The description of ppinteractions with very high multiplicity at 70 GeVc by Two Stage Gluon Model

1
GLUON DOMINANCE MODEL CLUSTER PRODUCTION
E. Kokoulina
GSTU, Belarus JINR, Russia
ISMD 2006
2
The unified approach to the multiplicity
distribution (MD) description at high energies
are based on essentials of QCD and on the main
experimental phenomena in multiparticle dynamics
pQCD hadronization
- annihilation
proton (nucleus) collisions
Soft Photons
proton-antiproton- annihilation
V. Kuvshinov E.K. Acta Phys.Polon.B13(1982).
ISMD 2006
3
The region of high multiplicity (HM) n gt
n(s) mean muliplicity.
Pn(s) -
multiplicity distributions (MD),
Q(s,z) - generating
function (GF)
Q(s,z) S Pn (s) z n .
-
ISMD 2006
4
ee- - annihilation
First stage (cascade) a) gluon fission b)
quark bremsstrahlung c) quark pair creation.
Second stage (hadronization) BD
K.Konishi et.al.NP B157 (1979) A.Giovannini.NP
B161 (1979).
Convolution of two stages
quark fission -gt NBD
ISMD 2006
5
ee- - annihilation
mean multiplicity of gluons on 1st
stage, mean (max possible)
number of hadrons, formed from one quark on the
2nd-stage,
V.Kuvshinov, E.K. (1978)
Results
ISMD 2006
6
ee- - annihilation
Pn
Pn
Pn
91.4 GeV
60 GeV
22 GeV
Pn
Pn
H(q)
133 GeV
161 GeV
161 GeV
Pn in -annihilation at 22 (TASSO),
60 (KEK), 91.4 (DELPHY), 133 and 161 GeV (OPAL)
H(q) at 161 GeV.
E. K. Minsk, NPCS (2002) ISMD32,2002.
ISMD 2006
7
ee- - annihilation

• - maximal (mean)
  multiplicity of hadrons from one gluon while its
  passing through of hadronization is constant -gt
  fragmentation mechanism of hadronization (one to
  one)
• gluon hadronization is softer than quark one

Results
ISMD 2006
8
ee- - annihilation
Second correlative moments
in GDM
at low energies
at high energies
ISMD 2006
9
ppinteractions (gluon dominance model approach)

• 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 free
• Gluons may give cascade
• Some of gluons (not of all) leave Quark-Gluon
  System (QGS) are evaporated and are converted
  to hadrons.

1st stage
2nd stage
ISMD 2006
10
pp interactions
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 in
1975 (S.Pokorski and L. Van Hove). This
assumption was supported by P.
Carruthers (1984).
Results
ISMD 2006
11
pp interactions (two schemes)

• Scheme with the gluon branch in QGS (TSMB)
• 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)
ISMD 2006
12
ppinteractions (convolution gluon hadron MD)

• 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)

ISMD 2006
13
pp interactions (TSMB)
- ratio of evaporated gluons to all active ones
gluon hadronization parameters on second stage
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.
ISMD 2006
14
pp interactions (TSTM)
After evaporation gluons leave QGS and fragment
to hadrons (not taking into account branch
inside QGS). MDPoisson(BD)
M - max number of evaporated gluons is rising
(from 6 to 10), max number of hadrons is limited
by MN ( 24-26 for charged particles at 69
GeV/c).
E.K. Acta Phys.Polon. B35(2004)295
ISMD 2006
15
pp interactions (2nd scheme)
ISMD 2006
16
pp interactions (comparison)
800 GeV/c
800 GeV/c
KNO-function S. Semenov et al. Sov.J.Nucl.Phys.
22 (1975) 792.
NBD MD A.Giovannini. Nucl.Phys. B161
(1979)429.
TSMT -
TSMT
KNO - - - - -
NBD - - - - -

• recombination mechanism of hadronization
• clan as independent intermediate gluon source

Results
ISMD 2006
17
pp interactions (f2)
GF
at low energy at high energy
ISMD 2006
18
pp interactions (neutral)
MD of p0 at 69 Gev/c (
), Limits to max charged, neutral total
multiplicities (26, 16, 42).
Mean multiplicity of p0 versus the number of nch
at n0ltnch

• gluon hadronization parameters for p0
• Centaur (yes, HM region), AntiCentaur (no)
  events
• cluster production

Results
ISMD 2006
19
pp interactions (ISR, 30-60 GeV)
Clan (cluster) superposition consisting from
one, two (or more) gluon fission
62 GeV
Soft ( ) semi-hard ( )
components, and so on.
Results
E.K., Nikitin V. et al. ISHEPP2004.
ISMD 2006
20
pp(nucleus) interactions (h/? ratio)
Au-Au 200 GeV/N, peripheral (60-92).
PHENIX. Nucl.Phys.A757(2005).
GDM
pp
PHENIX
GDM h/? for pp 70 GeV/c
1.19/-0.25 ,,, 800 GeV/c 1.49/-0.33
62 GeV 1.6 ( ).

• the dominance of active gluon plenty in
  nucleus central collisions leads to the new kind
  matter formation QGP
• agreement with h/? ratio

Results
ISMD 2006
21
Soft photons (SP excess)
Measured SP
s(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
ISMD 2006
22
Soft photons (SP excess)
The number of SP is estimated by MVB density ?(T
)n(T)/V

• estimation of SP emission region
• SP excess is the sign of hadronization

Results
M.Volkov,E.K., E.Kuraev. Part.
Nucl. Let., 5 (2004)122
ISMD 2006
23
_
pp annihilation (experiment)
J.Rushbrooke B.Webber. Phys.Rep. C44(1978)1.
32, 100 GeV/c
ISMD 2006
24
_
pp annihilation (GDM)
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
ISMD 2006
25
_
pp annihilation (GDM)
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.
(0)


(2)


(4)




ISMD 2006
26
_
pp annihilation (GDM)
14.75 GeV/c

• intermediate topology superposition
• hadronization predominance at annihilation

Results
ISMD 2006
27
Conclusions (GDM)

• the descripion MD, moments in -ee--, pp-,
  ppbar-interactions
• the evidence of the transition from the
  fragmentation hadronization mechanism in ee- -
  annihilation to the recombination one in hadron
  (nucleus) interactions
• the active role of gluons at MP
• the shoulder structure of MD at higher energies
  as the appearance of independent gluon clusters
  consisting from single gluon and also from two or
  more fission gluons

ISMD 2006
28
Conclusions (GDM)

• h/? ratio (the charged hadrons to p0 ) for pp-
  and peripheral nucleus interactions
• topological cross section differences and f2 in
  ppbar annihilation by the inclusion of
  intermediate quark topology
• the soft photons production as a sign of
  hadronization and estimates the emission region
  size
• Centauro (yes) and AntiCentauro (no) events

ISMD 2006
29
project THERMALIZATION
SVD-2 Collab. Belarus, Czech Republic, Russia,
Slovak Republic, Ukraine
Scientific programme multiparticle dynamics
study in pp(A) interactions with HM (ngt20) at
IHEP U-70.
Micro strip VD, 10000 channels.
C
SVD-2 setup
target
Drift tubes tracker, 2400 channels
Magnetic spectrometer
DeGa
V.V.Avdeichikov et al. JINR-P1-2004-190,
Proposal THERMALIZATION.
30
THERMALIZATION

• Search for new collective phenomena study
• BEC of identical particles (cold spots)
• ring events (Cerenkov-like radiation)
• MD at HM (to separate models)
• measuring of SP cross section

31
THERMALIZATION
Trigger scintillation hodoscope (camomile) for
the registration of rare events with HM
AS nmip, n
10 -20 signal trigger.
20 elements triangle h18, thickness 1.8 mm
Liquid hydrogen target
32
THERMALIZATION
One technical run was conducted (2005) at U-70
accelerator with hydrogen target and HM trigger.
Next scheduled physical run November, 2006.
Data of 2002 run for pA (SI,C.Pb) were studied
preliminary in the HM region (gt20 charged).
event pSi n_ch35
MD
Preliminary
33
THERMALIZATION
It was revealed interesting phenomena the
indication to the grouping of second particles in
certain direction. It is seen well cluster
production which consisted from few charged
(2-4). It is peak in the differences of absolute
value of angle ?? between particles distribution
.
N(??)
event n_ch22
?? (rad)
34
THERMALIZATION
Alignment task of detectors is an essential step
in the track reconstruction. W/o proper alignment
it is impossible to reach the ultimate position
and momentum resolution.
Functional minimization of the residual
functional by means MILLEPEDE (centipede) code
normal equation matrix of LLS
35
THERMALIZATION
Problems large number of parameters. All
alignment parameters (102) and track parameters
(105) are in functional, all are initially
correlated. Nonlinear task comes to linear one.
System of equation for global parameters only.
High accuracy.
What do we want to get (aligned detector)
Misalignment incorrectly known
geometry
36
THERMALIZATION
Solving for global parameters gives ?2 / dof for
114,000 tracks of alignment procedure in
magnetic spectrometer (18 proportional chambers)
6000
22500
Before alignment
After alignment
37
THERMALIZATION
Residual uj (upper, mm) and ?2 (lower).
70000
80000
70000
60000
-5. 0. 5.
-5. 0. 5.

-5. 0. 5.
-5. 0. 5.
45000
4th detector
40000
14th detector
8th detector
20000
11th detector
80000
0. 10.
0. 10.
0. 10.
0. 10.
(109231 events)
(104464 events)
(111479 events)
(109451 events)
Quality check of each detector.
38
THERMALIZATION
Alighnment parameters for silicon VD shifts,
angles, displacement.
Before alignment
After alignment
500 events
39
THERMALIZATION
Reconstruction of tracks at SVD-2 (test)
sequential histogramming Hough methods.
jdetector
u
idetector
uj
H2 - target
ui
z
zv
zi
zj
uv(uj ui )/(zj zi )
40
THERMALIZATION
225
70
zv
zv
nch 10
nch 28
41
THERMALIZATION
Track parameters
nch 10
nch 28
42
THANK YOU