yen-jie lee (mit) for the atlas and cms collaboration rhic & ags annual users’ meeting

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1 RHIC & AGS Annual Users' Meeting Yen-Jie Lee (MIT) Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting BNL, Upton, USA 18 June, 2014 Recent Open Heavy Flavor Results from ATLAS and CMS Experiment at LHC

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Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting BNL, Upton, USA 18 June, 2014. Recent Open Heavy Flavor Results from ATLAS and CMS Experiment at LHC. Study of open heavy flavor production at the LHC (1/4). Leptons from heavy quarks. μ +. μ -. K +. - PowerPoint PPT Presentation

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Page 1: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

1RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Yen-Jie Lee (MIT)

For the ATLAS and CMS collaboration

RHIC & AGS Annual Users’ Meeting

BNL, Upton, USA

18 June, 2014

Recent Open Heavy Flavor Results from ATLAS and CMS Experiment at LHC

Page 2: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

2RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (1/4)

μ+

Primary vertex

μ-

Leptons from heavy quarks

K+

b

Secondary vertex

Sample O(10%) of b cross-section

Page 3: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

3RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (2/4)

μ+

Primary vertex

μ-

Leptons from heavy quarks

Non-prompt J/ψ

J/ψ

K+

b

Secondary vertex

Dileptons channel sample O(0.1%) of b cross-section

Page 4: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

4RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (3/4)

μ+

Primary vertex

μ-

Leptons from heavy quarks

Non-prompt J/ψ

J/ψ

K+

Exclusive B meson decaysb

Secondary vertex

J/ψ+1(2) tracks decay channels sample O(0.01%) of b cross-section

Page 5: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

5RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (4/4)

b

μ+

Primary vertex

Secondary vertex

μ-

Leptons from heavy quarks

Non-prompt J/ψ

Exclusive B meson decays

J/ψ

K+

b-jet reconstructionb-tagged jet sample O(100%) of b cross-section and ~70-90% of the b quark energy

Page 6: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

6RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Requirements

b

μ+

Primary vertex

Secondary vertex

μ-

Leptons from heavy quarks

Non-prompt J/ψ

Exclusive B meson decays

J/ψ

K+

b-jet reconstructionRequirement: flexible trigger system, muon / electron detection, secondary vertex reconstruction, jet reconstruction

Page 7: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

7RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

ATLAS detector

Page 8: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

8RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

CMS detector

Inner tracker:charged particlesvertex, isolation

solenoid

EM and Hadron calorimetersphotons, isolation, jet reco

MuonMuon

HCALHCAL

ECALECAL

TrackerTracker |η|< 2.5

|η|< 3.0

|η|< 5.2

|η|< 2.4

Pb

Pb

Page 9: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

9RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Bottom Production

At NLO

Excitation of sea quarks b(b) + light

dijet, w/ b(b) at beam rapidity

Gluon splitting into b and b which can

also be reconstructed as a single

jet

Flavor Creation (FCR) Flavor Excitation (FEX) Gluon Splitting (GSP)

LO b-b production (FCR) not dominant at the LHC

arXiv:0705.1937

pp @ 14 TeV

Bottom production at the LHC

Page 10: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

10RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Flavor Creation Candidate (pp @ 7 TeV)

Reconstructed secondaryvertices from b and c quarks

Flavor Creation Candidate (pp @ 7 TeV)

b b

Page 11: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

11RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Gluon Splitting Candidate (pp @ 7 TeV)Gluon Splitting Candidate (pp @ 7 TeV)

b

bg

Page 12: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

12RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (1/4)

μ+

Primary vertex

μ-

1. Leptons from heavy quarks

K+

b

Secondary vertex

Page 13: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

13RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

• Separate signal muons (heavy flavor meson decay) from pion and kaon decays

• Momentum balance

• Scattering angle significance

Heavy flavor muon identification

ATLAS-CONF-2012-050

Signal

Background

μ

π

μ

Inner Detector pID

Muon Spectrometer pMS

Take the maximum:

Page 14: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

14RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Heavy flavor muon signal extraction

• Composite discriminant

r = 0.07

• Signal extracted from atwo component fit

ATLAS-CONF-2012-050

Page 15: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

15RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Suppression of heavy flavor muons in PbPb

Muon RCP vs muon pT Muon RCP vs Npart

(60-80% as reference)

ATLAS-CONF-2012-050

• Suppression of heavy flavor muons in central PbPb collisions with respect to peripheral events is observed ( RCP ~ 0.4)• RCP ~ constant vs. muon pT

Page 16: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

16RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (2/4)

μ+

Primary vertex

μ-

2. Non-prompt J/ψ

J/ψ

K+

b

Secondary vertex

Page 17: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

17RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Inclusive J/ψ production in PbPb

J/ψ B prompt J/ψ

direct J/ψ J/ψ ψ’,χC

inclusive J/ψ

CMS PAS HIN-12-014

Non-prompt J/ψ to dimuon channel

Page 18: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

18RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Non-prompt J/ψ suppression in PbPb

CMS PAS HIN-12-014

Suppression of non-prompt J/ψ in central PbPb collisions with respect to pp reference is observed ( RAA ~ 0.4)

Page 19: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

19RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (3/4)

μ+

Primary vertex

μ-

J/ψ

K+

3. Exclusive B meson decaysb

Secondary vertex

Page 20: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

20RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

B meson reconstruction

20

• B-meson reconstructed by combination of • J/ (decay to dimuon) • tracks (assigned pion or kaon mass, w/o

PID)

B+

B0

Bs

449

•B+→ J/ψ K+→μ+μ- K+

•B0→ J/ ψ K0* →μ+μ- K+π-

•Bs→ J/ ψ φ→μ+μ- K+K-

Page 21: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

21RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Open heavy flavor production in pp collisions

ATLAS and CMS have reported B meson (b baryon) cross-section measurements in pp collisions (pT = 5 GeV to 100 GeV)

Good agreement between pp data and FONLL calculation

5 GeV

Page 22: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

22RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

B meson production in pPb collisions at 5.02 TeV

B+J/ψK+

Three component fit for signal extraction:• Signal• Combinatorial background from J/ψ-

track(s)• Non-prompt component from other B-meson decays that form peaking

structures (e.g. in B+ analysis, bkg from B0→ J/ψ K0* )

First fully reconstructed B meson signal in heavy ion collisions!

BsJ/ψφ

B0J/ψK*0

CMS PAS HIN-14-004

Page 23: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

23RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

B meson production in pPb collisions

Raw yields are corrected by acceptance and efficiency

23

Acceptance Efficiency

CMS PAS HIN-14-004

Page 24: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

24RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Differential cross-section

pp reference : FONLL calculation is used(agreement with CDF, ATLAS and CMS data)

24

http://www.lpthe.jussieu.fr/~cacciari/fonll/fonllform.html

B+ Bs0

|yCM|<1.93

B0B+J/ψK+ BsJ/ψφB0J/ψK*0

Page 25: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

25RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Nuclear modification factor : RpAFONLL

RpAFONLL is compatible with unity within given

uncertainties for the three B-mesons

25

|yCM|<1.93CMS PAS HIN-14-004

Page 26: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

26RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Study of open heavy flavor production at the LHC (4/4)

μ+

Primary vertex

μ-

J/ψ

K+

4. b-jet reconstruction (Anti-kT r=0.3)UE background subtracted

b

Secondary vertex

Page 27: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

27RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Tagging and counting b-quark jets

Secondary vertex tagged using flight distance significance

Tagging efficiency estimated

in a data-driven way

Purity from template fits

to (tagged) secondary vtx

mass distributions

CMS HIN-12-003 ArXiv 1312.4198CMS PAS HIN-14-007

Page 28: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

28RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

b-jet RpAPYTHIA in pPb collisions at 5.02 TeV

CMS PAS HIN-14-007

b-jet RpAPYTHIA is compatible with unity within given uncertainties

Page 29: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

29RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

b-Jet RAA in PbPb collisions at 2.76 TeV

CMS HIN-12-003 ArXiv 1312.4198

Suppression of b-tagged jets in central PbPb collisions with respect to pp reference was observed ( RAA ~ 0.5)

Page 30: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

30RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Summary of open heavy flavor production in ATLAS and CMS

b

μ+

Primary vertex

Secondary vertex

μ-

1. Leptons from heavy quarks

2. Non-prompt J/ψ

3. Exclusive B meson decays

J/ψ

K+

4. b-jet reconstruction

Page 31: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

31RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Summary: RAA (CP) vs Npart

CMS Non-prompt J/ψ RAA ATLAS Heavy Flavor Muon RCP

( 60-80% as reference)

Page 32: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

32RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Summary: Flavor Dependence of Jet Quenching

π

D

Indication of RAA(B) > RAA(D) > RAA(π) at low pT

(However, spectra slope are different)

bJ/ψ

Page 33: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

33RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Summary: Flavor Dependence of Jet Quenching

π

DbJ/ψ

Indication of RAA(B) > RAA(D) > RAA(π) at low pT

(However, spectra slope are different)

Replace non-prompt J/ψ results by exclusive B meson to fix the x axis scale

Page 34: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

34RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Summary: Flavor Dependence of Jet Quenching

π

D

b-jet

Indication of RAA(B) > RAA(D) > RAA(π) at low pT

(However, spectra slope are different)

Indication of RAA(b-jet) ~ RAA(all jets) at high jet pT

bJ/ψ

b quark jet ~ inclusive jet (mainly gluon jets), contribution from gluon splitting?

Page 35: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

35RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Outlook: Statistical Reach in 2015 and beyond

B meson

b-jet

2013 5.02 TeV pPb data (35/nb)

2015-17 5.1 TeV PbPb data (1.5/nb)

B meson

b-jet

2011 2.76 TeV PbPb data (0.15/nb)

b-jet

… Stay tuned!

HL-LHC (10/nb): (b)-jet quenching at O(TeV) ttbar production

Page 36: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

36RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Backup slides

Page 37: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

37RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Open heavy flavor production in pp collisions

Good agreement between

POWHEG+PYTHIA and data

B+J/ψK+

Page 38: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

38RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

B+ production in pp collisions at 7 TeV

Page 39: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

39RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Supporting material for pp referenceData agrees with the FONLL expectation at 1.96(p-

pbar, CDF) and 7 TeV(p-p, ATLAS,CMS)Expect the same agreement at 5TeV collision also

39

arXiv: 1307.0126v2arXiv: 1307.0126v2Phys. Rev. D 75, 012010 (2007)Phys. Rev. D 75, 012010 (2007)

CDFCDF ATLAS, CMSATLAS, CMS

Page 40: Yen-Jie Lee (MIT) For the ATLAS and CMS collaboration RHIC & AGS Annual Users’ Meeting

40RHIC & AGS Annual Users' MeetingYen-Jie Lee (MIT)

Summary of optimal cuts

40

Variable for B-meson selection B+ B0 Bs

2 confidence level of B vertex fit >0.013 >0.16 >0.037

distance between the primary and the B-decay vertices

>3.4 >4.2 >3.4

cosine value of angle between the displacement and the momentum of the B-meson in the transverse plane

> -0.35 > 0.75 > 0.26

difference of the mass between track-pair and resonant meson (unit : GeV/c2)

<0.23 < 0.016