1. Quarkonia spectra in PbPb at 2.76 TeV Abdulla Abdulsalam (Dr. Prashant Shukla) BARC, Mumbai Outline Motivation Event selection Kinematic cuts Acceptance and efficiency study Summary and plans 1

2. Motivation Measurement of J/ψ→μ + μ - (BR=5.93%) J/ψ is a powerful tool to study hot and dense matter in the collision Measurement of B→ (BR=1.16%) J/ψ→μ + μ - B mesons containing b quark are abundantly produced in early stages of collision, loses energy in medium and carry information about the medium properties. Measurement in the same kinematic space as in pp for direct comparison. 2

3. Event Selection Minimum bias collisions  L1 BscMinBiasThreshold1 (L1a36)  OR L1 HcalHfCoincidencePm (L1a44) Default offline HI PAG selection  Coincidence of 3 HF towers above threshold  Selection of at least a two-track fitted vertex  Cluster-shape filter re-run offline  Reject BSC beam halo L1 technical bits Dimuon trigger  HLT HIL1DoubleMuOpen Core (until run 151020) only 1Z  HLT HIL2DoubleMu3 Core Statistics eq no of MB 51,016,587/0.97 (eff) = 52,594,419 ∫L = 6.88 μb -1 ( using Glauber calculation ) 3

4. The data sets and cuts  Data Set: CorePhysicsPromptRecoV3  Muon Quality Cuts: Same as used in Z0 to start with (no pT cut)  We present first quarkonia mass spectra in PbPb collision at CMS.  We fit Gaussian for invariant mass and polynomial1 & polynomial2 for fitting background  Optimisation of cuts for J/ψ study is in progress. 4

5. Muon Quality Cuts Triggered pT > 3 GeV/c for single muon 5

6. J/ψ: dimuon all acceptance yield by bin counting range =(3.0-3.2) GeV/c 2 N =351.56 ± 30.57 width = 34 MeV/c 2 Int.luminosity= 6.88μb -1 gaussian for invariant mass polynomial2 for background 6

7. J/ψ: dimuon pT > 6.5 GeV Comparative study with pp data dimuon pT [6.5, 30.0] yield by bin counting range =(3.0-3.2) GeV/c 2 N =253.75 ± 19.45 7

8. J/ψ: single muon pT > 4 GeV Comparing with pp data pT> 4 GeV, more clean N = 136.25 ± 12.56 gaussian for invariant mass polynomial2 for background 8

9. J/ψ: single muon |Eta| < 0.8 for barrel region most cleanest N = 64.31 ± 8.81 width =27 MeV/c 2 9

10. Dimuon mass in pT bins pT(6.5, 10) N = 143.98 ± 15.30 pT(10, 12) N = 50.14 ± 7.86 pT(12, 30) N = 64.95 ± 8.78 yield by bin counting range =(3.0-3.2) GeV/c 2 gaussian for invariant mass polynomail1 for background 10 pT(6.5,10)pT(10,12) pT(12,30)

11. Dimuon in different pT & y region dimuon pT > 6.5 & |y| < 1.2 N = 130.24 ± 13.48 dimuon pT > 2 & 1.2 < |y|<1.6 N = 69.20 ± 12.91 dimuon 1.6 < |y| < 2.4 N = 150.28 ± 23.74 gaussian for invariant mass Polynomial2 for background 11

12. J/ψ :Centrality Study 12

13. Jpsi Centrality all acceptance Centrality [0,10] N =110.53 ± 21.90 Centrality [30,60] N =102.10 ± 11.66 Centrality [60,100] N =9.24 ± 3.28 Centrality [10, 30] N =123.08 ± 17.80 13

14. Upsilon: single Muon pT > 4 GeV yield by bin counting range =(9.0-10) GeV/c 2 N = 54.12 ± 14.31 width = 140 MeV/c 2 gaussian for invariant mass polnomial2 for background 14

15. Acceptance and Efficiency Study 15

16. Input pT and rapidity distribution pT y y J/ψ rapidity distribution from NLO calculation b quark rapidity distribution from NLO calculation b quark pT distribution from NLO calculation 16 J/ψ pT distribution from NLO calculation b quark pT distribution from NLO calculation

17. Acceptance and Efficiency  J/Ψ from B-meson can be separated by the secondary vertex information. Reconstruction efficiency= 2.11% J/ Ψ →μ + μ - B→J/ Ψ→ μ + μ - Acceptance cuts |η| <0.8 Acceptance cuts |η| 3 Acceptance cuts |η| <2.1 Acceptance cuts |η| 3 Acceptance cuts |η| <2.4 Acceptance cuts |η| 3 19.02% 0.373% 74.37% 0.829% 84.49% 0.953% 14.82% 0.38% 66.8% 1.1% 78.46% 1.32%  J/Ψ → μ + μ - and B→ J/Ψ→ μ + μ - generated, reconstructed using CMSSW and calculated acceptance 17 Acceptance = each single muon in |Eta|< 2.4 Generated J/Ψ signal in y| < 2.4

18. Summary and plans 1.Successful study of J/ψ (eta, pT and centrality) from PbPb data at 2.76 TeV. 2. We are in the process of optimising muon quality cuts for quarkonia analysis. 3. We apply secondary vertex study to separate the primary J/ψ and secondary J/ψ. 18

19. THANK YOU 19