Possible effect of mixed phase and deconfinement upon spin correlations in the pairs generated in relativistic heavy-ion collisions

Valery V Lyuboshitz,Vladimir L Lyuboshitz

doi:10.1088/1742-6596/1137/1/012034

Abstract

Spin correlations for the ΛΛ and pairs, generated in relativistic heavy-ion collisions, and related angular correlations at the joint registration of space-parity nonconserving hadronic decays of two hyperons are theoretically analyzed. The correlation tensor components can be derived from the double angular distribution of products of two decays by the method of “moments”. The properties of the “trace” of the correlation tensor (a sum of three diagonal components), determining the angular correlations as well as the relative fractions of the triplet and singlet states of respective pairs, are discussed. In the present report, spin correlations for two identical (ΛΛ) and two non-identical () particles are generally considered within the conventional model of one-particle sources, implying that correlations vanish at sufficiently large relative momenta. However, under these conditions (especially at ultrarelativistic energies), for two non-identical particles () the two-particle annihilation sources – quark-antiquark and two-gluon ones – start playing a noticeable role and lead to the difference of the correlation tensor from zero. In particular, such a situation may arise, when the system passes through the “mixed phase” and – due to the multiple production of free quarks and gluons in the process of deconfinement of hadronic matter – the number of two-particle sources strongly increases.

Highlights

General structure of the spin density matrix of the pairs andSpin correlations for and pairs, generated in relativistic heavy-ion collisions, and respective angular correlations at joint registration of space-parity nonconserving hadronic decays of two hyperons provide important information on the character of multiple processes
! ! the character and mechanism of multiple processes, and the advantage of the and systems over other ones is conditioned by the fact that the P -odd decays p + ; and p+ +
& at sufficiently large relative momenta one should expect that the angular correlations in the decays ! p + ; and ! p + +, connected with the interaction of the and hyperons in the final state are absent

Summary

General structure of the spin density matrix of the pairs and

Spin correlations for and pairs, generated in relativistic heavy-ion collisions, and respective angular correlations at joint registration of space-parity nonconserving hadronic decays of two hyperons provide important information on the character of multiple processes. Where P is the polarization vector of the particle, n is the unit vector along the direction of proton momentum in the rest frame of the particle, is the coefficient of P -odd angular asymmetry ( = 0:642 ). ! the decays of two particles into the channel p + ;, normalized by unity ( the analyzing powers are h XX i 1 = = n1, 2 n2 ) It is described by the following formula [2,3]: d2 w(n1 d dn. Where P1 and P2 are polarization vectors of the first and second T particle, ik are the correlation tensor components, n1 and n2 are unit vectors in the respective rest frames of the first and second particle, defined in the common ( unified ) coordinate axes of the c.m. frame of the pair ( i k = f1 2 3g = fx y zg ).

Spin correlations at the generation of pairs in multiple processes

Summary