Nuclear Theory·nucl-th

Thursday·May 6, 2021

7 papers—4 primary·3 cross-listed

01
[Submitted on 4 May 2021]
Impact of momentum resolution on factorial moments due to power-law correlations between particles
Subhasis Samanta🇵🇱 · Tobiasz Czopowicz🇵🇱 · Marek Gazdzicki🇵🇱
The effect of momentum resolution on factorial moments due to the power-law correlation function is studied. The study is motivated by the search for the critical point of the strongly interacting matter in heavy-ion collisions using the intermittency method. We observe that factorial moments are significantly affected by the finite momentum resolution. The effect is superficially significant compared to intuitive expectations. The results depend on the power of the correlation function and the number of uncorrelated particles.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2105.01763 [pdf]
J.Phys.G(2021)·9 citations
02
[Submitted on 5 May 2021]
Necessity of selfconsistent calculations for the electromagnetic field in probing the nuclear symmetry energy using pion observables in heavy-ion collisions
Gao-Feng Wei🇨🇳 · Chang Liu🇨🇳 · Xin-Wei Cao🇨🇳 · Qi-Jun Zhi🇨🇳 · Wen-Jun Xiao🇨🇳 · Chao-Yun Long🇨🇳 · Zheng-Wen Long🇨🇳
Within an isospin- and momentum-dependent transport model, we investigate the necessity of selfconsistent calculations for the electromagnetic field in probing the nuclear symmetry energy using pion observables in heavy-ion collisions at intermediate energies. To this end, we perform the $^{96}$ Ru + $^{96}$ Ru collisions at 400 MeV/nucleon with two calculations scenarios for the electromagnetic field including the selfconsistent calculation and the most used Liénard-Wiechert formula, while the latter is a simplified one of the complete Liénard-Wiechert formula by neglecting the radiation field for practical calculations in heavy-ion collisions at intermediate and/or relativistic energies. As a comparison, we also consider the static Coulomb field formula for calculations of the electromagnetic field in heavy-ion collisions. It is shown that the most used simplified Liénard-Wiechert formula is not enough for the electromagnetic field calculation because the absent radiation field in this formula also affects significantly the charged pions as well as their $π^{-} / π^{+}$ ratio. Moreover, we also examine effects of the electromagnetic field in these scenarios on the double $π^{-} / π^{+}$ ratio of two isobar reaction systems of $^{96}$ Ru + $^{96}$ Ru and $^{96}$ Zr + $^{96}$ Zr at 400 MeV/nucleon. It is shown that the double $π^{-} / π^{+}$ ratio of two reactions tends to be less affected by the electromagnetic field calculation scenario and thus can still be an effective probe of the nuclear symmetry energy in heavy-ion collisions. Therefore, according to these findings, it is suggested that the selfconsistent calculation for the electromagnetic field should be carefully taken into account when using the pion observables to probe the nuclear symmetry energy in heavy-ion collisions.
Comments:
7 pages, 6 figures. Accepted for publication in Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2105.01866 [pdf]
PRC(2021)·4 citations
03
[Submitted on 5 May 2021]
Deep crustal heating for realistic compositions of thermonuclear ashes
Nikolay N. Shchechilin🇷🇺 · Mikhail E. Gusakov🇷🇺 · Andrey I. Chugunov🇷🇺
The deep crustal heating, associated with exothermal nuclear reactions, is believed to be a key parameter for describing the thermal evolution of accreting neutron stars. In this paper, we present the first thermodynamically consistent calculations of the crustal heating for realistic compositions of thermonuclear ashes. In contrast to previous studies based on the traditional approach, we account for neutron hydrostatic/diffusion (nHD) equilibrium condition imposed by superfluidity of neutrons in a major part of the inner crust and rapid diffusion in the remaining part of the inner crust. We apply a simplified reaction network to model nuclear evolution of various multi-component thermonuclear burning ashes (superburst, KEPLER, and extreme rp-process ashes) in the outer crust and calculate the deep crustal heating energy release Q, parametrized by the pressure at the outer-inner crust interface, P_{oi}. Using the general thermodynamic arguments, we set a lower limit on Q, Q>0.13-0.2 MeV per baryon (an actual value depends on the ash composition and the employed mass model).
Comments:
12 pages, 8 figures. Updated to AME2020. Accepted for publication in MNRAS
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2105.01991 [pdf]
MNRAS(2021)·23 citations
04
[Submitted on 4 May 2021]
Quantum baryon number fluctuations in subsystems of a hot and dense relativistic gas of fermions
Arpan Das🇵🇱 · Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱 · Rajeev Singh🇵🇱
Quantum features of the baryon number fluctuations in subsystems of a hot and dense relativistic gas of fermions are analyzed. We find that the fluctuations in small systems are significantly increased compared to their values known from the statistical physics, and diverge in the limit where the system size goes to zero. The numerical results obtained for a broad range of the thermodynamic parameters expected in heavy-ion collisions are presented. They can be helpful to interpret and shed new light on the experimental data.
Comments:
Journal version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2105.02125 [pdf]
Acta Phys.Polon.B(2022)·12 citations
05
[Submitted on 4 May 2021] (cross-list from hep-ph)
A dispersive estimate of scalar contributions to hadronic light-by-light scattering
Igor Danilkin🇩🇪 · Martin Hoferichter🇨🇭 · Peter Stoffer🇦🇹
We consider the contribution of scalar resonances to hadronic light-by-light scattering in the anomalous magnetic moment of the muon. While the $f_{0} (500)$ has already been addressed in previous work using dispersion relations, heavier scalar resonances have only been estimated in hadronic models so far. Here, we compare an implementation of the $f_{0} (980)$ resonance in terms of the coupled-channel $S$ -waves for $γ^{*} γ^{*} \to π π / K ˉ K$ to a narrow-width approximation, which indicates $a_{μ}^{HLbL} [f_{0} (980)] = - 0.2 (2) \times 1 0^{- 11}$ . With a similar estimate for the $a_{0} (980)$ , the combined effect is thus well below $1 \times 1 0^{- 11}$ in absolute value. We also estimate the contribution of heavier scalar resonances. In view of the very uncertain situation concerning their two-photon couplings we suggest to treat them together with other resonances of similar mass when imposing the matching to short-distance constraints. Our final result is a refined estimate of the $S$ -wave rescattering effects in the $π π$ and $K ˉ K$ channel up to about $1.3$ GeV and including a narrow-width evaluation of the $a_{0} (980)$ : $a_{μ}^{HLbL} [scalars] = - 9 (1) \times 1 0^{- 11}$ .
Comments:
9 pages, 2 figures; journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2105.01666 [pdf]
PLB(2021)·106 citations
06
[Submitted on 5 May 2021] (cross-list from hep-th)
$N = 4$ supersymmetric Yang-Mills thermodynamics to order $λ^{2}$
Qianqian Du🇨🇳 · Michael Strickland🇺🇸 · Ubaid Tantary🇺🇸
We calculate the resummed perturbative free energy of $N = 4$ supersymmetric Yang-Mills in four spacetime dimensions ( $SYM_{4, 4}$ ) through second order in the 't Hooft coupling $λ$ at finite temperature and zero chemical potential. Our final result is ultraviolet finite and all infrared divergences generated at three-loop level are canceled by summing over $SYM_{4, 4}$ ring diagrams. Non-analytic terms at $O (λ^{3/2})$ and $O (λ^{2} lo g λ)$ are generated by dressing the $A_{0}$ and scalar propagators. The gauge-field Debye mass $m_{D}$ and the scalar thermal mass $M$ are determined from their corresponding finite-temperature self-energies. Based on this, we obtain the three-loop thermodynamic functions of $SYM_{4, 4}$ to $O (λ^{2})$ . We compare our final result with prior results obtained in the weak- and strong-coupling limits and construct a generalized Padé approximant that interpolates between the weak-coupling result and the large- $N_{c}$ strong-coupling result. Our results suggest that the $O (λ^{2})$ weak-coupling result for the scaled entropy density is a quantitatively reliable approximation to the scaled entropy density for $0 \leq λ ≲ 2$ .
Comments:
28 pages, 8 figures; v3: fix to soft contribution and final result, misc typos fixed, conclusions unchanged
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2105.02101 [pdf]
JHEP(2021)·10 citations
07
[Submitted on 5 May 2021] (cross-list from hep-ph)
Heavy quark dynamics in a strongly magnetized quark-gluon plasma
Aritra Bandyopadhyay🇨🇳 · Jinfeng Liao🇺🇸 · Hongxi Xing🇨🇳
We present a calculation of the heavy quark momentum diffusion coefficients in a quark-gluon plasma under the presence of a strong external magnetic field, within the Lowest Landau Level (LLL) approximation. In particular, we apply the Hard Thermal Loop (HTL) technique for the resummed effective gluon propagator, generalized for a hot and magnetized medium. Using the derived effective HTL gluon propagator and the LLL quark propagator we analytically derive the full results for the longitudinal and transverse momentum diffusion coefficients as well as the energy losses for charm and bottom quarks beyond the static limit. We also show numerical results for these coefficients in two special cases where the heavy quark is moving either parallel or perpendicular to the external magnetic field.
Comments:
21 pages, 8 figures; Version published in Phys Rev D 105
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2105.02167 [pdf]
PRD(2022)·24 citations

Affiliations

first authorsco-authorsvia INSPIRE

Impact of momentum resolution on factorial moments due to power-law correlations between particles

Necessity of selfconsistent calculations for the electromagnetic field in probing the nuclear symmetry energy using pion observables in heavy-ion collisions

Deep crustal heating for realistic compositions of thermonuclear ashes

Quantum baryon number fluctuations in subsystems of a hot and dense relativistic gas of fermions

A dispersive estimate of scalar contributions to hadronic light-by-light scattering

N=4 supersymmetric Yang-Mills thermodynamics to order λ2

Heavy quark dynamics in a strongly magnetized quark-gluon plasma

Affiliations

$N = 4$ supersymmetric Yang-Mills thermodynamics to order $λ^{2}$