Physique du charme ouvert dans CBM à FAIR

Transcription

Open charm physics with the CBM experiment
Sélim SEDDIKI
22/09/2010
Rencontres QGP France 2010, Etretat 20-23 Septembre 2010
1
Outlook
• Brief overview of the FAIR facility
• The CBM physics program at high net baryon density
• The open charm physics at FAIR energy regime
• The CBM set-up: focus on the Micro-Vertex Detector (MVD)
• Requirements for the MVD
• Brief overview of the R&D on MVD sensors and integration
• Feasibility study of open charm reconstruction
• Open charm elliptic flow study
22/09/2010
Rencontres QGP France 2010,
Etretat 20-23 Septembre 2010
2
Facility for Antiproton and Ion Research (FAIR)
Unilac
L ~ 1km
CBM:
FAIR
100 m
• One of the major experiments
planned at FAIR
• Fixed target experiment
• Measure A-A coll.
(also p-A, p-p)
• FAIR: extension of GSI to provide the worldwide highest intensity heavy ion beams:
up to 109 Ions/s
• Two synchrotrons: SIS100: HI up to 11 A GeV (protons up to 30 GeV), expected for 2017
SIS300: HI up to 45 A GeV (Protons up to 90 GeV), expected for ~ 2019
22/09/2010
• FAIR energy regime → very
Etretat
20-23 Septembre
2010
high
net baryon
densities
3
High net baryon density regime at FAIR
Compilation by J. Randrup (CBM Physics Book, in preparation)
see also I.C. Arsene et al., Phys. Rev. C 75 (2007) 034902
4
Transport models:
 predict bulk data of AGS and SPS at FAIR energy regime
 coincide to predict ρB up to ~ 10ρ0 in central Au-Au coll. at Ebeam = 20 A GeV
22/09/2010
4
CBM physics program
CBM aims to explore the high net baryon density region
of the nuclear matter phase diagram
• Onset of deconfinement phase transition at high ρB (expected to be of 1st order)
• QCD critical point
 Predicted by LQCD (large uncertainties)
• In-medium modification of hadron properties at high ρB
 Chiral symmetry restoration
22/09/2010
State of the matter in the coreRencontres
of dense QGP
and cold
neutron
France
2010, stars (EoS at high ρB)
Septembre
 Complementary to RHIC andEtretat
LHC 20-23
program
at high2010
T and low ρB
5
Experimental exploration in the high ρB region
• Other high ρB physics programs (on-going and planned):
SPS (NA49, NA61) and RHIC low energy program (STAR, PHENIX), NICA(MPD)
→ only bulk observables measured in HI coll.
• Interaction rate x time = N(D+) / (Multi(D+) x BR x εreco)
Multi(D+) = 10-4 / central Au-Au coll @ 25 A GeV (HSD)
Assume: εreco = 1%, BR ~ 0.1
Goal: N(D+) > 104 / year → Interaction rate x time > 1012 coll. / year
• High interaction rate foreseen by CBM: ≤ 10 MHz
Also: beam availability at FAIR ~ 4 months (2 month 50% duty cycle)
→ Interaction rate x time ≤ 5 1013 coll. / year
→ rare probes accessible for the 1st time at FAIR energies, in particular charmed part.
