Gluon Gluon to jpsi jpsi CMS Meeting 8-20 CMS B-Physics meeting

Typical Feynman diagrams of pair production in p p collision at leading order in color-singlet scheme CMS Meeting 8-20 CMS B-Physics meeting

Typical Feynman diagrams of pair production in p p collision at leading order in color-singlet scheme The generator is on the basis of FDC system(arXiv: hep-ph/0407058), and the generator could generate events in color-singlet and –octet scheme, respectively. CMS Meeting 8-20 CMS B-Physics meeting

Comparison between theoretical cross-section calculations and the results of my generator (see arxiv-0903.0954v3 for mathematica results) Down limit (2jpsi) ( ) Theoretical calculations in Mathematica Generator results Single-color Octet-color 5GeV 1.08pb 1.15pb 1.329pb 1.492pb 6GeV 0.37pb 0.74pb 0.402pb 0.908pb 7GeV 0.14pb 0.49pb 0.144pb 0.583pb CMS Meeting 8-20 CMS B-Physics meeting

Signals If set the down limit of Pt of double jpsi at 5GeV，because if Pt of jpsi was lower than 5GeV, the c quark fragmentation is not appropriate. cross-section of single-color model is 1.125pb; cross-section of octet-color model is 1.131pb. (10 TeV) This result has included branching ratio of jpsi to mumu:5.6% for each jpsi CMS Meeting 8-20 CMS B-Physics meeting

CMSSW_3_1_1, 10 TeV Model Pre-selection Color-singlet (100,000 events) 93030 Color-octet (100,000 events) 88249 Pre-selection: dimuon with different charge, Pt >0.7, |eta|<2.5, invariant mass (3.0, 3.2) CMS Meeting 8-20 CMS B-Physics meeting

Recomuon Number (trackermuon) Octet Singlet Singlet CMS Meeting 8-20 CMS B-Physics meeting

Inva_mass fitting 2 Cut the first di-muon mass: 2.9-3.3; Two vertex fitting, chi-square<100. Fitting area 3.0-3.2 6566 CMS Meeting 8-20

(pt<3&&fabs(eta)<1)||(pt<3-(1. 5/0. 2 (pt<3&&fabs(eta)<1)||(pt<3-(1.5/0.2*(fabs(eta)-1))&&fabs(eta)<1.2&&fabs(eta)>1) ||(pt<1.5-(0.8/1.3*(fabs(eta)-1.2))&&fabs(eta)<2.5&&fabs(eta)>1.2)) CMS Meeting 8-20

Muon +track Cut the first di-muon mass: 2.9-3.3; Two vertex fitting, chi-square<100. Fitting area 3.0-3.2 11088.7 CMS Meeting 8-20

Event selection (logical order) Select first good jpsi: firstly, I require vertex fitting CL>0.001; then mass window:2.9-3.3 Bin according to Pt of first good jpsi:0-6,6-8,8-10, 10-12,12+ or 0-6, 6-8, 8-10, 10+ Require vertex fitting CL of the second muon pair or muon + track >0.001. So I can decrease background from mis-pairing. Fit invariant mass of second particle pair. Only could I attain the event number from fitted invariant mass of second particle pair!!! CMS Meeting 8-20

Efficiency The numerator is number of second particle pair after fitting. The denominator is generated events whose jpsi’s Pt is in responding Pt bin. Because Pt of both jpsi is equal, so I can choose Pt of any jpsi to calculate the denominator. I should check whether Pt of first jpsi is equal to that of fitted second particle pair. CMS Meeting 8-20

CMS Meeting 8-20

CMS Meeting 8-20

Octet MCjpsi Pt Bin:0-6,6-8,8-10,10-13,13+ CMS Meeting 8-20 CMS B-Physics meeting

0-6 512 6-8 1122 8-10 1290 10-13 1090 13+ 1432 CMS Meeting 8-20

0-6 1920 6-8 3608 8-10 2777 10-13 1284 13+ 965 CMS Meeting 8-20

Singlet MCjpsi Pt Bin: 0-6, 6-8, 8-10, 10+ CMS Meeting 8-20

1495 1376 698 240 CMS Meeting 8-20

3621 5133 1614 324 CMS Meeting 8-20

General Efficiency Trig is efficiency of trigger path to select events. Final-parti-reco is efficiency of final particles like muon, photon, jet, etc. CMS Meeting 8-20