1. Particle production in pp-interaction with high multiplicity at 50 GeV

2. Laboratory Of High Energy Physics. By: Kgotlaesele Senosi & Rotondwa Mudau Supervisor: Dr. Elena Kokoulina

3.  To register and study rare events with high multiplicity o There are not many theoretical predictions about multiplicity behaviour in this region o They are founded on phenomenological models and have between themselves distinctions

4.  Simulation predicted lower topological cross sections, two orders low compared to experiment (Mirabelle,70GeV).  Thermalization project is aimed at measuring cross-section at multiplicity 20- 30.  Investigations in this area are important for the understanding of hadron production.

5.  At the high number particle events it is possible that the collective behaviour of secondary particles will be revealed.  These collective phenomena manifest as hadron and as quark-gluon nature.  These phenomena: Bose-Einstein condensation, the hadronization of gluons, which are emitted out by partons in the nuclear environment (Cherenkov radiation analog) and others.

6.  С1-С4 – beam scintillate counters,  HT– hydrogen target,  PVD – precision vertex detector,  DT– drift tube tracker,  MS – magnetic spectrometer,  CC – Cherenkov counter,  EC – electromagnetic calorimeter,  HM –scintillator hodoscope. CC EC DT MS PVD, HM HT

7. Schematics of the SVD-2 setup

8.  Beam Telescope -ensures beam particle existence.  Hydrogen target -made of liquid hydrogen.  Hodoscope –high multiplicity trigger.  Vertex Detector –used for tracking.  Drift Tubes –enhance tracking.  Magnetic Spectrometer -used to measure momentum.

9.  Study of Multi-particle cross-section using an enhanced SVD-2 setup.  These entail determination of the vertex and tracking with better precision.  Drift Tube Detectors are introduced between the Silicon Strips and the Spectrometer to enhance tracking.

10.  The important task of any HEP experiment is to provide reconstruction of charged particle tracks.  A TDC reading provides a means for determining the distance r i between the anode wire and the track passing through the tube.  In this experiment tracks are uniformly distributed along r 0 in case of a long time run.

11.  Therefore r i /r 0 =P(t) holds true for the time dependence of the drift radius r(t) i.e. the probability of detecting it in the interval from 0 to T.  Hence the calibration function r(t)=r 0 P(t) can be obtained from the experimental time distribution.

13.  r i =(h i /S)*3, put a correspondence between the measured drift time, tdc i, drift radius, r i, h i – the height of i-column of tdc distribution figure for a given tdc i, measure of step, S=  h i, 3mm- radius of straw tube, radius r i  [0,3].  This leads to a calibration curve.

15.  The linear dependence of radius with time of drift shows proper functioning of the tubes.  The reconstruction of tracks can be done with using calibration function, matrix forms for all 9 planes of straw tube detector.  The calibration function is changed from one to another run and from one tube to other.

16.  BALILADZE et al. (Vol 51 No. 3, 2008)  E. Kokoulina, Acta Phys.Polon. B 35, 295 (2004).  E. S. Kokoulina and V. A. Nikitin, in Proceedings of Baldin Seminar on HEP Problems ―Relativistic Nuclear Physics and Quantum Chromodynamics‖, JINR, Dubna, Russia. p. 319 (2005).  V. V. Avdeichikov et al., Proposal ―Termalization‖ (in Russian), JINR-P1- 2004-190 (2005).  A. Aleev et al. (SVD-2 Collab.), in Proc. of the Intern. Conf.-School on Foundations and Advances in Nonlinear Science, Minsk, Belarus, 2006, p.1

17. СПАСИБО!!!!