Nuclear Theory·nucl-th

Thursday·February 29, 2024

10 papers—1 primary·9 cross-listed

01
[Submitted on 28 Feb 2024]
Polarized-deuteron scattering by spin-zero target nuclei at intermediate energies
Valery I. Kovalchuk
General analytical expressions for the observables in $d A$ -scattering reaction have been derived in the diffraction approximation. The resulting formulas describe the cross section and polarization states of the deuteron when it scattering by nuclei with zero spin in the ground state. The tabulated distributions of the target nucleus density and the realistic deuteron wave functions calculated on the basis of Nijmegen nucleon-nucleon potentials were used. The nucleon-nucleus phases were calculated in the framework of Glauber formalism and making use of the double-folding potential. The calculated cross sections and analyzing powers in elastic scattering of deuterons by $^{16} O$ and $^{40} Ca$ nuclei at 700 MeV are compared with the corresponding experimental data.
Comments:
16 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2402.18521 [pdf]
EPJA(2024)·1 citation
02
[Submitted on 22 Jan 2024] (cross-list from hep-lat)
Microscopic Origin of Criticality at Macroscale in QCD Chiral Phase Transition
Heng-Tong Ding🇨🇳 · Wei-Ping Huang🇨🇳 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸
We reveal that the criticality of the chiral phase transition in QCD at the macroscale arises from the microscopic energy levels of its fundamental constituents, the quarks. We establish a novel relation between cumulants of the chiral order parameter (i.e., chiral condensate) and correlations among the energy levels of quarks (i.e., eigenspectra of the massless Dirac operator), which naturally leads to a generalization of the Banks-Casher relation. Based on this novel relation and through (2+1)-flavor lattice QCD calculations using the HISQ action with varying light quark masses in the vicinity of the chiral phase transition, we demonstrate that the correlations among the infrared part of the Dirac eigenspectra exhibit same universal scaling behaviors as expected of the cumulants of the chiral condensate. We find that these universal scaling behaviors extend up to the physical values of the up and down quark masses.
Comments:
4 pages, 2 figures, talk presented at the 30th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions (Quark Matter 2023), September 3-9, 2023, Houston, Texas, USA. arXiv admin note: text overlap with arXiv:2401.10263
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2402.16867 [pdf]
EPJ Web Conf.(2024)·0 citations
03
[Submitted on 26 Feb 2024] (cross-list from hep-ph)
Exploring the Sensitivity to Non-Standard Neutrino Interactions of NaI and Cryogenic CsI Detectors at the Spallation Neutron Source
Sabya Sachi Chatterjee🇩🇪 · Stéphane Lavignac🇫🇷 · O. G. Miranda🇲🇽 · G. Sanchez Garcia🇪🇸
After the first observation of coherent elastic neutrino-nucleus scattering (CE $ν$ NS) by the COHERENT collaboration, many efforts are being made to improve the measurement of this process, making it possible to constrain new physics in the neutrino sector. In this paper, we study the sensitivity to non-standard interactions (NSIs) and generalized neutrino interactions (GNIs) of two experimental setups at the Spallation Neutron Source at Oak Ridge National Laboratory: a NaI detector with characteristics similar to the one that is currently being deployed there, and a cryogenic CsI detector proposed at the same facility. We show that a combined analysis of the data from these detectors, whose target nuclei have significantly different proton-to-neutron ratios, could help to partially break the parameter degeneracies arising from the interference between the Standard Model and NSI contributions to the CE $ν$ NS cross section, as well as between different NSI parameters. By contrast, only a slight improvement over the current CsI constraints is expected for parameters that do not interfere with the SM contribution.
Comments:
V2: 30 pages, 9 pdf figures, and 4 tables. Quenching factor for Iodine in the NaI detector corrected, improved analysis involving the combination with a future cryogenic CsI detector. Title modified. Accepted in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2402.16953 [pdf]
PRD(2024)·8 citations
04
[Submitted on 26 Feb 2024] (cross-list from hep-ph)
Resolving the Ultracollinear Paradox with Effective Field Theory
Matthew Baumgart🇺🇸 · Panagiotis Christeas🇺🇸
Naive intuition about scale decoupling breaks down in the presence of fermion masses. Kinematic enhancements can greatly extend the range where one needs to keep a finite mass in calculations to obtain a correct result at even the O(1) level. Treating a light fermion as massive though, leads to a known but somewhat obscure paradox, a seeming leading-order sensitivity to an arbitrarily small mass. We show how a proper formulation in effective field theory not only resolves the physical conundrum, but answers the very practical question of when fermion masses are required. This has important implications for the development of shower Monte Carlo above the weak scale.
Comments:
21 pages plus appendices, 8 figures. v2: literature discussion expanded
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2402.16961 [pdf]
PRD(2024)·0 citations
05
[Submitted on 27 Feb 2024] (cross-list from hep-ph)
Estimation of electric field in intermediate-energy heavy-ion collisions
Hidetoshi Taya🇯🇵 · Toru Nishimura🇯🇵 · Akira Ohnishi🇯🇵
We estimate the spacetime profile of the electric field in head-on heavy-ion collisions at intermediate collision energies $s_{NN} = O (3 - 10 GeV)$ . Using a hadronic cascade model (JAM; Jet AA Microscopic transport model), we numerically demonstrate that the produced field has strength $e E = O ((30 - 60 MeV)^{2})$ , which is supercritical to the Schwinger limit of QED and is non-negligibly large compared even to the hadron/QCD scale, and survives for a long time $τ = O (10 fm / c)$ due to the baryon stopping. We show that the produced field is nonperturbatively strong in the sense that the nonperturbativity parameters (e.g., the Keldysh parameter) are sufficiently large. This is in contrast to high-energy collisions $s_{NN} ≳ 100 GeV$ , where the field is extremely short-lived and hence is perturbative. Our results imply that the electromagnetic field may have phenomenological impacts on hadronic/QCD processes in intermediate-energy heavy-ion collisions and that heavy-ion collisions can be used as a new tool to explore strong-field physics in the nonperturbative regime.
Comments:
15 pages, 4 figures. v2: version to be published in PRC. Animations available on the author's website https://hidetoshitaya.github.io/misc/EMfieldinHIC.html
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2402.17136 [pdf]
PRC(2024)·13 citations
06
[Submitted on 27 Feb 2024] (cross-list from hep-ph)
Impact of strong magnetic field, baryon chemical potential, and medium anisotropy on polarization and spin alignment of hadrons
Bhagyarathi Sahoo🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳
The recent observation of global spin polarization of $Λ$ ( $Λ ˉ$ ) hyperons and the spin alignment of $ϕ$ and $K^{* 0}$ vector mesons create remarkable interest in investigating the particle polarization in the relativistic fluid produced in heavy-ion collisions at GeV/TeV energies. Among other sources of spin polarization phenomena, the Debye mass of a medium plays a crucial role in particle polarization. Any modification brought to the effective mass due to the temperature, strong magnetic field ( $e B$ ), baryonic chemical potential ( $μ_{B}$ ), medium anisotropy ( $ξ$ ), and vorticity, etc., certainly affects the particle spin polarization. In this work, we explore the global hyperon spin polarization and the spin alignment of vector mesons corresponding to the strong magnetic field, baryonic chemical potential, and medium anisotropy. We find that the degree of spin polarization is flavor-dependent for hyperons. Meanwhile, vector meson spin alignment depends on the hadronization mechanisms of initially polarized quarks and anti-quarks. Medium anisotropy significantly changes the degree of spin polarization compared to the magnetic field and baryon chemical potential.
Comments:
15 pages and 7-captioned figures. Same as the published version in EPJC
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2402.17344 [pdf]
EPJC(2025)·15 citations
07
[Submitted on 27 Feb 2024] (cross-list from hep-ph)
T-odd gluon distribution functions in a spectator model
Alessandro Bacchetta🇮🇹 · Francesco Giovanni Celiberto🇪🇸 · Marco Radici🇮🇹
We present a model calculation of T-odd transverse-momentum-dependent distributions of gluons in the nucleon. The model is based on the assumption that a nucleon can emit a gluon, and what remains after the emission is treated as a single spectator particle. This spectator particle is considered to be on-shell, but its mass is allowed to take a continuous range of values, described by a spectral function. The final-state interaction that is necessary to generate T-odd functions is modeled as the exchange of a single gluon between the spectator and the outgoing parton.
