Е. Кокоулина, А. Кутов *) , В. Никитин...

1

Е. Кокоулина, А. КутовЕ. Кокоулина, А. Кутов*)*),, В. Никитин и Ю. Петухов В. Никитин и Ю. Петухов

СВД -2 Коллаборация: СВД -2 Коллаборация: JINR, IHEP and SINP MSUJINR, IHEP and SINP MSU*) ОМ УрО РАН, Сыктывкар*) ОМ УрО РАН, Сыктывкар

Gold SandsGold Sands, , Belarus, Belarus, September ,September , 4-9, 4-9, 20020099

Поиск коллективных явлений в адронных

взаимодействиях

2

Outline

The extreme multiplicity puzzles

SVD-2 setup and data processing

Search of the collective phenomena

Gluon Dominance Model

Outlook

3

The extreme multiplicity puzzles

4

chn

mb

nch )(

The extreme multiplicity puzzlesThe extreme multiplicity puzzles1)1) MC PHYTHIA code has MC PHYTHIA code has

shown that standard shown that standard generator predicts a value generator predicts a value of the cross section which of the cross section which is in reasonably good is in reasonably good agreement with data at agreement with data at small multiplicity nsmall multiplicity nchch < 10, < 10, but it underestimates the but it underestimates the value value σσ(n(nchch) by two orders ) by two orders of the magnitude at nof the magnitude at nchch > > 18. 18.

2)2) The existing models are The existing models are very much sensitive in the very much sensitive in the region of the extreme, region of the extreme, more significantly than more significantly than mean multiplicity (ExMu).mean multiplicity (ExMu).

3)3) The various manifestation The various manifestation of the collective of the collective phenomena is caused by phenomena is caused by the dense system the dense system formation at the ExMu formation at the ExMu region.region.

chnNApp 2)(

5

SVD-2 setup and data processing

6

10 10

mm

MMSS

MSMSVDVD

EMEMCC

Č

DT

ScH

SVD-2 setupSVD-2 setupU-70 U-70 acceleration at acceleration at IHEP (Protvino), IHEP (Protvino), 50-70 GeV. The 50-70 GeV. The trigger systemtrigger system selects the rare selects the rare events with the events with the charged charged multiplicity more multiplicity more than 20 - 30. than 20 - 30. The The suppression suppression factorfactor of events of events with lower with lower multiplicity multiplicity amounts about amounts about 101044. The . The TargetTarget itself is a 7-cm itself is a 7-cm thick, 25mm-thick, 25mm-diameter vessel diameter vessel for liquid for liquid hydrogen. hydrogen.

MicroStrip Vertex Detector MicroStrip Vertex Detector Scintillator HodoscopeScintillator Hodoscope Drift Drift Tube TrackerTube Tracker Magnetic Spectrometer Cherenkov counter Magnetic Spectrometer Cherenkov counter ElectroMagnetic Calorimeter ElectroMagnetic Calorimeter

7

MC event generator is designed for the setup element simulation;

Data processing software for ExMu;

Alignment;

GEANT-3 program reconstruction analysis.

Software Software developmentdevelopment

8

Multiplicity Distributions (MD) in pp interactions at different trigger levels: 8, 10, 12.run 2008,PVD.


9

Kalman Filter as Track Fitter for SVD

1. Drift tubes calibration - from raw TDC time to drift distance.

2. Recognize track candidates – find track-like groups of hits: pattern recognition.

3. Taking into account REALITY: alignment.4. From track candidates to real track

parameters: track fitting.5. From tracks to vertexes: vertex fitting


10

Track fitting

It is necessary to take into account:

- non-uniform magnetic field (from table);- multiple scattering;- energy losses.


11

1. VD + MS reconstruction: track parameter determination; use MS data for momentum estimation.

2. DT track finding separately in Y,U,V planes, then build 3D tracks.

3. DT + MS track fitting: track parameters from 1 or 2 as initial values and Kalman Filtering procedure.

4. Taking into account non-uniform magnetic field,

multiple scattering, energy losses.5. Re-fit vertexes, if it is necessary.6. Kinematical fit (we can use the Vt++ library)

Analysis sequence


12


13


14

Search of the collective phenomena

15

1. Bose-Einstein Condensation (BEC);2. Ring Events (Cherenkov gluon

emission);3. Gluon Dominance Model (GDM);4. Excess of soft photon (SP) yield;5. Clusterization;6. Turbulence Phenomena …

Search of the collective Search of the collective phenomenaphenomena

16

M. Gorenstein and V. Begun had predicted an abrupt and anomalous increase of the scaled variance ω of

neutral- and charged- pion-number fluctuations in the vicinity of the BEC line [Phys.Lett.B651:114 (2007)].

Bose-Einstein Condensation


17

Ring Events in pp (n_ch >8), run 2008


Red Red - 7- 7thth order order PolynomialPolynomial

nch 9nch < 9

18

Monte-Carlo (nch 9)


19

Ring Events ,/,/1cos EpnC

n - the index of the refraction,

θC = 0.065 0.005, n = 1.0023 ± 0.0003

Our experiment:

Theory:

n (p) = 1+Δn (p) = 1+3mpr2 σ(p) h ρ(p) / 8πppr,

h – the number of scatters, ρ = Re F/ Im F, Δn (p) = 3 mp

3 Re F / 2p 2 = 0.0005 * Re F, at Re F =4.6 GeV (.92 fm)


20


21

hadronsgqqqZee ?),()( 0

First stage (cascade): a) gluon fission; b) quark bremsstrahlung; c) quark pair creation; NBD.

A.Giovannini. NP, B161 (1979).

Second stage (hadronization): BD

Convolution of two stages.

.)1(1PN

p

hpH

p zN

nQ

.!

)1)...(1(pk

p

p

m

p

pppm km

k

km

m

m

mkkkP


22

GDM parameters: mean multiplicity of hadrons from 1 gluon while its passing through of hadronization stage remains constant ~1 (14 -189, GeV). Fragmentation mechanism of hadronization: 1 parton to 1 hadron.

qq

1Meson

Baryon

B.Muller [nucl-th/0404015]


23


GDM had shown: quarks of initial protons are staying in leading particles (from 70 to 800 GeV/c). Multiparticle production is realized by gluons. We name them active ones.

Two schemes: with/without gluon branch. ConvolutionConvolution gluon gluon (Poisson/Farry) (Poisson/Farry) && hadron (PBD) hadron (PBD) MDs.MDs. pp–pp–

interactionsinteractions

24

recombination mechanism of hadronization

qq

qqq1

Meson

Baryon

B.Muller [nucl-th/0404015]

in pp–in pp–interactionsinteractions


25

In GDM for pp at 70 GeV the maximal possible number of new formed charged, neutral & total hadrons is limited and is equal to 26, 16 and 42 particles, accordingly.

Preliminary experimental data corroborate these predictions. From PVD data (which has constricted acceptance) we see events with maximal multiplicity 24 charged particles only.


26

01.0,/1.0 xcGeVpt

At HE σ(SP) are 5-8 times more in the comparison with the QED predictions. Assumption:

QG system or excited new formed hadrons set in almost equilibrium state during a short period (we use the black body emission spectrum): 1.0)(,40,4 nTnmbmb inin

Estimations of SP emission region: 4-6 fm.

Soft Photons (SP)Soft Photons (SP)


27

GDM and experimental MD’s Mirabel: Mirabel: ■■ - 50 - 50 GeV GeV - 70 - 70 GeV GeV

SVD: SVD: - 50 GeV - 50 GeV

- GDM- GDM

preliminarypreliminary

Run 2008, Run 2008, 50 GeV 50 GeV pp interactionspp interactions

88thth level HM level HM triggertrigger

28

Outlook

Software check-out for track Software check-out for track reconstruction in DT and MS with reconstruction in DT and MS with tracks reconstructed in PVD. tracks reconstructed in PVD.

The continuation of the searching of The continuation of the searching of the collective phenomena in pp (pA) the collective phenomena in pp (pA) interactions at the extreme interactions at the extreme multiplicity: the Bose-Einstein multiplicity: the Bose-Einstein condensation, ring events (dense condensation, ring events (dense groups in angle distributions), groups in angle distributions), clusterization, turbulence phenomena. clusterization, turbulence phenomena.

Soft photon studiesSoft photon studies

Е. Кокоулина, А. Кутов *) , В. Никитин...

Documents