Nuclear Theory·nucl-th

Thursday·November 22, 2018

9 papers—7 primary·2 cross-listed

01
Nucleon-to-Roper electromagnetic transition form factors at large- $Q^{2}$
Chen Chen🇧🇷 · Ya Lu🇨🇳 · Daniele Binosi🇮🇹 · Craig D. Roberts🇺🇸 · Jose Rodríguez-Quintero🇪🇸 · Jorge Segovia🇪🇸
High-precision nucleon-resonance electroproduction data on a large kinematic domain of energy and momentum transfer have proven crucial in revealing novel features of strong interactions within the Standard Model and unfolding structural details of baryon excited states. Thus, in anticipation of new data reaching to unprecedented photon virtuality, we employ a quark-diquark approximation to the three valence-quark bound-state problem to compute $γ^{*} p \to R^{+}$ and $γ^{*} n \to R^{0}$ transition form factors on $Q^{2} / m_{N}^{2} \in [0, 12]$ , where $m_{N}$ is the nucleon mass. Having simultaneously analysed both charged and neutral channels, we also provide a quark-flavour separation of the transition form factors. The results should be useful in planning new-generation experiments.
nucl-thhep-lathep-phnucl-exPRD(2019)·65 citations
02
Basis light front quantization for the charged light mesons with color singlet Nambu--Jona-Lasinio interactions
Shaoyang Jia🇺🇸 · James P. Vary🇺🇸
We apply the basis light front quantization (BLFQ) approach to describe the valence structures of the charged light meson ground states. Specifically, the light front wavefunctions of $π^{\pm}$ , $ρ^{\pm}$ , $K^{\pm}$ , and $K^{*\pm}$ are obtained as the eigenvectors of the light front effective Hamiltonians with confinement potentials supplemented by the color singlet Nambu--Jona-Lasinio (NJL) interactions. We adjust our model such that the spectrum of these ground states and the charge radii of the pseudoscalar states agree with experimental results. We present the elastic form factors and parton distribution amplitudes (PDAs) as illustrations of the internal structures of the pseudoscalar pions and kaons in terms of valence quarks.
nucl-thhep-phPRC(2019)·98 citations
03
Effect of Siegert's Theorem on Low-Energy Neutrino-Nucleus Interactions
A.C. Hayes🇺🇸 · J.L. Friar🇺🇸
We examine the importance of conserving the vector current in calculating low-energy neutrino-nucleus interactions by implicitly invoking Siegert's Theorem in describing the vector transverse electric current. We find that at low neutrino energies (E? <50 MeV), Siegert's Theorem can change neutrino cross sections for normal-parity non-spin-flip excitations by about a factor of two.The same is true of muon capture rates. At higher neutrino energies the effect of Siegert's Theorem diminishes, and by about 100 MeV the effect is very small.
nucl-thhep-exhep-phnucl-exPRC(2018)·2 citations
04
Four-body Faddeev-type equations for $K ˉ N N N$ quasi-bound state calculations
Nina Shevchenko🇨🇿
The paper is devoted to the $K ˉ N N N$ system, which is an exotic system consisting of an antikaon and three nucleons. Four-body Faddeev-type AGS equations, which are being used for evaluation of the possible quasi-bound state in the system are described.
nucl-thSpringer Proc.Phys.(2020)·0 citations
05
Statistical fluctuations of correlators in the Color Glass Condensate
Francois Gelis🇫🇷 · Naoto Tanji🇮🇹
In the McLerran-Venugopalan model, correlators of Wilson lines are given by an average over a Gaussian ensemble of random color sources. In numerical implementations, these averages are approximated by a Monte-Carlo sampling. In this paper, we study the statistical error made with such a sampling, with emphasis on the momentum dependence of this error. Using the example of the dipole amplitude, we consider various approximants that are all equivalent in the limit of infinite statistics but differ with finite statistics and compare their statistical errors. For correlation functions that are translation invariant, we show that averaging over the barycenter coordinate drastically reduces the statistical error and more importantly modifies its momentum dependence.
nucl-thhep-ph1 citation
06
Strongly intensive fluctuations and correlations in ultrarelativistic nuclear collisions in the model with string fusion
Vladimir Kovalenko (Saint Petersburg State University)🇷🇺
The several types of strongly intensive correlation variables are studied in nuclear collisions at LHC energy. These quantities are expected not to depend on centrality class width. They have been calculated in the dipole-based parton-string Monte Carlo model with string fusion. The centrality dependence of the mean transverse momentum correlation coefficient and strongly intensive quantity $Σ$ between multiplicity and $P_{T}$ have been obtained. Dynamical charge fluctuation $ν_{d y n}$ has been also calculated and compared with experimental data. It is shown that string fusion improves agreement with the experiment.
nucl-thhep-phEPJ Web Conf.(2019)·7 citations
07
Neutron transfer reactions in accreting neutron stars
Andrey I. Chugunov (Ioffe Institute)
I suggest a novel type of nuclear reactions in accreting neutron stars - neutron transfer, which is quantum tunneling of weakly bounded neutron from one nucleus to another. I estimate the rate of this process for fixed nuclei separation and then average the result over realistic distribution of nuclei to get the rate value for astrophysical conditions. The neutron transfer can modify reaction chains in accreting neutron stars, thus affecting their heating and cooling. In particular, it can suppress cooling by URCA pairs of nuclei, which is supposed to be crucial for the hottest neutron stars.
nucl-thastro-ph.HEMNRAS(2019)·13 citations
08
How Robust is the N = 34 Subshell Closure? First Spectroscopy of $^{52}$ Ar
H. N. Liu🇫🇷 · A. Obertelli🇩🇪 · P. Doornenbal🇯🇵 · C. A. Bertulani🇺🇸 · G. Hagen🇺🇸 · J. D. Holt🇨🇦 · G. R. Jansen🇺🇸 · T. D. Morris🇺🇸 · A. Schwenk🇩🇪 · R. Stroberg🇨🇦 · N. Achouri🇫🇷 · H. Baba🇯🇵 and 68 other authors
The first $γ$ -ray spectroscopy of $^{52}$ Ar, with the neutron number N = 34, was measured using the $^{53}$ K(p,2p) one-proton removal reaction at $\sim$ 210 MeV/u at the RIBF facility. The 2 $_{1}^{+}$ excitation energy is found at 1656(18) keV, the highest among the Ar isotopes with N $>$ 20. This result is the first experimental signature of the persistence of the N = 34 subshell closure beyond $^{54}$ Ca, i.e., below the magic proton number Z = 20. Shell-model calculations with phenomenological and chiral-effective-field-theory interactions both reproduce the measured 2 $_{1}^{+}$ systematics of neutron-rich Ar isotopes, and support a N = 34 subshell closure in $^{52}$ Ar.
↳ nucl-exnucl-thPRL(2019)·90 citations
09
Towards a holographic quark-hadron continuity
Kazem Bitaghsir Fadafan🇮🇷 · Farideh Kazemian🇮🇷 · Andreas Schmitt🇬🇧
We study dense nuclear and quark matter within a single microscopic approach, namely the holographic Sakai-Sugimoto model. Nuclear matter is described via instantons in the bulk, and we show that instanton interactions are crucial for a continuous connection of chirally broken and chirally symmetric phases. The continuous path from nuclear to quark matter includes metastable and unstable stationary points of the potential, while the actual chiral phase transition remains of first order, as in earlier approximations. We show that the model parameters can be chosen to reproduce low-density properties of nuclear matter and observe a non-monotonic behavior of the speed of sound as a function of the baryon chemical potential, as suggested by constraints from QCD and astrophysics.
↳ hep-phhep-thnucl-thJHEP(2019)·44 citations

Affiliations

first authorsco-authorsvia INSPIRE