Nuclear Theory·nucl-th

Wednesday·March 18, 2020

10 papers—5 primary·5 cross-listed

01
[Submitted on 17 Mar 2020]
Two-neutron halo structure of $^{31}$ F
N. Michel · J.G. Li · F.R. Xu · W. Zuo
We apply the Gamow shell model to study $^{25 - 31}$ F isotopes. As both inter-nucleon correlations and continuum coupling are properly treated therein, the structure shape of $^{31}$ F at large distance can be analyzed precisely. For this, one-nucleon densities, root-mean square radii and correlation densities are calculated in neutron-rich fluorine isotopes. It is then suggested that $^{31}$ F exhibits a two-neutron halo structure, built from both continuum coupling and nucleon-nucleon correlations.
Comments:
5 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2003.07542 [pdf]
PRC(2020)·38 citations
02
[Submitted on 17 Mar 2020]
Dispersion and suppression of sound near QCD critical point
Md Hasanujjaman🇮🇳 · Mahfuzur Rahaman🇮🇳 · Abhijit Bhattacharyya🇮🇳 · Jan-e Alam🇮🇳
We have used second order relativistic hydrodynamics equipped with equation of state which includes the critical point to study the propagation of perturbation in a relativistic QCD fluid. Dispersion relation for the sound wave has been derived to ascertain the fate of the perturbation in the fluid near the QCD critical end point (CEP). We observe that the threshold value of the wavelength of the sound in the fluid diverges at the CEP, implying that all the modes of the perturbations are dissipated at this point. Some consequences of the suppression of sound near the critical point have been discussed.
Comments:
To be published in Physical Review C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2003.07575 [pdf]
PRC(2020)·9 citations
03
[Submitted on 17 Mar 2020]
Ab initio study of $(ν_{ℓ}, ℓ^{-})$ and $(ν_{ℓ}, ℓ^{+})$ inclusive scattering in $^{12}$ C: confronting the MiniBooNE and T2K CCQE data
A. Lovato🇺🇸 · J. Carlson🇺🇸 · S. Gandolfi🇺🇸 · N. Rocco🇺🇸 · R. Schiavilla🇺🇸
We carry out an ab initio calculation of the neutrino flux-folded inclusive cross sections, measured on $^{12}$ C by the MiniBooNE and T2K collaborations in the charged-current quasielastic (CCQE) regime. The calculation is based on realistic two- and three-nucleon interactions, and on a realistic nuclear electroweak current with one-and two-nucleon terms that are constructed consistently with these interactions and reproduce low-energy electroweak transitions. Numerically exact quantum Monte Carlo methods are utilized to compute the nuclear weak response functions, by fully retaining many-body correlations in the initial and final states and interference effects between one- and two-body current contributions. We employ a nucleon axial form factor of the dipole form with $Λ_{A} = 1.0$ or $1.15$ GeV, the latter more in line with a very recent lattice QCD determination. The calculated cross sections are found to be in good agreement with the neutrino data of MiniBooNE and T2K, and antineutrino MiniBooNE data, yielding a consistent picture of nuclei and their electroweak properties across a wide regime of energy and momenta.
Comments:
13 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2003.07710 [pdf]
PRX(2020)·87 citations
04
[Submitted on 17 Mar 2020]
Predictions for charmed nuclei based on $Y_{c} N$ forces inferred from lattice QCD simulations
Johann Haidenbauer🇩🇪 · Andreas Nogga🇩🇪 · Isaac Vidaña🇮🇹
Charmed nuclei are investigated utilizing $Λ_{c} N$ and $Σ_{c} N$ interactions that have been extrapolated from lattice QCD simulations at unphysical masses of $m_{π} = 410$ -- $570$ MeV to the physical point using chiral effective field theory as guideline. Calculations of the energies of $Λ_{c}$ single-particle bound states for various charmed nuclei from $_{Λ_{c}}^{5}$ Li to $_{Λ_{c}}^{209}$ Bi are performed using a perturbative many-body approach. This approach allows one to determine the finite nuclei $Λ_{c}$ self-energy from which the energies of the different bound states can be obtained. Though the $Λ_{c} N$ interaction inferred from the lattice results is only moderately attractive, it supports the existence of charmed nuclei. Already the lightest nucleus considered is found to be bound. The spin-orbit splitting of the p- and d-wave states turns out to be small, as in the case of single $Λ$ hypernuclei. Additional calculations based on the Faddeev-Yakubovsky equations suggest that also $A = 4$ systems involving a $Λ_{c}$ baryon are likely to be bound, but exclude a bound $_{Λ_{c}}^{3}$ He state.
