}({\Xi }_{cc}^{+}\to \Lambda D^{\ast +})\in [0.38\%,2.63\%]$ and $\mathcal{B}\mathcal{R}({\Xi }_{cc}^{+}\to {\Sigma }^0{D}^{\ast +})\in [0.45\%,3.16\%]$ with ${\tau }_{{\Xi }_{cc}^{+}}=45$ fs; and $\mathcal{B}\mathcal{R}({\Omega }_{cc}^{+}\to {\Xi }^0{D}^{\ast +})\in [0.27\%,1.03\%]$, $\mathcal{B}\mathcal{R}({\Omega }_{cc}^{+}\to {\Xi }^0{D}^{+})\in [0.07\%,0.44\%]$ and $\mathcal{B}\mathcal{R}({\Omega }_{cc}^{+}\to {\Sigma }^0{D}^{\ast +})\in [0.06\%,0.45\%]$ with ${\tau }_{{\Omega }_{cc}^{+}}=75$ fs. By comparing the decay widths of pure color commensurate channels with those of pure bow-tie ones, we find that the bow-tie mechanism plays an important role in charm decays.

    hep-phCPC(2021)·21 citations
11. 11*

    Mass spectrum and strong decays of tetraquark $\bar{c}\bar{s}qq$ states

    Guang-Juan Wang🇨🇳 · Lu Meng🇨🇳 · Li-Ye Xiao🇨🇳 · Makoto Oka🇯🇵 · Shi-Lin Zhu🇨🇳

    We systematically study the mass spectrum and strong decays of the S-wave $\bar{c}\bar{s}qq$ states in the compact tetraquark scenario with the quark model. The key ingredients of the model are the Coulomb, the linear confinement, and the hyperfine interactions. The hyperfine potential leads to the mixing between different color configurations, as well as the large mass splitting between the two ground states with $I(J^P)=0(0^{+})$ and $I(J^P)=1(0^{+})$. We calculate their strong decay amplitudes into the ${\bar{D}}^{(\ast )}{K}^{(\ast )}$ channels with the wave functions from the mass spectrum calculation and the quark interchange method. We examine the interpretation of the recently observed $X_0(2900)$ as a tetraquark state. The mass and decay width of the $I(J^P)=1(0^{+})$ state are $M=2941$ MeV and ${\Gamma }_X=26.6$ MeV, respectively, which indicates that it might be a good candidate for the $X_0(2900)$. Meanwhile, we also obtain an isospin partner state $I(J^P)=0(0^{+})$ with $M=2649$ MeV and ${\Gamma }_{X\to \bar{D}K}=48.1$ MeV, respectively. Future experimental search for $X(2649)$ will be very helpful.

    hep-phhep-exhep-latEPJC(2021)·63 citations
12. 12*

    NLO Corrections to Light-Quark Mixed QCD-EW Contributions to Higgs Production

    Matteo Becchetti🇮🇹 · Roberto Bonciani🇮🇹 · Vittorio Del Duca🇨🇭 · Valentin Hirschi🇨🇭 · Francesco Moriello🇨🇭 · Armin Schweitzer🇨🇭

    We present for the first time the exact NLO QCD corrections to the light-quark part of the mixed QCD-EW contributions to Higgs production via gluon fusion at LHC13, with exact EW-boson mass dependence. The relevant two-loop real-emission matrix element is computed using a dynamic one-dimensional series expansion strategy whose stability and speed allows for a numerical phase-space integration using local IR subtraction counterterms. For ${\mu }_R={\mu }_F=M_H$, we find: \begin{equation}\sigma^{(\alpha_s^2\alpha^2+\alpha_s^3\alpha^2)}_{g g\rightarrow H+X} = 1.467(2)^{\;+18.7\%}_{\;-14.6\%}\;(\mu_R\;\text{var.})\;\pm 2\%\;(\text{PDF}) \ \textrm{pb},\end{equation} which we use to provide the best result including an estimate of suppressed contributions: \begin{equation}\sigma^{(\text{EW},\textrm{best})}_{p p\rightarrow H+X} = 2.11 \pm 0.28 \ (\textrm{theory}) \ \mathrm{pb}.\end{equation}

    hep-phPRD(2021)·45 citations
13. 13*

    The high energy spectrum of internal positrons from radiative muon capture on nuclei

    Ryan Plestid🇺🇸 · Richard J. Hill🇺🇸

    The Mu2e and COMET collaborations will search for nucleus-catalyzed muon conversion to positrons (${\mu }^{-}\to e^{+}$) as a signal of lepton number violation. A key background for this search is radiative muon capture where either: 1) a real photon converts to an $e^{+}{e}^{-}$ pair "externally" in surrounding material, or 2) a virtual photon mediates the production of an $e^{+}{e}^{-}$ pair "internally". If the $e^{+}$ has an energy approaching the signal region then it can serve as an irreducible background. In this work we describe how the near end-point internal positron spectrum can be related to the real photon spectrum from the same nucleus, which encodes all non-trivial nuclear physics.

    hep-phhep-exnucl-thPRD(2021)·5 citations
14. 14*

    Luminous solar neutrinos II: Mass-mixing portals

    Ryan Plestid🇺🇸

    Solar neutrinos can be efficiently upscattered to MeV scale heavy neutral leptons (HNLs) within the Earth's mantle. HNLs can then decay to electron-positron pairs leading to energy deposition inside large-volume detectors. In this paper we consider mass-portal upscattering of solar neutrinos to HNLs of mass 20 MeV $\ge m_N\ge 2m_e$. The large volume of the Earth compensates for the long decay-length of the HNLs leading to observable rates of $N\to {\nu }_{\alpha }{e}^{+}{e}^{-}$ in large volume detectors. We find that searches for mantle-upscattered HNLs can set the novel limits on mixing with third generation leptons, $|U_{\tau N}|$ for masses in the MeV regime; sensitivity to mixing with first- and second-generation leptons is not competitive with existing search strategies.

    hep-phastro-ph.HEastro-ph.SRPRD(2021)·29 citations
15. 15*

    Decaying dark matter, the $H_0$ tension, and the lithium problem

    Luis A. Anchordoqui🇺🇸

    It has long been known that the sharpened tension between the observed and inferred values of the Hubble constant $H_0$ can be alleviated if a fraction of dark matter particles of type $\chi$ were produced non-thermally in association with photons $\gamma$ through the decays of a heavy and relatively long-lived state, viz. $X\to \chi +\gamma$. It was recently proposed that this model can also resolve the longstanding lithium problem if $M=4$ MeV and $m=0.04$ keV, where $M$ and $m$ are respectively the masses of $X$ and $\chi$. We confront this proposal with experiment and demonstrate that cold dark matter decaying before recombination cannot resolve the $H_0$ problem. Moreover, we show that the best case scenario for alleviating the $H_0$ tension within the context of cold dark matter decaying before recombination arises when the particles decay exclusively into dark radiation, while leaving completely unmodified the production of light elements. To this end we calculate the general functional form describing the number of equivalent light neutrino species $\Delta N_{eff}$ carried by $\chi$. We show that to resolve the $H_0$ tension at the $1\sigma$ level a 55% correction in $m$ is needed and that the required $\Delta N_{eff}$ is excluded at 95% CL by Planck data. We argue in favor of a more complex model of dynamical dark matter to relax the $H_0$ tension.

    hep-phastro-ph.COPRD(2021)·28 citations
16. 16*

    Principle of Multiple Point Criticality in Multi-Scalar Dark Matter Models

    Kristjan Kannike🇪🇪 · Niko Koivunen🇪🇪 · Martti Raidal🇪🇪

    The principle of multiple point criticality (PMPC), which allowed the prediction of the Higgs boson mass before its discovery, has so far been applied to radiatively generated vacua. If this principle is fundamental, following from some presently unknown underlying physics, the PMPC must apply to all vacua, including the multiple vacua of multi-scalar models dominated by tree-level terms. We first motivate this idea and then exemplify it by applying the PMPC to various realizations of singlet scalar dark matter models. We derive constraints on the dark matter properties from the requirement of degenerate vacua and show that some scalar dark matter models are ruled out by the PMPC, while in others the allowed parameters space is constrained.

    hep-phNPB(2021)·14 citations
17. 17*

    Self-interacting Dark Matter from Primordial Black Holes

    Nicolás Bernal🇨🇴 · Óscar Zapata🇨🇴

    The evaporation of primordial black holes (PBH) with masses ranging from $\sim 10^{-1}$ to $\sim 10^9$ g could have generated the whole observed dark matter (DM) relic density. It is typically assumed that after being produced, its abundance freezes and remains constant. However, thermalization and number-changing processes in the dark sector can have a strong impact, in particular enhancing the DM population by several orders of magnitude. Here we estimate the boost from general arguments such as the conservation of energy and entropy, independently from the underlying particle physics details of the dark sector. Two main consequences can be highlighted: $i)$ As the DM abundance is increased, a smaller initial energy density of PBHs is required. $ii)$ Thermalization in the dark sector decreases the mean DM kinetic energy, relaxing the bound from structure formation and hence, allowing light DM with mass in the keV ballpark.

    hep-phJCAP(2021)·87 citations
18. 18*

    Enhancing searches for resonances with machine learning and moment decomposition

    Ouail Kitouni🇺🇸 · Benjamin Nachman🇺🇸 · Constantin Weisser🇺🇸 · Mike Williams🇺🇸

    A key challenge in searches for resonant new physics is that classifiers trained to enhance potential signals must not induce localized structures. Such structures could result in a false signal when the background is estimated from data using sideband methods. A variety of techniques have been developed to construct classifiers which are independent from the resonant feature (often a mass). Such strategies are sufficient to avoid localized structures, but are not necessary. We develop a new set of tools using a novel moment loss function (Moment Decomposition or MoDe) which relax the assumption of independence without creating structures in the background. By allowing classifiers to be more flexible, we enhance the sensitivity to new physics without compromising the fidelity of the background estimation.

    hep-phhep-exphysics.data-anJHEP(2020)·32 citations
19. 19*

    Present and future status of light dark matter models from cosmic-ray electron upscattering

    James B. Dent🇺🇸 · Bhaskar Dutta🇺🇸 · Jayden L. Newstead🇦🇺 · Ian M. Shoemaker🇺🇸 · Natalia Tapia Arellano🇺🇸

    Non-relativistic Dark Matter (DM) can be accelerated by scattering on high-energy cosmic-ray (CR) electrons. This process leads to a sub-population of relativistic or semi-relativistic DM which extends the experimental reach for direct detection in the sub-GeV mass regime. In this paper we examine the current and future potential of this mechanism for constraining models of light dark matter. In particular, we find that Super-Kamiokande and XENON1T data can already provide leading constraints on the flux of dark matter that has been accelerated to high energies from cosmic ray electrons. We also examine future projected sensitivities for DUNE and Hyper-K, and contrary to previous findings, conclude that DUNE will be able supersede Super-K bounds on cosmic-ray upscattered DM for a variety of DM models.

    hep-phastro-ph.COhep-exPRD(2021)·50 citations
20. 20*

    Mining the Geodesic Equation for Scattering Data

    Clifford Cheung🇺🇸 · Nabha Shah🇺🇸 · Mikhail P. Solon🇺🇸

    The geodesic equation encodes test-particle dynamics at arbitrary gravitational coupling, hence retaining all orders in the post-Minkowskian (PM) expansion. Here we explore what geodesic motion can tell us about dynamical scattering in the presence of perturbatively small effects such as tidal distortion and higher derivative corrections to general relativity. We derive an algebraic map between the perturbed geodesic equation and the leading PM scattering amplitude at arbitrary mass ratio. As examples, we compute formulas for amplitudes and isotropic gauge Hamiltonians for certain infinite classes of tidal operators such as electric or magnetic Weyl to any power, and for higher derivative corrections to gravitationally interacting bodies with or without electric charge. Finally, we present a general method for calculating closed-form expressions for amplitudes and isotropic gauge Hamiltonians in the test-particle limit at all orders in the PM expansion.

    ↳ hep-thgr-qchep-phPRD(2021)·80 citations
21. 21*

    Ab initio benchmarks of neutrinoless double beta decay in light nuclei with a chiral Hamiltonian

    J. M. Yao🇺🇸 · A. Belley🇨🇦 · R. Wirth🇺🇸 · T. Miyagi🇨🇦 · C. G. Payne🇨🇦 · S. R. Stroberg🇺🇸 · H. Hergert🇺🇸 · J. D. Holt🇨🇦

    We report ab initio benchmark calculations of nuclear matrix elements (NMEs) for neutrinoless double-beta ($0\nu \beta \beta$) decays in light nuclei with mass number ranging from $A=6$ to $A=22$. We use the transition operator derived from light-Majorana neutrino exchange and evaluate the NME with three different methods: two variants of in-medium similarity renormalization group (IMSRG) and importance-truncated no-core shell model (IT-NCSM). The same two-plus-three-nucleon interaction from chiral effective field theory is employed, and both isospin-conserving ($\Delta T=0$) and isospin-changing ($\Delta T=2$) transitions are studied. We compare our resulting ground-state energies and NMEs to those of recent ab initio no-core shell model and coupled-cluster calculations, also with the same inputs. We show that the NMEs of $\Delta T=0$ transitions are in good agreement among all calculations, at the level of 10%. For $\Delta T=2$, relative deviations are more significant in some nuclei. The comparison with the exact IT-NCSM result allows us to analyze these cases in detail, and indicates the next steps towards improving the IMSRG-based approaches. The present study clearly demonstrates the power of consistent cross-checks that are made possible by ab initio methodology. This capability is crucial for providing meaningful many-body uncertainties in the NMEs for the $0\nu \beta \beta$ decays in heavier candidate nuclei, where quasi-exact benchmarks are not available.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2021)·44 citations
22. 22*

    Numerical modeling of cosmic rays in the heliosphere: Analysis of proton data from AMS-02 and PAMELA

    Emanuele Fiandrini🇮🇹 · Nicola Tomassetti🇮🇹 · Bruna Bertucci🇮🇹 · Federico Donnini🇮🇹 · Maura Graziani🇮🇹 · Behrouz Khiali🇮🇹 · Alejandro Reina Conde🇪🇸

