Mon·Feb 14, 2022Monday·February 14, 2022

1. 01*

   The $1D$-wave bottom-strange baryons and possible interpretation of ${\Xi }_b(6327{)}^0$ and ${\Xi }_b(6333{)}^0$

   Wen-Jia Wang🇨🇳 · Yu-Hui Zhou🇨🇳 · Li-Ye Xiao🇨🇳 · Xian-Hui Zhong🇨🇳

   Inspired by the LHCb's newest observation of two new excited ${\Xi }_b^0$ states, we systematically study the strong decays of the low-lying $\lambda$- and $\rho$-modes $1D$-wave ${\Xi }_b$ and ${\Xi }_b^{{}^{\prime }}$ baryons using the chiral quark model within the $j$-$j$ coupling scheme. Based on the measured masses and strong decay properties of ${\Xi }_b(6327{)}^0$ and ${\Xi }_b(6333{)}^0$, we explain the two states as the $\lambda$-mode $1D$ ${\Xi }_b$ states with $J^P=3/2^{+}$ and $J^P=5/2^{+}$, respectively. Moreover, under this assignment, another dominant decay channel of ${\Xi }_b(6327{)}^0$ is ${\Xi }_b^{\prime }\pi$ and that of ${\Xi }_b(6333{)}^0$ is ${\Xi }_b^{\ast }\pi$. Hence, the decay modes ${\Xi }_b^{\prime }\pi$ and ${\Xi }_b^{\ast }\pi$ may be another ideal channels as well to decode the inner structure of ${\Xi }_b(6327{)}^0$ and ${\Xi }_b(6333{)}^0$, respectively. For other unseen $1D$ ${\Xi }_b$ and ${\Xi }_b^{\prime }$ states, our results indicate: (i) ${\Xi }_b|J^P={\frac{3}{2}}^{+},2{⟩}_{\rho }$ and ${\Xi }_b|J^P={\frac{5}{2}}^{+},2{⟩}_{\rho }$ are most likely to be narrow states with a width of $\Gamma \simeq (12-30)$ MeV, and dominantly decay into ${\Sigma }_{b}K$ and ${\Sigma }_b^{\ast }K$, respectively; (ii) The $1D$ ${\Xi }_b^{\prime }$ baryons are not broad states, and the widths vary in the range of $\Gamma \simeq (14-46)$ MeV. These states have a good potential to be observed in their dominant decay processes.

   hep-phPRD(2022)·13 citations
2. 02*

   Parametrization of the nuclear structure function

   G.R.Boroun🇮🇷 · B.Rezaei🇮🇷

   In this paper, the parametrization of the nuclear structure function which is directly constrained by the dynamics of QCD in its high-energy limit is considered. This simple parameterization of the nuclear structure function is obtained from the proton experimental data by relying on a Froissart-bounded parametrization of the proton structure function. This phenomenological model describes high-energy QCD in the presence of saturation effects. Numerical calculations and comparison with available data from NMC, EMC and E665 Collaborations demonstrate that the suggested method by N.Armesto, C.A.Salgado and U.A. Wiedemann (ASW model) provides reliable ratio of nuclear structure functions $F_2^A/A{F}_2^p$ at low $x$ for light and heavy nuclei. The magnitude of nuclear shadowing is predicted for various kinematic regions and can be applied as well in analysis of ultra-high energy processes by future experiments at electron-ion colliders.

   hep-phPRC(2023)·4 citations
3. 03*

   Longitudinal dynamics for mesons on the light cone

   Yang Li🇨🇳 · James P. Vary🇺🇸

   We survey a set of proposed light-front models for confinement in the valence quark sector of the mesons and portray similarities as well as differences. We present the spectroscopies for the light mesons that result from a selection of longitudinal confinement forms. We note that the Sturm-Liouville theory provides a unifying framework for many elements of this comparison.

