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


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


The LHC, Heavy Flavours The LHC, Heavy Flavours and ALICE and ALICE


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


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


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


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


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.


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


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%)


|η| < 0.9:B = 0.4 TTRDTPCITS with: - Si pixel- Si drift- Si strip

TrackingTracking


longitudinal coverage:

|| < 1 (tracking), ||<2 (multiplicity)

Inner Tracking System (ITS)Inner Tracking System (ITS)


ITS InstallationITS Installation


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


Expected resolution Expected resolution on track impact parameter on track impact parameter

track impact parameter (dtrack impact parameter (d00))


Benchmark channelsBenchmark channels


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


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


Electrons (from b) pElectrons (from b) ptt spectrum spectrum

Error compositionstat error

stat syst error

11% from overall normalization not included


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


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


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!


Additional measurements Additional measurements under investigationunder investigation


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)


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!


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...


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]


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


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)


Coming up: ppComing up: pp


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


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


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

Heavy Flavour in ALICE

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