22/09/2010
6
Charm is a penetrating probe of the dense early stage
Initial stage
High density phase
"freeze-out"
cc quarks produced within few 0.1 fm / c (~ 1 / mc) after the collision
→ Charmed particles are probes of the early dense phase of the collision
22/09/2010
7
Charm is a very sensitive probe of the chiral symmetry restoration
HSD model (Cassing et al, NPA691(2001)753)
• Idea: the chiral symmetry restoration decreases the open charm production threshold
• FAIR energies in the range of charm production threshold
→ Open charm production very sensitive to in-medium effects
• Analogy: SIS18 energies in the range of strangeness production threshold
22/09/2010
8
Probe of the chiral symmetry restoration
- Open charm yield HSD model (Cassing et al, NPA691(2001)753)
Au+Au, 25 A GeV, central
__
-1
-2
(2mT) dN/dmT [GeV ]
-2
10
D+D
-4
10
-6
HSD
10
-8
bare
in-medium
DmD(r)= - 50 (MeV) r/r0
10
2.0
2.5
3.0
3.5
mT [GeV]
• Increase of about 1 order of magnitude of D-meson production rate
in the dense nuclear medium created in central Au(25A.GeV)-Au (HSD)
• Measure : p-p, p-A, A-A → D+, D-, D0, D0, Ds0, Ds0, (Λc)
22/09/2010
9
Probe of the chiral symmetry restoration
- Hidden charm ratio (and open charm yield) Xingbo Zhao and Ralf Rapp
M [MeV] (in the vacuum)
D+D-
3738
ψ'
3686
J/ψ
3097
D-meson production
threshold reduced
in the dense nuclear
medium
• New absorption mechanism in dense nuclear medium ψ'→D+D- at FAIR energies
• Measure : p-p, p-A, A-A → ψ' - J/ψ ratio, D+ D-
22/09/2010
10
Probe of the partonic phase
- Charmed particle yield O. Linnyk, E.L. Bratkovskaya, W. Cassing,
H. Stöcker, Nucl.Phys.A786:183-200,2007
A. Andronic, P. Braun-Munzinger,
K. Redlich, J. Stachel, arXiv:0708.1488
FAIR
Hadronic model (HSD)
p+n → p+ΛC
sthr= 5.1 GeV
p+p → p+p+J/ψ, sthr= 5.0 GeV
p+p → p+p+D++D-, sthr= 5.6 GeV
+D-,
Statistical hadronization model (SHM)
c-cbar production in partonic phase
p+p → p+p + cc-bar, sthr= 4.5 GeV
About 1 order of magnitude more charmed particles
produced at FAIR energies if a QGP is created
22/09/2010
11
- Hidden / open charm ratio [HSD: O. Linnyk et al., Int.J.Mod.Phys.E17, 1367 (2008)]
[SHM: A. Andronic et al., Phys. Lett. B 659 (2008) 149]
• If a QGP is formed, possible recombination cc states (charmonium) → D mesons
 Idea: J/ψ suppression in the QGP by color Debye screening
• About 1 order of magnitude smaller J/ψ - D D ratio at FAIR energy √s = 7-8 A.GeV
if a QGP is created
22/09/2010
• Measure: p-p, p-A, A-A →
Etretat
20-23 Septembre 2010
J/ψ,
all D-mesons
12
- Open charm elliptic flow arXiv:nucl-ex/0610029v3
Physics Letters B 595 (2004) 202–208
Thermal + flow
c-quark spectra at Tc
pQCD c-quark
distributions
• The valence quark number scaling of the elliptic flow at RHIC energies
is one of the strong indications for the formation of a QGP
→ Search for the disappearance of this scaling at FAIR energies
• From coalescence model (at RHIC energy), a sizeable magnitude of the
open charm v2 requires flow development in the partonic phase
22/09/2010
13
The CBM projected set-up
PSD
Beam on target
• Online
tracking, p determination, and vertexing :
→ Fast and rad. hard pixel/strip detectors (STS + MVD)
in a magnetic dipole field
• Hadron ID: TOF (& RICH)
22/09/2010
• photons, π0, η: ECAL
• electron ID: RICH & TRD
• Event characterization:
STS QGP
& PSD
Rencontres
France 2010,
14
The Micro-Vertex Detector (MVD) of CBM
PSD
Micro-Vertex Detector
Aim: Reconstruction of open charm via its
weak decay into charged hadrons
Strategy: Identify its decay vertex
22/09/2010
15
MVD detector 1
detector2
Target
(Gold)‫‏‬
UrQMD + Geant
Au(25AGeV)-Au
Beam: 25 AGeV Au Ions (up to 109/s)
Primary
vertex
Decay vertex
D+: short lived
• cτ ~ 320 μm
22/09/2010
• γ ~ 3 – 4 (β ~ 0.9)
~ 1000 part./coll
Requirements:
High precision of secondary decay vertex measurement (< 100 μm)
→ Light Material budget (< 0.3%X0)
→ Excellent spatial resolution (ζsp ~ 5μm)
→ Vacuum operation:
 Sensor cooling in vacuum
 Cabling in vacuum
16
22/09/2010
UrQMD + Geant
Au(25A.GeV)-Au
Beam on target
~ 1000 part./coll
Requirements:
• M(D+) ~ 10-4 – Au-Au central coll. @ 25 A.GeV
• ~10-100 kHz interaction rate to have > 104 D+/year
→ High frame R/O speed ~ 10 μs
• part. flux > 106-7 part./s in the detector acceptance
→ Radiation hardness > 1014 neq/cm2
22/09/2010
17
Monolithic Active Pixel Sensors (MAPS) for the MVD
Up to date
Pixel sensor technology:
~ 1013/cm2/year
> 1014/cm2/year
10 μs
Goal
~ 1014/cm2/year
~ 100 μs
Inapppropriate for CBM
Best compromise
σsp ↔ MB ↔ rad. tol.
Particle trajectory
MAPS working principle
Preamplifier
(one per pixel)
< 20µm
Diffusing electrons
On-going R&D program at IPHC-Strasbourg
→ to improve the radiation tolerance and speed of MAPS sensors
→ for several applications (CBM, STAR, ILC)
22/09/2010
18
Sensor integration for the CBM-MVD
Requirements:
• Mechanical stability (few μm precision)
• Low mass ladder (few 0.1%X0)
• Cooling of sensors in vacuum
→ low thermal nose sensors
• High speed DAQ system:
 MVD data flow > 10 GBytes / s
(also slow ctrl, bias of sensors)
IKF - Frankfurt
Aux. board with flex. finger
2 sensors
TPG:1500W/mK
RVC: light & stiff
TPG
RVC
TPG
FPC
Support
Cu heat sink
Cooling
pipes
Integration on a cooling support
→22/09/2010
Cool 1W/cm² …in vacuum
… with < 0.2 % X0
Heat sink
19
Open charm reconstruction study: result
D+ secondary vertex
resolution ~ 80μm
M = 1.2 10-4
~ 2.7%
~ 35 000 D+ after 1012 coll (1 year)
ZRECO - ZMC
• Realistic detector geometry and response
 MAPS thickness = 150μm
 MAPS spatial resolution: ζsp = 3μm
• Topological cuts: track impact parameter, vertex position, chi2
• Normalisation to account for the signal multiplicity:
 M(D+) = 1.2 10-4 for Au(25AGeV)-Au
 1012 collisions performed during 1 CBM running year (~ 2 months of beam on target)
• Preliminary study: no pile-up in the MVD, no δ-electron, (no fake hits)
• Preliminary conclusion:
22/09/2010
→ ~ few 104 D+ expected after 1Etretat
year20-23
(~ same
for D02010
)
Septembre
20
Reconstruction of the reaction plane
- Experimental set-up -
PSD
Silicon Tracking System (STS)
Projectile Spectator Detector (PSD)
CBM-PSD-note-2006-001
Heuser, ULISI, Feb 2010
2 independent sub-detectors
to measure the event plane
↔
cross-check of several
estimates of v2!
Z
1st
22/09/2010
Station (out of 8)
21
- Impact parameter (b) dependance of the event plane resolution -
•
•
•
•
UrQMD (event generation) & GEANT (transport)
Use of the event plane method: Poskanzer and S. Voloshin, arXiv:nucl-ex/9805001
v2 = v2reco / <cos(2 x ΦR - Φtrue)>
Evaluate the event plane ΦR with directed (1st harmonic) and elliptic flow (2nd harmonic)
Close to 1
↔
good RP resolution
PHENIX
Toward central coll.
→ low initial eccentricity ↔ low anisotropy in P devpt
→ for PSD: low acceptance
Toward peripheral coll.
→ low energy density (low P devpt)
→ for STS: low acceptance
v2 reconstruction for D-Mesons
- Differential v2(pT) • We assume 50K reconstructed D-mesons (D+, D-, D0, D0bar, etc) (~ one month of data taking)
• Thermal model + simulated anisotropy with v2 = a x PT
• A reaction plane resolution of 40 degrees (<2cos(ΔΦRP> ~ 0.4)
• Method: fit of the dN/dΦ distribution
• v2corr = v2reco / Corr, Corr = <2cos(ΔΦRP)>
• Two scenarii: strong and moderate v2 → can be distinguished within statistical errors
Strong charm elliptic flow
v2 = 15% pT
22/09/2010
Moderate charm elliptic flow
v2 = 5% pT
23
Summary
• CBM will explore the phase diagram of nuclear matter at high baryon net density
• It will measure rare, penetrating probes, as open charm, to search for the onset of
deconfinement phase transition and the chiral symmetry restoration
• Open charm particles will be measured using a Micro-Vertex Detector
• The extreme interaction rate of HI coll. leads to severe requirements for CBM detector,
and in particular the MVD, in terms of: R/O Speed, radiation hardness, precision
(measure of short lived open charm particles)
• The MAPS are nowadays the most promising technological choice in terms of precision
It is already close to satisfy CBM requirements in terms of radiation hardness and R/O speed
• The integration of MAPS sensors is also very challenging: high mechanical stability,
cooling / cabling of the sensors in the vacuum, extremely fast data acquisition system
and open charm trigger decision
• Realistic detector simulations → evaluation of performances for open charm physics
• Final MVD design in 2012 (TDR)
22/09/2010
24
Backup slides
22/09/2010
25
The Facility for Antiproton and Ion Research (FAIR)‫‏‬
FAIR project :
high intensity beam synchrotron SIS100/300 (GSI-Darmstadt)
Existing facility : ion beam source and injector
Futur facility : high intensity ion and anti-matter beam
for #experiments
HESR : ~ 1011 anti-protons (14 GeV) / s
HADES
PANDA :
Hadron strucure and dynamics
Quark confinement potential
Pulsed HI beam + PetaWatt laser
APPA :
Physic of dense plasma
Nuclear fusion in star
Super-FRS : < 109 rare isotopes (1 AGeV) / s
Also atomic physic application in radiobiology, etc
22/09/2010
NUSTAR :
Exotic nuclei (far off stability)
Nucleosynthesis in star
26
and supernovae
High net baryon density regime at FAIR
J. Randrup and J. Cleymans, hep-ph/0607065
ε* = ε - mNρ
• RHIC data  max ρB at Ebeam = 20 – 30 A.GeV
CBM: a rare probe experiment
Particle multiplicity x branching ratio
Au+Au collisions at 25 A GeV (HSD)
SPS Pb+Pb 30 A.GeV
CBM Au+Au 25 A.GeV
Need to measure reference systems:
 p-p (elementary cross-section)
 p-N (particle production & propagation in cold nuclear matter: ρB = ρ0 )
22/09/2010
28
Signatures for phase transitions at SPS ?
Experimental data exhibit structures in excitation
functions of observables at low SPS energies:
inverse slope parameter
[NA49, PRC 77, 024903 (2008)]
 limiting freeze-out temperature
 step in collective flow
maximum in the strangeness/entropy ratio
 Enhancement dynamical event-by-event fluctuations
A. Andronic et al.,
Phys. Lett. B 673 (2009).
In Pb-Pb: predicted by
statistical model assuming
Phase transition,
not by hadronic model
A. Andronic et al.,
B. Nucl. Phys. A 772, 167 (2006).
29
QCD critical point
LQCD calculations
Fodor & Katz, hep-lat/0402006
 At low B  smooth transition
(cross over)
 At high B  1st order transition
 Critical point: endpoint of the 1st order
transition line
 Large uncertainties on the position of
this point ( number of quark flavours
and mq used in the calculations)
 Predictions  µB : 200 to 1000 MeV
22/09/2010
30
QCD Critical Point
W. Henning, APS Division of Nuclear Physics (Town Meeting, 2007)
RM
NJL/inst
CJT
LSM
2
NJL
NJL/I
9.3 GeV
Observable : event-by-event fluctuations (<pt>, M, K/)
Strong enhancement near the critical point
22/09/2010
CBM 
Detailed excitation functions (small steps)
in theRencontres
FAIR energy
region
QGP France
2010,
31
Open charm elliptic flow at FAIR if no QGP
22/09/2010
32
22/09/2010
33
Charmonium suppression at FAIR energies
Xingbo Zhao,
Ralf Rapp
new NA60 data: 158 GeV p+A
E. Scomparin, QM2009
abs
abs
J/
J/
(158 GeV) = 7.6 ± 0.7 ± 0.6 mb
(400 GeV) = 4.3 ± 0.8 ± 0.6 mb
Measure excitation function of RAA,
i.e.22/09/2010
p+p → J/ψ+X, Rencontres
p+A →
QGPJ/ψ+X,
France 2010, A+A → J/ψ+X
34
RD on sensors
22/09/2010
35
R&D on MAPS sensors
Toward a R/O speed ~ few 10μs:
• Column parallel R/O
→ reduce #pixels read
sequentially per R/O cycle
• Full binary information
→ only “fired” and inactive pixels
• Zero suppression
Mimosa26
MAPS sensor
1152 discriminators
Zero suppression
On-chip functionalities validated with Mimosa26:
low noise, 99.5% detection efficiency, ~ 10-4 fake hit rate
R/O speed down to ~ 80 μs → can be improved by: (on the short terms)
• reducing #lines in pixel array (increase #sensors to be used)
• increasing CLK frequency of on-chip electronics
R&D on MAPS sensors (2)
Mimosa26
Toward a NI radiation hardness > 1014/cm2/year
• Decrease size of pixel
bulk damage in the epitaxial layer creates recombination centre for signal e→ reduce mean path between generation point and collection diode
• Depleted sensor
In undepleted sensors, the signal e- diffuse thermally to the collection diode
→ in depleted sensor, the signal e- collection is fasten by the E in the space charge region
Test on depleted Mimosa25 sensors demonstrated 3 1013 neq/cm2
13 n /cm2
Test
on
depleted
Mimosa26
sensors
demonstrated
10
eq
22/09/2010
20-23 Septembre
-> reasonnable projectionEtretat
for 2017:
1014 neq2010
/cm2
37
Radiation tolerance for # pixel pitch
Data taken with T = -20 degrees and CLK = 2.5 MHz
22/09/2010
38
Fake hit rates of irradiated MAPS (MIMOSA-18 and -19)
D. Doering, M. Domachowski
22/09/2010
-4 seems realistic
A fake hit rate
below
10
39
22/09/2010
40
3D technology
22/09/2010
41
22/09/2010
42
Hybrid pixels
22/09/2010
43
demonstrator
22/09/2010
44
Sensor integration for the CBM-MVD (2)
S. Amar-Youcef
Construction
Shadow of trigger scintillator
Beamtest @ CERN-SPS
(Nov 2009)
Achievements:
System design validated
Good noise: 21 e- ENC
22/09/2010
Spatial res.: < 6µm
signal
(a.u.)
M. Deveaux, 15th CBM collaboration
meeting
, 14th April 2010, GSI
MVD demonstrator project: R/O chain
Trb + Add-on board
2x
Sensors
LVDS analogue
output
LVTTL sync.
signals
Demo-aux
Anal. buffer
Clock distr.
JTAG for slow clt
On-chip for the
final design
Add-on board
Trb board
CDS
Interface to
Network TrbNET
(future)
zero-suppression
Transfert to PC
ADC
Low-V regulated
power supply
FPGA
Development platform
for data sparsification
22/09/2010
FEE
46
The MIMOSA-20 sensor
Mimosa20 wafer
ADC + CDS
sub1
2
22/09/2010
ADC + CDS
3
4
5
Data flow
Add-on
board
• The MIMOSA-20 pixel matrix
is separated in 2 banks
• Each bank is divided into 5
multiplexed sub-frames
47
Major processing steps of the zero-suppression
VHDL design and simulation software: Xilinx
Demultiplexing
Mod1
Input data flow
Mod2
Mod3
Mod4 Mod5
String:
Group of neighbouring
pixels with Q > Threshold
Buffers + multiplexer
Output
Buffer
strings
Output data flow
22/09/2010
48
Nitrogen liquid:
Melting at -210 degrees
22/09/2010
49
22/09/2010
51
DAQ and final MVD design
22/09/2010
52
Sensor expected performances
R&D roadmap for MAPS development on speed and rad. Tolerance
(Shown on CBM collaboration meeting …. )
A merger ds slide precedant
We assume the final sensor
data rate capability
22/09/2010
53
22/09/2010
55
22/09/2010
Up to 54 bits / line / bank
56
22/09/2010
57
Occupancy for the station at 5 cm from the target
Hits/coll./mm² at 5 cm
from the target
Au(25AGeV)-Au coll.
20 MimoSIS-1 sensors
to cover the CBM acceptance
S. Amar
~ 1 cm
~ 6 cm
16
Hot spots caused by δ-electrons
knocked out from the target
• Simulation of occupancies at current MVD positions in open charm reconstruction
feasibility studies (CBMroot / UrQMD / Geant) for Au(25AGeV)-Au mbias coll.
• Inclusion of δ-electrons produced in the target (1% interaction)
• The hits from δ-electrons dominate the occupancies close to the target
• These occupancies per pixel per frame may reach few 1 % (10µs integration time)
22/09/2010
60
Data flow estimation for the station at 5cm from the target
Compressed data rate [Mbytes / s]
55
760
95
170
240
275
105
365
540
1040
675
565
550 970
55
55
175
240
1080
Raw binary data rate
~ 140 Gbytes/s
155
705
845
980
~ 5.5 Gbytes / s to be handle by
the FEE for the station at 5 cm
Including:
• fake hits rate = 10-4
• and overheads
280
55
Preliminary design:
7 cables + 5 multiplexers (+ fast control logic) to drive the signal out of the vacuum
22/09/2010
61
Data flow at several distances from the target
MVD stations at 5 and 10 cm in current open charm reconstruction feasibility studies
On-FEE
line w/o hit suppression?
On-chip
fake hit suppression?
22/09/2010
62
MVD DAQ concept at the FEE level
FEE
CAVE
VACUUM
x3
5.5 Gbytes / s (5 cm)‫‏‬
6.5 Gbytes / s (10 cm)‫‏‬
11.5 Gbytes / s (15 cm)‫‏‬
10Gbit Ethernet protocol
with twisted pair copper cables
>20 Gbytes / s to deliver throught the network (~10m)‫‏‬
in case 3 stations at 5-10-15cm for the final MVD
For start signal & tracking request
22/09/2010
63
CBM physic and experiment
22/09/2010
64
Acceptance
Au+Au @ 25AGeV, GEANT, B=1T
Geometrical acceptance
86%
64%
incl. decay
70%
incl. decay
20%
 e+e+
40%
 K-++
22/09/2010
RencontresYcm
QGP France 2010,
65
Yp ~ 4
Mass Modification of D-meson in Hot Hadronic Matter
Mishra et al, PRC 69, 015202 (2004
D meson masses are expected to drop in dense matter
22/09/2010
66
+ and D- mesons 67
22/09/2010 collective flow
Rencontres
QGP
France
2010,
Measure
(v
,
v
)
of
D
1
2
Deconfinement of the nuclear matter (naive picture!)
At high T / μB the hadrons overlap
Hadrons
creation
Stopping
power
The high color charge density between 2
quarks screens them from each other
• No bound state of quarks possible
• They move freely in the medium and
form a Quark Gluon PlasmaRencontres QGP France 2010,
22/09/2010
68
Chiral transition of the nuclear matter (naive picture!)‫‏‬
QCD vacuum
hadron
non-perturbative interaction
q-q condensate
Confined quarks have effective constituent masses (~ 300 MeV/c2 for u, d and s quarks)
At high T / μB, the bare mass of light quarks should be restored (~ 5 / 100 MeV/c2 for u, d / s quark
Approximate
chiral symmetry restoration of the QCD lagrangian
22/09/2010
Approximate
The Higgs mechanism dominates for the heavy quarks (c and above)‫‏‬
69
22/09/2010
70
Elementary cross section of charm at threshold (SIS100)
Only few measure of elementary σJ/ψ‫‏‬at low E!
pC →‫‏‬D+ + X
D+ →‫‏‬π+ π+ K-
UrQMD+Geant
Elab = 30 GeV/c
pC →‫‏‬J/ψ‫‏‬+‫‏‬X
J/ψ‫‏→‏‬μ+ μFAIR
Measure
22/09/2010
: p-N →‫‏‬D,‫‏‬J/ψ,‫‏‬ψ'‫‏‬+‫‏‬X
71
Simulation
22/09/2010
72
UrQMD+Fluka
Energy density [Rad/year] 107 coll/s
5cm
Neutron fluence [neq/cm2/year] 107 coll/s
22/09/2010
73
22/09/2010
74
22/09/2010
75
22/09/2010
76
Open charm reconstruction study: results
Systematic studies for different spatial resolution and thickness of the MAPS
Need MAPS performances to measure open charm decay with great accuracy
22/09/2010
77
CBM - TOF
22/09/2010
78
Elliptic flow
22/09/2010
79
22/09/2010
80
22/09/2010
81
Signatures for partonic collectivity at RHIC
Senger, Trento, May 2009
 Large elliptic flow
 elliptic flow scales with number of participant quarks
 suppression of high momentum hadrons (jet quenching)
CBM peut faire ->
Measure
excitation function
of v2 France
versus
p for φ, Ω, D, and J/ψ.
22/09/2010
Rencontres QGP
2010, T
82
Etretat
20-23
Septembre
2010
Search for the disappearence of const. quark number scaling
Squeeze-out at low energy
22/09/2010
83
v2/ε: Data from SPS and RHIC
Hydrodynamical evolution at RHIC energy regim square(s) ~ 200 GeV
22/09/2010
84
PSD centered at X=8.9
(0-10)%
neutrons
protons
(10-20)%
2.5 – 7.5
330 (4-8fm) 680 (8-12fm)
7.5 – 12.5
520 (1040
12.5 – 17.5
540 (1040
17.5 – 22.5
410 (710
22.5 – 27.5
260 (340
22/09/2010
85
- Detector acceptance -
PSD
Silicon Tracking System (STS)
pT [GeV/c]
YCM (normalised to Yprojectile)
22/09/2010
Projectile Spectator
Detector (PSD)
YCM (normalised to Yprojectile)
STS → mid-Y / forward-Y coverage → n = 2 and 1
PSD → forward-Y coverage → n = 1
86
22/09/2010
87
v2 reconstruction for D+
- Statistical errors- on integrated v2 -
Current expectation
• We consider a sample of 10K reconstructed D+ mesons (~ one month of data taking)
• Simulated anisotropy with v2 = a x PT
• ΔΦRP ~ Gaus(0, ζRP)
• Method: fit of the dN/dΦ distribution
• v2corrbin = v2recobin/Corr, Corr = <2cos(ΔΦRP)>event
• A quite good accuracy on the integrated v2 is obtained, even fore moderate v2 magnitude
22/09/2010
88
22/09/2010
89
Interaction rate
SPS
RHIC
NICA
FAIR
~ 100 Hz
< 100 Hz
≤ 10 kHz
≤ 10 MHz
Few units
<1
Few hundreds
Few 105
<1
Few dozens
Few 104
@ √s < 10 A GeV
D+ Statistics / year
J/Ψ Statistics / year
22/09/2010
<1
90

Physique du charme ouvert dans CBM à FAIR

Transcription

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