Nuclear Theory·nucl-th

Wednesday·January 30, 2019

12 papers—7 primary·5 cross-listed

01
Theory of surrogate nuclear and atomic reactions with three charged particles in the final state proceeding through a resonance in the intermediate subsystem
A. M. Mukhamedzhanov · A. S. Kadyrov
Within a few-body formalism, we develop a general theory of surrogate nuclear and atomic reactions with the excitation of a resonance in the intermediate binary subsystem leading to three charged particles in the final state. The Coulomb interactions between the spectator and the resonance in the intermediate state and between the three particles in the final state are taken into account. Final-state three-body Coulomb multiple-scattering effects are accounted for using the formalism of the three-body Coulomb asymptotic states based on the work published by one of us (A.M.M.) under the guidance of L. D. Faddeev. An expression is derived for the triply differential cross section. It can be used for investigation of the Coulomb effects on the resonance line shape as well as the energy dependence of the cross section. We find that simultaneous inclusion of the Coulomb effects in the intermediate and final state decreases the effect of the final-state Coulomb interactions on the triply differential cross section.
nucl-thFew Body Syst.(2019)·5 citations
02
Rapidity Decorrelation from Hydrodynamic Fluctuations and Initial Fluctuations
Azumi Sakai🇯🇵 · Koichi Murase🇯🇵 · Tetsufumi Hirano🇯🇵
Rapidity decorrelation in high energy heavy-ion collisions is one of the hot topics in understanding longitudinal dynamics of the quark gluon plasma (QGP). In this study we employ an integrated dynamical model with full three dimensional relativistic hydrodynamics and perform event-by-event numerical simulations of Pb+Pb collisions at the LHC energy. We analyze factorization ratios to understand rapidity decorrelation from hydrodynamic fluctuations and initial longitudinal fluctuations. We show that factorization breaking happens due to both hydrodynamic fluctuations and initial longitudinal fluctuations. We conclude hydrodynamic fluctuations and initial longitudinal fluctuations are both important in understanding rapidity decorrelation.
nucl-thJPS Conf.Proc.(2019)·1 citation
03
Weak production of strange and charm ground-state baryons in nuclei
J. E. Sobczyk🇪🇸 · N. Rocco🇺🇸 · A. Lovato🇺🇸 · J. Nieves🇪🇸
We present results for the quasi-elastic weak production of $Λ$ and $Σ$ hyperons induced by $ν ˉ$ scattering off nuclei, in the kinematical region of interest for accelerator neutrino experiments. We employ realistic hole spectral functions and we describe the propagation of the hyperons in the nuclear medium by means of a Monte Carlo cascade. The latter strongly modifies the kinematics and the relative production rates of the hyperons, leading to a non-vanishing $Σ^{+}$ cross section, to a sizable enhancement of the $Λ$ production and to a drastic reduction of the $Σ^{0}$ and $Σ^{-}$ distributions. We also compute the quasi-elastic weak $Λ_{c}$ production cross section, paying special attention to estimate the uncertainties induced by the model dependence of the vacuum $n \to Λ_{c}$ weak matrix element. In this regard, the recent BESIII measurements of the branching ratios of $Λ_{c} \to Λ l^{+} ν_{l}$ ( $l = e, μ$ ) are used to benchmark the available theoretical predictions.
nucl-thhep-phPRC(2019)·15 citations
04
What could be learned about phase transitions, meson and nucleon structure in hot medium from a chiral quark-meson theory?
Christo V. Christov🇩🇪
In this contribution I summarize and discuss the results of the bulk thermodynamic characteristics, meson and nucleon structure in hot matter obtained in the framework of a chiral quark-meson theory. A hybrid NJL model is used in which a Dirac sea of quarks is combined with a Fermi sea of quarks or of nucleons. In the model mesons are described as collective $q ˉ q$ excitations and the nucleon appears as a baryon-number-one soliton of $N_{c}$ valence quarks coupled to both Dirac and Fermi sea. According to the model at some critical density and/or temperature phase transitions from nucleons to quarks as well as from Goldstone to Wigner phase are expected. At finite density the chiral order parameter and the constituent quark mass have a non-monotonic temperature dependence-at temperatures not close to the critical one they are less affected than in cold matter. The quark matter is rather soft against thermal fluctuations and the corresponding chiral phase transition is smooth. The nucleon matter is much stiffer and the phase transition is very sharp. In the case of quark matter a first-order transition is suggested at low temperatures ( $T < 80$ MeV) which changes to a second-order one at higher temperatures. In contrast to the quark matter in the case of nucleon matter the thermodynamic variables show large discontinuities which is a clear indication for a first-order phase transition. In hot medium at intermediate temperature the nucleon soliton is more bound and less swelled than in the case of cold matter. At some critical temperature, which for nucleon matter coincides with the critical temperature for the phase transition, no more a localized solution is found. According to this model scenario one should expect a first-order phase transition from nucleon to quark matter.
nucl-th0 citations
05
Propagation of Statistical Uncertainties of Skyrme Mass Models to Simulations of $r$ -Process Nucleosynthesis
T. M. Sprouse · R. Navarro Perez · R. Surman · M. R. Mumpower · G. C. McLaughlin · N. Schunck
Uncertainties in nuclear models have a major impact on simulations that aim at understanding the origin of heavy elements in the universe through the rapid neutron capture process ( $r$ process) of nucleosynthesis. Within the framework of the nuclear density functional theory, we use results of Bayesian statistical analysis to propagate uncertainties in the parameters of energy density functionals to the predicted $r$ -process abundance pattern, by way not only of the nuclear masses but also through the influence of the masses on $β$ -decay and neutron capture rates. We additionally make the first identifications of specific parameters of Skyrme-like energy density functionals which are correlated with particular aspects of the $r$ -process abundance pattern. While previous studies have explored the reduction in the abundance pattern uncertainties due to anticipated new measurements of neutron-rich nuclei, here we point out that an even larger reduction will occur when these new measurements are used to reduce the uncertainty of model predictions of masses, which are then propagated through to the abundance pattern. We make a quantitative prediction for how large this reduction will be.
nucl-thPRC(2020)·51 citations
06
Examination of an isospin-dependent single-nucleon momentum distribution for the isospin-asymmetric nuclear matter in heavy-ion collisions
Gao-Feng Wei🇨🇳 · Qi-Jun Zhi🇨🇳 · Xin-Wei Cao🇨🇳 · Zheng-Wen Long🇨🇳
Within a transport model using as the input nucleon momentum profiles from a parameterized isospin-dependent single-nucleon momentum distribution with a high momentum tail induced by short-range correlations, we employ the $^{197}$ Au + $^{197}$ Au collisions at 400 MeV/nucleon to examine on one hand effects of the short-range correlations on the pion and flow observables in probing the nuclear symmetry energy, and on the other hand how reliable are this isospin-dependent single-nucleon momentum distribution as well as the corresponding parameter settings. Besides significant effects of the short-range correlations on the pion and flow observables are observed, we also find that the theoretical simulations of $^{197}$ Au + $^{197}$ Au collisions with this momentum distribution using two sets of parameters extracted from the experimental analysis and the self-consistent Green's function prediction, respectively, can reproduce the neutron elliptic flows of the FOPI-LAND experiment and the $π^{-} / π^{+}$ ratios of the FOPI experiment under the symmetry energy setting in a certain range. Therefore, we conclude that this parameterized isospin-dependent single-nucleon momentum distribution is reliable for the isospin-asymmetric nuclear matter, correspondingly, two sets of parameters extracted from both the experimental analysis and the self-consistent Green's function prediction can not be ruled out according to the available experimental information at present.
nucl-thNucl.Sci.Tech.(2020)·12 citations
07
Comment on "How (not) to renormalize integral equations with singular potentials in effective field theory"
Manuel Pavon Valderrama🇨🇳
I critically discuss two of the potential inconsistencies pointed out in the recent manuscript by Epelbaum, Gasparyan, Gegelia and Meissner, published in Eur. Phys.J. A54, 186 (2018). The potential inconsistencies are: (i) a possible mismatch between the $ℏ$ expansion of the scattering amplitude and renormalization, (ii) an impossibility of "non-perturbative renormalization" to deal with repulsive singular interactions. The conclusion is that these inconsistencies do not happen.
nucl-thhep-phEPJA(2019)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE

Theory of surrogate nuclear and atomic reactions with three charged particles in the final state proceeding through a resonance in the intermediate subsystem

Rapidity Decorrelation from Hydrodynamic Fluctuations and Initial Fluctuations

Weak production of strange and charm ground-state baryons in nuclei

What could be learned about phase transitions, meson and nucleon structure in hot medium from a chiral quark-meson theory?

Propagation of Statistical Uncertainties of Skyrme Mass Models to Simulations of r-Process Nucleosynthesis

Examination of an isospin-dependent single-nucleon momentum distribution for the isospin-asymmetric nuclear matter in heavy-ion collisions

Comment on "How (not) to renormalize integral equations with singular potentials in effective field theory"

Affiliations

Propagation of Statistical Uncertainties of Skyrme Mass Models to Simulations of $r$ -Process Nucleosynthesis