Nuclear Theory·nucl-th

Tuesday·December 20, 2022

16 papers—6 primary·10 cross-listed

07
[Submitted on 17 Dec 2022] (cross-list from hep-ph)
Hot Spot model of Nucleon and Double Parton Scattering
B. Blok (Technion)🇮🇱 · R. Segev (Technion)🇮🇱 · M. Strikman (Penn State University)🇺🇸
We calculate the rate of double parton scattering (DPS) in proton - proton collisions in the framework of the recently proposed hot spot model of the nucleon structure. The resulting rate, especially for the case of three hot spots, appears to be in tension with the current experimental data on DPS at the LHC.
Comments:
12 pages 2 figures 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2212.08848 [pdf]
EPJC(2023)·4 citations
08
[Submitted on 17 Dec 2022] (cross-list from hep-ph)
Spatial diffusion of heavy quarks in background magnetic field
Sarthak Satapathy🇮🇳 · Sudipan De🇮🇳 · Jayanta Dey🇮🇳 · Sabyasachi Ghosh🇮🇳
The ratio of shear viscosity to entropy density shows a valley-shaped pattern well-known in the community of heavy-ion physics. Diffusion coefficients of heavy quark and meson shows the similar structure, and both sketches have become quite popular in the community. Present work has attempted a finite magnetic field extension of the diffusion coefficients of heavy quark and meson. Using Einstein's diffusion relation, we calculated heavy quark and heavy meson diffusion by the ratio of conductivity to susceptibility in the kinetic theory framework of relaxation time approximation. The relaxation time of heavy quark and meson are tuned from the knowledge of earlier works on spatial diffusion estimations, and then we have extended the framework for a finite magnetic field, where our outcomes have revealed two aspects - anisotropic and quantum aspects of diffusion with future possibilities of phenomenological signature.
Comments:
17 pages, 11 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2212.08933 [pdf]
PRC(2024)·13 citations
09
[Submitted on 18 Dec 2022] (cross-list from hep-lat)
Equation of state and speed of sound of (2+1)-flavor QCD in strangeness-neutral matter at non-vanishing net baryon-number density
D. Bollweg🇺🇸 · D. A. Clarke🇩🇪 · J. Goswami🇯🇵 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · Swagato Mukherjee🇺🇸 · P. Petreczky🇺🇸 · C. Schmidt🇩🇪 · Sipaz Sharma🇩🇪
We update results on the QCD equation of state in (2+1)-flavor QCD with non-zero conserved charge chemical potentials obtained from an eighth-order Taylor series. We present results for basic bulk thermodynamic observables of strangeness-neutral strong-interaction matter, i.e. pressure, number densities, energy and entropy density, and resum Taylor series results using Padé approximants. Furthermore, we calculate the speed of sound as well as the adiabatic compression factor of strangeness-neutral matter on lines of constant entropy per net baryon number. We show that the equation of state ( $P (n_{B}), ϵ (n_{B})$ ) is already well described by the $4^{th}$ -order Taylor series in almost the entire range of temperatures accessible with the beam energy scan in collider mode at the Relativistic Heavy Ion Collider.
Comments:
22 pages, 17 figures, minor revision and journal reference added
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09043 [pdf]
PRD(2023)·75 citations
10
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Bose-Einstein Condensation and Dissipative Dynamics in a Relativistic Pion Gas
Kshitish Kumar Pradhan🇮🇳 · Dushmanta Sahu🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳
Pion condensation in ultra-relativistic collisions presents a compelling theoretical phenomenon with significant implications for the dynamics of hadronic matter. Various theoretical frameworks offer insight into the nature of high-temperature Bose-Einstein condensation (BEC). The present study investigates the dissipative behavior of a relativistic pion gas undergoing Bose-Einstein condensation (BEC) in ultra-relativistic heavy-ion collisions. Further, we obtain viscosity ( $η$ ), bulk viscosity ( $ζ$ ), and speed of sound ( $c_{s}$ ) by employing the Boltzmann transport equation with the relaxation time approximation. Findings show a substantial drop in $η / s$ and $ζ / s$ with the fractional increase in condensation. This effect is becoming more evident in larger systems approaching the thermodynamic limit. Alongside the reduction in viscosities, the speed of sound also decreases with increasing condensation, indicating a softening of the equation of state. The analysis of finite-size effects reveals that larger systems exhibit more pronounced signatures of BEC. These results suggest that pion condensation can influence the hydrodynamic evolution of the hadronic phase in heavy-ion collisions, with consequential implications for interpreting collective flow observables and the underlying equation of state.
