Nuclear Theory·nucl-th

Friday·March 13, 2020

8 papers—4 primary·4 cross-listed

01
Effects of quark anomalous magnetic moment on the thermodynamical properties and mesonic excitations of magnetized hot and dense matter in PNJL model
Nilanjan Chaudhuri🇮🇳 · Snigdha Ghosh🇮🇳 · Sourav Sarkar🇮🇳 · Pradip Roy🇮🇳
Various thermodynamic quantities and the phase diagram of strongly interacting hot and dense magnetized quark matter are obtained with the $2$ -flavour Nambu-Jona-Lasinio model with Polyakov loop considering finite values of the anomalous magnetic moment (AMM) of the quarks. Susceptibilities associated with constituent quark mass and traced Polyakov loop are used to evaluate chiral and deconfinement transition temperatures. It is found that, inclusion of the AMM of the quarks in presence of the background magnetic field results in a substantial decrease in the chiral as well as deconfinement transition temperatures in contrast to an enhancement in the chiral transition temperature in its absence. Using standard techniques of finite temperature field theory, the two point thermo-magnetic mesonic correlation functions in the scalar ( $σ$ ) and neutral pseudoscalar ( $π^{0}$ ) channels are evaluated to calculate the masses of $σ$ and $π^{0}$ considering the AMM of the quarks.
nucl-thhep-phEPJA(2020)·46 citations
02
Dispersion (asymptotic) theory of charged particle transfer reactions at low energies and nuclear astrophysics: II. the asymptotic normalization coefficients and their nuclear-astrophysical application
R. Yarmukhamedov · K. I. Tursunmakhatov · N. Burtebayev
Within the asymptotic theory proposed by authors R. Yarmukhamedov and K.I. Tursunmakhatov [Phys. Rev. C (submitted 2019)] for the peripheral sub- and above-barrier transfer $A$ ( $x$ , $y$ ) $B$ reaction in the three-body ( $A$ , $a$ and $y$ ) model ( $x$ = $y$ + $a$ and $B$ = $A$ + $a$ , and $a$ is a transferred particle), the analysis of the experimental angular distributions of the differential cross sections is performed for the peripheral proton and triton transfer $^{9} Be (^{10} B,^{9} Be)^{10} B$ , $^{16} O (^{3} He, d)^{17} F$ and $^{19} F (p, α)^{16} O$ reactions at above-and sub-barrier projectile energies, respectively. New estimates and their uncertainties are obtained for magnitudes of the asymptotic normalization coefficients (respective the nuclear vertex constants) for $^{9} Be + p \to^{10} B$ , $^{16} O + p \to^{17} F$ and $^{16} O + t \to^{19} F$ . They are applied for calculations of the astrophysical $S$ factors for the nuclear-astrophysical $^{9} Be (p, γ)^{10} B$ , $^{16} O (p, γ)^{17} F$ and $^{19} F (p, α)^{16} O)$ reactions at thermonuclear energies. New values and their uncertainties are obtained for the astrophysical $S$ factors at stellar energies.
nucl-th0 citations
03
A collision geometry-based 3D initial condition for relativistic heavy-ion collisions
Chun Shen🇺🇸 · Sahr Alzhrani🇺🇸
We present a simple way to construct 3D initial conditions for relativistic heavy-ion collisions based on the Glauber collision geometry. Local energy and momentum conservation conditions are imposed to set non-trivial constraints on our parameterizations of longitudinal profiles for the system's initial energy density and flow velocity. After calibrating parameters with charged hadron rapidity distributions in central Au+Au collisions, we test model predictions for particle rapidity distributions in d+Au and peripheral Au+Au collisions in the Beam Energy Scan (BES) program at Relativistic Heavy-Ion Collider (RHIC). Simulations and comparisons with measurements are also made for Pb+Pb collisions at Super Proton Synchrotron (SPS) energies. We demonstrate that elliptic flow measurements in heavy-ion collisions at $s \sim 10$ GeV can set strong constraints on the dependence of Quark-Gluon Plasma shear viscosity on temperature and net baryon chemical potential.
nucl-thhep-phnucl-exPRC(2020)·144 citations
04
Benchmark calculations of electromagnetic sum rules with a symmetry-adapted basis and hyperspherical harmonics
R. B. Baker · K. D. Launey · S. Bacca · N. Nevo Dinur · T. Dytrych
We demonstrate the ability to calculate electromagnetic sum rules with the \textit{ab initio} symmetry-adapted no-core shell model. By implementing the Lanczos algorithm, we compute non-energy weighted, energy weighted, and inverse energy weighted sum rules for electric monopole, dipole, and quadrupole transitions in $^{4}$ He using realistic interactions. We benchmark the results with the hyperspherical harmonics method and show agreement within $2 σ$ , where the uncertainties are estimated from the use of the many-body technique. We investigate the dependence of the results on three different interactions, including chiral potentials, and we report on the $^{4}$ He electric dipole polarizability calculated in the SA-NCSM that reproduces the experimental data and earlier theoretical outcomes. We also detail a novel use of the Lawson procedure to remove the spurious center-of-mass contribution to the sum rules that arises from using laboratory-frame coordinates. We further show that this same technique can be applied in the Lorentz integral transform method, with a view toward studies of electromagnetic reactions for light through medium-mass nuclei.
nucl-thPRC(2020)·23 citations
05
$D^{(*)} N$ interaction and the structure of $Σ_{c} (2800)$ and $Λ_{c} (2940)$ in chiral effective field theory
Bo Wang🇨🇳 · Lu Meng🇨🇳 · Shi-Lin Zhu🇨🇳
We study the $D N$ and $D^{*} N$ interactions to probe the inner structure of $Σ_{c} (2800)$ and $Λ_{c} (2940)$ with the chiral effective field theory to the next-to-leading order. We consider the contact term, one-pion-exchange and two-pion-exchange contributions to characterize the short-, long- and mid-range interactions of the $D^{(*)} N$ systems. The low energy constants of the $D^{(*)} N$ systems are related to those of the $N N ˉ$ interaction with quark level Lagrangian that inspired by the resonance saturation model. The $Δ (1232)$ degree of freedom is also included in the loop diagrams. The attractive potential in the $[D N]_{J = 1/2}^{I = 1}$ channel is too weak to form bound state, which indicates the explanation of $Σ_{c} (2800)$ as the compact charmed baryon is more reasonable. Meanwhile, the potentials of the isoscalar channels are deep enough to yield the molecular states. We obtain the masses of the $[D N]_{J = 1/2}^{I = 0}$ , $[D^{*} N]_{J = 1/2}^{I = 0}$ and $[D^{*} N]_{J = 3/2}^{I = 0}$ systems to be $2792.0$ MeV, $2943.6$ MeV and $2938.4$ MeV, respectively. The $Λ_{c} (2940)$ is probably the isoscalar $D^{*} N$ molecule considering its low mass puzzle. Besides, the $Λ_{c} (2940)$ signal might contain the spin- $\frac{1}{2}$ and spin- $\frac{3}{2}$ two structures, which can qualitatively explain the significant decay ratio to $D^{0} p$ and $Σ_{c} π$ . We also study the $B ˉ^{(*)} N$ systems and predict the possible molecular states in the isoscalar channels. We hope experimentalists could hunt for the open charmed molecular pentaquarks in the $Λ_{c}^{+} π^{+} π^{-}$ final state.
↳ hep-phhep-exnucl-thPRD(2020)·42 citations
06
X17: A new force, or evidence for a hard $γ + γ$ process?
Benjamin Koch🇨🇱
It is investigated whether the "X17 puzzle" might be explained by a nuclear decay chain and a conversion of the two resulting highly energetic $γ$ s into an electron-positron pair. It is found that the corresponding kinematics fits perfectly to the experimental result. Also the conversion rates of this process are reasonable. However, the assumed nuclear chain reaction is not favored in the established nuclear models and no explanation for the isospin structure of the signal can be given. Thus, it has to be concluded that the process studied in this paper does not give a completely satisfying explanation of the "X17 puzzle".
↳ hep-phhep-exnucl-thNPA(2021)·18 citations
07
The Roper Resonance in a finite volume
Daniel Severt🇩🇪 · Ulf-G. Meißner🇩🇪
We calculate the energy levels corresponding to the Roper resonance based on a two-flavor chiral effective Lagrangian for pions, nucleons, deltas and the Roper resonance at leading one-loop order. We show that the Roper mass can be extracted from these levels for not too large lattice volumes.
↳ hep-lathep-phnucl-thCommun.Theor.Phys.(2020)·10 citations
08
On the Interpretation of the Balance Function
V. Vechernin🇷🇺
We construct a simple toy model and explicitly demonstrate that the Balance Function (BF) can become negative for some values of the rapidity separation and hence can not have any probabilistic interpretation. In particular, the BF can not be interpreted as the probability density for the balancing charges to occur separated by the given rapidity interval.
↳ hep-phnucl-thSymmetry(2022)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE