Nuclear Theory·nucl-th

Friday·September 23, 2022

15 papers—7 primary·8 cross-listed

01
[Submitted on 21 Sept 2022]
Charge Symmetry Breaking Effects on Neutron Beta Decay in Non-Relativistic Quark Models
Jacob W. Crawford🇺🇸 · Gerald A. Miller🇺🇸
A formalism for the study of charge symmetry breaking (CSB) effects is discussed and used to analyze the effects of charge symmetry breaking on neutron beta decay. The effect of including CSB reduces the beta decay matrix element by an amount on the order of $1 0^{- 4}$ , a value much larger than the previous estimate. A much smaller contribution due to proton recoil is treated as well, which is found to be on the order of $1 0^{- 6}$ . The current uncertainty in the value of $V_{u d}$ is also of order $1 0^{- 4}$ . An improvement of that uncertainty by an order of magnitude would require that charge symmetry breaking effects should be included in future analyses.
Comments:
8 pages, submitted to add citation
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2209.10603 [pdf]
PRC(2022)·9 citations
02
[Submitted on 22 Sept 2022]
Pion superfluid phase transition under external magnetic field including inverse magnetic catalysis effect
Shijun Mao🇨🇳 · Yvming Tian🇨🇳
Pion superfluid phase transition under external magnetic field including the inverse magnetic catalysis (IMC) effect is investigated by the Pauli-Villars regularized NJL model. Based on the Goldstone's theorem, we apply the massless Goldstone boson ( $π^{+}$ meson) to determine the onset of pion superfluid phase. The inverse magnetic catalysis effect is introduced by the magnetic field dependent coupling $G (e B)$ , which is a decreasing function of magnetic field. At fixed temperature and baryon chemical potential, the critical isospin chemical potential for pion superfluid phase transition including IMC effect increases as the magnetic field grows, which is similar as the case without IMC effect. This demonstrates that magnetic field disfavors the pion superfluid phase when considering or ignoring IMC effect. The critical isospin chemical potential at fixed magnetic field, temperature and baryon chemical potential is shifted to higher value by the IMC effect. Since it is more difficult to form pion superfluid with weaker coupling.
Comments:
5 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2209.10738 [pdf]
PRD(2022)·9 citations
03
[Submitted on 22 Sept 2022]
Microscopic description of the torque acting on fission fragments
Guillaume Scamps
When two fragments are created in a fission decay, any torque due to nuclear and Coulomb interaction can change the fragment's angular momentum. This article explores the character and magnitude of the angular momentum as a function of the initial conditions around the scission point using the time-dependent Hartree-Fock theory. To understand the torque acting on the fragments, the Frozen Hartree-Fock method is also used to determine the collective potential at scission. Two $^{240}$ Pu fission channel ( $^{132}$ Sn+ $^{108}$ Ru and $^{144}$ Ba+ $^{96}$ Sr ) are studied. These two channels cover different shapes (spherical, quadrupole, and octupole deformation) of the fragments. It is found that the angular momentum generated by the Coulomb interaction after fission is mainly collective, while this is not the case for the angular momentum generated at scission. The competition between rotational modes (bending, wriggling, and twisting) is discussed and shows that the angular momentum is generated mainly perpendicular to the fission axis.
Comments:
8 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2209.10759 [pdf]
PRC(2022)·18 citations
04
[Submitted on 22 Sept 2022]
Kaonic Hanbury-Brown-Twiss radii at 200 GeV and 5.02 TeV
Mubarak Alqahtani🇸🇦 · Michael Strickland🇺🇸
We use 3+1D quasiparticle anisotropic hydrodynamics (aHydroQP) to make predictions for kaon Hanbury-Brown-Twiss (HBT) radii in 200 GeV and 5.02 TeV heavy-ion collisions. Using previously determined aHydroQP parameters, we compute kaonic HBT radii and their ratios as a function of the mean transverse momentum of the pair $k_{T}$ . We first consider Au-Au collisions at 200 GeV, finding good agreement between aHydroQP predictions and experimental data up to $k_{T} \sim 0.8$ GeV. We then present predictions for kaonic HBT radii and their ratios in 5.02 TeV Pb-Pb collisions. Our aHydroQP predictions do not exhibit a clear $k_{T}$ scaling of the pion and kaon source radii, however, an approximate transverse mass $m_{T}$ scaling is observed, particularly at 200 GeV.
Comments:
10 pages, 7 figures; v2 - major revision, published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2209.10894 [pdf]
PRC(2023)·8 citations
05
[Submitted on 22 Sept 2022]
Effects of Initial Density Fluctuations on Cumulants in Au + Au Collisions at $s_{N N}$ = 7.7 GeV
Xiaoqing Yue🇨🇳 · Yongjia Wang🇨🇳 · Qingfeng Li🇨🇳 · Fuhu Liu🇨🇳
Within the ultrarelativistic quantum molecular dynamics (UrQMD) model, the effect of initial density fluctuations on cumulants of the net-proton multiplicity distribution in Au + Au Collisions at $s_{N N}$ = 7.7 GeV was investigated by varying the minimum distance $d_{min}$ between two nucleons in the initialization. It was found that the initial density fluctuations increased with the decrease of $d_{min}$ from 1.6 fm to 1.0 fm, and the influence of $d_{min}$ on the magnitude of the net-proton number fluctuation in a narrow pseudorapidity window ( $Δ η \leq$ 4) was negligible even if it indeed affected the density evolution during the collision. At a broad pseudorapidity window ( $Δ η \geq$ 4), the cumulant ratios were enlarged when the initial density fluctuations were increased with the smaller value of $d_{min}$ , and this enhancement was comparable to that observed in the presence of the nuclear mean-field potential. Moreover, the enhanced cumulants were more evident in collisions with a larger impact parameter. The present work demonstrates that the fingerprint of the initial density fluctuations on the cumulants in a broad pseudorapidity window is clearly visible, while it is not obvious as the pseudorapidity window becomes narrow.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2209.10923 [pdf]
Universe(2022)·2 citations
06
[Submitted on 21 Sept 2022]
Cross effects in spin hydrodynamics: A revisit Entropy analysis and statistical operator
Jin Hu🇨🇳
We revisit the construction of first-order spin hydrodynamics and find that the constitution relations receive the corrections from the cross effects resulting from spin-orbit coupling. Starting from a routine entropy analysis, we show how to identify cross effects and new cross transport coefficients from the second law of thermodynamics. Interestingly, the conventional transport coefficient heat conductivity $κ$ is bounded from below by the product of cross transport coefficients, which means the threshold of heat conduction is changed. With recourse to Zubarev's non-equilibrium statistical operator, we reproduce the construction of first-order spin hydrodynamics and identification of cross effects in a more rigorous way. By seeking the dispersion relations of normal modes, we find that these cross effects suppress the attenuation of sound modes and heat mode appearing in conventional hydrodynamics and also have impacts on the damping of non-hydrodynamic spin modes.
Comments:
The version published in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2209.10979 [pdf]
PRC(2023)·23 citations
07
[Submitted on 22 Sept 2022]
Chiral restoration of strange baryons
Eduardo S. Fraga🇧🇷 · Rodrigo da Mata🇧🇷 · Savvas Pitsinigkos🇬🇧 · Andreas Schmitt🇬🇧
We review the results of a phenomenological model for cold and dense nuclear matter exhibiting a chiral phase transition. The idea is to model the quark-hadron phase transition under neutron star conditions within a single model, but without adding quark degrees of freedom by hand. To this end, strangeness is included in the form of hyperonic degrees of freedom, whose light counterparts provide the strangeness in the chirally restored phase. In the future, the model can be used for instance to compute the surface tension at the (first-order) chiral phase transition and to study the possible existence of inhomogeneous phases.
Comments:
6 pages, 4 figures, contribution to proceedings of QCD@Work, 27-30 June 2022
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2209.10980 [pdf]
EPJ Web Conf.(2022)·0 citations
08
[Submitted on 21 Sept 2022] (cross-list from hep-lat)
Chiral spin symmetry and hot/dense QCD
L. Ya. Glozman🇦🇹
Above the chiral symmetry restoration crossover around T_{ch} ~ 155 MeV a new regime arises in QCD, a stringy fluid, which is characterized by an approximate chiral spin symmetry of the thermal partition function. This symmetry is not a symmetry of the Dirac Lagrangian and is a symmetry of the electric part of the QCD Lagrangian. In this regime the medium consists of the chirally symmetric and approximately chiral spin symmetric hadrons that are made of the chirally symmetric quarks connected into the color singlet compounds by a confining chromoelectric field. This regime is evidenced by the approximate chiral spin symmetry of the spatial and temporal correlators and by the breakdown of the thermal perturbation theory at the crossover between the partonic (the quark-gluon plasma) and stringy fluid regimes at ~ 3 T_{ch}. The chiral spin symmetry smoothly disappears above ~ 3T_{ch} which means that the chromoelectric confining interaction gets screened. A direct evidence that the stringy fluid medium consists of densely packed hadrons is the pion spectral function that shows a distinct pion state and its first radial excitation above T_{ch}. Another direct evidence of the hadron degrees of freedom in the stringy fluid is the bottomonium spectrum with the 1S,2S,3S and 1P,2P radial and orbital excitations that become broad with temperature. The hadrons between T_{ch} and ~ 3 T_{ch} in the stringy fluid interact strongly which makes the stringy fluid more a liquid rather than a gas. We discuss how this chiral spin symmetric regime extends into the finite chemical potentials domain and present a qualitative sketch of the QCD phase diagram.
Comments:
39 pages. The review has been significantly extended. Accepted by Progress in Particle and Nuclear Physics
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2209.10235 [pdf]
PPNP(2023)·35 citations
09
[Submitted on 21 Sept 2022] (cross-list from hep-ph)
Coupled-channel dynamics with chiral long-range forces in the open-charm sector of QCD
Matthias F.M. Lutz🇩🇪 · Xiao-Yu Guo🇨🇳 · Yonggoo Heo🇩🇪 · C.L. Korpa🇭🇺
We perform an analysis of Lattice QCD data in the open-charm sector based on the chiral SU(3) Lagrangian. The low-energy constants are adjusted to recover the open-charm meson masses on Lattice QCD ensembles from HPQCD, ETMC and HSC with pion and kaon masses smaller than 550 MeV. A significant set of low-energy parameters is obtainable only if the most recent information from HSC on scattering observables is included in our global fit. For the first time our analysis considers the effect of left-hand cuts as developed in terms of a generalized potential approach (GPA) previously by one of the authors. Here we use coupled-channel interaction terms at the one-loop level. The elastic s-wave and p-wave $D π$ , $D K$ and $D K ˉ$ scattering phase shifts on ensembles with nominal pion masses of about 239 MeV and 391 MeV are reproduced faithfully. Based on such low-energy parameters we predict s- and p-wave phase shifts and inelasticities at physical quark masses, where the statistical uncertainties in the phase shifts are smaller than 1 degree always. Most striking would be the exotic s-wave $D_{s} π$ channel, for which we predict a resonance state at about 2.287 GeV where the phase shift passes through 90 degrees.
Comments:
73 pages, 8 figures, 28 tables, the revised manuscript includes a table with the pole masses of the 0^+ resonances
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2209.10601 [pdf]
PRD(2022)·17 citations
10
[Submitted on 22 Sept 2022] (cross-list from hep-lat)
Report of the Snowmass 2021 Topical Group on Lattice Gauge Theory
Zohreh Davoudi🇺🇸 · Ethan T. Neil🇺🇸 · Christian W. Bauer🇺🇸 · Tanmoy Bhattacharya🇺🇸 · Thomas Blum🇺🇸 · Peter Boyle🇺🇸 · Richard C. Brower🇺🇸 · Simon Catterall🇺🇸 · Norman H. Christ🇺🇸 · Vincenzo Cirigliano🇺🇸 · Gilberto Colangelo🇨🇭 · Carleton DeTar🇺🇸 and 26 other authors
Lattice gauge theory continues to be a powerful theoretical and computational approach to simulating strongly interacting quantum field theories, whose applications permeate almost all disciplines of modern-day research in High-Energy Physics. Whether it is to enable precision quark- and lepton-flavor physics, to uncover signals of new physics in nucleons and nuclei, to elucidate hadron structure and spectrum, to serve as a numerical laboratory to reach beyond the Standard Model, or to invent and improve state-of-the-art computational paradigms, the lattice-gauge-theory program is in a prime position to impact the course of developments and enhance discovery potential of a vibrant experimental program in High-Energy Physics over the coming decade. This projection is based on abundant successful results that have emerged using lattice gauge theory over the years: on continued improvement in theoretical frameworks and algorithmic suits; on the forthcoming transition into the exascale era of high-performance computing; and on a skillful, dedicated, and organized community of lattice gauge theorists in the U.S. and worldwide. The prospects of this effort in pushing the frontiers of research in High-Energy Physics have recently been studied within the U.S. decadal Particle Physics Planning Exercise (Snowmass 2021), and the conclusions are summarized in this Topical Report.
Comments:
57 pages, 1 figure. Submitted to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021). Topical Group Report for TF05 - Lattice Gauge Theory
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2209.10758 [pdf]
46 citations
11
[Submitted on 22 Sept 2022] (cross-list from quant-ph)
Preparations for Quantum Simulations of Quantum Chromodynamics in 1+1 Dimensions: (II) Single-Baryon $β$ -Decay in Real Time
Roland C. Farrell🇺🇸 · Ivan A. Chernyshev🇺🇸 · Sarah J. M. Powell🇨🇦 · Nikita A. Zemlevskiy🇺🇸 · Marc Illa🇺🇸 · Martin J. Savage🇺🇸
A framework for quantum simulations of real-time weak decays of hadrons and nuclei in a 2-flavor lattice theory in one spatial dimension is presented. A single generation of the Standard Model is found to require 16 qubits per spatial lattice site after mapping to spin operators via the Jordan-Wigner transformation. Both quantum chromodynamics and flavor-changing weak interactions are included in the dynamics, the latter through four-Fermi effective operators. Quantum circuits which implement time evolution in this lattice theory are developed and run on Quantinuum's H1-1 20-qubit trapped ion system to simulate the $β$ -decay of a single baryon on one lattice site. These simulations include the initial state preparation and are performed for both one and two Trotter time steps. The potential intrinsic error-correction properties of this type of lattice theory are discussed and the leading lattice Hamiltonian required to simulate $0 ν β β$ -decay of nuclei induced by a neutrino Majorana mass term is provided.
Comments:
27 pages, 11 figures. Typo fixed in v3
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2209.10781 [pdf]
PRD(2023)·130 citations
12
[Submitted on 22 Sept 2022] (cross-list from astro-ph.HE)
Parameterisations of thermal bomb explosions for core-collapse supernovae and 56Ni production
Liliya Imasheva (1,2) · H.-Thomas Janka (1,3) · Achim Weiss (1,2) ((1) MPI Astrophysics, Garching, (2) LMU, Munich, (3) TUM, Garching)
Thermal bombs are a widely used method to artificially trigger explosions of core-collapse supernovae (CCSNe) to determine their nucleosynthesis or ejecta and remnant properties. Recently, their use in spherically symmetric (1D) hydrodynamic simulations led to the result that {56,57}Ni and 44Ti are massively underproduced compared to observational estimates for Supernova 1987A, if the explosions are slow, i.e., if the explosion mechanism of CCSNe releases the explosion energy on long timescales. It was concluded that rapid explosions are required to match observed abundances, i.e., the explosion mechanism must provide the CCSN energy nearly instantaneously on timescales of some ten to order 100 ms. This result, if valid, would disfavor the neutrino-heating mechanism, which releases the CCSN energy on timescales of seconds. Here, we demonstrate by 1D hydrodynamic simulations and nucleosynthetic post-processing that these conclusions are a consequence of disregarding the initial collapse of the stellar core in the thermal-bomb modelling before the bomb releases the explosion energy. We demonstrate that the anti-correlation of 56Ni yield and energy-injection timescale vanishes when the initial collapse is included and that it can even be reversed, i.e., more 56Ni is made by slower explosions, when the collapse proceeds to small radii similar to those where neutrino heating takes place in CCSNe. We also show that the 56Ni production in thermal-bomb explosions is sensitive to the chosen mass cut and that a fixed mass layer or fixed volume for the energy deposition cause only secondary differences. Moreover, we propose a most appropriate setup for thermal bombs.
Comments:
24 pages, 12 figures; version accepted by MNRAS after minor revision
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2209.10989 [pdf]
MNRAS(2022)·13 citations
13
[Submitted on 22 Sept 2022] (cross-list from nucl-ex)
Imaging the initial condition of heavy-ion collisions and nuclear structure across the nuclide chart
Jiangyong Jia🇺🇸 · Giuliano Giacalone🇩🇪 · Benjamin Bally🇫🇷 · James Daniel Brandenburg🇺🇸 · Ulrich Heinz🇺🇸 · Shengli Huang🇺🇸 · Dean Lee🇺🇸 · Yen-Jie Lee🇺🇸 · Wei Li🇺🇸 · Constantin Loizides🇺🇸 · Matthew Luzum🇧🇷 · Govert Nijs🇺🇸 and 9 other authors
High-energy nuclear collisions encompass three key stages: the structure of the colliding nuclei informed by low-energy nuclear physics, the initial condition (IC) leading to the formation of quark-gluon plasma (QGP), and the hydrodynamic expansion and hadronization of the QGP leading to final-state hadrons observed experimentally. Recent advances in experimental and theoretical methods have ushered in a precision era, enabling an increasingly accurate understanding of these stages. However, most approaches involve simultaneously determining both QGP properties and initial conditions from a single collision system, creating complexity due to the coupled contributions of various stages to the final-state observables. To avoid this, we propose leveraging known knowledge of low-energy nuclear structure and hydrodynamic observables to constrain the IC independently. By conducting comparative studies of collisions involving isobar-like nuclei - species with similar mass numbers but different structures - we disentangle the initial condition's impacts from the QGP properties. This approach not only refines our understanding of the IC but also turns high-energy experiments into a precision tool for imaging nuclear structures, offering insights that complement traditional low-energy approaches. Opportunities for carrying out such comparative experiments at the LHC and other facilities could significantly advance both high-energy and low-energy nuclear physics. Additionally, this approach has implications for the future EIC. While the possibilities are extensive, we focus on selected proposals that could benefit both the high-energy and low-energy nuclear physics communities. Originally prepared as input for the long-range plan of U.S. nuclear physics, this white paper reflects the status as of September 2022, with a brief update on developments since then.
Comments:
25 pages, 6 figures, include a brief update on progress since Oct 2022
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2209.11042 [pdf]
Nucl.Sci.Tech.(2024)·128 citations
14
[Submitted on 22 Sept 2022] (cross-list from hep-ph)
Kinematical higher-twist corrections in $γ^{*} γ \to M M ˉ$
Cédric Lorcé🇫🇷 · Bernard Pire🇫🇷 · Qin-Tao Song🇫🇷
We estimate kinematical higher-twist (up to twist 4) corrections to the $γ^{*} (q_{1}) γ (q_{2}) \to M (p_{1}) M ˉ (p_{2})$ amplitudes at large $Q^{2} = - q_{1}^{2}$ and small $s = (q_{1} + q_{2})^{2}$ , where $M$ is a scalar or pseudoscalar meson. This process is known to factorize at leading twist into a perturbatively calculable coefficient function and generalized distribution amplitudes (GDAs). The kinematical higher-twist contributions of order $s / Q^{2}$ and $m^{2} / Q^{2}$ turn out to be important in the cross section, considering the kinematics accessible at Belle and Belle II. We present numerical estimates for the cross section for $γ^{*} γ \to π^{0} π^{0}$ with the $π π$ GDA extracted from Belle measurements and with the asymptotic $π π$ GDA as inputs to study the magnitude of the kinematical corrections. To see how the target mass corrections of order $m^{2} / Q^{2}$ affect the cross section, we also perform the calculation for $γ^{*} γ \to η η$ by using a model $η η$ GDA.In the range $s > 1$ GeV $^{2}$ , the kinematical higher-twist corrections account for $\sim 15%$ of the total cross section, an effect which is not negligible. Since $π π$ GDAs are the best way to access the pion energy-momentum tensor (EMT), our study demonstrates that an accurate evaluation of EMT form factors requires the inclusion of kinematical higher-twist contributions.
Comments:
17 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2209.11140 [pdf]
PRD(2022)·17 citations
15
[Submitted on 22 Sept 2022] (cross-list from hep-ph)
A Better Angle on Hadron Transverse Momentum Distributions at the EIC
Anjie Gao🇺🇸 · Johannes K. L. Michel🇺🇸 · Iain W. Stewart🇺🇸 · Zhiquan Sun🇺🇸
We propose an observable $q_{*}$ sensitive to transverse momentum dependence (TMD) in $e N \to e h X$ , with $q_{*} / E_{N}$ defined purely by lab-frame angles. In 3D measurements of confinement and hadronization this resolves the crippling issue of accurately reconstructing small transverse momentum $P_{h T}$ . We prove factorization for $d σ_{h} / d q_{*}$ for $q_{*} ≪ Q$ with standard TMD functions, enabling $q_{*}$ to substitute for $P_{h T}$ . A double-angle reconstruction method is given which is exact to all orders in QCD for $q_{*} ≪ Q$ . $q_{*}$ enables an order-of-magnitude improvement in the expected experimental resolution at the EIC.
Comments:
5 pages + 4 figures, 9 pages of supplemental material
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2209.11211 [pdf]
PRD(2023)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE