1 High Multiplicity Study E.Kokoulina, A.Kutov for SVD-2 Collaboration JINR, Russia & GSTU, Belarus...

1

High High Multiplicity Multiplicity

StudyStudyE.Kokoulina, A.Kutov for SVD-2 Collaboration JINR, Russia & GSTU, Belarus

ISMD 2007, LBNL Berkeley, August, 4-9

2

OUTLOUTLINEINE IntroductionIntroduction

Gluon Dominance Model (eGluon Dominance Model (e++ee--, , pp, pA, pp)pp, pA, pp)

“ “Thermalization” project status Thermalization” project status

OutlookOutlook


__

3

IntroductiIntroductionon

We use the unified approach to the multiplicity description at HEP. It is based on essentials of QCD and on the main experimental phenomena in multiparticle dynamics.

We are interested the high multiplicity (HMHM) region: n > n(s).

_


4

- annihilation

ee

proton (nucleus) collisionsproton-antiproton- annihilation

pQCD & hadronizationSoft Photons

V. Kuvshinov, E.K. Acta Phys.Polon. B13 (1982).

IntroductiIntroductionon

THERMALIZATION project


5

ee

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

hadronsgqqqZee ?),()( 0

Second stage (hadronization): BD

.)1(1PN

p

hpH

p zN

nQ

Convolution: of two stages.

!

)1)...(1(pk

p

p

m

p

pppm km

k

km

m

m

mkkkP

quark fission -> NBD

Gluon Dominance Model Gluon Dominance Model (GDM): e(GDM): e++ee-- annihilation annihilation


6

Pn in -annihilation at 22 (TASSO) and 161 GeV (OPAL) ; H(q) at 161 GeV.

ee

E. K. Minsk, NPCS (2002)]; ISMD32,2002.

22 GeV

Pn 161

GeV

Pn H(q)

161 GeV

GDM: eGDM: e++ee-- - annihilation - annihilation


qq

nn nn

7

s s

hgn

)( hgg nN - maximal (average)

multiplicity of hadrons from one gluon while its passing through of hadronization is constant -> fragmentation mechanism of hadronization (one to one)

gluon hadronization is softer than quark one:

2.~/ qg NN

gN

GDM: eGDM: e++ee-- - annihilation - annihilation


8

After an inelastic collision of two protons the part of energy are converted into the thermal (the dissipating energy) and one or few gluons become freeGluons may give cascadeSome of gluons (not of all) leave Quark-Gluon System (QGS) – are evaporated and are converted to hadrons.

1st

stage

2nd

stage

GDM: pp - interactionsGDM: pp - interactions


9

Our model study had shown: quarks of initial protons are staying in leading particles (from 70 to 800 GeV/c). Multiparticle production (MP) is realized by gluons*). We name them active ones. _________________________________________*The dominance role of gluons at multiparticle production (MP) was proposed S.Pokorski and L. Van Hove (1975), P. Carruthers (1984).



10

1. Scheme with the branch of gluon in QGS (TSMB)

2. Scheme without the gluon branch (TSTM)

E.K. and V.Nikitin. 7th Int. school-seminar The actual problems of Microworld Physics, Gomel, Belarus. 1 (2004)



11

MD of active gluons at the moment of impact (Poisson)

MD of branch gluons (Furry) for the first scheme

MD at the hadronization stage (BD)

GDM: pp – interactions GDM: pp – interactions (scheme with branch) (scheme with branch)


12

- ratio of evaporated gluons to all active ones;

gluon hadronization parameters on second stage;

)5.0(~Nn h ,

N ~40. This value is very likely to the number of partons in the glob of cold QGP, which leads to production of soft photon excess. P.Lichard & L.Van Hove. Phys.Let. B245 (1990) 605.

GDM: pp – interactions GDM: pp – interactions (scheme with branch)(scheme with branch)


13

E.K. Acta Phys.Polon. B35(2004)295

pp –pp – interactions (scheme interactions (scheme without branch)without branch)

After evaporation gluons leave QGS and fragment to hadrons. MD is convolution Poisson and BD

69 GeV/c 800 GeV/c

chn chn

nPnP


14

p, GeV/c

Mg

N

69 2.48 +/-

0.20

6 4.24 +/-.13

1.63 +/-0.12

~2

102 2.75 +/

0.08

8 3.13 +/-.56

1.64 +/-0.04

2.2

205 2.82 +/- 0.20

8 4.50 +/-.10

2.02 +/-0.12

2.0

300 2.94 +/- 0.34

10 4.07 +/-.86

2.22 +/-0.23

9.8

405 2.70 +/-.30

9 4.60 +/-.24

2.66 +/-0.22

16.4

800 3.41 +/-2.55

10 20.3 +/-10.4

2.41 +/-1.69

10.8

m hn 2

pp –pp – interactions (without interactions (without branch)branch)


15

Hadronization Hadronization MechanismsMechanisms recombination mechanism

clan as independent intermediate gluon sourceqq

qqq

qq

Recombination:

1Meson

Baryon

Fragmentation:

1Meson

Baryon

B.Muller [nucl-th/0404015]


16

Mean multiplicity of π0 versus the number of nch

2

1

2

1

/)()(0

n

nn

n

nnnchtotnch

tot tot

tottotPnnPnn

pp – interactionspp – interactions (neutral)(neutral)

MD of π0 at 69 Gev/c Limits to max charged, neutral & total multiplicities (26, 16, 42).

gluon hadronization parameters for π0

Centaur (yes, HM region), AntiCentaur (no)

particle number limits

V. Grishin. Phys.El.Part.and At.Yad. 10 (1989)689.

)(0 chnn


17

62 GeV

E.K., Nikitin V. et al. ISHEPP2004.

.1!

1!

)(

)2(22

22

2

22

)2(2

2

1

11

2

2

2

2

22

1

1

1

1

11

nNmhnh

nNm

M

m

mm

nNmhnhnNm

M

m

mm

n

N

n

N

nC

m

me

N

n

N

nC

m

mesP

14.23.3 hn

)1( 21

.13/9/,8.1~/

,25.015.1,03.059.32

21

21

ndf

mm

1 2

pp – interactionspp – interactions (ISR, 30-60 GeV)(ISR, 30-60 GeV)Clan

(cluster) superposition consisting from one, two (or more) gluon fission

Soft ( ) & semi-hard ( ) components, and so on.

Pn

n


1 2

18

GDM h/ for pp: 70 GeV/c = 1.19+/-0.25 ,,, 800 GeV/c = 1.49+/-0.33 … 62 GeV ~ 1.6 ( ).

PHEN

IXh

hch

h

ch

n

n

nsmh

sn

sn

000 2

1

)(

1)/(

)(

2/)(

076.10 hn

pp(nucleus) – pp(nucleus) – interactions (h/interactions (h/ ratio) ratio)Au-Au 200 GeV/N, peripheral (60-92%).

GDM: PHENIX. Nucl.Phys.A757(2005).

the dominance of active gluon plenty in nucleus central collisions leads to the new kind matter formation –QGP

agreement with h/ ratio

pp


19

1.0)(,40,4 nTnmbmb inin

Soft photons Soft photons (SP excess)(SP excess)

Measured SP:

01.0,/1.0 xcGeVptσ(SP) are 5-8 times larger than expected ones from QED.

Assumption: QGS or excited new formed hadrons set in almost equilibrium state during a short period. That is why we use the black body emission spectrum:

.

1

8 3

3

T

h

ecd

dn


20

383

10112.4/)()(725.2,2

244.0)(

mVTnMVBKThc

kTVTn rr

3

3

3968

3

101010112.4/)()(,)()(

fm

T

TVTnT

T

TTnTn

rrr

)()(3 TLnTL L(fm)

L(fm)

10 11. 30 3.5

15 6.9 40 2.6

25 4.1 50 2.0

tp tp2 tppT

M.Volkov,E.K., E.Kuraev. Part. & Nucl. Let., 5 (2004)122

Soft photons Soft photons (SP excess)(SP excess) The number of SP is estimated by MVB

density ρ(T )=n(T)/V:

estimation of SP emission region

SP excess is the sign of hadronization


21

pp – annihilation pp – annihilation (experiment)(experiment)

__

J.Rushbrooke & B.Webber. Phys.Rep. C44(1978)1.)(sn

2f

)( 2GeVs

22 )1( nnnf

)(sn

n

)()( pppp nnn

32, 100 GeV/c


22

mNhm zNnzQzmQ )1(/1),1(),(

GDM: pp – GDM: pp – annihilation annihilation

.0/)(~ 22 Nnmf h

Experiments (10-100 GeV/c): a tendency to the production of leading mesons. f2 behavior explanation. The simple scheme with appearance at first moment of m active gluons. GF and f2 :

E.K. AIP. 828 (2006) 81

__


23

GDM: pp – GDM: pp – annihilation annihilation

__

GDM includes intermediate quark topologies at the initial stage making only from valent quarks (“0”-, “2-”) or valent and vacuum ones (“4-”, “6-”). MD are superposition of them.

p

p

+ +0 00

0 + +

+ + + +…

(“0”)

(“2”)

(“4”)


24

,/ nnnP

.05.0:40:15:: 420 ccc

.5.1~/,61.074.1

,18.036.32 ndfn

mh

GDM: pp – GDM: pp – annihilationannihilation

__

14.75 GeV/c

mNhM

m

Gm

mNhM

m

Gm z

N

nPzcz

N

nPczQ )1(1)1(1)(

202

20

.)1(14

44

mNM

m

hGm z

N

nPzc

intermediate topology superposition

hadronization predominance at annihilation

Pn


25

Scientific programme: multiparticle dynamics study in p+p(A) interactions with HM (n>20) at IHEP U-70.

SVD-2 Collab.: Belarus, Czech Republic, Russia, Slovak Republic, Ukraine

project project “THERMALIZATIO“THERMALIZATION”N”

SVD-2 setup

V.V.Avdeichikov et al. JINR-P1-2004-190, Proposal ”THERMALIZATION”.

Micro strip VD, 10000 channels.

Drift tubes tracker, 2400 channels

Magnetic spectrometer

DeGa

Č

target


10 10

mm

26

Liquid hydrogen target

Trigger scintillation hodoscope (“camomile”) for the registration of rare events with HM:

20 elements: triangle h=18, thickness 1.8 mm

Project Project “THERMALIZATI“THERMALIZATIONON


27

project project “THERMALIZATIO“THERMALIZATION”N” Search for & new

collective phenomena study:

1. BEC of identical particles.

2. Ring events (Cerenkov gluon).

3. Soft photon cross section.

4. Grouping of secondary.


28


1) M.I.Gorenstein & V.V.Begun, BITP, Ukraine [hep-ph/0611043]:at HM the experimental manifestation of BEC may be founded by the sharp increase of neutral meson multiplicity fluctuations at fixed total multiplicity.


29

project project “THERMALIZATIO“THERMALIZATION”N”2) RUN

2002: Ring event search [Seminar NPCS,Minsk,2006]. 4) RUN 2002: the indication to the grouping of secondary in the certain direction [Hep-ph/0612364]

Preliminary

Preliminary


30


MD in pC, pSi and pPb

RUN 2002

pC

pSi pPb


31

project project “THERMALIZATIO“THERMALIZATION”N”Alignment taskAlignment task of detectors is an essential step

in the track reconstruction:

beforeafter

2006 data


32


Z, mm

X, mm

Y, mm


33

““THERMALITHERMALIZATION”ZATION”

n=n=2222


34

““THERMALITHERMALIZATION”ZATION”

Multiplicity distributions for X and Y planes (n_beam<5)

Integrated MD for X, Y planes

Preliminary

Preliminary


35

• Data pA (Si,C, Pb) 2002 run will be study

• A set of pp data in 2007-2009 runs will be obtained.

• We expect interest phenomena in the HM region will be got.

OutlOutlookook


Date post:	17-Jan-2016
Category:	Documents
Upload:	eugene-riley
View:	214 times
Download:	0 times

1 High Multiplicity Study E.Kokoulina, A.Kutov for SVD-2 Collaboration JINR, Russia & GSTU, Belarus...

Documents