   hep-phnucl-thPRD(2022)·14 citations
4. 04*

   Fragmentation Functions for ${\Xi }^{-}/{\bar{\Xi }}^{+}$ Using Neural Networks

   Maryam Soleymaninia🇮🇷 · Hadi Hashamipour🇮🇷 · Hamzeh Khanpour🇮🇷 · Hubert Spiesberger🇩🇪

   We present a determination of fragmentation functions (FFs) for the octet baryon ${\Xi }^{-}/{\bar{\Xi }}^{+}$ from data for single inclusive electron-positron annihilation. Our parametrization in this QCD analysis is provided in terms of a Neural Network (NN). We determine fragmentation functions for ${\Xi }^{-}/{\bar{\Xi }}^{+}$ at next-to-leading order and for the first time at next-to-next-to-leading order in perturbative QCD. We discuss the improvement of higher-order QCD corrections, the quality of fit, and the comparison of our theoretical results with the fitted datasets. As an application of our new set of fragmentation functions, named SHKS22, we present predictions for ${\Xi }^{-}/{\bar{\Xi }}^{+}$ baryon production in proton-proton collisions at the LHC experiments.

   hep-phNPA(2023)·14 citations
5. 05*

   A dispersive analysis of ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}\gamma$ and ${\eta }^{\prime }\to {\ell }^{+}{\ell }^{-}\gamma$

   Simon Holz🇩🇪 · Christoph Hanhart🇩🇪 · Martin Hoferichter🇨🇭 · Bastian Kubis🇩🇪

   We present a dispersive representation of the ${\eta }^{\prime }$ transition form factor that allows one to account, in a consistent way, for the effects of $\rho$-$\omega$ mixing in both the isoscalar and the isovector contributions. Using this formalism, we analyze recent data on ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}\gamma$ to constrain the isovector part of the form factor, individually and in combination with data for the pion vector form factor. As a first application, we use our results, in combination with the most recent input for the isoscalar part of the form factor, to predict the corresponding spectrum of ${\eta }^{\prime }\to {\ell }^{+}{\ell }^{-}\gamma$, in particular we find the slope parameter $b_{{\eta }^{\prime }}=1.431(23){\text{GeV}}^{-2}$. With forthcoming data on the latter process, our results establish the necessary framework to improve the evaluation of the ${\eta }^{\prime }$-pole contribution to the anomalous magnetic moment of the muon using experimental input from both ${\eta }^{\prime }$ decay channels.

   hep-phhep-exnucl-thEPJC(2022)·61 citations
6. 06*

   Resolving Combinatorial Ambiguities in Dilepton $t\bar{t}$ Event Topologies with Neural Networks

   Haider Alhazmi🇺🇸 · Zhongtian Dong🇺🇸 · Li Huang🇺🇸 · Jeong Han Kim🇰🇷 · Kyoungchul Kong🇺🇸 · David Shih🇺🇸

   We study the potential of deep learning to resolve the combinatorial problem in SUSY-like events with two invisible particles at the LHC. As a concrete example, we focus on dileptonic $t\bar{t}$ events, where the combinatorial problem becomes an issue of binary classification: pairing the correct lepton with each $b$ quark coming from the decays of the tops. We investigate the performance of a number of machine learning algorithms, including attention-based networks, which have been used for a similar problem in the fully-hadronic channel of $t\bar{t}$ production; and the Lorentz Boost Network, which is motivated by physics principles. We then consider the general case when the underlying mass spectrum is unknown, and hence no kinematic endpoint information is available. Compared against existing methods based on kinematic variables, we demonstrate that the efficiency for selecting the correct pairing is greatly improved by utilizing deep learning techniques.

   hep-phPRD(2022)·8 citations
7. 07*

   Modular symmetry anomaly and non-perturbative neutrino mass terms in magnetized orbifold models

   Shota Kikuchi🇯🇵 · Tatsuo Kobayashi🇯🇵 · Kaito Nasu🇯🇵 · Hikaru Uchida🇯🇵 · Shohei Uemura🇯🇵

   We study the modular symmetry anomaly in magnetized orbifold models. The non-perturbative effects such as D-brane instanton effects can break tree-level symmetry. We study which part of the modular symmetry is broken explicitly by Majorana mass terms with three generations of neutrinos. The modular weight of neutrino mass terms does not match with other coupling terms in tree-level Lagrangian. In addition, the $Z_N$ symmetry of the modular flavor symmetry is broken and a certain normal subgroup of the modular flavor symmetry remains in neutrino mass terms.

   ↳ hep-thhep-phPRD(2022)·18 citations
8. 08*

   Algebraic approach to quarkyoniclike configuration and stable diquarks in dense matter

   Aaron Park🇰🇷 · Su Houng Lee🇰🇷

   We study the color-spin interaction energy of a quark, a diquark and a baryon with their surrounding baryons and/or quark matter. This is accomplished by classifying all possible flavor and spin states of the resulting multiquark configuration in both the flavor SU(2) and SU(3) symmetric cases. We find that while the baryon has the lowest interaction energy when there is only a single surrounding baryon, the quark has the lowest interaction energy when the surrounding has more than three baryons or becomes a quark gas. As the short range nucleon-nucleon interactions are dominated by the color-spin interactions, our finding suggests that the baryon modes near other baryons are suppressed due to larger repulsive energy compared to that of a quark and thus provides a quark model basis for the quarkyoniclike phase in dense matter. At the same time, when the internal interactions are taken into account, and the matter density is high so that the color-spin interaction becomes the dominant interaction, the diquark becomes the lowest energy configuration and will thus appear in both the dense baryonic and/or quark matter.

   ↳ nucl-thhep-phPRD(2022)·4 citations
9. 09*

   Vacuum Birefringence in a Supercritical Magnetic Field and a Subcritical Electric Field

   Chul Min Kim🇰🇷 · Sang Pyo Kim🇰🇷

   Recent ultra-intense lasers of subcritical fields and proposed observations of the x-rays polarization from highly magnetized neutron stars of supercritical fields have attracted attention to vacuum birefringence, a unique feature of nonlinear electrodynamics. We propose a formulation of vacuum birefringence that incorporates the effects of the weaker electric field added to the extremely strong magnetic field. To do so, we first derive a closed analytical expression for the one-loop effective Lagrangian for the combined magnetic and electric fields by using an explicit formula of the one-loop effective Lagrangian for an arbitrarily strong magnetic field. We then employ the expression to derive the polarization and magnetization of the vacuum, from which the permittivity and permeability for weak probe fields are obtained. Finally, we find the refractive indices and the associated polarization vectors for the case of parallel magnetic and electric fields. The proposed formulation predicts that an electric field along the magnetic field reduces the birefringence and rotates the polarization vectors. Such effects should be taken into account for accurate polarimetry of the x-rays from magnetized neutron stars, which will prove the fundamental aspect of the strong field quantum electrodynamics (QED) and explore the extreme fields of astrophysical bodies.

   ↳ astro-ph.HEhep-phphysics.plasm-phEPJC(2023)·18 citations
10. 10*

    Overview of the physics prospects in MOMENT

    Sampsa Vihonen🇨🇳

    MuOn-decay MEdium-baseline NeuTrino beam facility (MOMENT) is a recently proposed neutrino oscillation experiment that is currently under consideration in China. Based on a novel accelerator concept, MOMENT is capable of delivering 15 MW neutrino beam produced with the decay of positively and negatively charged muons. In this study, the physics performance of MOMENT is briefly reviewed in its baseline setup, involving a 150 km baseline length and large gadolinium-doped Water Cherenkov detector. The prospects are discussed in the case of precision measurements on the Dirac CP phase ${\delta }_{CP}$, which MOMENT is shown to be able to measure by about 8${}^{\circ }$...18${}^{\circ }$ resolution at 1$\sigma$ CL. It is examined how MOMENT performs as an independent experiment and also as a complementary facility to the future superbeam experiments.

    ↳ hep-exhep-phPoS(2022)·4 citations
11. 11*

    Lattice studies of the $Sp(4)$ gauge theory with two fundamental and three antisymmetric Dirac fermions

    Ed Bennett🇬🇧 · Deog Ki Hong🇰🇷 · Ho Hsiao🇹🇼 · Jong-Wan Lee🇰🇷 · C.-J. David Lin🇹🇼 · Biagio Lucini🇬🇧 · Michele Mesiti🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇮🇪

    We consider the $Sp(4)$ gauge theory coupled to $N_f=2$ fundamental and $n_f=3$ antisymmetric flavours of Dirac fermions in four dimensions. This theory serves as the microscopic origin for composite Higgs models with $SU(4)/Sp(4)$ coset, supplemented by partial top compositeness. We study numerically its lattice realisation, and couple the fundamental plaquette action to Wilson-Dirac fermions in mixed representations, by adopting a (rational) hybrid Monte Carlo method, to perform non-trivial tests of the properties of the resulting lattice theory. We find evidence of a surface (with boundaries) of first-order bulk phase transitions in the three-dimensional space of bare parameters (one coupling and two masses). Explicit evaluation of the Dirac eigenvalues confirms the expected patterns of global symmetry breaking. After investigating finite volume effects in the weak-coupling phase of the theory, for the largest available lattice we study the mass spectra of the lightest spin-0 and spin-1 flavoured mesons composed of fermions in each representation, and of the lightest half-integer spin composite particle made of fermions in different representations -- the chimera baryon. This work sets the stage for future systematical studies of the non-perturbative dynamics in phenomenologically relevant regions of parameter space.

    ↳ hep-lathep-phhep-thPRD(2022)·61 citations
12. 12*

    Resummed lattice QCD equation of state at finite baryon density: strangeness neutrality and beyond

    Szabolcs Borsanyi🇩🇪 · Zoltan Fodor🇩🇪 · Jana N. Guenther🇩🇪 · Ruben Kara🇩🇪 · Paolo Parotto🇺🇸 · Attila Pasztor🇭🇺 · Claudia Ratti🇺🇸 · Kalman K. Szabo🇩🇪

    We calculate a resummed equation of state with lattice QCD simulations at imaginary chemical potentials. This work presents a generalization of the scheme introduced in 2102.06660 to the case of non-zero ${\mu }_S$, focusing on the line of strangeness neutrality. We present results up to ${\mu }_B/T\le 3.5$ on the strangeness neutral line $⟨S⟩=0$ in the temperature range $130\mathrm{MeV}\le \mathrm{T}\le 280\mathrm{MeV}$. We also extrapolate the finite baryon density equation of state to small non-zero values of the strangeness-to-baryon ratio $R=⟨S⟩/⟨B⟩$. We perform a continuum extrapolation using lattice simulations of the 4stout-improved staggered action with 8, 10, 12 and 16 timeslices.

    ↳ hep-lathep-phnucl-thPRD(2022)·69 citations
13. 13*

    "Stairway to Heaven" -- Spectroscopy of Particle Couplings with Gravitational Waves

    Daniel G. Figueroa🇪🇸 · Adrien Florio🇺🇸 · Nicolas Loayza🇪🇸 · Mauro Pieroni🇬🇧

    We discuss the possibility to measure particle couplings with stochastic gravitational wave backgrounds (SGWBs). Under certain circumstances a sequence of peaks of different amplitude and frequency -- a $stairway$ -- emerges in a SGWB spectrum, with each peak probing a different coupling. The detection of such signature opens the possibility to reconstruct couplings (spectroscopy) of particle species involved in high energy phenomena generating SGWBs. Stairway-like signatures may arise in causally produced backgrounds in the early Universe, e.g. from preheating or first order phase transitions. As a proof of principle we study a preheating scenario with an inflaton $\varphi$ coupled to multiple $daughter$ fields $\{{\chi }_j\}$ with different coupling strengths. As a clear stairway signature is imprinted in the SGWB spectrum, we reconstruct the relevant couplings with various detectors.

