Общелабораторный семинар ЛФВЭ

Докладчик: Кокоулина Е.С. ( ЛФВЭ)

Title: Puzzles of Multiplicity

Abstract:
One of the observables in high energy physics is the multiplicity – the number of sec-ondary particles produced in the event. The most popular one is a multiplicity of charged particles. Experimenters also restore multiplicity of neutral particles. The main statistical characteristics of multiplicity are its average value and variance. pQCD al-lows us to calculate hard processes but it has a hard time at the description of the had-ronization stage. It’s suggested to add to the quark-gluon stage the phenomenological scheme of hadronization and calculate multiplicity distribution for electron-positron annihilation in wide energy area. The comparison of this model with data is also planned.

Title: Active role of gluons in hadron interactions

Abstract:
Multiparticle production processes attract the attention of physicists in both experi-mental and theoretical studies. Until now, no MC-event generator has been able to fully describe data at different energies. QCD works by quark-gluon language. The transition toward observable hadrons is extremely difficult, since pQCD has hard time in this re-gion. This project offers to apply the gluon dominance model (GDM) for description of multiplicity distributions (MD) in hadron interactions within two stages: the quark-gluon cascade and hadronization, which is described phenomenologically. Based on da-ta on pp interactions, within the framework of Gluon Dominance Model, the active role of the gluon component in the formation of secondary particles is confirmed. The ratio of two contributions, emission of a gluon by a quark to its fission is estimated. The study of gluon structure of the proton and search for collective phenomena in pp colli-sions can be performed at the SPD facility of the future NICA collider (JINR, Dubna).

Title: Multiplicity distributions of neutral pions in hadron interactions

Abstract:
At energy of U-70 accelerator (50 GeV) and high multiplicity, π-mesons predominate among secondary particles. Pions are spin-zero mesons. They are the lightest hadrons copiously produced in high energy collisions. The gluon dominance model describes multiplicity distributions (MD) of charged pions at wide energy region. This model can be applied to the description of MD of π0-mesons. The SVD-Collaboration could regis-ter events with high multiplicity including neutral particles. Moreover, in this region it was shown a significant growth of scaled variance. The difference between theoretical prediction and experimental value variates by seven standard deviations. The task of this project is to apply the gluon dominance model to the description of MD of neutral pions, find out its parameters at the quark-gluon stage and hadronization in pp interac-tions at 50 GeV/c proton beams.