heavy flavours & quarkonia @ lhc
DESCRIPTION
Heavy flavours & quarkonia @ LHC. motivations selected physics channels quarkonia, B-hadron x-section, « hadronic » charm, heavy flavour quenching. [email protected]. - PowerPoint PPT PresentationTRANSCRIPT
[email protected] [email protected] Sibiu, 20/08/08
• motivationsmotivations
• selected physics channelsselected physics channels
quarkonia, quarkonia, B-hadron x-section, B-hadron x-section, « hadronic » charm, « hadronic » charm,
heavy flavour quenchingheavy flavour [email protected]
[email protected] [email protected] Sibiu, 20/08/08
Heavy-flavour x-sections @ LHC
c(LHC) = c(RHIC) × 10
b(LHC) = b(RHIC) × 100
W(LHC) = (RHIC) × 10
Z(LHC) = (RHIC)
K. Safarik
[email protected] [email protected] Sibiu, 20/08/08
Dileptons @ LHC
world data on total x-section of e+e- hadrons (PDG06)
a similar plot is accessible in Pb-Pb @ LHC within a few weeks
(p
b)
s (GeV)
J/ (1S) Z0
350·103 700·103 300·103 500·103 25·103 11·103
typical number of reconstructed resonances in min-bias PbPb @ 5.5 TeV (1 month)
[email protected] [email protected] Sibiu, 20/08/08
Single leptons @ LHC
simulation by Z. Conesa del Valle
pp @ 14 TeV
charm bottom W±
charm bottom W±
4·108 4·105 11·103
expected number of measured muons in min-bias PbPb @ 5.5 TeV (1 month)
[email protected] [email protected] Sibiu, 20/08/08
A closer look at heavy-quark cross-section
hep-ph/0601164, J. Phys. G 32 (2006) 1295, J. Phys. G 35 (2008) 054001
• NLO predictions for pp @ LHC: a factor ~ 2 uncertainty
• (14 TeV) / (5.5 TeV) ~ 10%
measuring (c,b) in pp @ 14TeV is top priority
charm thermal production ~ 25%
(assumes large medium temperature)
PbPb @ 5.5 TeV
charm
pp @ 14 TeV
bottom
(14 TeV) / (5.5 TeV)
[email protected] [email protected] Sibiu, 20/08/08
Quarkonia suppression @ LHC
• whether J/ melts or not @ RHIC it will be strongly either suppressed or regenerated @ LHC
• use (2S) to unravel J/ sup. vs. reco. reco. is small: L. Grandchamp et al., PRC 73 (2006) 064906
• (1S) melts significantly only at LHC
• additional suppression by hard gluons
• relevance of quarkonium ratios vs. pt R.
Vogt in J. Phys. G 35 (2008) 054001
quarkonium dissociation temperatures
A. Mocsy & P. Petreczky, Phys. Rev. Lett. 99 (2007) 211602
PbPb @ 5.5 TeV
RHICLHC
hard gluon induced quarkonium breakup hep-ph/0311048
[email protected] [email protected] Sibiu, 20/08/08
Charmonium regeneration @ LHC
1. peculiar centrality dependence
2. predictions strongly depend on cc
3. (re-)dissociation by comovers
4. regeneration smaller <p2t>
note: N(B J/) / N(direct J/) ~ 20% in 4
A. Andronic et al., Phys. Lett. B 652 (2007) 259, J. Phys. G 35 (2008) 054001, A. Capella et al., arXiv:0712.4331 [hep-ph], R. Thews et al., J. Phys. G 35 (2008) 054001
1. 2. 3.
4.
[email protected] [email protected] Sibiu, 20/08/08
Heavy quark quenching @ LHC: new ratios available
N. Armesto et al., Phys. Rev. D 71 (2005) 054027, J. Phys. G 35 (2008) 054001
BAA
DAA
hAAbcqg RRREEE
hAA
BDAA
hBD RRR )(/)( DAA
BAA
DBAA RRR /
• isolate mass dep. of E
• sensitivity disappears at large pt
• lower sensitivity to qhat
• RD/h probes color charge dep. of E
• RB/h probes mass dep. of E
[email protected] [email protected] Sibiu, 20/08/08
Heavy quark quenching @ LHC: new reference available
Z. Conesa del Valle et al., Phys. Lett. B 663 (2008) 202, J. Phys. G 35 (2008) 054001
• heavy quark energy loss:
• shifts down the (c,b)/W crossing point by ~ 5-7 GeV/c
• suppresses muon yield by a factor 2-5 for 2 < pt < 20 GeV/c
• W affected by shadowing only
[email protected] [email protected] Sibiu, 20/08/08
Heavy flavour flow @ LHC
more details in “Heavy Ion Collisions at the LHC, Last Call for Predictions”, May-June 2007, CERN
proceedings: J. Phys. G 35 (2008) 054001
• resonance interactions increase v2
• v2 quantitatively similar at RHIC & LHC
H. van Hess et al., Phys. Rev. C 73 (2006) 034913, J. Phys. G 35 (2008) 054001
[email protected] [email protected] Sibiu, 20/08/08
Heavy flavours with ALICE
electron-muon coincidences: open charm & bottom
ITS, TPC, TRD, ToF (||<0.9)
(di-)electrons: J/, ’, , ’,’’, open charm, open bottom, W±,Z0
muon spectrometer (-2.5<<-4)
(di-)muons: J/, ’, , ’,’’, open charm, open bottom, W±, Z0
ITS, TPC, TRD, ToF (||<0.9)
hadrons: D0, D±,…
[email protected] [email protected] Sibiu, 20/08/08
Heavy flavours with CMS & ATLAS
muon spectrometer & silicon tracker in central barrel & end-caps (||<2.5)
studies limited to J/, ’, , ’,’’ reconstruction & b-jet tagging
J/, ’, , ’,’’, open bottom, Z0
[email protected] [email protected] Sibiu, 20/08/08
Acceptance for heavy flavour measurements
• complementarity between the 3 experiments
• ATLAS & CMS acceptance is large in & limited to high pt
• ALICE combines hadrons, electrons, muons & covers low pt & high • ATLAS, CMS & ALICE-electrons/hadrons have inner tracking
• ATLAS & CMS electron/hadron channels not yet investigated
[email protected] [email protected] Sibiu, 20/08/08
Selected physics channels
• Quarkonia
• B from secondary J/
• B from dileptons
• B from single leptons
• D0 K
• Heavy flavour quenching
only “published” results
[email protected] [email protected] Sibiu, 20/08/08
Quarkonia
[email protected] [email protected] Sibiu, 20/08/08
Expected performances for quarkonia
ALICE +- ALICE e+e- CMS +- ATLAS +-
acceptance -4<<-2.5 ||<0.9 ||<2.4 ||<2.5
charmonia
(J/) (MeV) 74 30 35 (w/o bkg) 68
S (×103) 677 120 146 8-216 (pt)
S/S+B 413 245 234 52-164 (pt)
bottomonia
() (MeV) 109 90 68-90 (bkg level) 145 (||<2)
S , ’, ’’ 6800,1800,100 900,350,- 20300,5900,3500 10000-15000
S/S+B , ’, ’’ 67,30,21 21,8 36,-,- 45-46
From A. Dainese @ HP2006, updated according to ALICE: J. Phys. G 32 (2006) 1295, W. Sommer et al. @ QM2006, CMS: J. Phys. G 34 (2007) 2307, CMS/note-2006/089, ATLAS: L. Rosselet @ HEP2007
• J/, : first detailed studies within one month
• ’: difficult (small S/B), ’, ’’: need 2-3 runs
WARNING: different simulation frameworks & different assumptions
bkg assumes dN/d = 2500-5000, S & S/S+B: one month min-bias PbPb (CC for ALICE e+e-)
[email protected] [email protected] Sibiu, 20/08/08
Normalization for suppression studies
normalisation pros. cons.
open heavy flavours
most naturalquenching, thermal (charm) production
excited states sensitivity to medium size & temperature
hard partons, exp. reach (e.g. ’)
Z0, W± statistics, no hot medium effects
prod. mechanisms (gg vs. qqbar), Q2
RAA, Rcp “easy”mix cold & hot nuclear effects (i.e. need pA)
there is no golden normalization
[email protected] [email protected] Sibiu, 20/08/08
Observables with bottomonia
ALICE: J. Phys. G 32 (2006) 1295, CMS: J. Phys. G 34 (2007) 2307
suppression 1: TC = 270 MeV, TD/TC = 4.0 (1.4) for ϒ(ϒ’)
suppression 2: TC = 190 MeV, TD/TC = 2.9 (1.1) for ϒ(ϒ’)
• statistics: one month PbPb @ 5.5 TeV
• large sensitivity to dissociation temperatures and medium size
[email protected] [email protected] Sibiu, 20/08/08
More with quarkonia
R. Analdi, E. Scomparin, D. Stocco
polarization dN/dy in pp
• pp: test production mechanisms
• AA: probe QGP formation• probe gluon distribution at low x
• pp @ 14 TeV: J/ & pol. vs. pt
• PbPb @ 5.5TeV: J/ pol. vs. centrality, pol. needs 2-3 runs
(gen - rec) vs. pt
pp @ 14 TeV
[email protected] [email protected] Sibiu, 20/08/08
Open charm & bottom: accessible channels
charm: exclusive hadronic
channels
• D0 K (tested in pp & PbPb)
• D+ K (tested in pp & PbPb)
• D±s KK (under study)
• D* D0 (under study)
• D0 K (under study)
• c pK (under study)
charm & bottom: semi-inclusive leptonic
channels
• c l + X (à la CDF & D0)
• b l + X (à la CDF & D0)
• b J/ + X (à la CDF & D0)
• b J/ + l (under study)
• bbbar 3 (should work in pp)
• bbbar l+l-,l-l+ (Bchain & BBdiff)
• bbbar l-l-,l+l+ (Bchain & B osc.)
more exotic (and more challenging): QQbar e, b > 5 prongs, b
J/ + X, etc
[email protected] [email protected] Sibiu, 20/08/08
Selected physics channels
• Quarkonia
• B from secondary J/
• B from dileptons
• B from single leptons
• D0 K
• Heavy flavour quenching
only “published” results
[email protected] [email protected] Sibiu, 20/08/08
Secondary J/ from B hadron decay
ALICE: CERN/LHC 2005-030, CERN/LHCC 99-13, ATLAS: EPJC 33 (2004) s1023, CMS: CMS NOTE 2006/031, 2001/008
(d0) < 50 µm for pt > 1.5/2/3 GeV/c in ALICE/CMS/ATLAS
• disentangle primary & secondary J/
• measure inclusive b cross-section
• probe b quark in-medium energy loss
N(B J/) / N(direct J/) ~ 20% in 4 @ LHC
[email protected] [email protected] Sibiu, 20/08/08
secondary J/ from B decay in CMS, pt
> 5 GeV/c
Using secondary J/ from B decay to probe b quark energy loss
energy loss is included in 2 scenarios:
• collisional energy loss
• collisional + radiative energy loss
with energy loss:
• yield reduced by a factor ~ 4
• distribution gets significantly narrower
I.P. Lokhtin & A.M. Snigirev, Eur. Phys. J. C 21(2001)155
[email protected] [email protected] Sibiu, 20/08/08
B signal from high-mass dimuons with vertexing
J. Phys. G 34 (2007) 2307
from BBbar
from Drell-Yan
min-bias PbPb one
month
r > 50 m suppresses Drell-Yan rate by 2 orders of magnitude with ~ 30% loss of signal
[email protected] [email protected] Sibiu, 20/08/08
B signal from dimuons w/o vertexing
R. Guernane et al., ALICE-INT-2005-018, J. Phys. G 32 (2006) 1295
Mass (GeV/c2) 0-5 5-20
N from bb 41461793 6983130
unlike-sign totalunlike-sign from bottomunlike-sign from charm like-sign from bottom
• unfold mass continuum
• large statistics is expected
• systematics to be estimated
central PbPb (5%), one month
[email protected] [email protected] Sibiu, 20/08/08
B hadron cross-section from single leptons
J. Phys. G 32 (2006) 1295, DIMUONnet
pp @ 14 TeV B +X
First step: extract Nl B
w/o 2nd vertex: unfold lepton dN/dpt via combined fit
large statistics constrains fit
107 PbPb (5%) evts (1 month)
pt > 2 GeV/c, 200 < d0 < 600 m
80000 e from B, S/(S+B) = 80%
2.1·1012 pp evts (1 year)
pt > 2 GeV/c
1.7·108 from B
with 2nd vertex: cut on dca & subtract remaining background
large purity of lepton sample
PbPb @ 5.5 TeV B
e+X
[email protected] [email protected] Sibiu, 20/08/08
MC
minttmin
tt )(
)(1
dt)(
lB
BBBlBB pp
L
Npp
total number of lB
integrated luminosity
lepton global detection efficiency
Second step: correct for efficiency, acceptance & decay kinematics
B hadron cross-section from single leptons
J. Phys. G 32 (2006) 1295, DIMUONnet
[email protected] [email protected] Sibiu, 20/08/08
B hadron cross-section from single leptons
• method widely used (UA1, CDF, D0)
• large pt reach, (very) small statistical errors, systematics ~ 10-15%
• allows to get B RAA(pt), should work for charm as well
• similar performances to be expected in ATLAS & CMS
J. Phys. G 32 (2006) 1295, DIMUONnet
Third step: the B-hadron inclusive differential cross-section
B semi-muonic decays
pp, s = 14 TeV
w/o 2nd vertex with 2nd vertex
[email protected] [email protected] Sibiu, 20/08/08
107 central PbPb (5%)
• S ~ 13000• S/B ~ 10 %• S/(S+B) ~ 40
D0 K (3.8%) c = 123 m
J. Phys. G 32 (2006) 1295
background assumes dN/d = 6000 @ = 0
cos(pointing) > 0.98 d0K
d0 < - 40 000 m2
increase S/B by 103
Hadronic charm
[email protected] [email protected] Sibiu, 20/08/08
system pp pPb PbPb
s (TeV) 14 8.8 5.5
trig MB MB CC
Nevt 109 108 107
time (months) 8 1 1
pt min (GeV/c) 0.5 0.5 1
Estat (%) 3 2 7
Esyst (%) 14 16 17
the most precise measurement of the total charm x-section in
pp collisions @ LHC
J. Phys. G 32 (2006) 1295
Hadronic charm differential x-section
[email protected] [email protected] Sibiu, 20/08/08
mc, F/0, R/0, PDF
expected experimental errors are much smaller than theoretical uncertainties
bars: quadratic sum of statistical & systematic errors
J. Phys. G 32 (2006) 1295
Testing QCD with hadronic charm in pp collisions @ 14 TeV
[email protected] [email protected] Sibiu, 20/08/08
tDpp
tDAA
coll
DAA dpdN
dpdN
NR
/
/1
tepp
teAA
coll
eAA dpdN
dpdN
NR
/
/1
J. Phys. G 32 (2006) 1295
1 nominal year: 107 central Pb-Pb events, 109 pp events statistics: bars, systematics: bands
sensitivity to shadowing for pt <~ 7 GeV/c & to energy loss for pt >~ 7GeV/c
Heavy quark quenching: traditional ratios
[email protected] [email protected] Sibiu, 20/08/08
D from eB from e/ AAAADB RRR
hAA
DAAhD RRR //
J. Phys. G 32 (2006) 1295
sensitivity to color charge dependence
sensitivity to mass dependence
1 nominal year: 107 central Pb-Pb events, 109 pp events statistics: bars, systematics: bands
Heavy quark quenching: more ratios
[email protected] [email protected] Sibiu, 20/08/08
Heavy flavours at the LHC provide a rich physics program
more analyses (not discussed here) are under study: heavy flavour flow, charm baryons, e- coincidences,
b-tagged jets, Z0, W±,…
first collisions in one month!