Narrow Results

In this letter, by using the properties of the entropy function and the fundamental equation of thermodynamics, we discuss the reasons that there exist different proposals for relativistic temperature transformation. Further, we illustrate this point by studying a concrete thermodynamic system-blackbody radiation.

The Hagedorn temperature, T_H is determined from the number of hadronic resonances including all mesons and baryons. This leads to a stable result T_H = 174 MeV consistent with the critical and the chemical freeze-out temperatures at zero chemical potential. We use this result to calculate the speed of sound and other thermodynamic quantities in the resonance hadron gas model for a wide range of baryon chemical potentials following the chemical freeze-out curve. We compare some of our results to those obtained previously in other papers.

Currently the quantitative description of confinement inside nuclear matter is exclusively limited to computer experiments, mainly on lattices, and concentrating upon calculating the static potential. There is no independent reference for comparison and support of the results, especially when it comes to the quark potential in the continuum limit. Yet, we are entitled to be optimistic, for the basic results of these calculations seem to be correct from an entirely different point of view, suggested by Manton's geometrization of Skyrme theory. The present work shows the reasons of this point of view, and offers a static potential that might serve as independent reference for comparison and endorsement of any lattice calculations, and in fact of any structural hypotheses of nuclear matter. A historical review of the pertinent key moments in the history of modeling of nuclear matter, as well as an outlook anticipating the necessary future work, close the argument.

Single particle transverse mass spectra and HBT radii of identical pion and identical kaon are analyzed with a blast-wave parametrization under the assumptions of local thermal equilibrium and transverse expansion. Under the assumptions, temperature parameter $T$ and transverse expansion rapidity $\rho$ are sensitive to the shapes of transverse mass $m_{\mathrm{\text{T}}}$ spectrum and HBT radius $R_{\mathrm{\text{s}}}(K_{\mathrm{\text{T}}})$. Negative and positive correlations between $T$ and $\rho$ are observed by fitting $m_{\mathrm{\text{T}}}$ spectrum and HBT radius $R_{\mathrm{\text{s}}}(K_{\mathrm{\text{T}}})$, respectively. For a Monte Carlo simulation using the blast-wave function, $T$ and $\rho$ are extracted by fitting $m_{\mathrm{\text{T}}}$ spectra and HBT radii together utilizing a combined optimization function ${\chi }^2$. With this method, $T$ and $\rho$ of the Monte Carlo sources can be extracted. Using this method for A Multi-Phase Transport (AMPT) model at Relativistic Heavy Ion Collider (RHIC) energy, the differences of $T$ and $\rho$ between pion and kaon are observed obviously, and the tendencies of $T$ and $\rho$ versus collision energy $\sqrt{s_{\mathrm{\text{NN}}}}$ are similar with the results extracted directly from the AMPT model.

Analysis of the fusion reactions of halo nuclei is one of the important subjects of nuclear physics. In addition, temperature-dependent analysis of fusion cross-sections of these nuclei is a deficient topic in the literature. In order to overcome this deficiency, the fusion cross-sections of ⁶He, ⁸He and ${}^{11}$Li which are the most important halo nuclei are analyzed by using both temperature-independent potential and temperature-dependent potential. All the theoretical results are compared with each other as well as the experimental data. It is seen that the results of temperature-independent potential are in good agreement with the data while the temperature-dependent potential has a significant impact on the fusion cross-sections. Finally, the changes with the temperature of both real and nuclear potentials of all the reactions are investigated.