Physics at NICA

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Physics at NICA

• Evidence for deconfinement at SPS RHIC
• Call for the new generation experiments
• Thermal hadron production phase diagram
• Fluctuation signature of the CP
• Femtoscopic signature of the QGP 1-st order PT
  searching for large scales
• Spin physics at NICA
• Conclusions

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Evidence for deconfinement at SPS

• - Strangeness enhancement K/pi horn
• Plateau in ltmTgt in the entire SPS energy range
• J/? suppression
• UrQMD too small tr. flow at top SPS energies ?
  too large femtoscopic radii
• 
  too large
  Rout /Rside

NA49 anomalies in hadron production Horn
sharp maximum in the K/pi or
strangeness-to-entropy ratio in the transition
region Step - plateau in the excitation
function of the apparent temperature or ltmtgt of
hadrons
NA50 anomalous J/y suppression in
central AA
QGP
HG
Mixed phase
Quarkonium suppression by color screening
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Evidence for deconfinement at RHIC

• Large elliptic flow v2/? close to ideal liquid
  value at top RHIC energies
• CQNS of v2
• Jet quenching

Strong high pT suppression in hadron production ?
highly opaque matter for colored probes (not for
photons)
Constituent quark number scaling of elliptic flow
? partonic collectivity in a relativistic quantum
liquid
sQGP matter at RHIC
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Lessons from the 1st generation HI experiments

• Evidence for the onset of deconfinement _at_ low
  SPS
• energies vsNN 7 GeV sQGP matter _at_ RHIC
• 2nd generation HI experiments (STAR, NA61) will
  soon
• continue the exploration of the QCD phase
  diagram
• But, a further research program in studying the
  QCD phase diagram with the existing detectors
  appears to have drawbacks due limitations either
  in accelerator parameters (energy range,
  luminosity) or by constrains in experimental
  setups (acceptance, event rates, etc..)

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Motivation for the next generation of HI
experiments

3nd generation experiment with dedicated
detectors are required for more sensitive and
detailed study
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2nd generation HI experiments
STAR/PHENIX _at_ BNL/RHIC. Originally designed
for higher energies (?sNN gt 20 GeV), low
luminosity for LES program Llt1026 cm-2s-1 for
Au79, too few energies.
NA61 _at_ CERN/SPS. Fixed target, non-uniform accepta
nce, few energies (10,20,30,40,80,160A GeV), poor
nomenclature of beam species
3nd generation HI experiments
CBM _at_ FAIR/SIS-100/300 Fixed target, E/A10-40
GeV, high luminosity, But, max. energies in 2018!
MPD _at_ JINR/NICA. Collider, small enough energy
steps in the range ?sNN 4-11 GeV, a variety of
colliding systems, L1027 cm-2s-1 for Au79 at 9
GeV.
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Why the NICA and FAIR energy range is so important

• The energies of the NICA and FAIR sit right on
  top of the region where the baryon density at the
  freeze-out is expected to be the highest. It will
  thus allow to analyze the highest baryonic
  density under laboratory conditions.
• Also, in this energy range the system occupies a
  maximal space-time volume in the mixed
  quark-hadron phase (the phase of coexistence of
  hadron and quark-qluon matter similar to the
  water-vapor coexistence-phase).

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FREEZE-OUT AND PHASE DIAGRAMS
Critical end-point
1st order PT
Ivanov, Russkikh,Toneev 06
At lower energies the system spents an essential
time in the mixed phase
Randrup, Cleymans 06

• NICAFAIR
• ?sNN 9 AGeV

The freeze-out baryon density is maximal at
?sNN (44) GeV covered by NICA and FAIR
?SNN 4-11 GeV is a most promising energy region
to search for mixed phase critical end-point
Besides NICA FAIR also RHIC SPS plan to
partly cover this energy range

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NICA complex
Booster 2.109 ions/bunch E/A 608
MeV Q32, electron cooling
The MultiPurpose Detector is proposed for study
of hot and dense baryonic matter in collisions of
heavy ions over mass range A1-197 at a
centre-of-mass energy vsNN 4-11 GeV.
MPD
SPD
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Thermal Model
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if added heavy resonances (motivated by ee-) ?
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!
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Lattice says crossover at µ 0 but CP location
is not clear CP T 170 MeV, µ B gt 200 MeV
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QCD phase diagram

• The most intriguing and little studied
• region of the QCD phase diagram
• Characterized by the highest net
• baryon density
• Allows to study in great detail
• properties of the phase transition
• region
• Has strong discovery potential in
• searching for the Critical End Point
• and manifestation of Chiral
• Symmetry Restoration
• Recently became very attractive
• for heavy-ion community
• RHIC/BNL, SPS/CERN,
• FAIR/GSI, NICA/JINR

Deconfined matter (high e,T,nB) e gt1 GeV/fm3,
Tgt150 MeV, nBgt(3-5)n0
Challenge comprehensive experimental program
requires scan over the QCD phase diagram by
varying collision parameters system size, beam
energy and collision centrality
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CP
?
______
_________
___
?
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CP signals in multiplicity and pt fluctuations
for ? 3 and 6 fm
assuming CP at T162 MeV
µB360 MeV Gaussian fluctuation shape with
the width of 10 MeV in T
30 MeV in µB
? D(N)/N
?pt (D(?pti)/N)1/2-(D(pt))1/2
?pt ? 40 (10) MeV/c for ? 6 (3) fm ? 10
(2.5) for NA49 acc. 0.24 M. Stephanov .. 99
B. Berdnikov .. 00 ? lt3 fm due to finite
fireball lifetime ? lt 2 (.5) MeV if max
partonic energy fraction 20 as expected in
PHSD
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Cassing Bratkovskaya Parton-Hadron-String-Dynam
ics
Perspectives at FAIR/NICA energies
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Elliptic flow energy dependence points to the
increasing fraction of partonic matter with
increasing energy a saturation on the ideal
liquid level at the top RHIC energy
v2 for midrapidity 25 most central collisions
v2/e vs particle density in the transverse plane
AGS
RHIC
IDEAL
SPS
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Femtoscopic signature of QGP
3D 1-fluid Hydrodynamics
Initial energy density ?0

• Long-standing signature of QGP
• increase in ??, ROUT/RSIDE due to the Phase
  transition
• hoped-for turn on as QGP threshold in ?0 is
  reached
• ?? decreases with decreasing Latent heat
  increasing tr. Flow
• 
  (high ?0 or initial tr.
  Flow)

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Femto-puzzle I Small space-time scales at RHIC
energies basically solved due to the initial
flow
Femto-puzzle II No signal of a bump in Rout near
the QGP threshold (expected at AGS-SPS
energies) !? likely solved due to a decrease of
partonic phase at these energies
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Radii vs fraction ?1 of the large scale very
weak sensitivity
r
? solving Femtoscopy Puzzle II
r1
Input ?1, ?21-?1, r115, r25 fm 1-G Fit r , ?
2-G Fit ?1, ?2, r1,r2
r2
?
?2
?1
?1
?1
Typical stat. errors
in 1-G (3d) fit
? (r1)/0.06 fm
e.g., NA49 central PbPb 158 AGeV Y0-05,
pt0.25 GeV/c Rout5.29.08.42 Rside4.66.06.14
Rlong5.19.08.24 ?0.52.01.09
? (?1)/0.01
?1
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Imaging
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Other physics at NICA. Study of
density fluctuations in AA collisions

• High nucleon density region inside a nuclei due
  to density fluctuations (fluctons)
• D.Blokhintsev, GETF 6, 995 (1958), A.M.
  Baldin et al. Sov. J. Nucl.Phys. 18, 79 (1973)
• Flucton-flucton (nucleon-flucton) interactions
  in low-A nuclei collisions
• triggered by a midrapidity high-pt product
  (p,g)

Study of the properties of dense medium

• Baryon clusterization in momentum space and
  emision time (femtoscopy)
• Strangeness and resonace production
• Exotic strange multibaryon states with L,p,p,K0

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Spin physics _at_ NICA. Protonss spin
Main quest what is the distribution of nucleon
spin among constituents? How quarks and gluons
carry spin and orbital angular momentum?
½ ½?? ?G Lq Lg
Recent data (CERN, DESY, JLAB, SLAC)
?? ? 0.3
quark contribution
gluon contribution
?G lt 0.3
Lq, Lg angular orbital momentum contributions
(unknown)
DG is less then speculated ? missing spin
contribution (spin crisis continues)
New (precise) measurements of many (new) PDFs
(Parton Distribution Functions) required
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Spin physics _at_ NICA (2)

• NICA advantages
• Beams p,d(h), L 1032 cm-2s-1
• Polarization transversal and longitudinal ( gt
  50)
• Collision energy up to vs 25 GeV

• Spin physics program with polarized beams
  at NICA
• Comprehensive studies of DY and J/Y production
  processes
• (polarized and unpolarized)
• Spin effects in one and two hadron production
  processes
• Spectroscopy of quarkonia and diffractive
  processes

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Spin physics _at_ NICA (3)
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Spin physics _at_ NICA polarized MMT-DY
The SSA for 100k DY events 3 years of running

• sin(??S)
• access to transversity
• Boer-Mulders PDFs Sissakian,
  Shevchenko, Nagaytsev,
• PRD 72 (2005), EPJ C46 (2006)
• sin(?-?S)
• access to Sivers PDFs
• Efremov, PLB 612(2005), PRD 73(2006)

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Experiments on MMT-DY measurements
Experiment Status Remarks
E615 Finished Only unpolarized MMT-DY
NA10 Finished Only unpolarized MMT-DY
E886 Running Only unpolarized MMT-DY
RHIC Running Detector upgrade for MMT-DY measurements (collider)
PAX Plan gt 2016 Problem with polarization (collider)
COMPASS Plan gt 2010 Only valence PDFs
J-PARC Plan gt 2011 low s (60-100 GeV2), only unpolarized proton beam
SPASCHARM NICA Plan? Plan gt 2015 s 140 GeV2 for unpolarized proton beam s 670 GeV2 for polarized proton beams, high luminosity (collider)

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Conclusions I

• FO points calculated within Thermal Model seem to
  be close to QGP phase boundary for small µB lt 400
  MeV (vs NN gt 10 GeV)
• Absence of fluctuation signal of CP and 1-st
  order PT at
• µB gt 400 MeV (vs NN lt 10 GeV) is likely due
  to a dramatic decrease of partonic phase with
  decreasing energy
• This decrease solves also the Femtoscopic Puzzle
  II Absence of clear Rout bump signal near the
  QGP threshold (expected at AGS-SPS energies)
• Search for the effects of QGP 1-st order PT
  (threshold and CP) can be successful only in
  dedicated high statistics and precise experiments
  like NICA and FAIR
• Good prospects for spin physics research at NICA

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Conclusions II

• The strategic plans of JINR in HEP is targeting
  to
• the development of home accelerator facility
• corresponding scientific program
• NICA /MPD /SPD project provides good
  opportunity for the frontier experimental
  researches at JINR in the forthcoming decade
• New laboratory - LHEP was founded (May 4, 2008)
  to concentrate efforts for realization of these
  plans

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Last year we have celebrated the 90th Anniversary
of the birth of one of the Femtoscopy fathers
Mikhail Isaakovich Podgoretsky (22.04.1919-19.04.
1995) This year, it is just 20 years from his
first visit in Nantes, participating at
CORINNE90 and in fact stimulating our GDRE
collaboration
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Welcome to the collaboration!
Thank you for attention!
April 2, 2008
A.N.Sissakian, A.S.Sorin
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Spare Slides
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Cassing Bratkovskaya
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?, ??, Flow Radii x-out, y-side, z-long
BW Retiere_at_LBL05
pion
0.73c
0.91c
? Emission points at a given tr. velocity
px 0.15 GeV/c
0.3 GeV/c
Rz2? ??2? (T/mt)
Ry2 ?y2?
Kaon
Rx2 ?x2?-2vx?xt?vx2?t2?
?t2? ? ?(?-???)2? ? (??)2
px 0.53 GeV/c
1.07 GeV/c
For a Gaussian density profile with a radius RG
and linear flow velocity profile ?F (r) ?0 r/
RG
Proton
Ry2 RG2 / 1 ?02 mt /T
px 1.01 GeV/c
2.02 GeV/c
Rz ? ??? evolution time Rx ? ??
emission duration
Rx , Ry ? ?0 tr. flow velocity ptspectra
? T temperature
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