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Measurements of open heavy-flavour production in pp and p-Pb - - PowerPoint PPT Presentation

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Measurements of open heavy-flavour production in pp and p-Pb collisions with ALICE Sarah LaPointe INFN Torino For the ALICE collaboration The 7th international workshop on charm physics May 18-22, 2015 Why study open heavy flavour? Heavy

slide-1
SLIDE 1

Measurements of open heavy-flavour production in pp and p-Pb collisions with ALICE

Sarah LaPointe INFN Torino For the ALICE collaboration The 7th international workshop on charm physics May 18-22, 2015

slide-2
SLIDE 2

Why study open heavy flavour?

(GeV) s

10

2

10

3

10

4

10

b) µ (

c c

σ

10

2

10

3

10

4

10

ALICE (total unc.) ALICE extr. unc. ATLAS Preliminary (total unc.) ATLAS extr. unc. LHCb Preliminary (total unc.) PHENIX STAR HERA-B (pA) E653 (pA) E743 (pA) NA27 (pA) NA16 (pA) E769 (pA) NLO (MNR)

ALI−PUB−15089

JHEP 1207 (2012) 191

(GeV) s

2

10

3

10

4

10 b) µ /dy (

b b

σ d 1 10

2

10

= 2.76 TeV, |y|<0.8 s ALICE, pp = 7 TeV, |y|<0.9 s ALICE, pp = 1.96 TeV, |y|<0.6 s p CDF, p = 0.63 TeV, |y|<1.5 s p UA1, p = 0.2 TeV, |y|<0.35 s PHENIX, pp FONLL ALICE extr. unc. ALICE extr. unc.

ALI-PUB-82157

Phys.Lett. B738 (2014) 97

  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 2

  • Heavy quarks (charm and beauty) are produced via

initial high-Q2 parton scattering processes

  • Abundant production of heavy quarks

Increase in σQQ from RHIC to the LHC: ~ 10*σcc (RHIC) ~ 50*σbb (RHIC)

pp collisions

  • Tests of perturbative QCD (pQCD)
  • Multi-parton interactions (MPI) influence heavy-

flavour (HF) production at the LHC

  • Reference system for p-Pb and Pb-Pb collisions
  • Study jet structure and fragmentation
slide-3
SLIDE 3

Why study open heavy flavour?

  • Study cold nuclear matter effects, to better evaluate hot matter effects in

Pb-Pb collisions

  • Modification of parton distributions in nuclei
  • shadowing / gluon saturation at low Bjorken x
  • kT-broadening from multiple soft scatterings
  • Study partonic energy loss from initial- and final-state radiation
  • Investigate potential final-state effects
  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 3

JHEP 0904(2009) 65

p-Pb collisions

Results from Pb-Pb collisions C. Bianchin (this session)

Experimental overview ➜ A. Dainese (this morning)

slide-4
SLIDE 4

A Large Ion Collider Experiment

TOF - PID w/ Time Of Flight TPC - Tracking and PID w/ dE/dx Muon spectrometer - Trigger, tracking, and PID ITS - Trigger, event topology, tracking, PID

Central barrel |η|<0.9 Muon arm -4 <η<-2.5

EMCal - Trigger, energy measurement ZDC - trigger, event topology VZERO - trigger, event topology

S.LaPointe Charm 2015: The 7th International Workshop on Charm Physics 4

slide-5
SLIDE 5 dE/dx

σ

e

〉 dE/dx 〈 dE/dx -

  • 10
  • 8
  • 6
  • 4
  • 2

2 4 6 8 10 E/p 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

1 10

e

K+p

π

15/05/2012 =2.76 TeV s pp EMCal Trigger Events <4.5 GeV/c

T

Track 3.5<p | < 0.7

e

η | ALI−PERF−14772

Open heavy-flavour program

Mid-rapidity D mesons (D0, D+, D*, Ds) via hadronic decays

  • Select displaced vertex topologies using TPC and ITS
  • Particle ID using TPC and TOF
  • Invariant mass analysis
  • FONLL-pQCD based correction for beauty feed-down

Single electrons from semi-leptonic HF-hadron decays

  • Electron ID using TPC, TOF, and EMCal (high pT)
  • Background estimation:
  • MC cocktail
  • e+e- invariant-mass method
  • Beauty-decay electrons using ITS - exploiting displacement from

primary vertex

JHEP, 1210 (2012) 137

)

2

) (GeV/c π π Invariant Mass (K

1.7 1.75 1.8 1.85 1.9 1.95 2

2

Entries/11 MeV/c

1000 2000 3000 4000 5000 6000

<24GeV/c

T

and charge conjugate, 2<p

+

π

+

π

  • K

→

+

D = 5.02 TeV, 102 M events

NN

s

  • min. bias p-Pb,

6/07/2013

2

0.0003 GeV/c ± = 1.869 µ

2

0.0003 GeV/c ± = 0.010 σ 0.8 ± ) 59.7 σ Significance (3 133 ± ) 7166 σ S (3 ) 0.9926 σ S/B (3

ALI−PERF−52390

S.LaPointe Charm 2015: The 7th International Workshop on Charm Physics 5

Forward rapidity

ALI-PUB-13314

Single muons from semi-leptonic HF-hadron decays

  • Muon spectrometer
  • Estimation of background sources
  • For pp collisions a MC simulation is used
  • For p-Pb collisions, data-tuned MC cocktail
slide-6
SLIDE 6

Heavy-flavour production cross sections

  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 6

  • pQCD predictions describe the data within uncertainties

FONLL: JHEP 1210 (2012) 37, GM-VFNS: EPJ C72 (2012) 2082, kT-factorization: PRD 87 (2013) 094022

  • Measurements of HF-decay electrons complementary to the high-pT ATLAS result
  • Similar situation for pp collisions at √s = 2.76 TeV

GeV/c

t

p

5 10 15 20 25

b/GeV/c) µ (

|y|<0.5

|

t

/ dp σ d

  • 2

10

  • 1

10 1 10

2

10

3

10

ALICE

  • 1

= 5 nb

int

= 7 TeV, L s , pp

+

D

2.1% BR norm. unc. (not shown) ± 3.5% lumi, ±

  • stat. unc.
  • syst. unc.

FONLL GM-VFNS

(GeV/c) t p 5 10 15 20 25

FONLL Data

0.5 1 1.5 2 2.5 3 3.5

(GeV/c)

t

p

5 10 15 20 25 GM-VFNS Data

0.5 1 1.5 2 2.5 3 3.5 ALI−PUB−12507

JHEP 1201 (2012) 128, Ds in PLB 178 (2012) 279

)

2

dy) (mb/(GeV/c)

t

/(dp σ

2

) d

t

p π 1/(2

  • 9

10

  • 8

10

  • 7

10

  • 6

10

  • 5

10

  • 4

10

  • 3

10

  • 2

10

  • 1

10

e → ALICE c, b e → ATLAS c, b e, |y| < 0.5 → FONLL c, b e, |y| < 2 excl. 1.37 < |y| < 1.52 → FONLL c, b = 7 TeV s pp,

(GeV/c)

t

p

  • 1

10 × 4 1 2 3 4 5 6 7 8 910 20 30

Data/FONLL

0.5 1 1.5 2 2.5 3 3.5 4 4.5

ALI−PUB−16461

ALICE: PRD 86 (2012) 11200 ATLAS: PLB 707 (2012) 438 PLB 708 (2012) 265

pp collisions at √s = 7 TeV

D mesons HF-decay muons HF-decay electrons

slide-7
SLIDE 7
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 7

  • pT-differential production cross section of electrons from beauty-hadron decays
  • Compatibility with FONLL, GM-VFNS and kT-factorization calculations

)

2

) c dy) (mb/(GeV/

T

p /(d σ

2

) d

T

p π 1/(2

  • 8

10

  • 7

10

  • 6

10

  • 5

10

  • 4

10

  • 3

10

  • 2

10 = 2.76 TeV s ALICE pp,

1.9% normalization uncertainty not shown

(a) e → c) → b ( data FONLL factorization

T

k GM-VFNS

Data/Theory 0.5 1 1.5 2 2.5 3

FONLL (b)

Data/Theory 0.5 1 1.5 2 2.5 3

(c)

  • factorization

T

k ) c (GeV/

T

p 2 4 6 8 10

Data/Theory 0.5 1 1.5 2 2.5 3

(d) GM-VFNS

ALI-PUB-82148

PLB 738 (2014) 97-108

Electrons from beauty-hadron decays

Normalized counts (a.u.)

1 10

2

10

3

10

PYTHIA e → c) → b ( e → c Conversions (V0) Dalitz decays Data Conversions (V0) = 2.76 TeV s ALICE pp, (a)

m) µ ( d

  • 600
  • 400
  • 200

200 400 600

Data/MC

0.5 1 1.5 2 2.5 3 Conversions (V0) (b)

ALI-PUB-82084

)

  • 1

(rad

e-h

) ϕ ∆ /d N (d

e

N 1/

1 1.5 2 2.5 3 3.5 4

(a) MB Trigger Sample c < 2.5 GeV/

e T

p 1.5 < c > 0.3 GeV/

h T

p | < 0.9 η | /NDF = 19/18

2

χ

= 2.76 TeV s ALICE pp, (rad) ϕ ∆

  • 3
  • 2
  • 1

1 2 3 1 2 3 4 5 6 7 8

e → Data: c,b MC fit e → MC: c ) e → (c → MC: b

(b) EMCal Trigger Sample c < 6.0 GeV/

e T

p 4.5 < c > 0.3 GeV/

h T

p | < 0.7 η | /NDF = 8.5 / 9

2

χ

ALI-PUB-82098

  • relatively long lifetime (cτ~500 μm) ➜ broad impact parameter distribution
  • decay kinematics ➜ ∆φ between electron-hadron wider than for other sources

Beauty-hadron decays

FONLL: JHEP 1210 (2012) 37, GM-VFNS: EPJ C72 (2012) 2082, kT -factorization: PRD 87 (2013) 094022

Impact-parameter analysis electron-hadron azimuthal correlation

pp collisions at √s = 7 TeV

slide-8
SLIDE 8

(rad) ϕ ∆

  • 1

1 2 3 4 5 )

  • 1
  • baseline (rad

ϕ ∆ d

assoc

N d

D

N 1

  • 0.5

0.5 1 1.5 2 2.5 3 3.5

scale uncertainty

  • 10%
+13%

=7 TeV Data s pp =7 TeV s Simulations, pp Pythia8 Pythia6, Perugia2010 Pythia6, Perugia2011

baseline uncertainty

D meson - charged particle correlation

ALICE Preliminary

| < 1.0 η ∆ , | c > 1.0 GeV/

assoc T

p , c < 16 GeV/

D T

p 8 <

*+

,D

+

,D Average D

ALI−PREL−78716

(rad) ϕ ∆

  • 1

1 2 3 4 5 )

  • 1
  • baseline (rad

ϕ ∆ d

assoc

N d

D

N 1

  • 0.5

0.5 1 1.5 2 2.5 3 3.5

scale uncertainty

  • 10%
+13%

=7 TeV Data s pp =7 TeV s Simulations, pp Pythia8 Pythia6, Perugia2010 Pythia6, Perugia2011

baseline uncertainty

D meson - charged particle correlation

ALICE Preliminary

| < 1.0 η ∆ , | c > 0.5 GeV/

assoc T

p , c < 8 GeV/

D T

p 5 <

*+

,D

+

,D Average D

ALI−PREL−78598

  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 8

  • Baseline subtracted azimuthal correlation of D mesons and charged hadrons
  • Different PYTHIA tunes consistent with the measurement
  • Data from Run-II at the LHC will provide more precision ➜ constrain models

D meson-hadron azimuthal correlations

Measure the associated hadron yield on the near (∆φ around 0) and away side (∆φ around π)

  • Sensitive to quark fragmentation
  • Insight into cc production mechanisms

5 < pTD < 8 GeV/c

  • pTAssoc. > 0.5 GeV/c

8 < pTD < 16 GeV/c

  • pTAssoc. > 1 GeV/c

PYTHIA8 Perugia 2010 Perugia 2011

pp collisions at √s = 7 TeV

slide-9
SLIDE 9

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c <4 GeV/

T

p meson, 2< D c <4 GeV/

T

p meson, 2<

+

D c <4 GeV/

T

p meson, 2<

+

D*

ALICE |<0.5 y = 7 TeV, | s pp

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92901

  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 9

Multiplicity dependence of D-meson production

Self-normalized D-meson yields as a function of charged-particle multiplicity

arXiv:1505.00664

  • Measured for different D-meson species
  • Increase of D-meson per-event yield

with increasing charged-particle yield

  • Within the uncertainties, no pT-

dependence of D-meson yield vs. multiplicity observed

  • Similar rising trend observed for J/ψ

measured in the central and forward rapidity regions PLB 712(2012)165

  • Increase of beauty production with

increasing multiplicity

pp collisions at √s = 7 TeV

slide-10
SLIDE 10
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 10

Multiplicity dependence of D-meson production

Self-normalized D-meson yields as a function of charged-particle multiplicity

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c <4 GeV/

T

p meson, 2< D c <4 GeV/

T

p meson, 2<

+

D c <4 GeV/

T

p meson, 2<

+

D*

ALICE |<0.5 y = 7 TeV, | s pp

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92901

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c < 2 GeV/

T

p 1 < c < 4 GeV/

T

p 2 < c < 8 GeV/

T

p 4 < c < 12 GeV/

T

p 8 < c < 20 GeV/

T

p 12 <

= 7 TeV s ALICE, pp |<0.5 y meson, |

+

, D*

+

,D Average D

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92929

arXiv:1505.00664

  • Measured for different D-meson species
  • Increase of D-meson per-event yield

with increasing charged-particle yield

  • Within the uncertainties, no pT-

dependence of D-meson yield vs. multiplicity observed

  • Similar rising trend observed for J/ψ

measured in the central and forward rapidity regions PLB 712(2012)165

  • Increase of beauty production with

increasing multiplicity

pp collisions at √s = 7 TeV

slide-11
SLIDE 11
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 11

Multiplicity dependence of D-meson production

Self-normalized D-meson yields as a function of charged-particle multiplicity

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c < 2 GeV/

T

p 1 < c < 4 GeV/

T

p 2 < c < 8 GeV/

T

p 4 < c < 12 GeV/

T

p 8 < c < 20 GeV/

T

p 12 <

= 7 TeV s ALICE, pp |<0.5 y meson, |

+

, D*

+

,D Average D

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92929

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c <4 GeV/

T

p |<0.5, 2< y meson |

+

, D*

+

, D Average D >0

T

p |<0.9, y , |

  • e

+

e → ψ J/ >0

T

p <4.0, y , 2.5<

  • µ

+

µ → ψ J/

= 7 TeV s ALICE, pp

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92964

arXiv:1505.00664

pp collisions at √s = 7 TeV

  • Measured for different D-meson species
  • Increase of D-meson per-event yield

with increasing charged-particle yield

  • Within the uncertainties, no pT-

dependence of D-meson yield vs. multiplicity observed

  • Similar rising trend observed for J/ψ

mesons at central and forward rapidity

PLB 712(2012)165

  • Increase of beauty production with

increasing multiplicity

slide-12
SLIDE 12
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 12

  • Measured for different D-meson species
  • Increase of D-meson per-event yield

with increasing charged-particle yield

  • Within the uncertainties, no pT-

dependence of D-meson yield vs. multiplicity observed

  • Similar rising trend observed for J/ψ

mesons central and forward rapidity

PLB 712(2012)165

  • Increase of beauty production with

increasing multiplicity

Multiplicity dependence of D-meson production

Self-normalized D-meson yields as a function of charged-particle multiplicity

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c < 2 GeV/

T

p 1 < c < 4 GeV/

T

p 2 < c < 8 GeV/

T

p 4 < c < 12 GeV/

T

p 8 < c < 20 GeV/

T

p 12 <

= 7 TeV s ALICE, pp |<0.5 y meson, |

+

, D*

+

,D Average D

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92929

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c <4 GeV/

T

p |<0.5, 2< y meson |

+

, D*

+

, D Average D >0

T

p |<0.9, y , |

  • e

+

e → ψ J/ >0

T

p <4.0, y , 2.5<

  • µ

+

µ → ψ J/

= 7 TeV s ALICE, pp

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92964

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

c <4 GeV/

T

p |<0.5, 2< y meson |

+

, D*

+

, D Average D >0

T

p |<0.9, y , |

  • e

+

e → ψ Non-prompt J/

= 7 TeV s ALICE, pp

not shown 〉 η /d N d 〈 ) / η /d N 6% unc. on (d ± +6%/-3% normalization unc. not shown

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9

B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis:

ALI−PUB−92971

arXiv:1505.00664

pp collisions at √s = 7 TeV

slide-13
SLIDE 13
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 13

  • Assessment of initial-state, cold nuclear matter effects
  • Investigate possible final-state effects


p-Pb collisions at √s = 5.02 TeV

slide-14
SLIDE 14
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 14

Nuclear modification factor for HF-decay electrons

  • RpPb of HF-decay electrons compatible with unity
  • Data described by FONLL+EPS09 parametrization of shadowing, within the

uncertainties NPB 373(1992)295, JHEP 0904 (2009) 065

  • RpPb of electrons from beauty hadron decays is also compatible with unity

(GeV/c)

T

p 2 4 6 8 10 12 14 nuclear modifiation factor 0.5 1 1.5 2 2.5 3

normalization uncertainty )/2, TPC-TOF, ALICE reference

  • + e

+

(e → ALICE b,c )/2, TPC-EMCal, ALICE reference

  • + e

+

(e → ALICE b,c )/2, TPC-EMCal, FONLL reference

  • + e

+

(e → ALICE b,c FONLL + EPS09 shad.

< 1.06

CMS

= 5.02 TeV, min. bias, -0.14 < y

NN

s p-Pb,

ALI−DER−53763

RpPb = dσpPb/dpT A × dσpp/dpT

slide-15
SLIDE 15
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 15

Nuclear modification factor for HF-decay electrons

  • RpPb of HF-decay electrons compatible with unity
  • Data described by FONLL+EPS09 parametrization of shadowing, within the

uncertainties NPB 373(1992)295, JHEP 0904 (2009) 065

  • RpPb of electrons from beauty-hadron decays is also compatible with unity

) c (GeV/

T

p

2 4 6 8 10 12 14

pPb

R

0.5 1 1.5 2 2.5 3 e → ALICE b,c e → c) → ALICE b ( normalization uncertainty

ALICE Preliminary

< 0.14

CMS

y = 5.02 TeV, min. bias, -1.06 <

NN

s p-Pb,

ALI−PREL−76745

RpPb = dσpPb/dpT A × dσpp/dpT

slide-16
SLIDE 16
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 16

Nuclear modification factor for HF-decay muons

  • RpPb of HF-decay muons at forward rapidity compatible with unity
  • RpPb of HF-decay muons at backward slightly greater than unity at low pT
  • Data described by models that include cold nuclear matter effects

MNR pQCD calculation with EPS09 parametrization of shadowing NPB 373(1992)295, JHEP 0904 (2009) 065

  • I. Vitev - coherent scattering, kT-broadening, and energy loss in cold nuclear matter PRC 75 (2007) 064906
  • Z. B. Zhang et. al. - incoherent multiple scattering PLB 740 (2015) 23

) c (GeV/

T

p

2 4 6 8 10 12 14 16

pPb

R

0.5 1 1.5 2 2.5

c,b decays ←

±

µ = 5.02 TeV,

NN

s p-Pb <-2.96

cms

  • 4<y

NLO (MNR) with EPS09 shadowing .: incoherent multiple scattering et al

  • Z. B. Kang

systematic uncertainty on normalization

ALICE Preliminary

ALI−PREL−90691

) c (GeV/

T

p

2 4 6 8 10 12 14 16

pPb

R

0.5 1 1.5 2 2.5

c,b decays ←

±

µ = 5.02 TeV,

NN

s p-Pb <3.54

cms

2.5<y

NLO (MNR) with EPS09 shadowing broad + CNM Eloss

T

Vitev: coherent scattering + k systematic uncertainty on normalization

ALICE Preliminary

ALI−PREL−90686

Forward Backward probe low Bjorken x in Pb probe high Bjorken x in Pb Pb-going p-going

slide-17
SLIDE 17
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 17

Nuclear modification factor for D mesons

  • RpPb of D mesons compatible with unity within the pT range covered
  • The RpPb can be described by:

MNR pQCD calculation with EPS09 parametrization of shadowing NPB 373(1992)295, JHEP 0904 (2009) 065

  • I. Vitev - coherent scattering, kT-broadening, and energy loss in cold nuclear matter PRC 75 (2007) 064906

CGC - color glass condensate NPA 920 (2013) 78

.

) c (GeV/

T

p

5 10 15 20 25

pPb

R

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

*+

, D

+

, D Average D <0.04

cms

y

  • 0.96<

CGC (Fujii-Watanabe) pQCD NLO (MNR) with CTEQ6M+EPS09 PDF broad + CNM Eloss

T

Vitev: power corr. + k

ALICE =5.02 TeV

NN

s p-Pb,

ALI−PUB−79415

PRL 113 (2014) 232301

) c (GeV/

T

p

5 10 15 20 25 pPb

R

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Prompt D =5.02 TeV

NN

s p-Pb, <0.04

cms

y

  • 0.96<

) c (GeV/

T

p

5 10 15 20 25 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

+

Prompt D

) c (GeV/

T

p

5 10 15 20 25 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

+

Prompt D*

) c (GeV/

T

p

5 10 15 20 25 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

+ s

Prompt D ALICE

ALI−PUB−79396

slide-18
SLIDE 18
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 18

Multiplicity dependence of D-meson production

  • D-meson production vs. multiplicity ➜ similar trend in pp and p-Pb collisions
  • pp collisions: high multiplicity events attributed to MPI
  • p-Pb collisions: high multiplicity events also from multiple binary nucleon-

nucleon collisions

  • CMS reports similar trend from Υ measurements in pp and p-Pb collisions

〉

T

p d y /d N

2

d 〈 ) /

T

p d y /d N

2

(d

5 10 15 20 25

= 7 TeV s pp, c <4 GeV/

T

p 2< = 5.02 TeV

NN

s p-Pb, c <4 GeV/

T

p Preliminary, 2<

ALICE |<0.5

lab

y meson, |

+

, D*

+

, D Average D

normalization unc. not shown +6%/-3% (2.2%) in pp (p-Pb) not shown 〉 η /d

ch

N d 〈 )/ η /d

ch

N

  • n (d

6% (3%) unc. in pp (p-Pb)

〉 η /d

ch

N d 〈 ) / η /d

ch

N (d

1 2 3 4 5 6 7 8 9 B feed-down unc.

0.4 − 0.2 − 0.2 0.4

1/2 (2) at low (high) multiplicity × B fraction hypothesis in pp and p-Pb:

ALI−PREL−93059

JHEP 04 (2014) 103

slide-19
SLIDE 19

(rad) ϕ ∆

  • 1

1 2 3 4 5 6

)

  • 1

) (rad ϕ ∆ / d

eh

) (dN

e

(1 / N

0.0 0.5 1.0 1.5 2.0

= 5.02 TeV

NN

s p-Pb, < 2.0 GeV/c

e T

1.0 < p < 2.0 GeV/c

h T

0.5 < p (e from c,b)-h correlation | < 1.6 η ∆ | < 0.9, | η |

  • 1

Global normalization uncertainty = 0.06 rad

p-Pb, V0A Multiplicity class: 0 - 20 % p-Pb, V0A Multiplicity class: 20 - 60 % p-Pb, V0A Multiplicity class: 60 - 100 %
  • Syst. on ped. estimation
  • Syst. from secondary particles
= 7 TeV s pp, pp, stat. uncertainty

ALI−PREL−61949

  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 19

HF electron-hadron correlations in p-Pb collsions

(rad) ϕ ∆

  • 1

1 2 3 4

)

  • 1

(rad η ∆ ) per ϕ ∆ / d

h

) (dN

e

(1 / N

3.0 3.1 3.2 3.3 3.4

= 5.02 TeV

NN

s p-Pb, (0-20%) - (60-100%), Multiplicity Classes from V0A < 2.0 GeV/c

e T

1.0 < p < 2.0 GeV/c

h T

0.5 < p | < 1.6 η ∆ | < 0.9, | η | (e from c,b)-h correlation

  • 1

Global normalization uncertainty = 0.022 rad ALI−PREL−62034

(0-20%)-(60-100%)

(rad) ϕ ∆

  • 1

1 2 3 4 5 6

)

  • 1

) (rad ϕ ∆ / d

eh

) (dN

e

(1 / N

0.0 0.5 1.0 1.5 2.0 2.5 3.0

= 5.02 TeV

NN

s p-Pb, < 4.0 GeV/c

e T

2.0 < p < 2.0 GeV/c

h T

0.5 < p (e from c,b)-h correlation | < 1.6 η ∆ | < 0.9, | η |

  • 1

Global normalization uncertainty = 0.11 rad

p-Pb, V0A Multiplicity class: 0 - 20 % p-Pb, V0A Multiplicity class: 20 - 60 % p-Pb, V0A Multiplicity class: 60 - 100 %
  • Syst. on ped. estimation
  • Syst. from secondary particles
= 7 TeV s pp, pp, stat. uncertainty

ALI−PREL−61956

1 < ptrigger

T

< 2 GeV/c 2 < ptrigger

T

< 4 GeV/c

In high multiplicity events:

At low electron pT a hint of near- and away-side enhancement Remove jet contribution by subtracting low multiplicity events Indication for double-ridge structure, as observed for light-flavor two particle correlations. PLB 719 (2013) 29, PLB

726 (2013) 164

HF possibly affected by the processes consistent with long-range correlations in ∆η of light-flavour hadrons Initial state: CGC arXiv:1302.7018 Final state: Hydrodynamics PLB 718 (2013) 1557

( r a d ) ϕ ∆

  • 1

1 2 3 4

η ∆

  • 1.5
  • 1.0
  • 0.5

0.0 0.5 1.0 1.5

)

  • 1

) (rad ϕ ∆ d η ∆ / d

h

N

2

) (d

e

(1 / N

3.0 3.1 3.2

= 5.02 TeV

NN

s p-Pb, (0-20%) - (60-100%), Multiplicity Classes from V0A (e from c,b)-h correlation < 2.0 GeV/c

e T

1.0 < p < 2.0 GeV/c

h T

0.5 < p ALI−PREL−62026

(0-20%)-(60-100%)

— pp √s = 7 TeV p-Pb multiplicity classes 0-20% 20-60% 60-100% For all: 0.5<pTAssoc.<2 GeV/c

slide-20
SLIDE 20

(rad) ϕ ∆

  • 1

1 2 3 4 5 )

  • 1
  • baseline (rad

ϕ ∆ d

assoc

N d

D

N 1

  • 0.5

0.5 1 1.5 2 2.5 3 3.5 4

scale uncertainty p-Pb

  • 9%

+12%

scale uncertainty pp

  • 10%

+13%

=7 TeV s pp =5.02 TeV

NN

s p-Pb baseline uncertainty pp baseline uncertainty p-Pb

D meson - charged particle correlation

ALICE Preliminary

| < 1.0 η ∆ , | c > 0.5 GeV/

assoc T

p , c < 8 GeV/

D T

p 5 <

*+

,D

+

,D Average D

ALI−PREL−79970

(rad) ϕ ∆

  • 1

1 2 3 4 5 )

  • 1
  • baseline (rad

ϕ ∆ d

assoc

N d

D

N 1

  • 0.5

0.5 1 1.5 2 2.5 3 3.5 4

scale uncertainty

  • 9%

+12%

=5.02 TeV Data

NN

s p-Pb =5.02 TeV s Simulations, pp Pythia8 Pythia6, Perugia2010 Pythia6, Perugia2011

baseline uncertainty

D meson - charged particle correlation

ALICE Preliminary

| < 1.0 η ∆ , | c > 0.5 GeV/

assoc T

p , c < 16 GeV/

D T

p 8 <

*+

,D

+

,D Average D

ALI−PREL−79835

  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 20

D meson-hadron correlations in p-Pb collisions

Azimuthal correlation of D mesons with charged hadrons in pp and p-Pb collisions

5 < pTD < 8 GeV/c, pTAssoc. > 0.5 GeV/c 8 < pTD < 16 GeV/c, pTAssoc. > 0.5 GeV/c

  • Distributions from pp and p-Pb collisions are comparable
  • Within the uncertainties the p-Pb measurement is consistent with various PYTHIA tunes
  • Better constraints of PYTHIA tunes with improved statistics available in Run-II at the LHC
slide-21
SLIDE 21
  • S. LaPointe

Charm: The 7th international conference on charm physics 2

  • S. LaPointe

Charm 2015: The 7th International Workshop on Charm Physics 21

Summary and outlook

pp collisions

  • Measured production cross sections allow us to test various pQCD predictions
  • FONLL, GM-VFNS, kT-factorization predictions are in agreement with data
  • Heavy quark fragmentation studies via D-meson azimuthal correlations
  • Consistent with various PYTHIA tunes
  • Heavy-flavour hadron yield vs. multiplicity
  • With increasing multiplicity, yield increases more than linearly
  • Models including MPI contributions reproduce the observed trend

p-Pb collisions

  • Heavy-flavour hadron yields
  • No strong suppression observed with respect to pp collisions
  • Increasing yields with increasing event multiplicity, as observed in pp collisions
  • D-meson azimuthal correlations
  • Consistent with various PYTHIA tunes
  • Electron-hadron azimuthal correlations at low pT
  • Double-ridge structure observed. CGC, hydrodynamic expansion, some other mechanism?

Outlook

  • Statistically larger data sample from Run-II at the LHC
  • More precise measurements of azimuthal correlations, beauty, and heavy flavour in jets
slide-22
SLIDE 22

Extras

slide-23
SLIDE 23

QpPb dependence of event activity

) c (GeV/

T

p 5 10 15 20 25 30 prompt D

mult pPb

Q 0.5 1 1.5 2 2.5 3

0-20% 20-40% 40-60% 60-100%

ALICE Preliminary = 5.02 TeV

NN

s p-Pb,

Filled markers : pp rescaled reference

  • extrapolated reference

T

p Open markers: pp

<0.04

cms

y

  • 0.96 <

+

, D* Average D

ZN Energy Event Classes

ALI−PREL−72234