Nuclear Theory·nucl-th

Wednesday·December 20, 2023

12 papers—3 primary·9 cross-listed

04
[Submitted on 18 Dec 2023] (cross-list from hep-ph)
Wee partons in QCD and gravity: double copy and universality
Himanshu Raj🇺🇸 · Raju Venugopalan🇺🇸
We discuss a quantitative "double copy" between radiation from shockwave collisions in Einstein gravity and in QCD. The correspondence extends to $2 \to N$ amplitudes in Regge asymptotics. The classicalization and unitarization of these amplitudes at maximal occupancy, corresponding to black hole and Color Glass Condensate (CGC) states respectively, are described by the emergent Goldstone dynamics of wee partons. We outline some consequences of the universal dynamics on both sides of the correspondence.
Comments:
4 pages, Talk in "Proceedings of XXXth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions (Quark Matter 2023)"
Subjects:
High Energy Physics — Phenomenology (hep-ph); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2312.11652 [pdf]
EPJ Web Conf.(2024)·2 citations
05
[Submitted on 18 Dec 2023] (cross-list from gr-qc)
First constraint on the dissipative tidal deformability of neutron stars
Justin L. Ripley🇺🇸 · Abhishek Hegade K.R.🇺🇸 · Rohit S. Chandramouli🇺🇸 · Nicolas Yunes🇺🇸
The gravitational waves (GWs) emitted by neutron star binaries probe the physics of matter at supra nuclear densities. During the late inspiral, tidal deformations raised on each star by the gravitational field of its companion depend crucially on the star's internal properties. The misalignment of a star's tidal bulge with its companion's gravitational field encodes the strength of internal dissipative processes, which imprint onto the phase of the gravitational waves emitted. We here analyze GW data from the GW170817 (binary neutron star) event detected by LIGO and Virgo and find the first constraint on the dissipative tidal deformability of a neutron star. From this constraint, \emph{assuming} a temperature profile for each star in the binary, we obtain an order of magnitude bound on the averaged bulk ( $ζ$ ) and shear ( $η$ ) viscosity of each star during the inspiral.: $ζ ≲ 1 0^{31} g cm^{- 1} s^{- 1}$ and $η ≲ 1 0^{28} g cm^{- 1} s^{- 1}$ . We forecast that these bounds could be improved by two orders of magnitude with third-generation detectors, like Cosmic Explorer, using inspiral data. These constraints already inform nuclear physics models and motivate further theoretical work to better understand the interplay between viscosity and temperature in the late inspiral of neutron stars.
Comments:
7 pages, 4 figures; edits in response to referee comments; minor typos corrected
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.11659 [pdf]
Nature Astron.(2024)·52 citations
06
[Submitted on 19 Dec 2023] (cross-list from hep-lat)
Finite-size behavior of higher-order cumulant ratios near criticality in two-dimensional Potts models
Rajiv V. Gavai🇮🇳 · Bedangadas Mohanty🇮🇳 · Jaydev Singh Rao🇮🇳 · Swati Saha🇮🇳
Theoretical considerations predict a specific hierarchy among ratios of net-baryon number cumulants ( $χ_{n}$ , where $n$ is the order of cumulant) in the vicinity of the transition from the low-temperature hadronic phase to the high temperature quark-gluon plasma phase at small baryon chemical potential, $μ_{B}$ , in the QCD phase diagram. This hierarchy, $\frac{χ _{6}}{χ _{2}} < \frac{χ _{5}}{χ _{1}} < \frac{χ _{4}}{χ _{2}} < \frac{χ _{3}}{χ _{1}}$ , has been observed by the STAR experiment in net-proton number (a proxy of net-baryon number) cumulant ratios over a broad range of collision energies. Motivated by these findings, we investigate whether similar ordering emerges generically in finite statistical systems undergoing second-order phase transitions. We employ two different spin models: the two-state and three-state Potts models in two dimensions, both exhibiting a transition from an ordered phase to a disordered phase at their respective critical temperatures. Monte Carlo simulations are performed on square lattices of varying sizes using the Wolff cluster algorithm. Cumulants of the total magnetization are calculated up to sixth order in both of these models in a temperature range near their corresponding critical temperatures. Higher-order cumulants exhibit extrema (peaks/troughs) whose magnitudes grow with both cumulant order and lattice size, reflecting enhanced critical fluctuations. Except within a narrow temperature window above the critical temperature, neither the complete hierarchy nor its exact reverse is realized over the studied temperature range in either model.
Comments:
To appear in Journal of Physics G: Nuclear and Particle Physics
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.12130 [pdf]
J.Phys.G(2026)·1 citation
07
[Submitted on 19 Dec 2023] (cross-list from nucl-ex)
Measurements of azimuthal anisotropies in $^{16}$ O+ $^{16}$ O and $γ$ +Au collisions from STAR
Shengli Huang🇺🇸
In this proceeding, we present the first measurements of azimuthal anisotropies, $v_{2}$ and $v_{3}$ , in $^{16}$ O+ $^{16}$ O collisions at 200 GeV as a function of transverse momentum and multiplicity, by using two- and four-particle correlation methods. We compare our measurements with STAR measurements of $v_{n}$ in \dau and \heau collisions to provide insight into the impact of system symmetry on initial condition for small systems. We also investigate the ratio $v_{2} {4} / v_{2} {2}$ as a function of centrality, which is expected to be sensitive to nucleon-nucleon correlation in the $^{16}$ O nucleus.
Comments:
4 Pages, 3 figures, Quark Matter 2023 Proceeding
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.12167 [pdf]
29 citations
08
[Submitted on 19 Dec 2023] (cross-list from hep-ph)
Heavy quark momentum diffusion coefficient during hydrodynamization via effective kinetic theory
Kirill Boguslavski🇦🇹 · Aleksi Kurkela🇳🇴 · Tuomas Lappi🇫🇮 · Florian Lindenbauer🇦🇹 · Jarkko Peuron🇫🇮
In these proceedings, we compute the heavy quark momentum diffusion coefficient using QCD effective kinetic theory for a plasma going through the bottom-up thermalization scenario until approximate hydrodynamization. This transport coefficient describes heavy quark momentum diffusion in the quark-gluon plasma and is used in many phenomenological frameworks, e.g. in the open quantum systems approach. Our extracted nonthermal diffusion coefficient matches the thermal one for the same energy density within 30\%. At large occupation numbers in the earliest stage, the transverse diffusion coefficient dominates, while the longitudinal diffusion coefficient is larger for the underoccupied system in the later stage of hydrodynamization.
Comments:
4 pages 3 figures, Proceedings for Quark Matter 2023
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.12200 [pdf]
EPJ Web Conf.(2024)·1 citation
09
[Submitted on 19 Dec 2023] (cross-list from hep-lat)
Heavy Quark Momentum Broadening in a Non-Abelian Plasma away from Thermal Equilibrium
Harshit Pandey🇮🇳 · Soeren Schlichting🇩🇪 · Sayantan Sharma🇮🇳
We perform classical-statistical real-time lattice simulations to compute real-time spectral functions and momentum broadening of quarks in the presence of strongly populated non-Abelian gauge fields. Based on a novel methodology to extract the momentum broadening for relativistic quarks, we find that the momentum distribution of quarks exhibit interesting non-perturbative features as a function of time due to correlated momentum kicks it receives from the medium, eventually going over to a diffusive regime. We extract the momentum diffusion coefficient for a mass range describing charm and bottom quarks and find sizeable discrepancies from the heavy quark limit.
Comments:
v2: published version
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2312.12280 [pdf]
PRL(2024)·28 citations
10
[Submitted on 19 Dec 2023] (cross-list from hep-ph)
Quarkonium transport in weakly and strongly coupled plasmas
Govert Nijs🇨🇭 · Bruno Scheihing-Hitschfeld🇺🇸 · Xiaojun Yao🇺🇸
