1/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Quarkonium production inAA collisions with CMS
International Workshop on Heavy Quarkonium – 2006BNL, Jun 27th 2006David d'Enterria
➢ Physics: Color screening (QGP), low-x QCD (CGC) at LHC➢ Experimental setup: CMS muon system (J/ψ,ϒμμ)➢ AA @ 5.5 TeV simulation studies: µ ident., QQbar reco. ➢ Results: efficiencies, J/ψ,ϒ mass resolutions, S/B, rates➢ Summary
CERN, Geneva
2/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Quarkonia: probe of high-density QCD media
➢ Dissociation (color screening) = hot QCD matter thermometer
➢ Probe of low-x gluon structure/evolution:
Lattice QQ free energy vs T:Spectral function vs T:
Suppression pattern vs ε :
[H.Satz, hep-ph/512217]
production via gg fusion: x~10-3 (10-5)Q2~10 GeV2
gluon saturation,non-linear QCD
[See e.g. K.Tuchin, this workshop]
_
3/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Quarkonia: from SPS and RHIC to LHC
➢ PbPb @ √sNN=5.5 TeV, pPb @ √sNN=8.8 TeV:
● Factor x30-45 increase in energy compared to AuAu,dAu @ RHIC
● 30-45 times lower Bjorken x=2pT/√s, ~ 10-3 (10-5)
● Large perturbative cross-sections.
● High luminosities (high rates).
Heavy-ion physics at LHC:
- Plasma hotter, longer-lived than @ RHIC
- Access to lower x, higher Q2
- Unprecedented gluon densities
- Availability of new probes (Y,Y',Y'')
ϒ
LHCRHIC
Vogt, hep-ph/0205330
4/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
J/ψ production in AA at the LHC
➢ J/ψ at LHC will clarify SPS/RHIC suppression:
SPS
30
enhanced suppression ?
enhanced regeneration ?
[H.Satz, hep-ph/512217]
RHICLHC
● Onset of direct J/ψ suppression (TD~1.5 -2 Tc) ?● Large(r) regeneration by ccbar recombination ?
Energy density (GeV/fm3)
5/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
ϒ production in AA at the LHC
➢ Large cross-sections: dσ /dy ~ 20 x RHIC➢ ϒ melts only at LHC: TD~ 4 Tc
➢ ϒ unaffected by final-state interactions: - Null hadronic absorption
- Small # bbar pairs small ϒ regeneration
➢ ϒ spectroscopy: TD (ϒ’) ~ TD (J/ψ): ϒ’/ ϒ vs pT very sensitive to system temperature & size
Gunion, Vogt, NPB 492 (1997) 301
“Cleaner” probe than J/ψ}
6/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Compact Muon Solenoid (|η|<5)
7/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
CMS Muon system
➢ 3 types of gaseous particle detectors for muon identification: - Drift Tubes (DT) in central barrel region - Cathode Strip Chambers (CSC) in endcap region - Resistive Plate Chambers (RPC) in barrel & endcaps
precise measurement of
muon position (momentum)
fast info for LVL-1 trigger
}
8/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
CMS Muon system
• Drift Tubes (DT) in central barrel• Resistive Plate Chambers (RPC) in barrel and endcaps
• Cathode Strip Chambers (CSC) in endcap region
9/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Muon reconstruction
Tracking + ( Ecal + Hcal ) + Muon-chambers for |η |<2.4
Silicon Microstripsand Pixels
Si TRACKER CALORIMETERS ECAL
HCALPlastic Sci/Steel sandwich
MUON BARRELDrift Tube Chambers (DT)
Resistive Plate Chambers (RPC)PbWO
4
10/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Muon reconstruction
● Best muon spectrometer at LHC (CMS)
● Excellent coverage: ~5 units of rapidity and 2π
● Strongest magnetic field: 4 T, 2 T (return yoke)
● Tag from mu-chambers, momentum resolution from Silicon tracker
● Ecal + Hcal + Magnet Iron absorbs hadrons
● Barrel: pTµ > 3.5 GeV/c
● Endcap: pLµ > 4.0 GeV/c
11/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Simulation studies
➢Signals (J/ψ ,ϒ ): CEM, NLO-pp, EKS98 PDF, TAA
-scaled
➢ Light-q background (π ,K): HIJING normalized to dNch
/dη=2500, 5000
➢Heavy-Q background (c,b): NLO-pp, CTEQ5M1 PDF, TAA
-scaled
(1) (2) (3)
(0) Reconstruct single decay muons (efficiencies, acceptances, trigger ...).
(1) Construct dimuon inv. mass spectrum.
(2) Construct dimuon combinatorial background (like-sign muon pairs)
(3) Subtract combinatorial-bckgd. + yield integration (2σ around peak)
Olga Kodolova, Marc Bedjidian CMS AN-2006/011
12/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
PbPb ϒ + X μ+μ - + X in CMS
➢ MC simulation & visualization of Upsilon event (PbPb, dN/dη|η=0
= 3500) using pp software framework
ϒ µ+µ-
13/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
J/ψ , ϒ : μ reconstruction algorithm
➢ Primary vertex determination: - select pairs of pixel hits
with ∆φ giving 0.5 < pT < 5 GeV
- extrapolate each pair in RZ to the beam line.
➢ Track finding: - start from track candidate in muon stations - extrapolate inwards from plane to plane using vertex constraints
➢ Track selection by cuts: - fit quality (χ2) - vertex constraint
Si layers
Si pixels
σZ = 190mm
µ-track
µ-stations
14/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
J/Ψ, ϒ acceptances
➢ J/Ψ accepted above pT~2 GeV/c (low-p
T muons absorbed in material
at y=0, but punchthrough at y~2). High-pT acceptance ~15%
➢ ϒ accepted (~35%) down to pT=0 GeV/c. High-p
T acceptance ~15%
acce
pta
nce
acce
pta
nce
Improved low pT
J/Ψ acceptanceat forward rapidities
ϒ
J/Ψ J/Ψ
η
pT
pT (GeV/c)
15/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
J/ψ triggering (pT-η acceptance)
➢ Two different Level-1 settings:
L1 : optimized for high luminosity pp OL1 : low quality muon candidate (used in HI)➢Trigger condition: two L1 or L2 opposite-sign candidates
26000 J/ψ generated: (OL1,L2) 252 events, (L1,L2) 113 events.
➢ Total trigger efficiency: 0.97% (OL1-L2 chain)
0.44% (L1-L2 chain)
artificial dip(η Jacobian)
16/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
ϒ triggering (pT-η acceptance)
➢ Two different Level-1 settings:
L1 : optimized for high luminosity pp OL1 : low quality muon candidate (used in HI)➢Trigger condition: two L1 or L2 opposite-sign candidates
15700 Y generated: (OL1,L2) 3322 events, (L1,L2) 2590 events.
➢ Total trigger efficiency: 21% (OL1-L2 chain)
16.5% (L1-L2 chain)
artificial dip(η Jacobian)
17/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Dimuon efficiency & purity vs dNch/dη
➢ ϒμμ embedded in PbPb event.
➢Efficiency:
ε(p,η)=εtrack-1
εtrack-2
εvtx
>80% for all multiplic. (barrel)
~65% for all multiplic. (barrel+endcap)
➢Purity = [true ϒ reco]/ [all ϒ reco]
~90% for all multiplicities
“realistic” LHC multiplicity range
18/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
μμ mass spectra (signal+background)
➢Pb-Pb, dNch
/dη|η=0
= 5000 , L = 0.5 nb-1
➢ Background: π/K (90% of Nch
) μμ (BR=63%)
➢ Background: c-,b-hadrons μ+X (BR~18% ,~38%)➢ Combinatorial backgd (mixed sources):
➢ J/ψ ,ψ ' peaks seen (S/B~0.6) All 3 ϒ peaks seen (S/B~0.07)
1 µ from π /K + 1 µ from J/ψ 1 µ from b/c + 1 µ from π /K
19/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
μμ mass spectra (signal+background)
➢Pb-Pb, dNch
/dη|η=0
= 2500 , L = 0.5 nb-1
➢ Background: π/K (90% of Nch
) μμ (BR=63%)
➢ Background: c-,b-hadrons μ+X (BR~18% ,~38%)➢ Combinatorial backgd (mixed sources):
➢ J/ψ ,ψ ' peaks seen (S/B~1.2) All 3 ϒ peaks seen (S/B~0.12)
1 µ from π /K + 1 µ from J/ψ 1 µ from b/c + 1 µ from π /K
20/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Heavy-quarks decays: b,c → µ / J/ψ +X
δr is transverse distance between the intersection points with the beam line belonging two different muon tracks
I. Lokhtin, CMS-NOTE 2001/008
➢ J/ψ from B decays: ~20% all J/ψ at LHC➢ Secondary vertex finding and correlated background rejection:
primary J/ψ
J/ψ from Bμ
μ
21/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
J/ψ mass spectra (like-sign subtraction)
➢ Best mass resolution at LHC:
σJ/ψ
= 35 MeV/c2 in barrel+endcap (both muons |η| < 2.4)
“high” multiplicity dN
ch/dη|
η=0 = 5000
“low” multiplicity dN
ch/dη|
η=0 = 2500
22/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
ϒ mass spectra (like-sign subtraction)
➢ Best mass resolution at LHC:
σϒ= 54 MeV/c2 (barrel), and σϒ= 90 MeV/c2 (barrel+endcap)
Barrel+ Endcap:(both
muons
|η| < 2.4)
Barrel:(both
muons
|η| < 0.8)
“high” multiplicity dN
ch/dη|
η=0 = 5000
23/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
QQbar rates at CMS (1 nominal PbPb run)
➢ Pb-Pb 5.5 TeV: 1-month, L = 0.5 nb-1
➢ J/ψ ,ϒ statistics = O(105),O(104): differential studies (dN/dpT, dN/dy,
centrality, ...) possible
24/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Summary
➢ J/ψ ,ϒ = unique probes of QCD media in A+A: - Step-wise “melting” pattern = absolute QGP thermometer - Production via gg fusion = probe of low-x QCD structure&evolution (CGC)
➢ Simulation studies of J/ψ ,ϒμμ in CMS (PbPb @ √sNN=5.5 TeV):
● Geometrical acceptances: ~15% (at high pT)
● Dimuon efficiency ~80% and purity ~90%, for all multiplicities● Best mass resolutions at LHC: σ
QQ ~ 1% m
QQ (barrel+endcap)
σJ/ψ
= 35 MeV/c2 (barrel+endcap), σϒ= 54 MeV/c2 (barrel alone)
● Full separation of ϒ family: bottomonium spectroscopy● Signal/Background: ~ 1(5), ~0.1(1) for J/ψ ,ϒ in barrel (+endcaps)● High rates expected (per year):
J/ψ ~ 180 kevents, ϒ ~ 25 kevents, ϒ ’ ~ 7 kevents, ϒ ’’ ~ 4 kevents
➢ Detailed differential studies (dN/dpT, dN/dy, centrality, ...) possible !
25/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Backup slides
26/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Charmonia Performances
ψ, ψ’ψ, ?ψ’ψ, ??ψ’ψ, ?ψ’perf.--few-20 GeV0-10 GeV0-20 GeVpt J/ψ
|η| < 2|η| < 2.5|η| < 0.9-4 < η < -2.5acc. η
60, --313, --245, --150, 7J/ψ , ψ ’
65 MeV
ALICE µ +µ - ATLAS µ +µ -CMS µ +µ -ALICE e+e-
70 MeV37 MeV35 MeVM res.
Bkg input: dNch/dy~2500-4000 in central Pb-Pb. for 1 month
central central central
BSS +/
min. bias
BSS +/
35
A.Dainese (HP'06)
27/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Bottomonia Performance
➢
ϒ, ?ϒ’, no ϒ’’
ϒ, ϒ’, ϒ’’ϒ, ?ϒ’, no
ϒ’’ϒ, ϒ’, ?ϒ’’perf.
--few-10 GeV--0-8 GeVpt ϒ
|η| < 2|η| < 0.8(2.4)|η| < 0.9-4 < η < -2.5acc. η
45, --, --50, 17, 1221, 8, --30, 12, 8ϒ ,ϒ ’,ϒ’’
90 MeV
ALICE µ +µ - ATLAS µ +µ -CMS µ +µ -ALICE e+e-
145 MeV54(85) MeV90 MeVM res.
|η|<2.4
|η|<0.8
central central min. bias central
BSS +/
Bkg input: dNch/dy~2500-4000 in central Pb-Pb. for 1 monthBSS +/
A.Dainese (HP'06)
28/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
J/ψ from B in CMS & ALICE
➢
primary J/ψ
J/ψ from B
energy LHCat 2.0~J/ψ all
B from J/ψ
J/ψ → µ+µ-
J/ψ → e+e-
CMS: CMS/NOTE 2001/008, ALICE: CERN/LHCC 99-13
A.Dainese (HP'06)
29/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
QQbar at the LHC
➢ Quarkonia measurements in heavy-ion collisions in CMS◆ Authors: ◆ Detailed study of background, reconstruction, signal extraction◆ Extended acceptance and higher efficiency triggering◆ Study as a function of bulk multiplicity◆ Increased acceptance and efficiency, include forward regions
30/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Quarkonia at LHC: experimental challenges
● Important contribution to ψ production from B → J/ψ (ψ ’) + X ● ~20% of J/ψ● ~40% of ψ’
● Normalization:
Drell-Yan not available for normalization (from qq, while quarkonia from gg at LHC; and small cross section at LHC)
W, Z?● Different Q2, x
Open heavy flavour, but …● Energy loss?● Thermal charm production?
Possible alternative: RAA (à la PHENIX)
Need to measure this!
31/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Quarkonia acceptances at LHC
➢
µ+µ-µ+µ- µ+µ-
e+e-
-4<η<-2.5
ϒJ/ψ
-4<η<-2.5
ac
ce
pta
nc
e (
%)
J/ψ ϒ
A.Dainese (HP'06)
32/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Low-x at the LHC (nucleus)
➢PbPb @ 5.5 TeV, pPb @ 8.8 TeV:
(i) Very high √s → Bjorken x=2pT/√s, ~30-45 times lower than AuAu,dAu @ RHIC
(ii) Very large perturbative cross-sections.
Nuclear xG(x,Q2) is basically unknown for x<10-3 !
Armesto, nucl-th/0410161
33/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Experimental access to low-x parton distrib. (II)
➢ Kinematical (x,Q2) domains covered experimentally:
➢ Most existing low-x nPDFs measurements are in the non-perturbative regime
e-p, p-p
e-A, p-A
much less nuclear PDF dataavailable:
Dd'E, nucl-ex/0404018
34/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Colour Glass Condensate
PomeronReggeon
MesonsIllustration only. There is no “PDFs” nowin the sense of pQCD factorization
➢ CGC: Effective field theory of QCD in high-energy (high density, small-x) limit.
• hadrons = classical fields (saturated gluon wave-function) below new scale: Q2<Qs
2
• “Sat. momentum”: A-“amplified”: Qs2 ~ A1/3 ~ 1.5,3 GeV2 RHIC,LHC
• Perturbative calculations (strong Fµν field ⇒ weak coupling αs<<1).
• had.+had: collision (amplitude level) of 1(2) gluon wave function(s): “resums” all mult. scatts. • Color Glass (“static” color sources = quarks) Condensate (high gluon occupation values).
➢ Quantum evolution: BK, JIMWLK: Non-linear, all-twist eqs. in saturation region
xG(x,Q2)= dNg/dy
Q2 = 10 GeV2
35/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Compact Muon Solenoid (|η|<5)
36/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Local Pattern Recognition (I)
● Barrel (DT):● Reconstruct position of each channel above threshold using
effective drift velocity● Reconstruct φ super-layer hits (time-space conversion)
● Drift velocity depends on B field and impact angle
● Cluster hits (linear fit): 2D segment● Fit 2D lines separately in r-φ and r-z through the 8+4 layers
of chamber● L/R ambiguities solved by best χ 2
● Combine into 3D segments, use segment position and direction for tracking
● Resolution: 100 µ m in φ view, direction ~1mrad
● Apply impact angle correction on time-to-distance relation and refit
● Calculate position (center of gravity) of the track-segment and its angle in the super-layer (+error matrix)
up to 12 hits/station
DT’s and CSC’s are multi-layer detectors: First step of muon reconstruction is local pattern recognition Reconstruct track segments in the DT and CSC detectors
Norbert NeumeisterCERN PH / HEPHY Vienna
37/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Local Pattern Recognition (II)
• Endcaps (CSC):– Reconstruct 3D hits
– Associate hits with linear fit (only one hit per layer)
– Fit “Gatti” function to the spatial shape of 3-strip charge distribution to determine centroid of cluster in layer
– Associate two projections by time coincidence
– Fit 3D segments through the collection of wire and strip clusters in chamber; linear fit
– Resolution: 120–250 µ m form bending coordinate, depending on chamber
up to 6 hits/station
Norbert NeumeisterCERN PH / HEPHY Vienna
38/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Standalone Muon Reconstruction
● All muon detectors (DTBX, CSC and RPC) are used● Seed generation:
– external: Level-1 trigger (vector at 2nd station) → Level-2 reconstruction
– internal: track segments from local pattern recognition ● Fit:
● Kalman filter technique applied to DT/CSC/RPC track segments● Use segments in barrel and 3D hits in endcaps● Trajectory building works from inside out● Apply χ 2 cut to reject bad hits● Track fitting works from outside in● Fit track with beam constraint
● Propagation:● Non constant magnetic field● Iron between stations, propagation through iron (more difficult
than in tracker!)● GEANE used for propagation through iron
Norbert NeumeisterCERN PH / HEPHY Vienna
39/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Global Muon Reconstruction
Start from standalone reconstructed muons:
• Seed generation– Get muon trajectory at innermost muon station– Propagate to outer tracker surface and to interaction point– Open window for track reconstruction
• define region of interest through tracker based on Level-2 track with parameters at vertex
• fixed/dynamic region– Create one or more seeds for each Level-2 muon
• Construction of trajectories for a given seed● Propagate from innermost layers out, including hits in muon chambers– Resolve ambiguities– Final fit of trajectories
tremendous gain in resolution
Inclusion of Tracker Hits
Norbert NeumeisterCERN PH / HEPHY Vienna
40/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Tracking Strategy
Rely on few measurement layers, each able to provide robust (clean) and precise coordinate determination
2 to 3 Silicon Pixel, and 10 to 14 Silicon Strip Measurement Layers
6 layersTOB
4 layersTIB
3 disks TID 9 disks TEC
R-phi (Z-phi) onlyR-phi (Z-phi) onlymeasurement layersmeasurement layers
R-phi (Z-phi) & StereoR-phi (Z-phi) & Stereomeasurement layersmeasurement layers
Radius ~ 110 cm, Length ~ 270 cm η~1.7
η~2.4
At high luminosity (~ 20 min. bias events every 25 ns):
R = 10 cm 25 cm 60 cm
Nch/(cm2*25ns) = 1.0 0.10 0.01
Norbert NeumeisterCERN PH / HEPHY Vienna
41/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Muon pT Resolution
Level-2:
Level-3:σ = 0.013 σ =
0.015σ = 0.018
σ = 0.12 σ = 0.14 σ = 0.17
barrel endcapsoverlap
Order of magnitude improvement
Norbert NeumeisterCERN PH / HEPHY Vienna
42/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Muon pT Resolution Norbert NeumeisterCERN PH / HEPHY Vienna
43/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
HLT muon track reconstruction
(G. Bagliesi – EPS 2003)
43
Inclusion of Tracker Hits: “Level-3”•Define a region of interest through tracker based on L2 track with parameters at vertex• Find pixel seeds, and propagate from innermost layers out, including muon
Standalone Muon Reconstruction: “Level-2”• Seeded by Level-1 muons• Kalman filtering technique applied to DT/CSC/RPC track segments•GEANE used for propagation through iron• Trajectory building works from inside out• Track fitting works from outside in• Fit track with beam constraint
Single muons10<Pt<100 GeV/c
Level-3Algorithmic efficiency
η
44/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Residuals and Pulls in r-φ / ndf2
χ 49.27/17
Constant 129
Mean 0.0436
Sigma 0.9774
xσ)/sim-xrec
(x-5 -4 -3 -2 -1 0 1 2 3 4 5
0
200
400
600
800
1000
1200
1400
2
-1000 -500 0 500 1000
X0sim X0
f it µm
0
200
400
600σ = 109 µm
residual pull
DT
CSC
/ ndf2χ 1231/23
Constant 1.272e+04
Mean 0.0002398
Sigma 0.02302
(cm)φsim-x
φrecx
-0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.20
2000
4000
600
800
1000
1200
1400 / ndf2χ 210.4/57
Constant 6310
Mean 0.01169
Sigma 1.238
φxσ )/φ
sim-xφ
rec (x
-5 -4 -3 -2 -1 0 2 3 4 50
1000
2000
3000
4000
5000
6000
7000
1
45/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
The CMS experiment (|η|<5)
Physics program: Higgs (EWSB), Beyond SM, Heavy-Ions, low-x QCD …
Silicon Tracker (|η| < 2.5):Si pixels, Si stripsGood eff. & purity for pT>1 GeV
Pixel occupancy (PbPb): 1-2%
∆p/p ≈ 2% for pT<70 GeV
Calorimeters (|η| < 5): EM: PbW0
4
HCAL: Scint.+steel
Magnet :4 T solenoid
Muon tracking (|η| < 2.5):
µ from Z0, J/ψ , ϒ
σm ≈ 50 MeV at the ϒ mass DAQ & Trigger
High rate capability for A+A, p+A, p+p
HLT: real time HI event reco
46/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Muon trigger system
➢
G. Bagliesi – EPS 2003 – Aachen 17-24/7/2003 46
Level-1 (~µs) 40 MHz High-Level ( ms-sec) 100 kHzEvent Size ~ 106 Bytes
40 MHzClock drivenCustom processors
100 kHzEvent drivenPC networkTotally software
100 HzTo mass storage
two trigger levelstwo trigger levels
All charged tracks with pt > 2 GeV
Reconstructed tracks with pt > 25 GeV
Operating conditions:one “good” event (e.g Higgs in 4 muons )
+ ~20 minimum bias events)
Combines information from the three independent trigger systems
47/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Silicon Tracker Layout
➢
6 layersOuterBarrel
9 Disks in the End Cap
1 Single detector 2 detectors back to back
4 layersInnerBarrel3 layersPixel Barrel
3 Disks2 Pixel Disks
70M Pixel channels, 11M Strip channels
Pixel: 100x150µm2, Inner Strips: 80µmx6.1cm, Outer Strips: ~150µmx9.1cm
48/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Tracker in heavy-ion environment
➢Simulated Central Pb+Pb Event
(HIJING+OSCAR+IGUANA)
Simulation dNch/dy ~ 3000
Channel Occupancy
Pixel Detector Occupancy of < 2%
(less than 10% for outermost layers)
Including Pulse Height Information
Key for successful tracking Excellent soft physics capabilities
Pixels InnerStrips
OuterStrips
Allows correction of detector effects Provides useful dE/dx information
49/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
Suppression scenario (ALICE)
➢• Suppression-1
Tc =270 MeVΤD/Tc=1.7 for J/Ψ ΤD/Tc= 4.0 for ϒ.
• Suppression-2 Tc=190 MeVΤD/Tc=1.21 for J/Ψ ΤD/Tc= 2.9 for ϒ.PRC72 034906(2005)
Hep-ph/0507084(2005)
Good sensitivity J/ψ , ϒ & ϒ ’
50/24Quarkonia '06, 27/06/2006 David d'Enterria (CERN)
γ γ , γ A : physics topics
➢ Typical diagrams for γγ and γA collisions:
Pomeron, gluon, or meson
QED, precision QCD
l +l -, C-even cc bb, W+W -...
QED in strong regime (Zαem
~1),heavy-Q spectroscopy, [quartic GC (W Wγγ), ...]
Precision QCD(low bckgd, simpler initial state than p,A+A)
Quarkonia, heavy-Q, jets ...
Nuclear GA(x,Q2), low-x physics,
QQbar in cold nuclear matter
➢ Physics:
➢ Measurements:
➢ Topics:
_ _
➢ All UPC measurements at RHIC: ZDC-triggered (neutron tagging) !
Dd'E, nucl-ex/0601001