    ↳ astro-ph.COhep-phPRD(2022)·20 citations
14. 14*

    QED and strong isospin corrections in the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon

    L. Parato🇫🇷 · Sz. Borsanyi🇩🇪 · Z. Fodor🇩🇪 · J. N. Guenther🇩🇪 · C. Hoelbling🇩🇪 · S. D. Katz🇭🇺 · L. Lellouch🇫🇷 · T. Lippert🇩🇪 · K. Miura🇩🇪 · K. K. Szabo🇩🇪 · F. Stokes🇩🇪 · B. C. Toth🇩🇪 · Cs. Torok🇩🇪 · L. Varnhorst (BMW Collaboration)🇩🇪

    Recently, the Budapest-Marseille-Wuppertal collaboration achieved sub-percent precision in the evaluation of the lowest-order hadronic vacuum polarization contribution to the muon $g_{\mu }-2$ (arXiv:hep-lat/2002.12347v3). At this level of precision, isospin-symmetric QCD is not sufficient. In this contribution we review how QED and strong-isospin-breaking effects have been included in our work. Isospin breaking is implemented by expanding the relevant correlation functions to second order in the electric charge $e$ and to first order in $m_u-m_d$. The correction terms are then computed using isospin-symmetric configurations. The choice of this approach allows us to better distribute the available computing resources among the various contributions.

    ↳ hep-lathep-phPoS(2022)·7 citations
15. 15*

    Applications of Machine Learning to Lattice Quantum Field Theory

    Denis Boyda🇺🇸 · Salvatore Calì🇺🇸 · Sam Foreman🇺🇸 · Lena Funcke🇺🇸 · Daniel C. Hackett🇺🇸 · Yin Lin🇺🇸 · Gert Aarts🇬🇧 · Andrei Alexandru🇺🇸 · Xiao-Yong Jin🇺🇸 · Biagio Lucini🇬🇧 · Phiala E. Shanahan🇺🇸

    There is great potential to apply machine learning in the area of numerical lattice quantum field theory, but full exploitation of that potential will require new strategies. In this white paper for the Snowmass community planning process, we discuss the unique requirements of machine learning for lattice quantum field theory research and outline what is needed to enable exploration and deployment of this approach in the future.

    ↳ hep-latcs.LGhep-ph54 citations
16. 16*

    Model selection and signal extraction using Gaussian Process regression

    Abhijith Gandrakota🇺🇸 · Amitabh Lath🇺🇸 · Alexandre V. Morozov🇺🇸 · Sindhu Murthy🇺🇸

    We present a novel computational approach for extracting weak signals, whose exact location and width may be unknown, from complex background distributions with an arbitrary functional form. We focus on datasets that can be naturally presented as binned integer counts, demonstrating our approach on the CERN open dataset from the ATLAS collaboration at the Large Hadron Collider, which contains the Higgs boson signature. Our approach is based on Gaussian Process (GP) regression - a powerful and flexible machine learning technique that allowed us to model the background without specifying its functional form explicitly, and to separate the background and signal contributions in a robust and reproducible manner. Unlike functional fits, our GP-regression-based approach does not need to be constantly updated as more data becomes available. We discuss how to select the GP kernel type, considering trade-offs between kernel complexity and its ability to capture the features of the background distribution. We show that our GP framework can be used to detect the Higgs boson resonance in the data with more statistical significance than a polynomial fit specifically tailored to the dataset. Finally, we use Markov Chain Monte Carlo (MCMC) sampling to confirm the statistical significance of the extracted Higgs signature.

    ↳ hep-exhep-phphysics.data-anJHEP(2023)·10 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.