Nuclear Theory·nucl-th

Friday·May 24, 2019

8 papers—4 primary·4 cross-listed

01
Gamow shell model description of $^{4}$ He( $d$ , $d$ ) elastic scattering reactions
A. Mercenne🇺🇸 · N. Michel🇫🇷 · M. Ploszajczak🇫🇷
Structure of weakly bound/unbound light nuclei is often related to the low-energy decay channels involving composite particles like deuteron or $α$ -particle. These channels are essential to understand the appearance of light nuclei in the Big Bang nucleosynthesis or the helium fusion. We generalize the Gamow shell model (GSM) in coupled-channel (GSM-CC) representation to include reaction channels with the composite particles. In the core + valence particle formulation, this unified microscopic approach for structure and reactions involving weakly bound/unbound nuclei can be also applied to study low-energy properties of heavy nuclei. As the first application of this generalized GSM-CC approach, we describe the structure of 6Li and deuteron - $α$ -particle elastic scattering using the same effective Furutani-Horiuchi-Tamagaki (FHT) type nucleon-nucleon interaction. Asymptotically, the deuteron structure including its continuum is described using the N3LO chiral force. The bulk of the data, including low-energy spectrum of 6Li, asymptotic normalization coefficients, and angular differential cross sections are satisfactorily described.
nucl-thPRC(2019)·32 citations
02
Condensation of interacting scalar bosons at finite temperatures
I. N. Mishustin🇩🇪 · D. V. Anchishkin🇩🇪 · L. M. Satarov🇩🇪 · O. S. Stashko🇺🇦 · H. Stoecker🇩🇪
Thermodynamical properties of an interacting system of scalar bosons at finite temperatures are studied within the framework of a field-theoretical model containing the attractive and repulsive self-interaction terms. Self-consistency relations between the effective mass and thermodynamic functions are derived in the mean-field approximation. We show that for a sufficiently strong attractive interaction a first-order phase transition develops in the system via the formation of a scalar condensate. An interesting prediction of this model is that the condensed phase appears within a finite temperature interval and is characterized by a constant scalar density of Bose particles.
nucl-thPRC(2019)·19 citations
03
Coulomb final state interaction in heavy ion collisions for Levy sources
Mate Csanad🇭🇺 · Sandor Lokos🇭🇺 · Marton I. Nagy🇭🇺
Investigation of momentum space correlations of particles produced in high energy reactions requires taking final state interactions into account, a crucial point of any such analysis. Coulomb interaction between charged particles is the most important such effect. In small systems like those created in e+e- or p+p collisions, the so-called Gamow factor (valid for a point-like particle source) gives an acceptable description of the Coulomb interaction. However, in larger systems such as central or mid-central heavy ion collisions, more involved approaches are needed. In this paper we investigate the Coulomb final state interaction for Levy-type source functions that were recently shown to be of much interest for a refined description of the space-time picture of particle production in heavy-ion collisions.
nucl-thhep-phUniverse(2019)·14 citations
04
Charmed hadron production in an improved quark coalescence model
Sungtae Cho🇰🇷 · Kai-Jia Sun🇺🇸 · Che Ming Ko🇺🇸 · Su Houng Lee🇰🇷 · Yongseok Oh🇰🇷
We study the production of charmed hadrons $D^{0}$ and $Λ_{c}^{+}$ in relativistic heavy-ion collisions using an improved quark coalescence model. In particular, we extend the usual coalescence model by letting a produced hadron to have the same velocity as the center-of-mass velocity of coalesced constituent quarks during hadronization to take into account the effect of collective flow in produced quark-gluon plasma. This results in a shift of charmed resonances of higher masses to larger transverse momenta ( $p_{T}$ ). Requiring all charm quarks of very low $p_{T}$ to be converted to hadrons via coalescence and letting charm quarks not undergoing coalescence to hadronize by independent fragmentation, we obtain a good description of the measured yield ratio $Λ_{c}^{+} / D^{0}$ as a function of $p_{T}$ in $Au + Au$ collisions at $s_{N N} = 200$ ~GeV by the STAR Collaboration at the Relativistic Heavy Ion Collider.
nucl-thhep-phPRC(2020)·58 citations
05
Analytic Transport from Weak to Strong Coupling in the O(N) model
Paul Romatschke🇺🇸
In this work, a second-order transport coefficient (the curvature-matter coupling $κ$ ) is calculated exactly for the 3+1d O(N) model at large N for any coupling value. Since the theory is `trivial' in the sense of possessing a Landau pole, the result for $κ$ only is free from cut-off artifacts much below the Landau pole in the effective field theory sense. Nevertheless, this leaves a large range of coupling values where this transport coefficient can be determined non-perturbatively and analytically with little ambiguity. Along with thermodyamic results also calculated in this work, I expect exact large N results to provide good quantitative predictions for N=1 scalar field theory with $ϕ^{4}$ interaction.
↳ hep-thcond-mat.str-elhep-phnucl-thPRD(2019)·19 citations
06
Estimation of attractive and repulsive interactions from the fluctuation observables at RHIC using van der Waals hadron resonance gas Model
Subhasis Samanta🇮🇳 · Bedangadas Mohanty🇮🇳
Experimental data on the moments of net-proton distribution in central Au-Au collisions for various center of mass energies ( $s_{NN}$ ) measured by the STAR collaboration at the Relativistic Heavy-Ion Collider (RHIC) are compared to the corresponding results from a van der Waals type interacting hadron resonance gas (VDWHRG) model. The parameters representing the attractive and repulsive interactions in the VDWHRG model have been extracted by fitting the $σ^{2}$ / $M$ , $S σ$ and $κ σ^{2}$ , where $M$ is the mean, $σ$ is the standard deviation, $S$ is the skewness and $κ$ the kurtosis of the net-proton distribution. Considering all the three moment products we observe that the strength of the repulsive interactions increases with decrease in $s_{NN}$ = 200 to 19.6 GeV while the strength of the attractive interaction is of the similar magnitude. For $s_{NN}$ = 11.5 and 7.7 GeV there is drop in the strength of both attractive and repulsive interactions relative to $s_{NN}$ = 19.6 GeV. On the other hand, if we consider only the higher order moment products, $S σ$ and $κ σ^{2}$ , which are more sensitive to critical point physics, a segregation with respect to the strength of the attractive parameter is observed. The data for $s_{NN}$ = 19.6 and 27 GeV supports a larger attractive strength compared to other energies. For this latter case, the repulsive interaction values are of similar order for most of the beam energies studied, except for 7.7 GeV where the parameter value is not well constrained due to large uncertainties.
↳ hep-phnucl-th2 citations
07
Discovery of an Exceptionally Strong $β$ -Decay Transition of $^{20}$ F and Implications for the Fate of Intermediate-Mass Stars
O. S. Kirsebom · S. Jones · D. F. Strömberg · G. Martínez-Pinedo · K. Langanke · F. K. Roepke · B. A. Brown · T. Eronen · H. O. U. Fynbo · M. Hukkanen · A. Idini · A. Jokinen and 12 other authors
A significant fraction of stars between 7-11 solar masses are thought to become supernovae, but the explosion mechanism is unclear. The answer depends critically on the rate of electron capture on $^{20}$ Ne in the degenerate oxygen-neon stellar core. However, due to the unknown strength of the transition between the ground states of $^{20}$ Ne and $^{20}$ F, it has not previously been possible to fully constrain the rate. By measuring the transition, we have established that its strength is exceptionally large and enhances the capture rate by several orders of magnitude. This has a decisive impact on the evolution of the core, increasing the likelihood that the star is (partially) disrupted by a thermonuclear explosion rather than collapsing to form a neutron star. Importantly, our measurement resolves the last remaining nuclear physics uncertainty in the final evolution of degenerate oxygen-neon stellar cores, allowing future studies to address the critical role of convection, which at present is poorly understood.
↳ astro-ph.SRastro-ph.HEnucl-exnucl-thPRL(2019)·48 citations
08
A qubit model for U(1) lattice gauge theory
Randy Lewis🇨🇦 · R. M. Woloshyn🇨🇦
A conceptually simple model for strongly interacting compact U(1) lattice gauge theory is expressed as operators acting on qubits. The number of independent gauge links is reduced to its minimum through the use of Gauss's law. The model can be implemented with any number of qubits per gauge link, and a choice as small as two is shown to be useful. Real-time propagation and real-time collisions are observed on lattices in two spatial dimensions. The extension to three spatial dimensions is also developed, and a first look at 3-dimensional real-time dynamics is presented.
↳ hep-latnucl-thquant-ph35 citations

Affiliations

first authorsco-authorsvia INSPIRE