Nuclear Theory·nucl-th

Thursday·December 18, 2014

15 papers—7 primary·8 cross-listed

01
Kinetic freeze out from an anisotropic fluid in high-energy heavy-ion collisions: particle spectra, Hanbury Brown-Twiss radii, and anisotropic flow
Nicolas Borghini🇩🇪 · Steffen Feld🇩🇪 · Christian Lang🇩🇪
Dissipative relativistic fluid-dynamical descriptions of the extended fireball formed in high-energy heavy-ion collisions are quite successful, yet require a prescription for converting the fluid into particles. We present arguments in favour of using a locally anisotropic momentum distribution for the particles emitted from the fluid, so as to smooth out discontinuities introduced by the usual conversion prescriptions. Building on this ansatz, we investigate the effect of the asymmetry on several observables of heavy ion physics.
nucl-thhep-phnucl-exEPJC(2015)·2 citations
02
On the lepton-nucleon neutral and charged current deep inelastic scattering cross sections
Xing-Long Li🇨🇳 · Yu-Liang Yan🇨🇳 · Xiao-Mei Li🇨🇳 · Dai-Mei Zhou🇨🇳 · Xu Cai🇨🇳 · Ben-Hao Sa🇨🇳
Based on the requirement in the simulation of lepton-nucleus deep inelastic scattering (DIS), we construct a fortran program LDCS 1.0 calculating the differential and total cross sections for the unpolarized charged lepton-unpolarized nucleon and neutrino-unpolarized nucleon neutral current (charged current) DIS at leading order. Any set of the experimentally fitted parton distribution functions could be employed directly. The mass of incident and scattered leptons is taken into account and the boundary conditions calculating the single differential and total cross section are studied. The calculated results well agree with the corresponding experimental data which indicating the LDCS 1.0 program is good. It is also turned out that the effect of tauon mass is not negligible in the GeV energy level.
nucl-thhep-ph1 citation
03
Stiffer EoS for Compact Star with New Scaling Law
Kyungmin Kim🇰🇷 · T.T.S. Kuo🇺🇸 · Hyun Kyu Lee🇰🇷 · Jaehyun Lee🇰🇷 · Mannque Rho🇫🇷
We present in this paper a simple and unequivocal prediction on the deformation of the compact star, that will be measured in gravity waves, with an EoS obtained in renormailzation-group implemented effective field theory anchored on scale and hidden-local symmetric Lagrangian endowed with topology change . The objective is not to offer a superior or improved EoS for compact stars but to confront with a forthcoming astrophysical observable the given model formulated in what is considered to be consistent with the premise of QCD. The model so obtained is found to satisfactorily describe the observation of a 2-solar mass neutron star with a minimum number of parameters. Specifically the observable we are considering in this paper is the tidal deformability parameter $λ$ (equivalently the Love number, $k_{2}$ ) in gravity waves. The merit of our prediction is that the prediction can be readily confirmed or falsified by forth-coming aLIGO and aVirgo gravity-wave observations and provide a valuable guidance for arriving at a better understanding of highly compressed baryonic matter.
nucl-thastro-ph.HEhep-ph1 citation
04
Hadron Resonance Gas Equation of State from Lattice QCD
V. Vovchenko🇩🇪 · D. V. Anchishkin🇺🇦 · M. I. Gorenstein🇺🇦
The Monte Carlo results in lattice QCD for the pressure and energy density at small temperature $T < 155$ MeV and zero baryonic chemical potential are analyzed within the hadron resonance gas model. Two extensions of the ideal hadron resonance gas are considered: the excluded volume model which describes a repulsion of hadrons at short distances and Hagedorn model with the exponential mass spectrum. Considering both of these models one by one we do not find the conclusive evidences in favor of any of them. The controversial results appear because of rather different sensitivities of the pressure and energy density to both excluded volume and Hagedorn mass spectrum effects. On the other hand, we have found a clear evidence for a simultaneous presence of both of them. They lead to rather essential contributions: suppression effects for thermodynamical functions of the hadron resonance gas due to the excluded volume effects and enhancement due to the Hagedorn mass spectrum.
nucl-thhep-lathep-phPRC(2015)·89 citations
05
Charge Symmetry Breaking in Electromagnetic Nucleon Form Factors in Elastic Parity-Violating Electron-Nucleus Scattering
Gerald A. Miller🇺🇸
The effects of charge symmetry breaking in nucleon electromagnetic form factors on parity- violating elastic electron-12C scattering is studied, and found to be much smaller than other known effects. The analysis of a planned experiment is discussed.
nucl-thhep-phnucl-exPRC(2015)·2 citations
06
Form Factors in the Algebraic Cluster Model
Roelof Bijker
I present a derivation of form factors in the Algebraic Cluster Model for an arbitrary number of identical clusters. The form factors correspond to representation matrix elements which are derived in closed form for the harmonic oscillator and deformed oscillator limits. These results are relevant for applications in nuclear, molecular and hadronic physics.
nucl-thnucl-exPhys.Scripta(2015)·3 citations
07
Valence and sea quarks in the nucleon
Roelof Bijker🇲🇽 · Elena Santopinto🇮🇹
In this contribution, we discuss the spin and flavor content of the proton in the framework of the unquenched quark model, and address the role of valence and sea quarks in the nucleon.
nucl-thhep-phJ.Phys.Conf.Ser.(2015)·3 citations
08
High order cumulants of the azimuthal anisotropy in the dilute-dense limit: Connected graphs
Vladimir Skokov🇺🇸
We analytically compute higher order cumulants of the azimuthal anisotropy, $c_{2} {2 m}$ , and corresponding $v_{2} {2 m}$ at high transverse momentum in the dilute-dense limit. The dense target is considered in the framework of the McLerran-Venugopolan model. The absolute values of the harmonics $v_{2} {2 m}$ of the azimuthal anisotropy are approximately equal, $∣ v_{2} {2 m} ∣ \approx ∣ v_{2} {2 m^{'}} ∣$ , for large $m$ and $m^{'}$ . However, the harmonics with order $2 m = 4 n$ are complex. We argue that this is a generic property of connected graphs, which remains true in the dense-dense limit.
↳ hep-phnucl-thPRD(2015)·29 citations
09
Polaronic atom-trimer continuity in three-component Fermi gases
Yusuke Nishida
Recently it has been proposed that three-component Fermi gases may exhibit a new type of crossover physics in which an unpaired Fermi sea of atoms smoothly evolves into that of trimers in addition to the ordinary BCS-BEC crossover of condensed pairs. Here we study its corresponding polaron problem in which a single impurity atom of one component interacts with condensed pairs of the other two components with equal populations. By developing a variational approach in the vicinity of a narrow Feshbach resonance, we show that the impurity atom smoothly changes its character from atom to trimer with increasing the attraction and eventually there is a sharp transition to dimer. The emergent polaronic atom-trimer continuity can be probed in ultracold atoms experiments by measuring the impurity spectral function. Our novel crossover wave function properly incorporating the polaronic atom-trimer continuity will provide a useful basis to further investigate the phase diagram of three-component Fermi gases in more general situations.
↳ cond-mat.quant-gashep-phnucl-thPRL(2015)·21 citations
10
Transport properties of hadronic matter in magnetic field
Guru Kadam🇮🇳
We study the effect of magnetic field on the transport properties like shear and bulk viscosities of hot and dense hadronic matter within hadron resonance gas model. We estimate the bulk viscosity using low energy theorems for bilocal correlators of the energy momentum tensor generalized to finite temperature, density and magnetic field. We use Gaussian ansatz for the spectral function at low frequency. We estimate shear viscosity coefficient using molecular kinetic theory. We find that vacuum contribution due to finite magnetic field dominates the bulk viscosity ({\zeta}) for the temperatures up to 0.1GeV and increases with magnetic field while ratio {\zeta}/s decreases with magnetic field. We also find that shear viscosity coefficient of hadronic matter decreases with magnetic field.
↳ hep-phnucl-thMod.Phys.Lett.A(2015)·32 citations
11
Observables in ultrarelativistic heavy-ion collisions from two different transport approaches for the same initial conditions
Rudy Marty🇩🇪 · Elena Bratkovskaya🇩🇪 · Wolfgang Cassing🇩🇪 · Joerg Aichelin🇫🇷
For nucleus-nucleus collisions at Relativistic-Heavy-Ion Collider (RHIC) energies we calculate observables in two conceptually transport theories, i.e. the n-body molecular dynamical model RSP and in the Parton-Hadron-String-Dynamics (PHSD), starting out from the same distribution of the initial energy density at the quark gluon plasma (QGP) formation time. The RSP is based on the Nambu Jona-Lasinio (NJL) Lagrangian whereas in PHSD the partons are described by the dynamical quasi-particle model (DQPM). Despite of the very different description of the parton properties, their interactions and of the hadronization in both approaches the final transverse momentum distributions of pions and kaons are rather similar. Thus it will be difficult to conclude from the final experimenal data on the details of the initial plasma properties.
↳ hep-phnucl-thPRC(2015)·19 citations
12
$X (3872)$ production from reactions involving $D$ and $D^{*}$ mesons
A. Martinez Torres🇧🇷 · K. P. Khemchandani🇧🇷 · F. S. Navarra🇧🇷 · M. Nielsen🇧🇷 · Luciano M. Abreu🇧🇷
In this proceeding we show the results found for the cross sections of the processes $D ˉ D \to π X (3872)$ , $D ˉ^{*} D \to π X (3872)$ and $D ˉ^{*} D^{*} \to π X (3872)$ , information needed for calculations of the $X (3872)$ abundance in heavy ion collisions. Our formalism is based on the generation of $X (3872)$ from the interaction of the hadrons $D ˉ^{0} D^{* 0} - c.c$ , $D^{-} D^{*+} - c.c$ and $D_{s}^{-} D_{s}^{*+} - c.c$ . The evaluation of the cross section associated with processes having $D^{*}$ meson(s) involves an anomalous vertex, $X D ˉ^{*} D^{*}$ , which we have determined by considering triangular loops motivated by the molecular nature of $X (3872)$ . We find that the contribution of this vertex is important. Encouraged by this finding we estimate the $X D ˉ^{*} D^{*}$ coupling, which turns out to be $1.95 \pm 0.22$ . We then use it to obtain the cross section for the reaction $D ˉ^{*} D^{*} \to π X$ and find that the $X D ˉ^{*} D^{*}$ vertex is also relevant in this case. We also discuss the role of the charged components of $X$ in the determination of the production cross sections.
↳ hep-phnucl-thJ.Phys.Conf.Ser.(2015)·0 citations
13
$X (3872)$ production in high energy heavy ion collisions
A. Martinez Torres🇧🇷 · K. P. Khemchandani🇧🇷 · F. S. Navarra🇧🇷 · M. Nielsen🇧🇷 · Luciano M. Abreu🇧🇷
We show the results obtained for the cross sections of the processes $D ˉ D$ , $D ˉ^{*} D$ , $D ˉ^{*} D^{*} \to π X (3872)$ , information which is necessary to determine the $X (3872)$ abundance in heavy ion collisions. Our formalism is based on the generation of $X (3872)$ from the interaction of the hadrons $D ˉ^{0} D^{* 0} - c.c$ , $D^{-} D^{*+} - c.c$ and $D_{s}^{-} D_{s}^{*+} - c.c$ an the calculation of the $X D ˉ^{*} D^{*}$ anomalous vertex considering $X (3872)$ as a molecule of the above hadrons channels.
↳ hep-phnucl-thActa Phys.Polon.Supp.(2015)·10 citations
14
MesonNet 2014 International Workshop. Mini-proceedings
P. Adlarson🇸🇪 · M. Bashkanov🇩🇪 · J. Bijnens🇩🇪 · L. Caldeira Balkeståhl🇸🇪 · B. Cao · G. Colangelo🇨🇭 · F. Curciarello🇮🇹 · V. De Leo🇮🇹 · K. Demmich🇩🇪 · G. Eichmann🇩🇪 · S. Eidelman🇷🇺 · S. Fang🇨🇳 and 34 other authors
The MesonNet International Workshop was held in the Laboratori Nazionali di Frascati from September the 29th to October the 1st, 2014, being the concluding meeting of the MesonNet research network within EU HadronPhysics3 project. MesonNet is a research network focused on light meson physics gathering experimentalist and theoreticians from Europe and abroad. An overview of the research projects related to the scope of the network is presented in these mini-proceedings.
↳ nucl-exhep-exhep-phnucl-th15 citations
15
P- and T-Violating Lagrangians in Chiral Effective Field Theory and Nuclear Electric Dipole Moments
J. Bsaisou🇩🇪 · Ulf-G. Meißner🇩🇪 · A. Nogga🇩🇪 · A. Wirzba🇩🇪
A scheme to derive hadronic interactions induced by effective multi-quark terms is presented within the framework of chiral effective field theory. It is employed to work out the list of parity- and time-reversal-symmetry-violating hadronic interactions that are relevant for the computation of nuclear contributions to the electric dipole moments of the hydrogen-2, helium-3 and hydrogen-3 nuclei. We also derive the scattering and Faddeev equations required to compute electromagnetic form factors in general and electric dipole moments in particular.
↳ hep-phhep-latnucl-thAnnals Phys.(2015)·90 citations

Affiliations

first authorsco-authorsvia INSPIRE