We report on progress in the nonperturbative understanding of quarkonium dynamics inside a thermal plasma. The time evolution of small-size quarkonium is governed by two-point correlation functions of chromoelectric fields dressed with an adjoint Wilson line, known in this context as generalized gluon distributions (GGDs). The GGDs have been calculated in both weakly and strongly coupled plasmas by using perturbative and holographic methods. Strikingly, the results of our calculations for a strongly coupled plasma indicate that the quarkonium dissociation and recombination rates vanish in the transport descriptions that assume quarkonium undergoes Markovian dynamics. However, this does not imply that the dynamics is trivial. As a starting point to explore the phenomenological consequences of the result at strong coupling, we show a calculation of the $Υ (1 S)$ formation probability in time-dependent perturbation theory. This is a first step towards the development of a transport formalism that includes non-Markovian effects, which, depending on how close the as of yet undetermined nonperturbative QCD result of the GGDs is to the strongly coupled $N = 4$ SYM result, could very well dominate over the Markovian ones in quark-gluon plasma produced at RHIC and the LHC.
Comments:
4 pages, 1 figure. Contribution to the proceedings of the 30th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions (Quark Matter 2023)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.12307 [pdf]
EPJ Web Conf.(2024)·6 citations
11
[Submitted on 19 Dec 2023] (cross-list from hep-ph)
Introducing the concept of the Widom line in the QCD phase diagram
G. Sordi🇬🇧 · A.-M. S. Tremblay🇨🇦
Critical phenomena emerging from the critical end point of a first-order transition are ubiquitous in nature. Here we bring the concept of a supercritical crossover, the Widom line, initially developed in the context of fluids, into the interacting matter described by quantum chromodynamics (QCD). We show that the existence of the putative critical end point between hadron gas and quark-gluon plasma in the temperature versus chemical potential of the QCD phase diagram implies the existence of a Widom line emerging from it in the supercritical region. We survey the thermodynamic anomalies already identified in simplified theoretical models of QCD exhibiting a critical end point, to show that they can be interpreted in terms of a Widom line. Then we suggest possible directions where the Widom line concept could provide new light on the QCD phase diagram.
Comments:
8 pages, 5 figures; accepted version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2312.12401 [pdf]
PRD(2024)·8 citations
12
[Submitted on 19 Dec 2023] (cross-list from physics.comp-ph)
ROSE: A reduced-order scattering emulator for optical models
Daniel Odell · Pablo Giuliani · Kyle Beyer · Manuel Catacora-Rios · Moses Y.-H. Chan · Edgard Bonilla · Richard J. Furnstahl · Kyle Godbey · Filomena M. Nunes
A new generation of phenomenological optical potentials requires robust calibration and uncertainty quantification, motivating the use of Bayesian statistical methods. These Bayesian methods usually require calculating observables for thousands or even millions of parameter sets, making fast and accurate emulators highly desirable or even essential. Emulating scattering across different energies or with interactions such as optical potentials is challenging because of the non-affine parameter dependence, meaning the parameters do not all factorize from individual operators. Here we introduce and demonstrate the Reduced Order Scattering Emulator (ROSE) framework, a reduced basis emulator that can handle non-affine problems. ROSE is fully extensible and works within the publicly available BAND Framework software suite for calibration, model mixing, and experimental design. As a demonstration problem, we use ROSE to calibrate a realistic nucleon-target scattering model through the calculation of elastic cross sections. This problem shows the practical value of the ROSE framework for Bayesian uncertainty quantification with controlled trade-offs between emulator speed and accuracy as compared to high-fidelity solvers. Planned extensions of ROSE are discussed.
Comments:
19 pages, 9 figures
Subjects:
Computational Physics (physics.comp-ph); Nuclear Theory (nucl-th)
arXiv:
2312.12426 [pdf]
PRC(2024)·43 citations

Affiliations

first authorsco-authorsvia INSPIRE