Nuclear fragmentation by tunneling

Fragmentation of nuclear system by tunneling is discussed in a molecular dynamics simulation coupled with imaginary time method. In this way we obtain informations on the fragmenting systems at low densities and temperatures. These conditions cannot be reached normally (i.e. above the barrier) in nucleus-nucleus or nucleon-nucleus collisions. The price to pay is the small probability of fragmentation by tunneling but we obtain observables which can be a clear signature of such phenomena.Comment: Phys.Rev.C (submitted

Kinetic description of hadron-hadron collisions

A transport model based on the mean free path approach to describe pp collisions is proposed. We assume that hadrons can be treated as bags of partons similarly to the MIT bag model. When the energy density in the collision is higher than a critical value, the bags break and partons are liberated. The partons expand and can make coalescence to form new hadrons. The results obtained compare very well with available data and some prediction for higher energies collisions are discussed. Based on the model we suggest that a QGP could already be formed in the pp collisions at high energies

Systematic analysis of hadron spectra in p+p collisions using Tsallis distribution

Using the experimental data from the STAR, PHENIX, ALICE and CMS programs on the rapidity and energy dependence of the $p_T$ spectra in p+p collisions, we show that a universal distribution exists. The energy dependence of temperature $T$ and parameter $n$ of the Tsallis distribution are also discussed in detail. A cascade particle production mechanism in p+p collisions is proposed.Comment: 13 pages, 8 figure