Nuclear Theory·nucl-th

Monday·December 4, 2023

8 papers—2 primary·6 cross-listed

01
[Submitted on 1 Dec 2023]
Generic multi-particle transverse momentum correlations as a new tool for studying nuclear structure at the energy frontier
Emil Gorm Dahlbæk Nielsen🇩🇰 · Frederik K. Rømer🇩🇰 · Kristjan Gulbrandsen🇩🇰 · You Zhou🇩🇰
The mean transverse momentum of produced particles, [pt], and its event-by-event fluctuations give direct access to the initial conditions of ultra-relativistic heavy-ion collisions and help probe the colliding nuclei's structure. The [pt] fluctuations can be studied via multi-particle pt correlations; so far, only the lowest four orders have been studied. Higher-order fluctuations can provide stronger constraints on the initial conditions and improved sensitivity to the detailed nuclear structure; however, their direct implementation can be challenging and is still lacking. In this paper, we apply a generic recursive algorithm for the genuine multi-particle pt correlations, which enables the accurate study of higher-order [pt] fluctuations without computationally heavy processing for the first time. With this algorithm, we will examine the power of multi-particle pt correlations through Monte Carlo model studies with different nuclear structures. The impact on the nuclear structure studies, including the nuclear deformation and triaxial structure, will be discussed. These results will demonstrate the usefulness of multi-particle pt correlations for studying nuclear structure in high-energy nuclei collisions at RHIC and the LHC, which could serve as complementary to existing low-energy nuclear structure studies.
Comments:
10 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.00492 [pdf]
EPJA(2024)·18 citations
02
[Submitted on 1 Dec 2023]
Shape coexistence and superdeformation in $^{28}$ Si
D. Frycz · J. Menéndez · A. Rios · A. M. Romero
We study the shape coexistence of differently deformed states within $^{28}$ Si using shell-model and beyond-mean-field techniques. Experimentally, $^{28}$ Si exhibits shape coexistence between an oblate ground state and an excited prolate structure. The oblate rotational band is described well within the $s d$ shell using the USDB interaction. However, for the prolate band, a modification of this interaction is required, lowering the single-particle energy of the $1 d_{3/2}$ orbit. Furthermore, we explore the possibility of a superdeformed configuration in $^{28}$ Si. Our calculations, spanning both the $s d$ and $p f$ shells, rule out the existence of a superdeformed $0^{+}$ bandhead within an excitation energy range of 10-20 MeV.
Comments:
6 pages, 4 figures. To be published in XXXVII Mazurian Lakes Conference Proceedings
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.00750 [pdf]
Acta Phys.Polon.Supp.(2024)·0 citations
03
[Submitted on 1 Dec 2023] (cross-list from hep-ph)
Spherically symmetric anisotropic strange stars
Luiz L. Lopes🇧🇷 · H. C. Das🇮🇹
In this work, we made an extensive study about the possible presence of anisotropies in strange stars. To accomplish this task, we use three different configurations for the strange matter: the unpaired matter, a two-flavor super-conducting (2SC) strange matter, and a fully three-flavor super-conducting strange matter (CFL). For each configuration, we calculate the relevant quantities for the strange stars, such as the mass-radius relation, the dimensionless tidal parameter, the moment of inertia, and the surface curvature for different degrees of anisotropies. Whenever possible, we compare our results with constraints found in the literature, especially focusing on the existence of very massive pulsars (PSR J0952-0607), as well as very light compact objects (HESS J1731-347).
Comments:
13 pages, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2312.00310 [pdf]
EPJC(2024)·9 citations
04
[Submitted on 1 Dec 2023] (cross-list from hep-ph)
Jet quenching parameter in QCD kinetic theory
Kirill Boguslavski🇦🇹 · Aleksi Kurkela🇳🇴 · Tuomas Lappi🇫🇮 · Florian Lindenbauer🇦🇹 · Jarkko Peuron🇫🇮
We study the jet quenching parameter $q^$ in a non-equilibrium plasma using the QCD effective kinetic theory. We discuss subleading terms at large jet momentum p, show that our expression for $q^$ reproduces thermal results at small and large transverse momentum cutoffs for infinite p and construct an interpolation between these limits to be used in phenomenological applications. Using simple non-equilibrium distributions that model pertinent features of the bottom-up thermalization scenario, we analytically assess how anisotropy, under- or overoccupation affect the jet quenching parameter. Our work provides more details on the $q^$ formula used in our preceding work [arXiv:2303.12595] and sets the stage for further numerical studies of jet momentum broadening in the initial stages of heavy-ion collisions from QCD kinetic theory.
Comments:
34 pages, 10 figures, accepted for publication in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.00447 [pdf]
PRD(2024)·42 citations
05
[Submitted on 1 Dec 2023] (cross-list from hep-lat)
Comparing phenomenological estimates of dilepton decays of pseudoscalar mesons with lattice QCD
Bai-Long Hoid🇨🇭 · Martin Hoferichter🇨🇭 · Jacobo Ruiz de Elvira🇪🇸
Dilepton decays of pseudoscalar mesons have been drawing particular interest, thanks to their sensitivity to both the QCD dynamics at low energy and also signals beyond the Standard Model. In this context, we shortly review our recent study on an improved Standard-Model prediction for the rare decay $π^{0} \to e^{+} e^{-}$ , and compare it with the first determination on the lattice that predicted also the $π^{0} \to γ γ$ decay width as a byproduct. In addition, we discuss our recent work on $K_{L} \to ℓ^{+} ℓ^{-}$ decays and its connection to lattice QCD. We comment on the current uncertainty estimates and discuss how they could be improved profiting from future experiments and progress in lattice QCD.
