Download - Heavy Flavour in ALICE
Federico Antinori - LBNL Heavy Quark Workshop - 3 November 2007Federico Antinori - LBNL Heavy Quark Workshop - 3 November 2007 11
Heavy Flavour in ALICEHeavy Flavour in ALICE
Federico AntinoriFederico Antinori(INFN Padova & CERN)(INFN Padova & CERN)
for the ALICE Collaborationfor the ALICE Collaboration
Federico Antinori - LBNL Heavy Quark Workshop - 3 November 2007Federico Antinori - LBNL Heavy Quark Workshop - 3 November 2007 22
ContentsContents The LHC, Heavy Flavours and ALICE The LHC, Heavy Flavours and ALICE
or “ALICE in Wonderland”or “ALICE in Wonderland”
Benchmark channelsBenchmark channels DD00 K K--++
B B e + X e + X B B µ + X µ + X
Additional measurements under investigationAdditional measurements under investigation DD++ K K--+ + ++
B B J/ J/+ X+ X vv22 DDss b tagged jetsb tagged jets
Coming up: ppComing up: pp
ConclusionConclusion
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The LHC, Heavy Flavours The LHC, Heavy Flavours and ALICE and ALICE
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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% cent)Pb-Pb 5.5 TeV (5% 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
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large cross-sectionslarge cross-sections low-x (a field of its own!)low-x (a field of its own!) bb
RHICbbLHC
ccRHIC
ccLHC
100
25
accessible x1, x2 regions in the ALICE experimentaccessible x1, x2 regions in the ALICE experiment
central detector
muonarm
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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!!
e.g. full reconstruction of D verticese.g. 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
11/2006 PSI J. Schukraft10
ALICE 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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ALICE StatusALICE Status
Timeline:Timeline: Installation & commissioning ongoingInstallation & commissioning ongoing Global commissioning in December & February (cosmics)Global commissioning in December & February (cosmics) April 2008 on: cosmics, then pp run (commissioning April 2008 on: cosmics, then pp run (commissioning
physics)physics) 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))
Startup configuration:Startup configuration: complete: ITS, TPC, TOF, HMPID, muon arm, PMD, trigger dets complete: ITS, TPC, TOF, HMPID, muon arm, PMD, trigger dets
(V0, T0, ZDC, Acorde)(V0, T0, ZDC, Acorde) partially complete: PHOS (3/5), TRD (5/18), DAQ/HLT (20-30%)partially complete: PHOS (3/5), TRD (5/18), DAQ/HLT (20-30%)
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|η| < 0.9:B = 0.4 TTRDTPCITS with: - Si pixel- Si drift- Si strip
TrackingTracking
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longitudinal coverage:
|| < 1 (tracking), ||<2 (multiplicity)
Inner Tracking System (ITS)Inner Tracking System (ITS)
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ITS InstallationITS Installation
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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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Benchmark channelsBenchmark channels
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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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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 clarify the heavy flavour quenching storyshould 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
low mass
high mass
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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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Additional measurements Additional measurements under investigationunder investigation
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DD++ K K--++++
Preliminary study: performance comparable to that for Preliminary study: performance comparable to that for D D00 KK--++
Pb-Pb significance ~ 30(1 month)
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DDss++
DDss++
as probe of hadronization?as probe of hadronization? from string fragmentation: cs / cd ~ 1/3from string fragmentation: cs / cd ~ 1/3
after decays: Dafter decays: Dss++ (cs) / D (cs) / D++ (cd) ~ 0.6 (cd) ~ 0.6
from recombination: cs / cd ~ N(s) / N(d)from recombination: cs / cd ~ N(s) / N(d) how large at LHC?how large at LHC?
experimentally accessible?experimentally accessible? DD++ (c (c ~ 310 µm) ~ 310 µm) K K--++++ with BR ~ 9.2 % with BR ~ 9.2 %
in Alice: expect similar performance as for Din Alice: expect similar performance as for D00 K K--++
DDss++ (c (c ~ 150 µm) ~ 150 µm) K K--KK++++ with BR ~ 4.4 % with BR ~ 4.4 %
but mostly resonant decays: but mostly resonant decays: ++ or K or K00**KK++ (non resonant only 20 %) (non resonant only 20 %)
favours bkgnd rejection (for Dfavours bkgnd rejection (for D++ K K--++++, non-resonant ~ 96 %), non-resonant ~ 96 %) may be well visible (expecially if Dmay be well visible (expecially if Dss
++/D/D++ is large!) is large!)
Under study!Under study!
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Heavy Flavour vHeavy Flavour v22
vv22 = azimuthal anisotropy = azimuthal anisotropy elliptic flow elliptic flow
can get charm vcan get charm v22 from from direct charm elliptic flowdirect charm elliptic flow non-flowing c recombining with flowing matternon-flowing c recombining with flowing matter azimuthally dependent energy lossazimuthally dependent energy loss ...?...?
in general, vin general, v22 0 if charm “strongly coupled” with azimuthally 0 if charm “strongly coupled” with azimuthally asymmetric medium...asymmetric medium...
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Non photonic el. v2 @ RHICNon photonic el. v2 @ RHIC
to what extent can one accommodate small vto what extent can one accommodate small v22 with large with large suppression?suppression?
[S.Butsyk@QM`05]
[Xin Dong@QM05]
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Reconstructed D vReconstructed D v22 at LHC? at LHC?
Full reconstruction of D decays at LHC Full reconstruction of D decays at LHC qualitatively different measurement from non-photonic electrons!qualitatively different measurement from non-photonic electrons! better correlation with original heavy-quark momentum better correlation with original heavy-quark momentum b vs cb vs c
First indications from preliminary studies in ALICE: First indications from preliminary studies in ALICE: expected error ~ few % (D vexpected error ~ few % (D v22))
3030
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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Heavy flavour jets?Heavy flavour jets? 2 GeV 20 GeV 100 GeV 200 GeV
Mini-Jets 100/event 1/event 100k/month
Well visible event-by-event! e.g. 100 GeV jet + underlying eventWell visible event-by-event! e.g. 100 GeV jet + underlying event
For high energy jets: For high energy jets: Nb ~ Nu,dNb ~ Nu,d
heavy flavour rich!heavy flavour rich!
b-tagged jets?b-tagged jets? study quenching of b study quenching of b
jets!jets!
Preliminary look: impact Preliminary look: impact parameter tagging looks parameter tagging looks promising (full simulation promising (full simulation needed)needed)
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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 electron id in TRD and TPC, electron impact parameter from ITSelectron id in TRD and TPC, electron impact parameter from ITS
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ConclusionConclusion
Heavy flavours kindly provide us with a very Heavy flavours kindly provide us with a very promising tool to study the properties of the strongly promising 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 well equipped for heavy flavour physicsALICE is well equipped for heavy flavour physics