At energy of U-70 (50 GeV), 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 of charged pions at wide energy region. This model can be appied to the description multiplicity of neutral pions. The SVD-Collaboration could register events with high multiplicity including neutral particles. Moreover, in this region it shown the significant growth of the scaled variance. The difference between theoretical prediction and experimental value variates by seven standard deviations. The main task of this project is to apply the gluon dominance model to the description of multiplicity of neutral pions and seaching for the parameters of quark-gluon stage and hadonization at 50 GeV-proton beams of U-70 accelеrator.
Tasks
1. Getting of multiplicity distributions of neutral pions from SVD-data. The description of multiplicity distribution for pi-mesons and calculation of their digital characteristics (mean value, variance, second correlative moment).
2. The calculation of the scaled variance from SVD-Data.
3. Application of the model to the description another available data from bubble chambers.
4. The inclusion in the model of the gluonic branching and comparison with data.
Preliminary schedule by topics/tasks
1st - 2nd weeks: 1st task; 3th - 4th weeks: 2nd -3rd tasks; 5th - 6 th weeks: 4th - 5th tasks
Required skills
Good knowledge of C++ language and the cernroot software are greeted.
(http://root.cern.ch)
Acquired skills and experience
statistical methods of data proceedings, theoretical description of multiplicity production for neutral particles, Bose-Einstain (pionic) condensate,
Recommended literature
Begun V.V. and Gorenstein M.I. Bose-Einstein condensation of pions in high multiplicity events. Phys. Lett. B 653, N2-4, 190-195, 2007.
Begun V.V. and Gorenstein M.I. Bose-Einstein condensation in the relativ-istic pion gas: Thermodynamic limit and finite size effects. Phys.Rev. C77 N6 (2008) 064903.
Csorgo T. and Zimany J. Analytic Solution of the pion-Laser mod-el.Phys.Rev.Lett.80, N5, 916-919, 1998. 117 Lednicky R. et al. Multiboson effects in multiparticle production. Phys.Rev.C61, 034901, 2000 (19p.). Kokoulina, Elena. Neutral Pion Fluctuations in pp Collisions at 50 GeV by SVD-2, Progress of Theoretical Physics Supplement. 193, 306-309, 2012.
Kokoulina, Elena, Kutov Andrey, Kalyada Andrey, Salyanko Ruslan. The evidence for the pion condensate formation in pp interactions at U-70, Proceedings of Science, Изд:SISSA, 1-8, 2013.
