Nuclear Theory·nucl-th

Wednesday·September 27, 2017

13 papers—6 primary·7 cross-listed

01
Sub-leading correction of two-gluon rapidity correlations of strong colour field
Ye-Yin Zhao🇨🇳 · Ming-Mei Xu🇨🇳 · Heng-Ying Zhang🇨🇳 · Yuan-Fang Wu🇨🇳
In the framework of Color Glass Condensate (CGC) effective field theory (EFT), we calculate two-gluon rapidity correlations in the leading and sub-leading orders of $p_{⊥} / Q_{s}$ . In the leading order, both short- and long-range rapidity correlations are enhanced. In contrast, the contribution of sub-leading order is mainly short range quantum correlations. It is much smaller than that of the leading one, but is not negligible. Transverse momentum dependence of rapidity correlation shows that the leading order is sensitive to the saturation momentum of two incident particles, but the sub-leading one is not.
nucl-thhep-ph4 citations
02
The interplay of short-range correlations and nuclear symmetry energy in hard photon productions from heavy-ion reactions at Fermi energies
Gao-Chan Yong · Bao-An Li
Within an isospin- and momentum-dependent transport model for nuclear reactions at intermediate energies, we investigate the interplay of the nucleon-nucleon short-range correlations (SRC) and nuclear symmetry energy $E_{sy m} (ρ)$ on hard photon spectra in collisions of several Ca isotopes on $^{112}$ Sn and $^{124}$ Sn targets at a beam energy of 45 MeV/nucleon. It is found that over the whole spectra of hard photons studied, effects of the SRC overwhelm those due to the $E_{sy m} (ρ)$ . The energetic photons come mostly from the high-momentum tails (HMT) of single-nucleon momentum distributions in the target and projectile. Within the neutron-proton dominance model of SRC based on the consideration that the tensor force acts mostly in the isosinglet and spin-triplet nucleon-nucleon interaction channel, there are equal numbers of neutrons and protons, thus a zero isospin-asymmetry in the HMTs. Therefore, experimental measurements of the energetic photons from heavy-ion collisions at Fermi energies have the great potential to help us better understand the nature of SRC without any appreciable influence by the uncertain $E_{sy m} (ρ)$ . These measurements will be complementary to but also have some advantages over the ongoing and planned experiments using hadronic messengers from reactions induced by high-energy electrons or protons. Since the underlying physics of SRC and $E_{sy m} (ρ)$ are closely correlated, a better understanding of the SRC will in turn help constrain the nuclear symmetry energy more precisely in a broad density range.
nucl-thnucl-exPRC(2017)·43 citations
03
Proton pairing in neutron stars from chiral effective field theory
Yeunhwan Lim · Jeremy W. Holt
We study the $^{1} S_{0}$ proton pairing gap in beta-equilibrated neutron star matter within the framework of chiral effective field theory. We focus on the role of three-body forces, which strongly modify the effective proton-proton spin-singlet interaction in dense matter. We find that three-body forces generically reduce both the size of the pairing gap and the maximum density at which proton pairing may occur. The pairing gap is computed within BCS theory, and model uncertainties are estimated by varying the nuclear potential and the choice of single-particle spectrum in the gap equation. We find that a second-order perturbative treatment of the single-particle spectrum suppresses the proton $^{1} S_{0}$ pairing gap relative to the use of a free spectrum. We estimate the critical temperature for the onset of proton superconductivity to be $T_{c} = (3.7 - 6.0) \times 1 0^{9}$ K, which is consistent with previous theoretical results in the literature and marginally within the range deduced from a recent Bayesian analysis of neutron star cooling observations.
nucl-thPRC(2021)·19 citations
04
Mixed Phase within the Multi-polytrope Approach to High Mass Twins
David Alvarez-Castillo🇩🇪 · David Blaschke🇷🇺 · Stefan Typel🇩🇪
We present a multi-polytrope approach to describe high-mass twins fulfilling chiral effective field theory estimations of the neutron star equation state and test it against the appearance of mixed phases at the hadron-quark interface. In addition, we discuss astrophysical applications of this method and expected future measurements that shall further constrain neutron star matter and the understanding of the QCD phase diagram.
nucl-thastro-ph.HEhep-phAstron.Nachr.(2017)·7 citations
05
Effects of retarded electrical fields on observables sensitive to the high-density behavior of nuclear symmetry energy in heavy-ion collisions at intermediate energies
Gao-Feng Wei🇨🇳 · Bao-An Li🇺🇸 · Gao-Chan Yong🇨🇳 · Li Ou🇨🇳 · Xin-Wei Cao🇨🇳 · Xu-Yang Liu🇨🇳
Within the isospin- and momentum-dependent transport model IBUU11, we examine the relativistic retardation effects of electrical fields on the $π^{-} / π^{+}$ ratio and neutron-proton differential transverse flow in heavy-ion collisions at intermediate energies. Compared to the static Coulomb fields, the retarded electric fields of fast-moving charges are known to be anisotropic and the associated relativistic corrections can be significant. They are found to increase the number of energetic protons in the participant region at the maximum compression by as much as 25\% but that of energetic neutrons by less than 10\% in $^{197}$ Au+ $^{197}$ Au reactions at a beam energy of 400 MeV/nucleon. Consequently, more $π^{+}$ and relatively less $π^{-}$ mesons are produced, leading to an appreciable reduction of the $π^{-} / π^{+}$ ratio compared to calculations with the static Coulomb fields. Also, the neutron-proton differential transverse flow, as another sensitive probe of high-density symmetry energy, is also decreased appreciably due to the stronger retarded electrical fields in directions perpendicular to the velocities of fast-moving charges compared to calculations using the isotropic static electrical fields. Moreover, the retardation effects on these observables are found to be approximately independent of the reaction impact parameter.
nucl-thhep-phPRC(2018)·10 citations
06
Properties of nuclei up to $A = 16$ using local chiral interactions
D. Lonardoni · J. Carlson · S. Gandolfi · J. E. Lynn · K. E. Schmidt · A. Schwenk · X. B. Wang
We report accurate quantum Monte Carlo calculations of nuclei up to $A = 16$ based on local chiral two- and three-nucleon interactions up to next-to-next-to-leading order. We examine the theoretical uncertainties associated with the chiral expansion and the cutoff in the theory, as well as the associated operator choices in the three-nucleon interactions. While in light nuclei the cutoff variation and systematic uncertainties are rather small, in $^{16}$ O these can be significant for large coordinate-space cutoffs. Overall, we show that chiral interactions constructed to reproduce properties of very light systems and nucleon-nucleon scattering give an excellent description of binding energies, charge radii, and form factors for all these nuclei, including open-shell systems in $A = 6$ and 12.
nucl-thPRL(2018)·109 citations

Affiliations

first authorsco-authorsvia INSPIRE

Sub-leading correction of two-gluon rapidity correlations of strong colour field

The interplay of short-range correlations and nuclear symmetry energy in hard photon productions from heavy-ion reactions at Fermi energies

Proton pairing in neutron stars from chiral effective field theory

Mixed Phase within the Multi-polytrope Approach to High Mass Twins

Effects of retarded electrical fields on observables sensitive to the high-density behavior of nuclear symmetry energy in heavy-ion collisions at intermediate energies

Properties of nuclei up to A=16 using local chiral interactions

Affiliations

Properties of nuclei up to $A = 16$ using local chiral interactions