Nuclear Theory·nucl-th

Tuesday·April 10, 2018

10 papers—8 primary·2 cross-listed

01
From Coulomb excitation cross sections to non-resonant astrophysical rates in three-body systems: $^{17}$ Ne case
Yu.L. Parfenova · L.V. Grigorenko · I.A. Egorova · N.B. Shulgina · J.S. Vaagen · M.V. Zhukov
Coulomb and nuclear dissociation of $^{17}$ Ne on light and heavy targets are studied theoretically. The dipole E1 strength function is determined in a broad energy range including energies of astrophysical interest. Dependence of the strength function on different parameters of the $^{17}$ Ne ground state structure and continuum dynamics is analyzed in a three-body model. The discovered dependence plays an important role for studies of the strength functions for the three-body E1 dissociation and radiative capture. The constraints on the $[s^{2}] / [d^{2}]$ configuration mixing in $^{17}$ Ne and on $p$ -wave interaction in the $^{15}$ O+ $p$ channel are imposed based on experimental data for $^{17}$ Ne Coulomb dissociation on heavy target.
nucl-thPRC(2018)·11 citations
02
A critical examination of constraints on the equation of state of dense matter obtained from GW170817
I. Tews🇺🇸 · J. Margueron🇺🇸 · S. Reddy🇺🇸
The correlation of the tidal polarizabilities $Λ_{1}$ - $Λ_{2}$ for GW170817 is predicted by combining dense-matter equations of state (EOSs) that satisfy nuclear physics constraints with the chirp mass and mass asymmetry for this event. Our models are constrained by calculations of the neutron-matter EOS using chiral effective field theory Hamiltonians with reliable error estimates up to once or twice the nuclear saturation density. In the latter case, we find that GW170817 does not improve our understanding of the EOS. We contrast two distinct extrapolations to higher density: a minimal model (MM) which assumes that the EOS is a smooth function of density described by a Taylor expansion and a more general model parametrized by the speed of sound that admits phase transitions. This allows us to identify regions in the $Λ_{1}$ - $Λ_{2}$ plots that could favor the existence of new phases of matter in neutron stars. We predict the combined tidal polarizability of the two neutron stars in GW170817 to be $80 \leq Λ ~ \leq 580$ ( $280 \leq Λ ~ \leq 480$ for the MM), which is smaller than the range suggested by the LIGO-Virgo data analysis. Our analysis also shows that GW170817 requires a NS with $M = 1.4 M_{⊙}$ to have a radius $9.0 < R_{1.4} < 13.6$ ~km ( $11.3 < R_{1.4} < 13.6$ ~km for the MM).
nucl-thastro-ph.HEhep-phPRC(2018)·361 citations
03
Photon production from Pb+Pb collisions at { $s_{NN}$ } = 5.02 TeV at LHC and at { $s_{NN}$ } = 39 TeV at FCC
Pingal Dasgupta🇮🇳 · Somnath De🇮🇳 · Rupa Chatterjee🇮🇳 · Dinesh K. Srivastava🇮🇳
We calculate the production of prompt and thermal photons from Pb+Pb collisions at 5.02A TeV at the Large Hadron Collider (LHC) and at 39A TeV at the proposed Future Circular Collider (FCC) facility. The photon spectra and anisotropic flow at these energies are compared with the results obtained from 2.76A TeV Pb+Pb collisions at the LHC for three different centrality bins. The prompt photons originating from initial hard scatterings are found to increase by a factor of 1.5 to 2 at 5.02A TeV in the $p_{T}$ region 2 to 15 GeV and the enhancement is found to be about 5 to 15 times at FCC energy compared to 2.76A TeV in the same $p_{T}$ region. The evolution of the Quark-Gluon Plasma (QGP) formed in Pb+Pb collisions at LHC and FCC energies are studied using a hydrodynamical model and the $p_{T}$ spectra and elliptic flow of thermal photons are calculated using state-of-the-art photon rates. The relative enhancement in the production of thermal photons is found to be more compared to prompt photons at FCC than at the LHC energies. Although the production of direct (prompt+thermal) photons is found to enhance significantly with increase in beam energy, the photon elliptic flow increases only marginally and does not show strong sensitivity to the collision energy.
nucl-thPRC(2018)·19 citations
04
Many-body calculations with Deuteron based single-particle bases and their associated natural orbits
Giovanni Puddu
We use the recently introduced single-particle states obtained from localized Deuteron wave-functions as a basis for nuclear many-body calculations. We show that energies can be substantially lowered if the natural orbits obtained from this basis are used. We use this modified basis for $^{10} B$ , $^{16} O$ and $^{24} M g$ employing the bare $N N L O_{o pt}$ Nucleon-Nucleon interaction. The lowering of the energies increases with the mass. Although in principle natural orbits require a full scale preliminary many-body calculation, we found that an approximate preliminary many-body calculation, with a marginal increase in the computational cost, is sufficient. The use of natural orbits based on an harmonic oscillator basis leads to a much smaller lowering of the energies for a comparable computational cost.
nucl-thPhys.Scripta(2018)·1 citation
05
Baryon number diffusion with critical fluctuations
Marlene Nahrgang (SUBATECH, Nantes)🇫🇷 · Marcus Bluhm (Wroclaw U.)🇵🇱 · Thomas Schaefer (North Carolina State U.)🇺🇸 · Steffen A. Bass (Duke U.)🇺🇸
The description of dynamical fluctuations near the QCD critical point in heavy-ion collisions is crucial for understanding the existing and upcoming experimental data from the beam energy scan programs. In this talk we discuss the evolution of fluctuations of the net-baryon density as given by a stochastic diffusion equation. We study equilibrium as well as dynamical systems for which we can show the impact of nonequilibrium effects on the second-order moment.
nucl-thNPA(2017)·9 citations
06
Nuclear Equation of state for Compact Stars and Supernovae
G. Fiorella Burgio (INFN Sezione di Catania)🇮🇹 · Anthea F. Fantina (GANIL, France)🇫🇷
The equation of state (EoS) of hot and dense matter is a fundamental input to describe static and dynamical properties of neutron stars, core-collapse supernovae and binary compact-star mergers. We review the current status of the EoS for compact objects, that have been studied with both ab-initio many-body approaches and phenomenological models. We limit ourselves to the description of EoSs with purely nucleonic degrees of freedom, disregarding the appearance of strange baryonic matter and/or quark matter. We compare the theoretical predictions with different data coming from both nuclear physics experiments and astrophysical observations. Combining the complementary information thus obtained greatly enriches our insights into the dense nuclear matter properties. Current challenges in the description of the EoS are also discussed, mainly focusing on the model dependence of the constraints extracted from either experimental or observational data (specifically, concerning the symmetry energy), the lack of a consistent and rigorous many-body treatment at zero and finite temperature of the matter encountered in compact stars (e.g. problem of cluster formation and extension of the EoS to very high temperatures), the role of nucleonic three-body forces, and the dependence of the direct URCA processes on the EoS.
nucl-thastro-ph.HEastro-ph.SRAstrophys.Space Sci.Libr.(2018)·76 citations
07
Reconstructing the impact parameter of proton-nucleus and nucleus-nucleus collisions
Rudolph Rogly🇫🇷 · Giuliano Giacalone🇫🇷 · Jean-Yves Ollitrault🇫🇷
In proton-nucleus and nucleus-nucleus collision experiments, one determines the centrality of a collision according to the multiplicity or energy deposited in a detector. This serves as a proxy for the true collision centrality, as defined by the impact parameter. We show that the probability distribution of impact parameter in a given bin of experiment-defined centrality can be reconstructed without assuming any specific model for the collision dynamics, in both proton-nucleus and nucleus-nucleus systems. The reconstruction is reliable up to about 10\% centrality, and is more accurate for nucleus-nucleus collisions. We perform an application of our procedure to experimental data from all the CERN Large Hadron Collider (LHC) collaborations, from which we extract, in Pb+Pb and $p$ +Pb collisions, the corresponding distributions of impact parameter.
nucl-thhep-phnucl-exPRC(2018)·38 citations
08
Zero-temperature limit and statistical quasiparticles in many-body perturbation theory
Corbinian Wellenhofer🇩🇪
The order-by-order renormalization of the self-consistent mean-field potential in many-body perturbation theory for normal Fermi systems is investigated in detail. Building on previous work mainly by Balian and de Dominicis, as a key result we derive a thermodynamic perturbation series that manifests the consistency of the adiabatic zero-temperature formalism with perturbative statistical mechanics---for both isotropic and anisotropic systems---and satisfies at each order and for all temperatures the thermodynamic relations associated with Fermiliquid theory. These properties are proved to all orders.
nucl-thcond-mat.stat-mechPRC(2019)·10 citations
09
Correlations and the ridge in the Color Glass Condensate beyond the glasma graph approximation
Tolga Altinoluk🇵🇱 · Néstor Armesto🇪🇸 · Douglas E. Wertepny🇪🇸
We consider two-gluon production in dilute-dense collisions within the Color Glass Condensate framework, applicable to both proton-nucleus and heavy-light ion collisions. We go beyond the glasma graph approximation which is valid in the dilute-dilute limit and show the correspondence between the glasma graphs and the $k_{T}$ -factorized approach that we use in our calculation. We then identify the classical uncorrelated, and the Hanbury-Brown-Twiss (HBT) and Bose enhancement correlated contributions, with the Bose enhancement contribution being suppressed by the number of degrees of freedom with respect to the uncorrelated piece. We show that both the HBT and the Bose enhancement pieces survive the inclusion of higher order contributions in density and that they stem from the quadrupole piece of the two-gluon inclusive cross section. Finally, we illustrate the results using a toy model that allows a simple numerical implementation.
↳ hep-phnucl-thJHEP(2018)·24 citations
10
B $\to f_{2} (1270)$ form factors with light-cone sum rules
Maximilian Emmerich🇩🇪 · Matthias Strohmaier🇩🇪 · Andreas Schäfer🇩🇪
We construct the quark-antiquark chiral odd distribution amplitudes including twist-four mass contributions for tensor mesons. We also give quark-antiquark-gluon distribution amplitudes, where we calculate the input parameters with QCD sum rules. With the help of equations of motion we determine the twist-three and twist-four distribution amplitudes including SU(3) breaking terms. We use QCD light-come sum rules to derive the form factors for the decay B $\to f_{2} (1270)$ with vector, axial-vector and tensor currents. We also give the $q^{2}$ dependence of the form factors.
↳ hep-phnucl-thPRD(2018)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE