Nonextensive critical effects in relativistic nuclear mean field models

We present a possible extension of the usual relativistic nuclear mean field models widely used to describe nuclear matter towards accounting for the influence of possible intrinsic fluctuations caused by the environment. Rather than individually identifying their particular causes we concentrate on the fact that such effects can be summarily incorporated in the changing of the statistical background used, from the usual (extensive) Boltzman-Gibbs one to the nonextensive taken in the form proposed by Tsallis with a dimensionless nonextensivity parameter $q$ responsible for the above mentioned effects (for $q \rightarrow 1$ one recovers the usual BG case). We illustrate this proposition on the example of the QCD-based Nambu - Jona-Lasinio (NJL) model of a many-body field theory describing the behavior of strongly interacting matter presenting its nonextensive version. We check the sensitivity of the usual NJL model to a departure from the BG scenario expressed by the value of $| q - 1|$, in particular in the vicinity of critical points.Comment: 7 pages, 10 figure

ΛN\Lambda N space-exchange correlation effects in Λ5_\Lambda ^5He hypernucleus

A complete realistic study of $_\Lambda ^5$He hypernucleus is presented using a realistic Hamiltonian and wave function. This study takes into account all relevant dynamical correlations along with $\Lambda N$ space-exchange correlation (SEC). We also compute $\Lambda NN$ force and the corelation induced by this force. The SEC affects the central repulsive $\lambda N$ correlation significantly at $r \le 2.0$ fm, specially at its peak and in its vicinity. SEC significantly affects energy breakdown of the hypernucleus, $\Lambda$-seperation energy, nuclear core (NC) polarization and density profiles. A lage NC polarization is found with and without SEC, respectively. The SEC effect is relatively large in two-pion exchange component of $\Lambda NN$ force. Therefore, any attempt to pin down the strength of this force with no SEC would be flawed.Comment: 4 pages, two figure

Consequences of temperature fluctuations in observables measured in high energy collisions

We review the consequences of intrinsic, nonstatistical temperature fluctuations as seen in observables measured in high energy collisions. We do this from the point of view of nonextensive statistics and Tsallis distributions. Particular attention is paid to multiplicity fluctuations as a first consequence of temperature fluctuations, to the equivalence of temperature and volume fluctuations, to the generalized thermodynamic fluctuations relations allowing us to compare fluctuations observed in different parts of phase space, and to the problem of the relation between Tsallis entropy and Tsallis distributions. We also discuss the possible influence of conservation laws on these distributions and provide some examples of how one can get them without considering temperature fluctuations.Comment: Revised version of the invited contribution to The European Physical Journal A (Hadrons and Nuclei) topical issue about 'Relativistic Hydro- and Thermodynamics in Nuclear Physics' guest eds. Tamas S. Biro, Gergely G. Barnafoldi and Peter Va