Comments:
7 pages; proceedings of the 40th International Symposium on Lattice Field Theory (LATTICE2023)
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.00520 [pdf]
PoS(2024)·4 citations
06
[Submitted on 1 Dec 2023] (cross-list from hep-ph)
Partial-wave projection of the one-particle exchange in three-body scattering amplitudes
Andrew W. Jackura🇺🇸 · Raúl A. Briceño🇺🇸
As the study of three-hadron physics from lattice QCD matures, it is necessary to develop proper analysis tools in order to reliably study a variety of phenomena, including resonance spectroscopy and nuclear structure. Reconstructing the three-particle scattering amplitude requires solving integral equations, which can be written in terms of data-constrained dynamical functions and physical on-shell quantities. The driving term in these equations is the so-called one-particle exchange, which leads to a kinematic divergence for particles on-mass-shell. A vital component in defining three-particle amplitudes with definite parity and total angular momentum, which are used in spectroscopic studies, is to project the one-particle exchange into definite partial waves. We present a general procedure to construct exact analytic partial wave projections of the one-particle exchange contribution for any system composed of three spinless hadrons. Our result allows one full control over the analytic structure of the projection, which we explore for some low-lying partial waves with applications to three pions.
Comments:
73 pages, 17 figures, 4 appendices, ancillary Mathematica notebook at https://github.com/ajackura/partial_wave_three_body_ope_notebook
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2312.00625 [pdf]
PRD(2024)·27 citations
07
[Submitted on 1 Dec 2023] (cross-list from hep-ph)
Functional Renormalization Group Study of Thermodynamic Geometry Around the Phase Transition of Quantum Chromodynamic
Fabrizio Murgana🇮🇹 · Vincenzo Greco🇮🇹 · Marco Ruggieri🇮🇹 · Dario Zappalà🇮🇹
We investigate the thermodynamic geometry of the quark-meson model at finite temperature, $T$ , and quark number chemical potential, $μ$ . We extend previous works by the inclusion of fluctuations exploiting the functional renormalization group approach. We use recent developments to recast the flow equation into the form of an advection-diffusion equation. We adopt the local potential approximation for the effective average action. We focus on the thermodynamic curvature, $R$ , in the $(μ, T)$ plane, in proximity of the chiral crossover, up to the critical point of the phase diagram. We find that the inclusion of fluctuations results in a smoother behavior of $R$ near the chiral crossover. Moreover, for small $μ$ , $R$ remains negative, signaling the fact that bosonic fluctuations reduce the capability of the system to completely overcome the fermionic statistical repulsion of the quarks. We investigate in more detail the small $μ$ region by analyzing a system in which we artificially lower the pion mass, thus approaching the chiral limit in which the crossover is actually a second order phase transition. On the other hand, as $μ$ is increased and the critical point is approached, we find that $R$ is enhanced and a sign change occurs, in agreement with mean field studies. Hence, we completely support the picture that $R$ is sensitive to a crossover and a phase transition, and provides information about the effective behavior of the system at the phase transition.
Comments:
12 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2312.00665 [pdf]
PRD(2024)·8 citations
08
[Submitted on 29 Nov 2023] (cross-list from hep-lat)
Theoretical Developments in Lattice Gauge Theory for Applications in Double-beta Decay Processes and Quantum Simulation
Saurabh V. Kadam🇺🇸
Double beta decays are rare nuclear processes that can occur in two modes: two-neutrino double beta decay, observed in the Standard Model, and neutrinoless double beta decay, a hypothetical process with profound implications for Particle Physics. To draw reliable conclusions from their experimental constraints, it is necessary to have accurate predictions of the underlying hadronic interactions described by quantum chromodynamics (QCD), a non-Abelian gauge theory with the symmetry group SU(3). QCD predictions require non-perturbative methods for calculating observables, and lattice QCD (LQCD), a numerical method based on QCD formulated on a finite space-time grid, is the only reliable first-principles technique for obtaining quantitative results. However, LQCD needs formal prescriptions to match numerical results with observables. This thesis provides such prescriptions for double beta decays using the finite volume effects in the LQCD framework. Matching relations that connect two-nucleon double beta decay amplitudes to quantities accessible via LQCD calculations, namely the nuclear matrix elements and two-nucleon energy spectra in a finite volume are provided. The impact of uncertainties is examined on the precision with which low-energy constants of the corresponding effective field theories can be determined from future LQCD calculations. Hamiltonian simulation of QCD is another non-perturbative method of solving QCD which can be more suitable in some cases than the conventional LQCD. The rise of tensor network methods and quantum simulation has made Hamiltonian simulation of lattice gauge theories (LGTs) a reality. Towards the goal of simulating QCD, a loop-string-hadron (LSH) formulation of an SU(3) LGT with matter in 1+1 dimensions is developed in this thesis, motivated by recent studies that showed the LSH formulation of an SU(2) LGT to be advantageous over other formulations.
Comments:
PhD Thesis: 324 pages, 38 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2312.00780 [pdf]
6 citations

Affiliations

first authorsco-authorsvia INSPIRE