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

Laboratory Of High Energy Physics.

By: Kgotlaesele Senosi & Rotondwa Mudau

Supervisor: Dr. Elena Kokoulina

To register and study rare events with high multiplicity oThere are not many theoretical predictions about

multiplicity behaviour in this region o They are founded on phenomenological models

and have between themselves distinctions

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.

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.

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

Schematics of the SVD-2 setup

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.

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.

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 ri between the anode wire and the track passing through the tube.

In this experiment tracks are uniformly distributed along r0 in case of a long time run.

Therefore ri/r0=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)=r0P(t) can be obtained from the experimental time distribution.

ri=(hi/S)*3, put a correspondence between the measured drift time, tdci, drift radius, ri, hi – the height of i-column of tdc distribution figure for a given tdci, measure of step, S=hi, 3mm- radius of straw tube, radius ri [0,3].

This leads to a calibration curve.

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.

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

СПАСИБО!!!!