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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 responsible for the above mentioned effects (for
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 ,
in particular in the vicinity of critical points.Comment: 7 pages, 10 figure
On the possibility of q-scaling in high energy production processes
It has been noticed recently that transverse momenta (p_T) distributions
observed in high energy production processes exhibit remarkably universal
scaling behaviour. This is the case when a suitable variable replaces the usual
p_T. On the other hand, it is also widely known that transverse momentum
distributions in general follow a power-like Tsallis distribution, rather than
an exponential Boltzmann-Gibbs, with a (generally energy dependent)
nonextensivity parameter q. Here we show that it is possible to choose a
suitable variable such that all the data can be fitted by the same Tsallis
distribution (with the same, energy independent value of the q-parameter). Thus
they exhibit q-scaling.Comment: Final version, accepted by J.Phys.
Possible Implication of a Single Nonextensive Distribution for Hadron Production in High-Energy Collisions
Multiparticle production processes in collisions at the central rapidity
region are usually considered to be divided into independent "soft" and "hard"
components. The first is described by exponential (thermal-like) transverse
momentum spectra in the low- region with a scale parameter associated
with the temperature of the hadronizing system. The second is governed by a
power-like distributions of transverse momenta with power index at
high- associated with the hard scattering between partons. We show that
the hard-scattering integral can be approximated as a nonextensive distribution
of a quasi-power-law containing a scale parameter and a power index , where is the nonextensivity parameter. We demonstrate that the whole
region of transverse momenta presently measurable at LHC experiments at central
rapidity (in which the observed cross sections varies by orders of
magnitude down to the low region) can be adequately described by a single
nonextensive distribution. These results suggest the dominance of the
hard-scattering hadron-production process and the approximate validity of a
"no-hair" statistical-mechanical description of the spectra for the whole
region at central rapidity for collisions at high-energies.Comment: 10 pages, 3 figures; presented by G.Wilk at the XLIV International
Symposium on Multiparticle Dynamics; 8 - 12 September 2014 - Bologna, ITAL
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