We propose that the dense quark matter could be a source of the high-energy secondary hadrons. These particles can be created from hadronization of the parton(s), which possess the energy of grouped partons from coherent interactions as a result of their collective behav- ior in high dense medium. The medium might be formed in the centre of some massive stars, and it could be a source of the super high-energy cosmic rays. In this work we consider some experimental results as an evidence on collective phenomenon, that can lead to coherent interactions in high dense medium and production of the high-energy secondary hadrons.
Cosmic rays can provide us an important information on appearance and evolution of the Universe. Since super high energy particle beams (greater than 10 17-18 eV ) are not available in ground-based laboratories, super high energy cosmic rays are the only resource to study interactions of the particles in this energy domain. The source of super high energy cosmic are still unknown. 1) The electromagnetic fields generated by some massive stars are considered as plausible sources for the super high energy cosmic rays 2) , however, some theoretical predictions show that these fields could be too weak to accelerate particles to energies of order 10 15 eV . In conclusion, we see that it is necessary to look for a new source mechanism of super high energy cosmic rays, that doesn't involve acceleration. §2.
The dense quark matter can be a source of the super high energy particles under following 3 conditions satisfied simultaneously:
Dense and/or hot quark matter with density ρ » ρ 0 , and/or with temperature T » T 0 ( ρ 0 and T 0 are the values of the density and the temperature of the normal nuclear matter);
Collective behavior of partons in the medium and formation of coherent parton group;
Coherent interaction in the system. In these conditions the maximum energy of the produced partons are limited only by the values of the total energy of the system, where the values of energy will depend on the parameters of the system. typeset using PTPT E X.cls Ver.0.9 §3. What did we have until now?
It is widely discussed that the dense and/or hot quark matter can be formed in the center of some massive stars , for example as a result of supernova explosion, and could lead to the neutron stars formation. 3) 3.2. Second Condition -Collective Behaviour
At relativistic energies we had the first signal on collective behavior -JIN R Cumulative effect. It lead to the notion of production of particles with energies beyond the kinematic limit of free nucleon collisions. 4) The effect was deeply discussed in the paper 5) and below you can see some ideas from it. Few interesting points:
-observation of the pions with energies ⋍ 8 GeV in D + A reactions at 5 A GeV ; -in the B + A → C + X reactions the particles C were produced with x > 1. The values of the x can be defined as
, here u and s are the Mandelstam invariants, m, ε, p and θ are the mass of nucleon, the total energies, the 3 momentum and the emission angle for the C particles respectively, in the lab frame. For free nucleon collisions the values of x must be limited by 1. But as we can see from Fig. 1 6) for hadron-nuclear interactions at JIN R energies particles were emitted with x > 1. The JINR cumulative effect has very peculiar properties, some of them are listed below:
It has been observed for photon-nuclear; lepton-nuclear; hadron-nuclear and nuclear-nuclear interactions.
The strong A-dependences were indicated for the invariant inclusive cross sections of the cumulative particles( f (p) = ε dσ dp ) 3. The inverse of the slope for ε dσ dp behavior as a function of x has a universal value < x >⋍ 0.16
The theoretical interpretation of the effect proposed that it is a result of nucleon collective phenomena and the cumulative particles could be produced from the system of collected nucleons-coherent groups of nucleons. The latter could be formed as a result of fluctuations of nuclear density 7) , the interaction of the projectile with target nucleons , and nucleon percolation. 8) So we can say that JIN R cumulative effect can be considered as a phenomenon with nucleons collective behavior and coherent interactions.
European Muon Collaboration (EM C) investigated the muon deep inelastic scattering on iron and deuterium. 9) They found the big disagreement between experimental result and theoretical expectations. The experimental result shown that the F 2 and hence the quark and gluon distributions of a nucleon bound in a nucleus differ from those of a free nucleon. None of the popular models suggested to explain the EM C effect seem satisfactory and present a new point of view on the effect as a simple relativistic phenomenon. 10) The effect can also be considered as a result of nucleon collective phenomena.
Azimuthal anisotropy observed experimentally at RHIC and LHC shows a collective behavior, which is likely to be formed at an early, parton, stage of the space-time evolution of the produced hot and dense matter 11)-. 13) The anisotropy indicates that matter under extreme conditions behaves as a nearly ideal liquid rather than an ideal gas of quarks and gluons. Scaling behavior of v 2 vs p T 12)-13) gives a possibility to assume that the collective behavior of the partons defines the dynamics of the expansion in the longitudinal plane namely (see Fig. 2)
The first measurement of elliptic flow of charged particles in P b -P b collisions at the center of mass energy per nucleon pair √ s N N = 2.76 A GeV 14) , with the ALICE detector, demonstr
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