Comments:
32 pages, 7 (multiple) figures, 2 appendices with details of calculations
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2402.17556 [pdf]
EPJC(2024)·47 citations
08
[Submitted on 27 Feb 2024] (cross-list from cond-mat.quant-gas)
Many-body perturbation theory for strongly correlated effective Hamiltonians using effective field theory methods
Raphaël Photopoulos · Antoine Boulet
Introducing low-energy effective Hamiltonians is usual to grasp most correlations in quantum many-body problems. For instance, such effective Hamiltonians can be treated at the mean-field level to reproduce some physical properties of interest. Employing effective Hamiltonians that contain many-body correlations renders the use of perturbative many-body techniques difficult because of the overcounting of correlations. In this work, we develop a strategy to apply an extension of the many-body perturbation theory starting from an effective interaction that contains correlations beyond the mean field level. The goal is to re-organize the many-body calculation to avoid the overcounting of correlations originating from the introduction of correlated effective Hamiltonians in the description. For this purpose, we generalize the formulation of the Rayleigh-Schrödinger perturbation theory by including free parameters adjusted to reproduce the appropriate limits. In particular, the expansion in the bare weak-coupling regime and the strong-coupling limit serves as a valuable input to fix the value of the free parameters appearing in the resulting expression. This method avoids double counting of correlations using beyond-mean-field strategies for the description of many-body systems. The ground state energy of various systems relevant for ultracold atomic, nuclear, and condensed matter physics is reproduced qualitatively beyond the domain of validity of the standard many-body perturbation theory. Finally, our method suggests interpreting the formal results obtained as an effective field theory using the proposed reorganization of the many-body calculation. The results, like ground state energies, are improved systematically by considering higher orders in the extended many-body perturbation theory while maintaining a straightforward polynomial expansion.
Comments:
16 pages, 5 figures, 5 tables
Subjects:
Quantum Gases (cond-mat.quant-gas); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2402.17627 [pdf]
SciPost Phys.(2025)·0 citations
09
[Submitted on 27 Feb 2024] (cross-list from hep-ph)
Dual chiral density wave induced oscillating Casimir effect
Daisuke Fujii🇯🇵 · Katsumasa Nakayama🇯🇵 · Kei Suzuki🇯🇵
The Casimir effect is known to be induced from photon fields confined by a small volume, and also its fermionic counterpart has been predicted in a wide range of quantum systems. Here, we investigate what types of Casimir effects can occur from quark fields in dense and thin quark matter. In particular, in the dual chiral density wave, which is a possible ground state of dense quark matter, we find that the Casimir energy oscillates as a function of the thickness of matter. This oscillating Casimir effect is regarded as an analog of that in Weyl semimetals and is attributed to the Weyl points in the momentum space of quark fields. In addition, we show that an oscillation is also induced from the quark Fermi sea, and the total Casimir energy is composed of multiple oscillations.
Comments:
15 pages, 11 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2402.17638 [pdf]
PRD(2024)·9 citations
10
[Submitted on 28 Feb 2024] (cross-list from quant-ph)
On the exact solution for the Schrödinger equation
Yair Mulian
For almost 75 years, the general solution for the Schrödinger equation was assumed to be generated by an exponential or a time-ordered exponential known as the Dyson series. We study the unitarity of a solution in the case of a singular Hamiltonian and provide a new methodology that is not based on the assumption that the underlying space is $L^{2} (R)$ . Then, an alternative operator for generating the time evolution that is manifestly unitary is suggested, regardless of the choice of Hamiltonian. The new construction involves an additional positive operator that normalizes the wave function locally and allows us to preserve unitarity, even when dealing with infinite dimensional or non-normed spaces. Our considerations show that Schrödinger and Liouville equations are, in fact, two sides of the same coin and together they provide a unified description for unbounded quantum systems.
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Theory (hep-th); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2402.18499 [pdf]
Particles(2024)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE