Nuclear Theory·nucl-th

Friday·October 28, 2022

11 papers—6 primary·5 cross-listed

01
Ab initio no-core shell model study of neutron-rich $^{18, 19, 20}$ C isotopes
Priyanka Choudhary · Praveen C. Srivastava
We implement the ab initio no-core shell model approach to study neutron-rich $^{18}$ C, $^{19}$ C and $^{20}$ C isotopes. For this purpose, we employ charge-dependent Bonn 2000 (CDB2K), inside non-local outside Yukawa (INOY) and chiral next-to-next-to-next-to-leading order (N $^{3}$ LO) nucleon-nucleon interactions. Low-lying energy spectra, electromagnetic properties and point-proton radii for these nuclei up to basis space $N_{max}$ = 4 are calculated. Binding energies obtained with INOY interaction are in better agreement with the experimental values as compared to other \textit{ab initio} interactions. We also show the behavior of ground state energy and point-proton radii with the NCSM parameters, $ℏ$ $Ω$ and $N_{max}$ . We report a strong sensitivity of the B(E2) values from the first excited $2^{+}$ to the ground state of $^{18}$ C and $^{20}$ C to the nuclear interaction. Shell model calculations with YSOX interaction are also performed, and corresponding results are compared with ab initio one.
nucl-thNPA(2023)·9 citations
02
Nuclear Matter and Neutron Stars from Relativistic Brueckner-Hartree-Fock Theory
Hui Tong · Chencan Wang · Sibo Wang
The momentum and isospin dependence of the single-particle potential for the in-medium nucleon are the key quantities in the Relativistic Brueckner-Hartree-Fock (RBHF) theory. It depends on how to extract the scalar and the vector components of the single-particle potential inside nuclear matter. In contrast to the RBHF calculations in the Dirac space with the positive-energy states (PESs) only, the single-particle potential can be determined in a unique way by the RBHF theory together with the negative-energy states (NESs), i.e., the RBHF theory in the full Dirac space. The saturation properties of symmetric and asymmetric nuclear matter in the full Dirac space are systematically investigated based on the realistic Bonn nucleon-nucleon potentials. In order to further specify the importance of the calculations in the full Dirac space, the neutron star properties are investigated. The direct URCA process in neutron star cooling will happen at density $ρ_{DURCA} = 0.43, 0.48, 0.52$ fm $^{- 3}$ with the proton fractions $Y_{p, DURCA} = 0.13$ . The radii of a $1.4 M_{⊙}$ neutron star are predicated as $R_{1.4 M_{⊙}} = 11.97, 12.13, 12.27$ km, and their tidal deformabilities are $Λ_{1.4 M_{⊙}} = 376, 405, 433$ for potential Bonn A, B, C. Comparing with the results obtained in the Dirac space with PESs only, full-Dirac-space RBHF calculation predicts the softest symmetry energy which would be more favored by the gravitational waves (GW) detection from GW170817. Furthermore, the results from full-Dirac-space RBHF theory are consistent with the recent astronomical observations of massive neutron stars and simultaneous mass-radius measurement.
nucl-thApJ(2022)·27 citations
03
Properties of the diffusion and drift kinetic coefficients in momentum space for a cold Fermi system
Sergiy V. Lukyanov
Using the methods of kinetic theory expressions for the diffusion and drift coefficients for a cold Fermi system are obtained. Their dependences on the momentum are calculated for the step distribution function as well as in the case of excitation of a particle-hole pair.
nucl-thNucl.Phys.Atom.Energy(2023)·4 citations
04
Light nuclei production in pp and pA collisions in the Baryon Canonical Ensemble
Natasha Sharma🇮🇳 · Lokesh Kumar🇮🇳 · Pok Man Lo🇵🇱 · Krzysztof Redlich🇵🇱
The increase in yields of light nuclei with charged particle multiplicity, as reported by the ALICE collaboration at CERN in p-p and p-Pb collisions at the LHC energy is investigated in the thermal hadron resonance gas model. The model is extended to account for exact baryon number conservation. The focus is on the production of protons, deuterons, $^{3}$ He, and $_{Λ}^{3}$ H. A very good description of proton and deuteron yields is obtained as a function of charged particle multiplicity in the mid-rapidity region using the same fixed temperature as in central Pb-Pb collisions. The yields of light nuclei $^{3}$ He and $_{Λ}^{3}$ H though qualitatively explained as a function of multiplicity, are lower than the model expectation. One of the possible reasons could be that for $^{3}$ He and $_{Λ}^{3}$ H, the chemical equilibrium is not yet reached at small multiplicities.
nucl-thhep-phPRC(2023)·9 citations
05
Centrality dependence of proton and light nuclei yields as a consequence of baryon annihilation in the hadronic phase
Volodymyr Vovchenko🇺🇸 · Volker Koch🇺🇸
The centrality dependence of the $p / π$ ratio measured by the ALICE Collaboration in 5.02 TeV Pb-Pb collisions indicates a statistically significant suppression with the increase of the charged particle multiplicity once the centrality-correlated part of the systematic uncertainty is eliminated from the data. We argue that this behavior can be attributed to baryon annihilation in the hadronic phase. By implementing the $B B ˉ \leftrightarrow 5 π$ reaction within a generalized partial chemical equilibrium framework, we estimate the annihilation freeze-out temperature at different centralities, which decreases with increasing charged multiplicity and yields $T_{ann} = 132 \pm 5$ MeV in 0-5% most central collisions. This value is considerably below the hadronization temperature of $T_{had} \sim 160$ MeV but above the thermal (kinetic) freeze-out temperature of $T_{kin} \sim 100$ MeV. Baryon annihilation reactions thus remain relevant in the initial stage of the hadronic phase but freeze out before (pseudo-)elastic hadronic scatterings. One experimentally testable consequence of this picture is a suppression of various light nuclei to proton ratios in central collisions of heavy ions.
nucl-thhep-phnucl-exPLB(2022)·16 citations
06
Cold Neutron-Deuteron Capture and Wigner-SU(4) Symmetry
Xincheng Lin🇺🇸 · Hersh Singh🇺🇸 · Roxanne P. Springer🇺🇸 · Jared Vanasse🇺🇸
We calculate the cold neutron-deuteron ( $n d$ ) capture cross section, $σ_{n d}$ , to next-to-next-to leading order (NNLO) using the model-independent approach of pionless effective field theory (EFT( $π /$ )). At leading order we find $σ_{n d} = 0.315 \pm 0.217$ mb, while the experimental result is 0.508(15) mb [Jurney, Bendt and Browne in Phys. Rev. C 25, 2810 (1982)] for a laboratory neutron velocity of 2200 m/s. At next-to-leading-order (NLO), we show that $σ_{n d}$ is sensitive to the low energy constant (LEC), $L_{1}^{(0)}$ , of the two-nucleon isovector current appearing at NLO. A fit of $L_{1}^{(0)}$ at NLO to the triton magnetic moment yields a NLO prediction of $σ_{n d} = 0.393 \pm 0.164$ mb, where the error comes from propagating the error from the $L_{1}^{(0)}$ fit. At next-to-next-to-leading-order (NNLO), we find that a new three-nucleon magnetic moment counterterm is required for renormalization group invariance of both $σ_{n d}$ and the triton magnetic moment. Fitting the NNLO correction to $L_{1}^{(0)}$ (denoted $L_{1}^{(1)}$ ) to cold neutron-proton capture ( $σ_{n p}$ ) yields a NNLO prediction of $σ_{n d} = 0.447 \pm 0.130$ mb, where the error comes from propagating the error from the $L_{1}^{(1)}$ fit. We also study different fittings of $L_{1}^{(0)}$ and $L_{1}^{(1)}$ to $σ_{n p}$ , $σ_{n d}$ , and/or the triton magnetic moment. For example, fitting $L_{1}^{(0)}$ simultaneously to $σ_{n p}$ , $σ_{n d}$ , and the triton magnetic moment at NLO, and fitting $L_{1}^{(1)}$ simultaneously to $σ_{n p}$ and $σ_{n d}$ at NNLO, yields $σ_{n d} = 0.480 \pm 0.114$ mb and $0.511 \pm 0.042$ mb, respectively, where errors are naively estimated from EFT( $π /$ ) power counting. In addition, we discuss how Wigner-SU(4) symmetry may alter the naive EFT( $π /$ ) expansion of $σ_{n d}$ .
nucl-thPRC(2023)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE

Ab initio no-core shell model study of neutron-rich 18,19,20C isotopes

Nuclear Matter and Neutron Stars from Relativistic Brueckner-Hartree-Fock Theory

Properties of the diffusion and drift kinetic coefficients in momentum space for a cold Fermi system

Light nuclei production in pp and pA collisions in the Baryon Canonical Ensemble

Centrality dependence of proton and light nuclei yields as a consequence of baryon annihilation in the hadronic phase

Cold Neutron-Deuteron Capture and Wigner-SU(4) Symmetry

Affiliations

Ab initio no-core shell model study of neutron-rich $^{18, 19, 20}$ C isotopes