    Galactic cosmic rays (CRs) inside the heliosphere are affected by solar modulation. To investigate this phenomenon and its underlying physical mechanisms, we have performed a data-driven analysis of the temporal dependence of the CR proton flux over the solar cycle. The modulation effect was modeled by means of stochastic simulations of cosmic particles in the heliosphere. The model were constrained using measurements of CR protons made by AMS-02 and PAMELA experiments on monthly basis from 2006 to 2017. With a global statistical analysis of these data, we have determined the key model parameters governing CR diffusion, its dependence on the particle rigidity, and its evolution over the solar cycle. Our results span over epochs of solar minimum, solar maximum, as well as epochs with magnetic reversal and opposite polarities. Along with the evolution of the CR transport parameters, we study their relationship with solar activity proxies and interplanetary parameters. We find that the rigidity dependence of the parallel mean free path of CR diffusion shows a remarkable time dependence, indicating a long-term variability in the interplanetary turbulence that interchanges across different regimes over the solar cycle. The evolution of the diffusion parameters show a delayed correlation with solar activity proxies, reflecting the dynamics of the heliospheric plasma, and distinct dependencies for opposite states of magnetic polarity, reflecting the influence of charge-sign dependent drift in the CR modulation.

    ↳ astro-ph.HEastro-ph.SRhep-phphysics.space-phPRD(2021)·29 citations
23. 23*

    Closed-form Brückner $G$-matrix and nuclear matter in EFT($/\pi$)

    Ting-Wei Pan🇨🇳 · Ji-Feng Yang🇨🇳

    The closed-form Brükner $G$ matrix for nuclear matter is computed in the ${}^1{S}_0$ channel of EFT($/\pi$) and renormalized in nonperturbative context. The nuclear medium environment yields additional constraints that are consistent with off-shell $T$ matrix renormalization, keeping the power counting intact and simplifying the running behaviors of the EFT couplings. With the $G$ obtained we computed the energy per particle for neutron and symmetric nuclear matter to demonstrate the physical relevance of certain 'physical' parameters that arise from nonperturbative renormalization. We also explored the pairing phenomenon in ${}^1{S}_0$ channel by examining the poles of the closed-form $G$ matrix with a given density, where again the physical relevance of the same set of physical parameters are clearly illustrated.

    ↳ nucl-thhep-phhep-thPLB(2021)·0 citations
24. 24*

    Two-particle correlations at high-energy nuclear collisions, peripheral-tube model revisited

    Yogiro Hama🇧🇷 · Takeshi Kodama🇧🇷 · Wei-Liang Qian🇧🇷

    In this paper, we give an account of the peripheral-tube model, which has been developed to give an intuitive and dynamical description of the so-called ridge effect in two-particle correlations in high-energy nuclear collisions. Starting from a realistic event-by-event fluctuating hydrodynamical model calculation, we first show the emergence of ridge + shoulders in the so-called two-particle long-range correlations, reproducing the data. In contrast to the commonly used geometric picture of the origin of the anisotropic flow, we can explain such a structure dynamically in terms of the presence of high energy-density peripheral tubes in the initial conditions. These tubes violently explode and deflect the near radial flow coming from the interior of the hot matter, which in turn produces a two-ridge structure in single-particle distribution, with approximately two units opening in azimuth. When computing the two-particle correlation, this will result in characteristic three-ridge structure, with a high near-side ridge and two symmetric lower away-side ridges or shoulders. Several anisotropic flows, necessary to producing ridge + shoulder structure, appear naturally in this dynamical description. Using this simple idea, we can understand several related phenomena, such as centrality dependence and trigger-angle dependence.

    ↳ nucl-thhep-phJ.Phys.G(2021)·13 citations
25. 25*

    Is $N=2$ Large?

    Ryuichiro Kitano🇯🇵 · Norikazu Yamada🇯🇵 · Masahito Yamazaki🇯🇵

    We study $\theta$ dependence of the vacuum energy for the 4d SU(2) pure Yang-Mills theory by lattice numerical simulations. The response of topological excitations to the smearing procedure is investigated in detail, in order to extract topological information from smeared gauge configurations. We determine the first two coefficients in the $\theta$ expansion of the vacuum energy, the topological susceptibility $\chi$ and the first dimensionless coefficient $b_2$, in the continuum limit. We find consistency of the SU(2) results with the large $N$ scaling. By analytic continuing the number of colors, $N$, to non-integer values, we infer the phase diagram of the vacuum structure of SU(N) gauge theory as a function of $N$ and $\theta$. Based on the numerical results, we provide quantitative evidence that 4d SU(2) Yang-Mills theory at $\theta =\pi$ is gapped with spontaneous breaking of the CP symmetry.

    ↳ hep-lathep-phhep-thJHEP(2021)·23 citations
26. 26*

    Future Physics Perspectives on the Equation of State from Heavy Ion Collisions to Neutron Stars

    Veronica Dexheimer🇺🇸 · Jorge Noronha🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸 · Claudia Ratti🇺🇸 · Nicolás Yunes🇺🇸

    With the computational power and algorithmic improvements available today, the ongoing STAR/RHIC and HADES/GSI experiments, the future FAIR and NICA facilities becoming operational, and the new precise measurements from NICER and LIGO/VIRGO, the high-energy nuclear physics and astrophysics communities are in the unique position to set very stringent constraints on the equation of state of strongly interacting matter. We review the state-of-the-art of different approaches used in the description of hot and ultradense baryonic matter in and out of equilibrium, and discuss the regions in the phase diagram where heavy-ion collisions and neutron star mergers can overlap. Future perspectives are discussed to help define a comprehensive, multi-disciplinary strategy to map out the phase diagram of strongly interacting matter from heavy ion collisions to neutron stars.

    ↳ nucl-thastro-ph.HEgr-qchep-ph+1J.Phys.G(2021)·79 citations
27. 27*

    Vorticity and Spin Polarization in Heavy Ion Collisions: Transport Models

    Xu-Guang Huang🇨🇳 · Jinfeng Liao🇺🇸 · Qun Wang🇨🇳 · Xiao-Liang Xia🇨🇳

    Heavy ion collisions generate strong fluid vorticty in the produced hot quark-gluon matter which could in turn induce measurable spin polarization of hadrons. We review recent progress on the vorticity formation and spin polarization in heavy ion collisions with transport models. We present an introduction to the fluid vorticity in non-relativistic and relativistic hydrodynamics and address various properties of the vorticity formed in heavy ion collisions. We discuss the spin polarization in a vortical fluid using the Wigner function formalism in which we derive the freeze-out formula for the spin polarization. Finally we give a brief overview of recent theoretical results for both the global and local spin polarization of $\Lambda$ and $\bar{\Lambda }$ hyperons.

    ↳ nucl-thhep-phnucl-exLect.Notes Phys.(2021)·63 citations
28. 28*

    Investigating Heavy-flavor vs Light-flavor Puzzle with Event Topology and Multiplicity in Proton+Proton Collisions at $\sqrt{s}$ = 13 TeV using PYTHIA8

    Suman Deb🇮🇳 · Raghunath Sahoo🇮🇳 · Dhananjaya Thakur🇨🇳 · Sushanta Tripathy🇲🇽 · Arvind Khuntia🇵🇱

    Heavy-flavored hadrons are unique probes to study the properties of hot and dense QCD medium produced in ultra-relativistic heavy-ion collisions at RHIC and the LHC. Transverse spherocity is one of the event-topology variables used to separate jetty and isotropic events from the pool of event samples. This study aims to understand the production dynamics of heavy-flavors through the transverse momentum spectra, double differential yield and mean transverse momentum of J/$\psi$, ${\mathrm{D}}^0$ and ${\Lambda }_c^{+}$ as a function of charged-particle multiplicity and transverse spherocity. Further to investigate the possibility of hardonization of the charm quarks, transverse spherocity dependence ratios like ${\Lambda }_c^{+}$/${\mathrm{D}}^0$ and ${\Lambda }^0$/$K^{-}$ are studied. For the current analysis, the events are generated by using 4C tuned PYTHIA8 for pp at $\sqrt{s}$ = 13 TeV, which is quite successful in explaining the heavy-flavor particle production at the LHC energies.

    ↳ nucl-exhep-exhep-phhep-th+1J.Phys.G(2021)·8 citations
29. 29*

    Advanced extraction of the deuteron charge radius from electron-deuteron scattering data

    Jingyi Zhou🇺🇸 · Vladimir Khachatryan🇺🇸 · Haiyan Gao🇺🇸 · Douglas W. Higinbotham🇺🇸 · Asia Parker🇺🇸 · Xinzhan Bai🇺🇸 · Dipangkar Dutta🇺🇸 · Ashot Gasparian🇺🇸 · Kondo Gnanvo🇺🇸 · Mahbub Khandaker🇺🇸 · Nilanga Liyanage🇺🇸 · Eugene Pasyuk🇺🇸 · Chao Peng🇺🇸 · Weizhi Xiong🇺🇸

    To extract the charge radius of the proton, $r_p$, from the electron scattering data, the PRad collaboration at Jefferson Lab has developed a rigorous framework for finding the best functional forms - the fitters - for a robust extraction of $r_p$ from a wide variety of sample functions for the range and uncertainties of the PRad data. In this paper we utilize and further develop this framework. Herein we discuss methods for searching for the best fitter candidates as well as a procedure for testing the robustness of extraction of the deuteron charge radius, $r_d$, from parametrizations based on elastic electron-deuteron scattering data. The ansatz proposed in this paper for the robust extraction of $r_d$, for the proposed low-$Q^2$ DRad experiment at Jefferson Lab, can be further improved once there are more data.

    ↳ nucl-exhep-phnucl-thPRC(2021)·10 citations
30. 30*

    Probing Fundamental Physics with Gravitational Waves: The Next Generation

    Scott E. Perkins🇺🇸 · Nicolás Yunes🇺🇸 · Emanuele Berti🇺🇸

    Gravitational wave observations of compact binary mergers are already providing stringent tests of general relativity and constraints on modified gravity. Ground-based interferometric detectors will soon reach design sensitivity and they will be followed by third-generation upgrades, possibly operating in conjunction with space-based detectors. How will these improvements affect our ability to investigate fundamental physics with gravitational waves? The answer depends on the timeline for the sensitivity upgrades of the instruments, but also on astrophysical compact binary population uncertainties, which determine the number and signal-to-noise ratio of the observed sources. We consider several scenarios for the proposed timeline of detector upgrades and various astrophysical population models. Using a stacked Fisher matrix analysis of binary black hole merger observations, we thoroughly investigate future theory-agnostic bounds on modifications of general relativity, as well as bounds on specific theories. For theory-agnostic bounds, we find that ground-based observations of stellar-mass black holes and LISA observations of massive black holes can each lead to improvements of 2-4 orders of magnitude with respect to present gravitational wave constraints, while multiband observations can yield improvements of 1-6 orders of magnitude. We also clarify how the relation between theory-agnostic and theory-specific bounds depends on the source properties.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2021)·141 citations
31. 31*

    Pulsar glitches from quantum vortex networks

    Giacomo Marmorini🇯🇵 · Shigehiro Yasui🇯🇵 · Muneto Nitta🇯🇵

    Neutron stars or pulsars are very rapidly rotating compact stars with extremely high density. One of the unsolved long-standing problems of these enigmatic celestial bodies is the origin of pulsars' glitches, i.e., the sudden rapid deceleration in the rotation speed of neutron stars. Although many glitch events have been reported, there is no consensus on the microscopic mechanism responsible for them. One of the important characterizations of the glitches is the scaling law $P(E)\sim E^{-\alpha }$ of the probability distribution for a glitch with energy $E$. Here, we reanalyse the accumulated up-to-date observation data to obtain the exponent $\alpha \approx 0.88$ for the scaling law, and propose a simple microscopic model that naturally deduces this scaling law without any free parameters. Our model explains the appearance of these glitches in terms of the presence of quantum vortex networks arising at the interface of two different kinds of superfluids in the core of neutron stars; a $p$-wave neutron superfluid in the inner core which interfaces with the $s$-wave neutron superfluid in the outer core, where each integer vortex in the $s$-wave superfluid connects to two half-quantized vortices in the $p$-wave superfluid through structures called "boojums."

    ↳ astro-ph.HEhep-phnucl-thSci.Rep.(2024)·16 citations
32. 32*

    Permutationless Many-Jet Event Reconstruction with Symmetry Preserving Attention Networks

    Michael James Fenton🇺🇸 · Alexander Shmakov🇺🇸 · Ta-Wei Ho🇹🇼 · Shih-Chieh Hsu🇺🇸 · Daniel Whiteson🇺🇸 · Pierre Baldi🇺🇸

    Top quarks, produced in large numbers at the Large Hadron Collider, have a complex detector signature and require special reconstruction techniques. The most common decay mode, the "all-jet" channel, results in a 6-jet final state which is particularly difficult to reconstruct in $pp$ collisions due to the large number of permutations possible. We present a novel approach to this class of problem, based on neural networks using a generalized attention mechanism, that we call Symmetry Preserving Attention Networks (SPA-Net). We train one such network to identify the decay products of each top quark unambiguously and without combinatorial explosion as an example of the power of this technique.This approach significantly outperforms existing state-of-the-art methods, correctly assigning all jets in $93.0$ of $6$-jet, $87.8$ of $7$-jet, and $82.6$ of $\ge 8$-jet events respectively.

    ↳ hep-excs.LGhep-phPRD(2022)·69 citations
33. 33*

    Oscillons of Axion-Like Particle: Mass distribution and power spectrum

    Masahiro Kawasaki🇯🇵 · Wakutaka Nakano🇯🇵 · Hiromasa Nakatsuka🇯🇵 · Eisuke Sonomoto🇯🇵

    In string theory, the simultaneous existence of many Axion-Like Particles (ALPs) are suggested over a vast mass range, and a variety of potentials have been developed in the context of inflation. In such potentials shallower than quadratic, the prominent instability can produce localized dense objects, oscillons. Because of the approximate conservation of their adiabatic invariant, oscillons generally survive quite long, maybe up to the current age of the universe in the case of ultra-light ALPs with $m\sim 10^{-22}\mathrm{eV}$. Such oscillons can have significant effects on the evolution of the recent universe. In this paper, we investigate the oscillons of the pure-natural type potential by classical lattice simulation to explore the key quantities necessary for phenomenological application: the number density of oscillons, the oscillon mass distribution, the energy ratio of oscillons to the ALP field, and the power spectrum. Then, we evolve these values in consideration of the analytic decay rate.

    ↳ astro-ph.COhep-phJCAP(2021)·23 citations
34. 34*

    VegasFlow: accelerating Monte Carlo simulation across platforms

    Juan M. Cruz-Martinez🇮🇹 · Stefano Carrazza🇮🇹

    In this work we demonstrate the usage of the VegasFlow library on multidevice situations: multi-GPU in one single node and multi-node in a cluster. VegasFlow is a new software for fast evaluation of highly parallelizable integrals based on Monte Carlo integration. It is inspired by the Vegas algorithm, very often used as the driver of cross section integrations and based on Google's powerful TensorFlow library. In this proceedings we consider a typical multi-GPU configuration to benchmark how different batch sizes can increase (or decrease) the performance on a Leading Order example integration.

    ↳ physics.comp-phhep-phPoS(2021)·5 citations
35. 35*

    Radiative and chiral corrections to elastic lepton-proton scattering in chiral perturbation theory

    Pulak Talukdar🇮🇳 · Vanamali C. Shastry🇮🇳 · Udit Raha🇮🇳 · Fred Myhrer🇺🇸

    A unified treatment of both chiral and radiative corrections to the low-energy elastic lepton-proton scattering processes is presented in Heavy Baryon Chiral Perturbations Theory. The proton hadronic chiral corrections include the next-to-next-to leading order corrections whereas the radiative corrections include the next-to-leading order terms in our novel power counting scheme. We find that the net fractional well-defined chiral corrections with respect to the leading order Born cross section can be as large as $10\%$ ($20\%$) for electron (muon) scattering process for MUon proton Scattering Experiment (MUSE) kinematics. We show {\it via} our model-independent treatment of the low-energy lepton-proton kinematics, that the largest theoretical uncertainty is due to the recent different published values of the proton's rms radius while, e.g., the next higher order hadronic chiral terms are expected to give rather nominal errors. For the radiative corrections we demonstrate a systematic order by order cancellation of all infrared singularities and present our finite ultraviolet regularization results. We find that the radiative corrections for muon-proton scattering is of the order of $2\%$, whereas for electron scattering the radiative corrections could be as large as $25\%$. We attribute such a contrasting result partially to the fact that in muon scattering the leading radiative order correction goes through zero in some intermediate low-momentum transfer region, leaving the sub-leading radiative chiral order effects to play a dominant role in this particular kinematic region. For the low-energy MUSE experiment, the often neglected lepton mass as well as the Pauli form factor contributions of the relativistic leptons are incorporated in all our computations.

    ↳ nucl-thhep-phPRD(2021)·15 citations
36. 36*

    Is entanglement a probe of confinement?

    Niko Jokela🇫🇮 · Javier G. Subils🇪🇸

    We study various entanglement measures in a one-parameter family of three-dimensional, strongly coupled Yang-Mills-Chern-Simons field theories by means of their dual supergravity descriptions. A generic field theory in this family possesses a mass gap but does not have a linear quark-antiquark potential. For the two limiting values of the parameter, the theories flow either to a fixed point or to a confining vacuum in the infrared. We show that entanglement measures are unable to discriminate confining theories from non-confining ones with a mass gap. This lends support on the idea that the phase transition of entanglement entropy at large-N can be caused just by the presence of a sizable scale in a theory and just by itself should not be taken as a signal of confinement. We also examine flows passing close to a fixed point at intermediate energy scales and find that the holographic entanglement entropy, the mutual information, and the F-functions for strips and disks quantitatively match the conformal values for a range of energies.

    ↳ hep-thhep-phquant-phJHEP(2021)·60 citations
37. 37*

    Hidden spin-isospin exchange symmetry

    Dean Lee🇺🇸 · Scott Bogner🇺🇸 · B. Alex Brown🇺🇸 · Serdar Elhatisari🇹🇷 · Evgeny Epelbaum🇩🇪 · Heiko Hergert🇺🇸 · Morten Hjorth-Jensen🇺🇸 · Hermann Krebs🇩🇪 · Ning Li🇺🇸 · Bing-Nan Lu🇺🇸 · Ulf-G. Meißner🇩🇪

    The strong interactions among nucleons have an approximate spin-isospin exchange symmetry that arises from the properties of quantum chromodynamics in the limit of many colors, $N_c$. However this large-$N_c$ symmetry is well hidden and reveals itself only when averaging over intrinsic spin orientations. Furthermore, the symmetry is obscured unless the momentum resolution scale is close to an optimal scale that we call ${\Lambda }_{\mathrm{large}-N_c}$. We show that the large-$N_c$ derivation requires a momentum resolution scale of ${\Lambda }_{\mathrm{large}-N_c}\sim 500$ MeV. We derive a set of spin-isospin exchange sum rules and discuss implications for the spectrum of ${}^{30}$P and applications to nuclear forces, nuclear structure calculations, and three-nucleon interactions.

    ↳ nucl-thhep-lathep-phnucl-exPRL(2021)·35 citations
38. 38*

    On the width of the $K^{-}$D atom ground state

    N. Barnea🇮🇱 · E. Friedman🇮🇱 · A. Gal🇮🇱

    Experiments at DA$\Phi$NE-Frascati and at J-PARC are scheduled to produce $K^{-}$D atoms and observe their X-ray cascade down to the 1$S$ ground state (g.s.), thereby measuring its strong-interaction width and shift away from a purely Coulomb state. A width ${\Gamma }_{1S}\lesssim 1$ keV will ensure good resolution of the X-ray transitions feeding the 1$S$ g.s. Here we study the expected $K^{-}$D 1$S$ g.s. width from the perspective of global fits to level shifts and widths in heavier kaonic atoms across the periodic table, using $K^{-}$ nuclear optical potentials constructed from $\bar{K}N$ chiral interaction models. Special attention is paid to the subthreshold energy at which the $\bar{K}N$ subsystem interacts in the $K^{-}$D atomic g.s. Within this approach we predict strong-interaction upward level shift of close to 700 eV and width of about 1.2 to 1.3 keV for the $K^{-}$D atom 1$S$ g.s., in fair agreement with genuinely three-body $K^{-}$D atom calculations. Comparison is made with ${\pi }^{-}$D atom phenomenology.

    ↳ nucl-thhep-phnucl-exNPA(2021)·2 citations
39. 39*

    Mass-dependent sequential freeze-out of hadrons

    Sayan Mitra🇮🇳

    Fluctuation measurements of hadron yields at heavy-ion collisions can reproduce the phase transition parameters of QCD matter. The fluctuation results produce accurate parameters near zero baryonic chemical potential(${\mu }_B$) being very sensitive in that region. In this work, using the Hadron Resonance Gas Model(HRG), we determine the freeze-out temperatures of the hadrons using individual fluctuation results and find that sequential freeze-out of hadrons during the QCD phase transition near zero ${\mu }_B$ is dependent on the mass of produced hadronic species. Using recently published results of net-$\Lambda$ fluctuations and some other fluctuation results, we study the phase diagram at low baryonic chemical potential and center-of-mass energies ranging from 19.6 - 200 GeV/$c^2$ and find significant, quantitative evidence to support our claim.

    ↳ nucl-thhep-ph1 citation
40. 40*

    Fuzzballs and Observations

    Daniel R. Mayerson🇫🇷

    The advent of gravitational waves and black hole imaging has opened a new window into probing the horizon scale of black holes. An important question is whether string theory results for black holes can predict interesting and observable features that current and future experiments can probe. In this article I review the budding and exciting research being done on understanding the possibilities of observing signals from fuzzballs, where black holes are replaced by string-theoretic horizon-scale microstructure. In order to be accessible to both string theorists and black hole phenomenologists, I give a brief overview of the relevant observational experiments as well as the fuzzball paradigm in string theory and its explicitly constructable solutions called microstate geometries.

    ↳ hep-thastro-ph.HEgr-qchep-phGen.Rel.Grav.(2020)·73 citations
41. 41*

    Self-Dualities and Renormalization Dependence of the Phase Diagram in 3d $O(N)$ Vector Models

    Giacomo Sberveglieri🇮🇹 · Marco Serone🇮🇹 · Gabriele Spada🇫🇷

    In the classically unbroken phase, 3d $O(N)$ symmetric ${\varphi }^4$ vector models admit two equivalent descriptions connected by a strong-weak duality closely related to the one found by Chang and Magruder long ago. We determine the exact analytic renormalization dependence of the critical couplings in the weak and strong branches as a function of the renormalization scheme (parametrized by $\kappa$) and for any $N$. It is shown that for $\kappa ={\kappa }_{\ast }$ the two fixed points merge and then, for $\kappa <{\kappa }_{\ast }$, they move into the complex plane in complex conjugate pairs, making the phase transition no longer visible from the classically unbroken phase. Similar considerations apply in 2d for the $N=1$ ${\varphi }^4$ theory, where the role of classically broken and unbroken phases is inverted. We verify all these considerations by computing the perturbative series of the 3d $O(N)$ models for the vacuum energy and for the mass gap up to order eight, and Borel resumming the series. In particular, we provide numerical evidence for the self-duality and verify that in renormalization schemes where the critical couplings are complex the theory is gapped. As a by-product of our analysis, we show how the non-perturbative mass gap at large $N$ in 2d can be seen as the analytic continuation of the perturbative one in the classically unbroken phase.

    ↳ hep-thcond-mat.stat-mechhep-lathep-phJHEP(2021)·16 citations
42. 42*

    Model-independent energy budget for LISA

    Felix Giese🇩🇪 · Thomas Konstandin🇩🇪 · Kai Schmitz🇨🇭 · Jorinde van de Vis🇩🇪

    We provide an easy method to obtain the kinetic energy fraction in gravitational waves, generated during a cosmological first-order phase transition, as a function of only the wall velocity and quantities that can be determined from the particle physics model at the nucleation temperature. This generalizes recent work that achieved this goal for detonations. Here we present the corresponding results for deflagrations and hybrids. Unlike for detonations, the sound speed in the symmetric phase also enters the analysis. We perform a detailed comparison between our model-independent approach and other approaches in the literature. We provide a Python code snippet to determine the kinetic energy fraction $K$ as a function of the wall velocity, the two speeds of sound and the strength parameter of the phase transition. We also assess how realistic sizable deviations in speed of sound are close to the phase transition temperature in a specific model.

    ↳ astro-ph.COhep-phJCAP(2021)·150 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.