Theoretical search for collective effects in multiparticle production

Abstract

An absolutely stabilized laser diode system for high-resolution spectroscopy of the 4 2 S 1=2 -3 2 D 5=2 electric-quadrupole-allowed transition in calcium ions at 729 nm is developed. Both its short-term and long-term stabilities are examined. A system for laser cooling of single calcium ions using an ultraviolet laser diode for excitation of the 4 2 S 1=2 -4 2 P 1=2 transition is also constructed, and by using it we have observed quantum jumps of single calcium ions with a high stability and a high signal-tobackground ratio.

The quark–gluon medium

“…The modifications of QCD cascades taking into account "pionization", i.e. the interaction with additional strongly interacting degrees of freedom, were analytically studied in [50,51,52,53] for the case of non-angular ordered cascades and in [54,55] for the angular-ordered ones.…”

Scaling laws for density correlations and fluctuations in multiparticle dynamics

“…Besides, the analogy breaks down completely for values of q exceeding the multiplicities effectively contributing to the moments. Nevertheless, this analogy is used in [314,315] to derive the dependence of the pressure in a Feynman-Wilson liquid on its chemical potential and some peculiar features are found in hadron-hadron reactions (see also the review paper [316]).…”

Study of the dependence of direct soft photon production on the jet characteristics in hadronic Z 0 decays

“…Since the direct coupling of photons to neutral particles (e.g. via magnetic moment) is quite weak, this means that the excess photons under study are coupled either to the individual quarks and/or quark-antiquark pairs constituting a parton shower, or via some collective effect (for example, one of those mentioned in [52]) to a jet as a whole.…”