Comments:
13 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2003.07768 [pdf]
EPJA(2020)·14 citations
05
[Submitted on 17 Mar 2020]
Quantal diffusion approach for multinucleon transfer processes in the $^{58, 64}$ Ni+ $^{208}$ Pb reactions: Toward the production of unknown neutron-rich nuclei
Kazuyuki Sekizawa · Sakir Ayik
Background: In recent years, substantial efforts have been made for the study of multinucleon transfer reactions at energies around the Coulomb barrier both experimentally and theoretically, aiming at the production of unknown neutron-rich heavy nuclei. It is crucial to provide reliable theoretical predictions based on microscopic theories with sufficient predictive power. Purpose: This paper aims to clarify the applicability of the quantal diffusion approach based on the stochastic mean-field (SMF) theory for multinucleon transfer processes. Isotope production cross sections are evaluated for the reactions of $^{64}$ Ni+ $^{208}$ Pb at $E_{c . m .}$ =268 MeV and $^{58}$ Ni+ $^{208}$ Pb at $E_{c . m .}$ =270 MeV and are compared with available experimental data. Methods: Three-dimensional time-dependent Hartree-Fock (TDHF) calculations are carried out for a range of initial orbital angular momenta with Skyrme SLy4d functional. Quantal diffusion equations, derived based on the SMF theory, for variances and covariance of neutron and proton numbers of reaction products are solved, with microscopic drift and diffusion coefficients obtained from the time evolution of occupied single-particle orbitals in TDHF. Secondary deexcitation processes, both particle evaporation and fission, are simulated by a statistical model, GEMINI++. Results: We find that the quantal diffusion approach reproduces the measured cross sections for abundant reaction products, including both projectile-like and target-like fragments, as well as fragments of transfer-induced fission. The results underline the importance of beyond mean-field effects in describing multinucleon transfer processes. We emphasize that the quantal diffusion description does not involve any adjustable parameters, once an energy density functional is given. Possible future directions are discussed. (Shortened due to the word limit)
Comments:
26 pages, 12 figures (plus 4 figures, 2 tables in Appendix); v2 - Version accepted for publication in Physical Review C; Supplemental movies can be found at https://www.youtube.com/playlist?list=PLKTmRVRArzsQUKpMiOXAzliVSgzjD0ZG2
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2003.07786 [pdf]
PRC(2020)·46 citations
06
[Submitted on 16 Mar 2020] (cross-list from hep-th)
Hydrodynamic attractors in phase space
Michal P. Heller🇩🇪 · Ro Jefferson🇩🇪 · Michał Spaliński🇵🇱 · Viktor Svensson🇩🇪
Hydrodynamic attractors have recently gained prominence in the context of early stages of ultra-relativistic heavy-ion collisions at the RHIC and LHC. We critically examine the existing ideas on this subject from a phase space point of view. In this picture the hydrodynamic attractor can be seen as a special case of the more general phenomenon of dynamical dimensionality reduction of phase space regions. We quantify this using Principal Component Analysis. Furthermore, we adapt the well known slow-roll approximation to this setting. These techniques generalize easily to higher dimensional phase spaces, which we illustrate by a preliminary analysis of a dataset describing the evolution of a 5-dimensional manifold of initial conditions immersed in a 16-dimensional representation of the phase space of the Boltzmann kinetic equation in the relaxation time approximation.
Comments:
9 pages, 5 figures. Matches published version and includes new supplemental material on dimensionality reduction in kinetic theory
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2003.07368 [pdf]
PRL(2020)·47 citations
07
[Submitted on 16 Mar 2020] (cross-list from hep-ph)
Predictive power of transverse-momentum-dependent distributions
Manvir Grewal🇺🇸 · Zhong-Bo Kang🇺🇸 · Jian-Wei Qiu🇺🇸 · Andrea Signori🇮🇹
We investigate the predictive power of transverse-momentum-dependent (TMD) distributions as a function of the light-cone momentum fraction $x$ and the hard scale $Q$ defined by the process. We apply the saddle point approximation to the unpolarized quark and gluon transverse momentum distributions and evaluate the position of the saddle point as a function of the kinematics. We determine quantitatively that the predictive power for an unpolarized transverse momentum distribution is maximal in the large- $Q$ and small- $x$ region. For cross sections the predictive power of the TMD factorization formalism is generally enhanced by considering the convolution of two distributions, and we explicitly consider the case of $Z$ and $H^{0}$ boson production. In the kinematic regions where the predictive power is not maximal, the distributions are sensitive to the non-perturbative hadron structure. Thus, these regions are critical for investigating hadron tomography in a three-dimensional momentum space.
Comments:
25 pages - published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2003.07453 [pdf]
PRD(2020)·29 citations
08
[Submitted on 17 Mar 2020] (cross-list from hep-ph)
Molecular picture for the $Ω (2012)$ revisited
Natsumi Ikeno🇯🇵 · Genaro Toledo🇪🇸 · Eulogio Oset🇪🇸
We conduct a study of the interaction of the $K ˉ Ξ^{*}$ , $η Ω$ ( $s$ -wave) and $K ˉ Ξ$ ( $d$ -wave) channels within a coupled channel unitary approach where the transition potential between the $K ˉ Ξ^{*}$ and $η Ω$ channels is obtained from chiral Lagrangians. The transition potential between $K ˉ Ξ^{*}$ , $η Ω$ and $K ˉ Ξ$ is taken in terms of free parameters, which together with a cut off to regularize the meson-baryon loops are fitted to the $Ω (2012)$ data. We find that all data including the recent Belle experiment on $Γ_{Ω^{*} \to π K ˉ Ξ} / Γ_{Ω^{*} \to K ˉ Ξ}$ , are compatible with the molecular picture stemming from meson baryon interaction of these channels.
Comments:
19 pages, 4 figures, 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2003.07580 [pdf]
PRD(2020)·44 citations
09
[Submitted on 17 Mar 2020] (cross-list from hep-ph)
Revisiting the $Ω (2012)$ as a hadronic molecule and its strong decays
Jun-Xu Lu🇨🇳 · Chun-Hua Zeng🇨🇳 · En Wang🇨🇳 · Ju-Jun Xie🇨🇳 · Li-Sheng Geng🇨🇳
Recently, the Belle collaboration measured the ratios of the branching fractions of the newly observed $Ω (2012)$ excited state. They did not observe significant signals for the $Ω (2012) \to K ˉ Ξ^{*} (1530) \to K ˉ π Ξ$ decay, and reported an upper limit for the ratio of the three body decay to the two body decay mode of $Ω (2012) \to K ˉ Ξ$ . In this work, we revisit the newly observed $Ω (2012)$ from the molecular perspective where this resonance appears to be a dynamically generated state with spin-parity $3/ 2^{-}$ from the coupled channels interactions of the $K ˉ Ξ^{*} (1530)$ and $η Ω$ in $s$ -wave and $K ˉ Ξ$ in $d$ -wave. With the model parameters for the $d$ -wave interaction, we show that the ratio of these decay fractions reported recently by the Belle collaboration can be easily accommodated.
Comments:
Published version. Published in Eur.\ Phys.\ J.\ C {\bf 80}, 361 (2020)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2003.07588 [pdf]
EPJC(2020)·38 citations
10
[Submitted on 17 Mar 2020] (cross-list from physics.atm-clus)
Derivation of K-matrix reaction theory in a discrete basis formalism
Y. Alhassid · G.F. Bertsch · P. Fanto
The usual derivations of the S and K matrices for two-particle reactions proceed through the Lippmann-Schwinger equation with formal definitions of the incoming and outgoing scattering states. Here we present an alternative derivation that is carried out completely in the Hamiltonian representation, using a discrete basis of configurations for the scattering channels as well as the quasi-bound configurations of the combined fragments. We use matrix algebra to derive an explicit expression for the K matrix in terms of the Hamiltonian of the internal states of the compound system and the coupling between the channels and the internal states. The formula for the K matrix includes explicitly a real dispersive shift matrix to the internal Hamiltonian that is easily computed in the formalism. That expression is applied to derive the usual form of the S matrix as a sum over poles in the complex energy plane. Some extensions and limitations of the discrete-basis Hamiltonian formalism are discussed in the concluding remarks and in the Appendix.
Subjects:
physics.atm-clus (physics.atm-clus); Nuclear Theory (nucl-th)
arXiv:
2003.07843 [pdf]
Annals Phys.(2020)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE