Nuclear Theory·nucl-th

Tuesday·January 19, 2016

14 papers—10 primary·4 cross-listed

01
Impact parameter dependence of pion ratio in probing the nuclear symmetry energy using heavy-ion collisions
Gao-Feng Wei🇨🇳 · Guo-Qiang He🇨🇳 · Xin-Wei Cao🇨🇳 · Yi-Xin Lu🇨🇳
The impact parameter dependence of \rpi ratio is examined in heavy-ion collisions at 400MeV/nucleon within a transport model. It is shown that the sensitivity of \rpi ratio on symmetry energy shows a transition from central to peripheral collisions, i.e., the stiffer symmetry energy leads to a larger \rpi ratio in peripheral collisions while the softer symmetry energy always leads this ratio to be larger in central collisions. After checking the kinematic energy distribution of \rpi ratio, we found this transition of sensitivity of \rpi ratio to symmetry energy is mainly from less energetic pions, i.e., the softer symmetry energy gets the less energetic pions to form a smaller \rpi ratio in peripheral collisions while these pions generate a larger \rpi ratio in central collisions. Undoubtedly, the softer symmetry energy can also lead more energetic pions to form a larger \rpi ratio in peripheral collisions. Nevertheless, considering that most of pions are insufficient energetic at this beam energy, we therefore suggest the \rpi ratio as a probe of the high-density symmetry energy effective only in central at most to midcentral collisions, thereby avoiding the possible information of low-density symmetry energy carried in \rpi ratio from peripheral collisions.
nucl-thAdv.High Energy Phys.(2016)·3 citations
02
The correlation between quarter point angle and nuclear radius
W. H. Ma · J. S. Wang · S. Mukherjee · Q. Wang · D. Patel · Y. Y. Yang · J. B. Ma · P. Ma · S. L. Jin · Z. Bai · X. Q. Liu
The main objective of the present work is to correlate quarter-point angle and nuclear radius or nuclear matter distribution. Various phenomenological formulae with parameters for strong absorption radius Rs are obtained and compared by fitting the experimental data of quarter point angle extracted from nuclear elastic scattering reaction systems. The parameterized formula of Rs related to the isospin and binding energy is recommended, that gives a good reproduction of nuclear matter radii of halo nuclei.
nucl-thCPC(2017)·3 citations
03
Violation of mass ordering for multi-strange hadrons at RHIC and LHC
Shiori Takeuchi🇯🇵 · Koichi Murase🇯🇵 · Tetsufumi Hirano🇯🇵 · Pasi Huovinen🇩🇪 · Yasushi Nara🇯🇵
We study effects of the hadronic rescattering on final observables especially for multi-strange hadrons such as $ϕ$ , $Ξ$ and $Ω$ in high-energy heavy-ion collisions within an integrated dynamical approach. In this approach, (3+1)-dimensional ideal hydrodynamics is combined with a microscopic transport model, JAM. We simulate the collisions with or without hadronic rescatterings and compare observables between these two options so that we quantify the effects of the hadronic rescattering. We find that the mean transverse momentum and the elliptic flow parameter of multi-strange hadrons are less affected by hadronic rescattering and, as a result, the mass ordering of the $p_{T}$ -differential elliptic flow parameter $v_{2} (p_{T})$ is violated: At the RHIC and the LHC energies the $v_{2} (p_{T})$ for $ϕ$ -mesons is larger than that for protons in the low- $p_{T}$ regions.
nucl-thhep-phnucl-exNPA(2016)·3 citations
04
A simple approach to $α$ -decay fine structure
D.S. Delion · Monika Patial · R.J. Liotta · R. Wyss
We propose a simple method to evaluate $α$ -transition rates to low-lying excited states in even-even nuclei. For this a realistic $α$ -daughter double folding interaction is approximated by a parabola in the region where the decay process takes place. This allows us to evaluate the penetration probability analytically. The main experimental features of branching ratios to excited states are reproduced by this simple approach.
nucl-thJ.Phys.G(2016)·12 citations
05
The hadronization time of heavy quark in nuclear matter
Taesoo Song🇩🇪 · Hamza Berrehrah🇩🇪
We study the hadronization time of heavy quark in nuclear matter by using the coalescence model and the spatial diffusion constant of heavy quark from lattice Quantum Chromodynamic calculations, assuming that the main interaction of heavy quark at the critical temperature is hadronization. It is found that the hadronization time of heavy quark is about 3 fm/c for $2 π T_{c} D_{s} = 6$ , if a heavy quark is combined with the nearest light antiquark in coordinate space without any correlation between momentum of heavy quark and that of light antiquark which form a heavy meson. However, the hadronization time reduces to 0.6-1.2 fm/c for charm and 0.4-0.9 fm/c for bottom, depending on heavy meson radius, in the presence of momentum correlation. Considering the interspace between quarks and antiquarks at the critical temperature, it seems that the hadronization of heavy quark does not happen instantaneously but gradually for a considerable time, if started from the thermal distribution of quarks and antiquarks.
nucl-thnucl-exPRC(2016)·17 citations
06
Formation of eta'(958) bound states by (gamma, d) reaction
Moeki Miyatani🇯🇵 · Natsumi Ikeno🇯🇵 · Hideko Nagahiro🇯🇵 · Satoru Hirenzaki🇯🇵
We have investigated the 6Li(gamma, d) reaction theoretically for the formation of the eta'(958) mesic nucleus. We have reported the numerical results in this article.
nucl-thnucl-exActa Phys.Polon.B(2016)·3 citations
07
Transverse momentum-flow correlations in relativistic heavy-ion collisions
Piotr Bozek🇵🇱
The correlation between the transverse momentum and the azimuthal asymmetry the flow is studied. A correlation coefficient is defined between the average transverse momentum of hadrons emitted in an event and the square of the elliptic or triangular flow coefficient. The hydrodynamic model predicts a positive correlation of the transverse momentum with the elliptic flow, and almost no correlation with the triangular flow in Pb-Pb collisions at LHC energies. In p-Pb collisions the new correlation observable is very sensitive to the mechanism of energy deposition in the first stage of the collision.
nucl-thhep-phnucl-exPRC(2016)·119 citations
08
Pionic dispersion relations in the presence of a weak magnetic field
Souvik Priyam Adhya🇮🇳 · Mahatsab Mandal🇮🇳 · Subhrajyoti Biswas🇮🇳 · Pradip K. Roy🇮🇳
In this work, dispersion relations of $π^{0}$ and $π^{\pm}$ have been studied in vacuum in the limit of weak external magnetic field using a phenomenological pion-nucleon $(π N)$ Lagrangian. For our purpose, we have calculated the results up to one loop order in self energy diagrams with the pseudoscalar $(P S)$ and pseudovector $(P V)$ pion-nucleon interactions. By assuming weak external magnetic field it is seen that the effective mass of pion gets explicit magnetic field dependence and it is modified significantly for the case of PS coupling. However, for the PV coupling, only a modest increase in the effective mass is observed. These modified dispersion relations due to the presence of the external field can have substantial influence in the phenomenological aspect of the mesons both in the context of neutron stars as well as relativistic heavy ion collisions.
nucl-thhep-phPRD(2016)·18 citations
09
Stability of superfluid vortices in dense quark matter
Mark G. Alford (1) · S. Kumar Mallavarapu (1) · Tanmay Vachaspati (2) · Andreas Windisch (1) ((1) Physics Department, Washington University, St. Louis, (2) Physics Department, Arizona State University)
Superfluid vortices in the color-flavor-locked (CFL) phase of dense quark matter are known to be energetically disfavored relative to well-separated triplets of "semi-superfluid" color flux tubes. However, the short-range interaction (metastable versus unstable) has not been established. In this paper we perform numerical calculations using the effective theory of the condensate field, mapping the regions in the parameter space of coupling constants where the vortices are metastable versus unstable. For the case of zero gauge coupling we analytically identify a candidate for the unstable mode, and show that it agrees well with the results of the numerical calculations. We find that in the region of the parameter space that seems likely to correspond to real-world CFL quark matter the vortices are unstable, indicating that if such matter exists in neutron star cores it is very likely to contain semi-superfluid color flux tubes rather than superfluid vortices.
nucl-thastro-ph.SRhep-phPRC(2016)·30 citations
10
Observable Properties of Quark-Hadron Phase Transition at the Large Hadron Collider
Rudolph C. Hwa🇺🇸 · C. B. Yang🇨🇳
Quark-hadron phase transition is simulated by an event generator that incorporates the dynamical properties of contraction due to QCD confinement forces and randomization due to the thermal behavior of a large quark system on the edge of hadronization. Fluctuations of emitted pions in the $(η, ϕ)$ space are analyzed using normalized factorial moments in a wide range of bin sizes. The scaling index $ν$ is found to be very close to the predicted value in the Ginzburg-Landau formalism. The erraticity indices $μ_{q}$ are determined in a number of ways that lead to the same consistent values. They are compared to the values from the Ising model, showing significant difference in a transparent plot. Experimental determination of $ν$ and $μ_{q}$ at the LHC are now needed to check the reality of the theoretical study and to provide guidance for improving the model description of quark-hadron phase transition.
nucl-thhep-phnucl-exActa Phys.Polon.B(2017)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE