Nuclear Theory·nucl-th

Tuesday·February 13, 2024

16 papers—9 primary·7 cross-listed

01
Reply to the "Comments to the paper "Detailed study of the astrophysical direct capture reaction $^{6} Li (p, γ)^{7} Be$ in ..." " by S.B. Dubovichenko, A.S. Tkachenko, R. Ya. Kezerashvili, arXiv:2401.04281 (2024)
E.M. Tursunov · S.A. Turakulov · K.I. Tursunmakhatov
The differences in potential models used in our work and in the original paper of the authors of the Comment are discussed. The neglecting of simple rules of reaction calculations is shown as a possible origin of the defect in the temperature dependence of the reaction rates in the work of the authors of the Comment.
nucl-thastro-ph.SR0 citations
02
Detecting anomalous CP violation in heavy ion collisions through baryon-electric charge correlations
David Frenklakh🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Andrea Palermo🇺🇸
The chiral magnetic effect (CME) and the chiral vortical effect (CVE) induce a correlation between baryon and electric currents. We show that this correlation can be detected using a new observable: a mixed baryon-electric charge correlator. This correlator is proportional to the baryon asymmetry, suggesting a novel way to separate the chiral effects from the background in heavy ion collisions.
nucl-thPRD(2024)·3 citations
03
Radiative neutron capture rate of $^{11}$ B $(n, γ)^{12}$ B reaction from the Coulomb dissociation of $^{12}$ B
Shubhchintak · G. Singh · R. Chatterjee · M. Dan
We calculate the $^{11}$ B $(n, γ)^{12}$ B reaction rate, an important constituent in nucleosynthesis networks, contributed by resonant as well as non-resonant capture. For the resonant rate, we use the narrow resonance approximation whereas the non-resonant contribution is calculated with the Coulomb dissociation method for which we use finite-range distorted wave Born approximation theory. We then compare our calculated rate of $^{11}$ B $(n, γ)^{12}$ B reaction with those reported earlier and with other charged particle reactions on $^{11}$ B.
nucl-thFew Body Syst.(2024)·3 citations
04
Consistent inclusion of fluctuations in first-order causal and stable relativistic hydrodynamics
Lorenzo Gavassino🇺🇸 · Nicki Mullins🇺🇸 · Mauricio Hippert🇺🇸
We construct, for the first time, a Bemfica-Disconzi-Noronha-Kovtun (BDNK) theory for linear stochastic fluctuations, which is proved to be mathematically consistent, causal, and covariantly stable. The Martin-Siggia-Rose action is shown to be bilocal in most cases, and the noise is not white. The presence of nonhydrodynamic modes induces long-range correlations in the primary fluid variables (temperature, chemical potential, and flow velocity). However, correlators of conserved densities remain localized in space, and coincide with those calculated within fluctuating Isreal-Stewart theory. We show that, in some cases, there is a nonlocal change of variables that maps the Israel-Stewart action into the BDNK action.
nucl-thgr-qchep-thPRD(2024)·15 citations
05
Second-Order Transport Coefficients in Neutron Star Mergers
Yumu Yang · Mauricio Hippert · Enrico Speranza · Jorge Noronha
In neutron stars, flavor-changing weak interactions determine the equilibrium fraction of protons over neutrons. In binary neutron-star mergers, violent changes in density modify this equilibrium value at timescales of milliseconds, comparable to those required for weak interactions to take place. As a result, the fraction of protons evolves out of phase with the density oscillations, giving rise to irreversible processes. The corresponding shift in pressure leads to dissipative work that can be modeled as an effective bulk-viscous correction. In this work, we derive the relevant equations of motion of Israel-Stewart hydrodynamics within this context. Using a toy model, we compute the second-order transport coefficients. Finally, we comment on the use of a realistic equation of state. Our results are expected to be useful for the study of viscous effects in numerical simulations of binary mergers.
nucl-thastro-ph.HEhep-ph1 citation
06
Examination of the $ϕ - N N$ bound-state problem with lattice QCD $N - ϕ$ potentials
Faisal Etminan🇮🇷 · Amanullah Aalimi🇮🇷
The developed Faddeev three-body equations are solved to search for bound-state solutions of a phi-meson $(ϕ)$ and two nucleons $(NN)$ system. The newly published spin $3/2$ $N- \ensuremath \phi$ potential based on the $(2+1)$ -flavor lattice QCD simulations near physical point, and realistic $NN$ Malfliet-Tjon (MT) potential, are employed. Our numerical calculations for $(I) J^{π} = (0) 2^{-}$ $ϕ -d$ system in maximum spin leads to ground state binding energy of about $7$ MeV and a matter radius of about $8$ fm. Our results indicates the possibility of the formation of new nuclear clusters.
nucl-thPRC(2024)·16 citations
07
Transport coefficients of transient hydrodynamics for the hadron-resonance gas and thermal-mass quasiparticle models
Gabriel S. Rocha🇺🇸 · Gabriel S. Denicol🇧🇷
We calculate all transport coefficients of second order transient hydrodynamics in two effective kinetic theory models: a hadron-resonance gas and a quasiparticle model with thermal masses tuned to reproduce QCD thermodynamics. We compare the corresponding results with calculations for an ultrarelativistic single-component gas, that are widely employed in hydrodynamic simulations of heavy ion collisions. We find that both of these effective models display a qualitatively different normalized bulk viscosity, when compared to the calculation for the single-component gas. Indeed, $ζ / [τ_{Π} (ε_{0} + P_{0})] ≃ 16.91 (1/3 - c_{s}^{2})^{2}$ , for the hadron-resonance gas model, and $ζ / [τ_{Π} (ε_{0} + P_{0})] ≃ 5 (1/3 - c_{s}^{2})$ for the quasiparticle model. Differences are also observed for many second-order transport coefficients, specially those related to the bulk viscous pressure. The transport coefficients derived are shown to be consistent with fundamental linear stability and causality conditions.
nucl-thhep-phPRD(2024)·9 citations
08
"To renormalize or not to renormalize ?'' in the proton-deuteron scattering calculations
H. Witała · J. Golak · R. Skibiński
We discuss two approaches which, by applying the screening method, permit one to include the long range proton-proton (pp) Coulomb force in proton-deuteron (pd) momentum-space scattering calculations. In the first one, based on Alt-Grassberger-Sandhas (AGS) equation, presented in Phys. Rev. C{\bf{71}}, 054005 (2005) and {\bf{73}}, 057001 (2006), one needs to renormalize elastic scattering amplitude before calculating observables. In the second treatment, proposed by us in Eur. Phys. Journal A {\bf{41}}, 369 (2009), {\bf{41}}, 385 (2009), and arXiv:2310.03433 [nucl.th], this renormalization is avoided. For the proton induced deuteron breakup reaction both approaches require renormalization of the corresponding transition amplitudes. We derive the basic equations underlying both methods under the assumption that all contributing partial wave states are included and explain why in our approach renormalization of the elastic scattering amplitude is superfluous. We show that in order to take into account in the screening limit all partial waves it is required that four additional terms, based on the 3-dimensional and partial-wave projected pp Coulomb t-matrices, identical for both approaches, must appear in transition amplitudes. We investigate importance of these terms for elastic pd scattering below the breakup threshold.
nucl-th0 citations
09
Statistical analysis of the fluctuations of an initial-state model with independently distributed hot spots
Nicolas Borghini🇩🇪 · Hendrik Roch🇩🇪 · Alicia Schütte🇩🇪
We determine the uncorrelated modes that characterize the fluctuations in a semi-realistic model for the initial state of high-energy nuclear collisions, consisting of hot spots whose positions are distributed independently. Varying the number of hot spots, their size, and the weights with which they contribute to the initial state, we find that the parameter that has the largest influence on the relative importance of the fluctuation modes is the source size, with more extended hot spots leading to a more marked predominance of the principal modes.
nucl-thhep-phEPJC(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE