Heavy Flavour in ALICE
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Transcript of Heavy Flavour in ALICE
F Antinori - 417th WE-Heraeus-Seminar - Bad Honnef - June 2008 11
Heavy Flavour in ALICEHeavy Flavour in ALICE
Federico AntinoriFederico Antinori(INFN Padova & CERN)(INFN Padova & CERN)
for the ALICE Collaborationfor the ALICE Collaboration
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ContentsContents The LHC, Heavy Flavours and ALICE The LHC, Heavy Flavours and ALICE
Expected performance (examples)Expected performance (examples) DD00 K K--++
DD++ K K--+ + ++
B B e + X e + X B B µ + X µ + X B B J/ J/+ X+ X ……
Coming up: proton-protonComing up: proton-proton
ConclusionConclusion
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The LHC, Heavy Flavours The LHC, Heavy Flavours and ALICE and ALICE
(or “ALICE in Wonderland”)(or “ALICE in Wonderland”)
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LHCLHC
Running conditions: Running conditions:
+ other ions (Sn, Kr, O) & energies (e.g.: pp @ 5.5 TeV)+ other ions (Sn, Kr, O) & energies (e.g.: pp @ 5.5 TeV)
*Lmax (ALICE) = 1031 ** Lint (ALICE) ~ 0.5 nb-1/year
Collision systemCollision system √√ssNNNN(TeV)(TeV) LL0 0 (cm(cm-2-2ss-1-1)) Run time Run time (s/year)(s/year)
geomgeom (b) (b)
pppp 14.014.0 101034 34 ** 101077 0.070.07
PbPbPbPb 5.55.5 10102727 101066 ** ** 7.77.7
pPbpPb 8.88.8 10102929 101066 1.91.9
ArArArAr 6.36.3 10102929 101066 2.72.7
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Heavy Flavour @ LHCHeavy Flavour @ LHC cccc and and bbbb rates rates
ALICE PPR (NTLO + shadowing)ALICE PPR (NTLO + shadowing)
115 115 // 4.64.60.65 0.65 // 0.850.856.6 6.6 // 0.20.2Pb-Pb 5.5 TeV (5% Pb-Pb 5.5 TeV (5% cent)cent)
0.160.16 // 0.0070.00711 // 1111.211.2 // 0.50.5 pp 14 TeVpp 14 TeV
shadowingshadowingsystemsystem NN x-sect (mb)NN x-sect (mb) total multiplicitytotal multiplicity
PbPbpp
PbPbpp
cc bbPbPb/pp PbPb/pp
bbRHIC
bbLHC
ccRHIC
ccLHC
100
25
Exploring the low-x region…Exploring the low-x region… Shadowing, saturation, …Shadowing, saturation, …
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p-A essential!p-A essential!
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Probing the medium...Probing the medium...
study medium with probes of known colour charge study medium with probes of known colour charge and massand mass e.g.: energy loss by gluon radiation expected to be:e.g.: energy loss by gluon radiation expected to be: parton-specific: stronger for gluons than quarks parton-specific: stronger for gluons than quarks
(colour charge ratio = 9/4)(colour charge ratio = 9/4) flavour-specific: stronger for lighter than for heavier quarks flavour-specific: stronger for lighter than for heavier quarks
(dead-cone effect)(dead-cone effect) study effect of medium on fragmentation (no extra study effect of medium on fragmentation (no extra
production of c, b at hadronization)production of c, b at hadronization) independent string fragmentation vs recombinationindependent string fragmentation vs recombination e.g.: De.g.: D++
ss/D/D++
+ measurement important for quarkonium physics+ measurement important for quarkonium physics open QQ production natural normalization for quarkonium open QQ production natural normalization for quarkonium
studiesstudies B meson decays non negligible source of non-prompt J/B meson decays non negligible source of non-prompt J/at at
LHCLHC
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Large suppression at RHIC!Large suppression at RHIC!
yet, region above 3-4 GeV yet, region above 3-4 GeV expected to be dominated expected to be dominated by beauty...by beauty...