Comments:
Same as the published version in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2212.09288 [pdf]
PRD(2025)·4 citations
11
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Studying the 3+1D structure of the Glasma using the weak field approximation
Andreas Ipp🇦🇹 · Markus Leuthner🇦🇹 · David I. Müller🇦🇹 · Soeren Schlichting🇩🇪 · Pragya Singh🇫🇮
We extend the weak field approximation for the Glasma beyond the boost-invariant approximation, which allows us to compute rapidity-dependent observables in the early stages of heavy-ion collisions. We show that in the limit of small fields, the weak field approximation agrees quantitatively with non-perturbative lattice simulations. Furthermore, we demonstrate that the rapidity profile of the transverse pressure is determined by longitudinal color correlations within the colliding nuclei.
Comments:
8 pages, 4 figures, parallel talk given at the XVth Quark Confinement and the Hadron Spectrum conference
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09363 [pdf]
EPJ Web Conf.(2022)·6 citations
12
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Twist-four gravitational form factor at NNLO QCD from trace anomaly constraints
Kazuhiro Tanaka (Juntendo Univ.)🇯🇵
It is known that the trace anomaly in the QCD energy-momentum tensor $T^{μν}$ can be attributed to the anomalies for each of the gauge-invariant quark part and gluon part of $T^{μν}$ , and their explicit three-loop formulas have been derived in the $MS$ scheme in the dimensional regularization. The matrix elements of this quark/gluon decomposition of the QCD trace anomaly allow us to derive the QCD constraints on the hadron's gravitational form factors, in particular, on the twist-four gravitational form factor, $C ˉ_{q, g}$ . Using the three-loop quark/gluon trace anomaly formulas, we calculate the forward (zero momentum transfer) value of the twist-four gravitational form factor $C ˉ_{q, g}$ at the next-to-next-to-leading-order (NNLO) accuracy. We present quantitative results for nucleon as well as for pion, leading to a model-independent determination of the forward value of $C ˉ_{q, g}$ . We find quite different pattern in the obtained results between the nucleon and the pion. In particular, for the nucleon, the present information from experiment and lattice QCD on the nonperturbative matrix elements arising in our NNLO formula allows us to obtain a prediction of the forward value of $C ˉ_{q, g}$ at the accuracy of a few percent level.
Comments:
40 pages, 5 figures; v3: typos corrected, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09417 [pdf]
JHEP(2023)·20 citations
13
[Submitted on 19 Dec 2022] (cross-list from hep-lat)
Monopole and instanton effects on connected and disconnected correlations for scalar density
Masayasu Hasegawa🇷🇺
This study investigates the effects on the connected and disconnected correlations for the scalar density that are induced by created monopoles and instantons in the QCD vacuum. To reveal the effects, we add a monopole and anti-monopole pair in the gauge field configurations in \textit{SU}(3) by applying the monopole creation operator to the vacuum. We vary the magnetic charges of the monopole and anti-monopole and increase the number of monopoles and anti-monopoles in the configurations. The Dirac operator of overlap fermions preserves the exact chiral symmetry in lattice gauge theory and exact zero-modes exist in its spectrum. The eigenvalues and eigenvectors of the overlap Dirac operator have been calculated using these configurations, and the numbers of instantons and anti-instantons which are created by these additional monopoles and anti-monopoles have been estimated from the numbers of topological charges in our previous studies. In this study, we demonstrate the preliminary results that instantons and monopoles influence the masses that are evaluated from the connected and disconnected correlation functions for the scalar density using low-lying eigenvalues and eigenvectors of the overlap Dirac operator.
Comments:
This report is a contribution to the proceedings of "the 6th International Conference on Particle Physics and Astrophysics'' and accepted for publication in Physics of Atomic Nuclei. This report contains 5 figures and 5 tables on 12 pages
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2212.09691 [pdf]
Phys.Atom.Nucl.(2023)·0 citations
14
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Inspection of the detection cross section dependence of the Gallium Anomaly
C. Giunti🇮🇹 · Y.F. Li🇨🇳 · C.A. Ternes🇮🇹 · Z. Xin🇨🇳
We discuss in detail the dependence of the Gallium Anomaly on the detection cross section. We provide updated values of the size of the Gallium Anomaly and find that its significance is larger than about $5 σ$ for all the detection cross section models. We discuss the dependence of the Gallium Anomaly on the assumed value of the half life of $^{71} Ge$ , which determines the cross sections of the transitions from the ground state of $^{71} Ga$ to the ground state of $^{71} Ge$ . We show that a value of the $^{71} Ge$ half life which is larger than the standard one can reduce or even solve the Gallium Anomaly. Considering the short-baseline neutrino oscillation interpretation of the Gallium Anomaly, we show that a value of the $^{71} Ge$ half life which is larger than the standard one can reduce the tension with the results of other experiments. Since the standard value of the $^{71} Ge$ half life was measured in 1985, we advocate the importance of new measurements with modern technique and apparatus for a better assessment of the Gallium Anomaly.
Comments:
v3: 11 pages, 4 figures, 3 tables, references added, typo corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2212.09722 [pdf]
PLB(2023)·27 citations
15
[Submitted on 19 Dec 2022] (cross-list from hep-ph)
Anisotropic fluctuations of angular momentum of heavy quarks in the Glasma
Pooja🇮🇳 · Santosh K. Das🇮🇳 · Vincenzo Greco🇮🇹 · Marco Ruggieri🇮🇹
We study the evolution of the angular momentum of the heavy quarks in the very early stage of high energy nuclear collisions, in which the background is made of evolving Glasma fields. Given the novelty of the problem, we limit ourselves to the use of toy heavy quarks with a large, unphysical mass, in order to implement the kinetic equations for the angular momentum in the non-relativistic limit. We find that as a consequence of the anisotropy of the background fields, angular momentum fluctuations are also anisotropic: we understand this in simple terms relating the fluctuations of the angular momentum, $L$ , to those of linear momentum. While orbital angular momentum diffuses and develops substantial fluctuations and anisotropies, the spin does not. Hence, we can identify the fluctuations of $L$ with those of the total angular momentum $J = L + S$ . Therefore, our study suggests that the total angular momentum of the heavy quarks in the early stage of high energy nuclear collisions will present anisotropic fluctuations.
Comments:
10 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2212.09725 [pdf]
Eur.Phys.J.Plus(2023)·18 citations
16
[Submitted on 19 Dec 2022] (cross-list from astro-ph.HE)
Prospects for constraining twin stars with next-generation gravitational-wave detectors
Philippe Landry🇨🇦 · Kabir Chakravarti🇨🇿
Neutron star equations of state with strong phase transitions may support twin stars, hybrid and hadronic stars with the same mass but different tidal deformabilities. The presence of twin stars in the population of merging neutron stars produces distinctive gaps in the joint distribution of binary tidal deformabilities and chirp masses. We analyze a simulated population of binary neutron star mergers recovered with a network of next-generation (XG) ground-based gravitational-wave detectors to determine how many observations are needed to infer, or rule out, the existence of twin stars. Using a hierarchical inference framework based on a simple parametric twin-star model, we find that a single week of XG observations may suffice to detect a tidal deformability difference of several hundred between twins and measure the mass scale at which twins occur to within a few percent. For less pronounced twins, XG observations will place a stringent upper bound on the tidal deformability difference.
Comments:
13 pages, 12 figures, 1 table
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2212.09733 [pdf]
13 citations

Affiliations

first authorsco-authorsvia INSPIRE