[Xin Dong@QM05]
n.p. electrons ~ as suppressed as n.p. electrons ~ as suppressed as expected for c only (no b)expected for c only (no b)
scaled to
M. Cacciari et al., hep-ph/0502203
[J.Bielcik @QM05] disentangling c/b is a mustdisentangling c/b is a must
full reconstruction of D vertices!full reconstruction of D vertices!
non phot. el.
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By the way: the factor 9/4? By the way: the factor 9/4?
energy loss should be energy loss should be proportional to: proportional to: CCRR = 4/3 for q, = 3 for g = 4/3 for q, = 3 for g
at RHIC, at 6-8 GeV pat RHIC, at 6-8 GeV pTT: : x ~ 10 x ~ 10-1-1
large quark contribution large quark contribution also for light flavours?also for light flavours?
at LHC, at same pat LHC, at same pTT: : x ~ a few 10 x ~ a few 10-4-4
quark contribution quark contribution negligiblenegligible
10ALICE Set-upALICE Set-up
HMPID
Muon Arm
TRD
PHOS
PMD
ITS
TOF
TPC
Size: 16 x 26 meters
Weight: 10,000 tons
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longitudinal coverage:
|| < 1 (tracking), ||<2 (multiplicity)
Inner Tracking System (ITS)Inner Tracking System (ITS)
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ITS and TPCITS and TPC
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Silicon Pixel Detector (SPD)Silicon Pixel Detector (SPD)
PIXEL CELL
z: 425 m
r: 50 m
Two layers:r = 4 cmr = 7 cm
9.8 M
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Expected resolution Expected resolution on track impact parameter on track impact parameter
track impact parameter (dtrack impact parameter (d00))
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Expected performanceExpected performance(examples)(examples)
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DD00 K K--++
expected ALICE expected ALICE performance performance S/B ≈ 10 %S/B ≈ 10 % S/S/(S+B) ≈ 40 (S+B) ≈ 40
(1 month Pb-Pb running)(1 month Pb-Pb running)
statistical.
systematic.
ppTT - differential - differential
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DD++ K K--++++
Performance comparable to that for DPerformance comparable to that for D00 KK--++
Pb-Pb significance ~ 30(1 month)
p-p
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Beauty to electronsBeauty to electrons Expected ALICE performance (1 month Pb-Pb)Expected ALICE performance (1 month Pb-Pb)
ee±± identification from TRD and dE/dx in TPC identification from TRD and dE/dx in TPC impact parameter from ITSimpact parameter from ITS
pt > 2 GeV/c , 200 < |d0| < 600 m80% purity
8 104 e from Bpt > 2 GeV/c , 200 < |d0| < 600 m
80% purity
8 104 e from B
S/(S+B)S/(S+B) S per 10S per 1077 central Pb-Pb events central Pb-Pb events
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Electrons (from b) pElectrons (from b) ptt spectrum spectrum
Error compositionstat error
stat syst error
11% from overall normalization not included
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tDpp
tDAA
collt
DAA dpdN
dpdN
NpR
/
/1)(
tepp
teAA
collt
eAA dpdN
dpdN
NpR
/
/1)(
Expected performance on D, B Expected performance on D, B RRAAAA
mb = 4.8 GeV
D0 K B e + X
1 year at nominal luminosity(107 central Pb-Pb events, 109 pp events)
should help clarify the heavy flavour quenching story!should help clarify the heavy flavour quenching story!
mass dependencecolour charge dependence
)()()( D from eB from e/ tAAtAAtDB pRpRpR )()()(/ t
hAAt
DAAthD pRpRpR
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Beauty to single muonsBeauty to single muons
expected in the muon armexpected in the muon arm
very high statistics and heavy flavour purity expectedvery high statistics and heavy flavour purity expected
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Beauty to dimuonsBeauty to dimuons Two main sources:Two main sources:
B µ+ + D + Xµ- + X
B B µ- + XX + µ+
“BDSAME” “BBDIFF”
consistency check!consistency check!
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low mass
high mass
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B B J/ J/ + X + X
More “exclusive” than B More “exclusive” than B e/µ + X e/µ + X better handle on B momentum distributionbetter handle on B momentum distribution
PreliminaryPreliminary pppp study: pseudoproper decay time study: pseudoproper decay time
(à la CDF)(à la CDF))/(
)/( /
Jp
MJLx
T
Jxy
CDF (data) ALICE
(prelim. simulation)
pT>0
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Many more under study…Many more under study…
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...
jets tagged-flavour heavy
v
prong-5 B
DD
pK
KD
KK,D
2
0*
c
0
*s
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Coming up: ppComing up: pp
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Example: DExample: D00 in pp in pp DD00 K K--++
1 year run 1 year run ~ 10 ~ 1099 events events ~ 20 shifts, 10 hrs each ~ 20 shifts, 10 hrs each a few 10 a few 1077 events events
reach out to 12 GeV or soreach out to 12 GeV or so
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Example: B Example: B e + X in pp e + X in pp
LHC CooldownLHC Cooldown
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ALICE Status1/5 PHOS, 4/18 TRD, 18/18 TOFHMPID0/6 EMCAL
Detector Status Today & for First Beam
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ALICE StatusALICE Status
Startup configuration:Startup configuration: complete: ITS, TPC, TOF, HMPID, muon arm, trigger detectors complete: ITS, TPC, TOF, HMPID, muon arm, trigger detectors
(V0, T0, ZDC, Acorde)(V0, T0, ZDC, Acorde) partially complete: PHOS (1/5), TRD (4/18), PMD (6/48), partially complete: PHOS (1/5), TRD (4/18), PMD (6/48),
DAQ/HLT (20-30%)DAQ/HLT (20-30%)
Timeline:Timeline: Global commissioning/cosmic runs I and II in Dec 2007 & Feb Global commissioning/cosmic runs I and II in Dec 2007 & Feb
20082008 Cosmic run III under wayCosmic run III under way LHC will close end July LHC will close end July first injection expected shortly after first injection expected shortly after commissioning run in 2008commissioning run in 2008 ““long run” in 2009long run” in 2009 followed by first Pb-Pb run (√s = 5.5 TeV, L = 5·10followed by first Pb-Pb run (√s = 5.5 TeV, L = 5·102525 cm cm-2-2ss-1-1))
Taking data!Taking data!
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ALICE sees particles!ALICE sees particles!
TPCTPC
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ITSITS
TPC + ITSTPC + ITS
ITS alignment with cosmicsITS alignment with cosmics
21982198 sensitive modules X sensitive modules X 66 d.o.f. each d.o.f. each = = 1318813188 alignment parametersalignment parameters to be to be determined!determined!
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ITS Alignment 06/05/2008ITS Alignment 06/05/2008Adam Jacholkowski 3535
SPD alignment QA plots SPD alignment QA plots (first sample of 940, 4P tracks)(first sample of 940, 4P tracks)
ITS Alignment 06/05/2008ITS Alignment 06/05/2008Adam Jacholkowski 3636
AliMillepede re-alignmentAliMillepede re-alignment(first test)(first test)
First particles from LHC!First particles from LHC!
TI2 injection test (15/6): muons from beam dumpTI2 injection test (15/6): muons from beam dump
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First particles from LHC!First particles from LHC!
Seen from an SPD half-sector:Seen from an SPD half-sector:
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inner layerinner layer
outer layerouter layer
transversal tracks!transversal tracks!
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ConclusionConclusion
With heavy flavours, Nature kindly provides us with a With heavy flavours, Nature kindly provides us with a beautiful tool to study the properties of the strongly beautiful tool to study the properties of the strongly interacting medium produced in ultra-relativistic interacting medium produced in ultra-relativistic nucleus-nucleus collisionsnucleus-nucleus collisions
At LHC At LHC very high ratesvery high rates very extended pvery extended pT T rangerange well developed jetswell developed jets
ALICE is very well equipped for this physicsALICE is very well equipped for this physics
The FUN is just starting!The FUN is just starting!