J/ψ→μ+μ- Trigger For the First 1/fb Data M. Yang G. M. Chen IHEP Beijing Sep. 25, 2006

Introduction With the first 1/fb data, it is intended to collect a large amount of: 1) prompt J/ψ to calibrate the detector and to study the polarization; 2) B hadrons contain J/ψ decay to check the performance of the detector; Bs→ J/ψ φ to study CP violation; And to collect enough Bc to measure it’s mass and life time They are all low pT stuff, low pT dimuon trigger is needed, but the HLT rates must be within the bandwidth allowed.

Dimuon trigger at 2x1033 L1 dimuon trigger threshold: 3GeV HLT pT threshold (GeV) HLT rate (Hz) Dimuon isolated 7, 7 4.8 ±0.4 Dimuon relaxed 10, 10 8.6±0.6 (PTDR vol2 Table E12)

MC Data Samples QCD, W+jets, Z+jets: CMS official production with OSCAR ORCA bbbar→μμ X, ccbar→μμX, B hadrons decay containing J/ψ →μμ, prompt J/ψ were produced by FAMOS in Beijing

QCD datasets Dataset σ(mb) No. of events jm03b_qcd_0_15 55.22 23999 1.50006 44999 jm03b_qcd_20_30 0.641733 89999 jm03b_qcd_30_50 0.155929 92997 jm03b_qcd_50_80 0.02093883 198993 jm03b_qcd_80_120 0.002949713 90000 jm03b_qcd_120_170 0.000499656 70000 jm03b_qcd_170_230 0.000100995 40000 jm03b_qcd_230_300 2.3855*10-5 20000 jm03b_qcd_300_380 6.39108*10-6 243983 jm03b_qcd_380_470 1.88967*10-6 5000

QCD dimuon efficiency withμPt > 3GeV Dataset events QCD →μ (eff)² QCD→μμ eff 0_15 23999 15 (3.92.0)*10-7 15_20 44999 153 (1.2 0.2)*10-5 1 ( 2.2 2.2 )*10-5 20_30 89999 572 (4.0 0.3)*10-5 6 ( 6.72.7)*10-5 30_50 92997 1139 (1.5 0.1)*10-4 20 (2.2 0.5)*10-4 50_80 198993 5116 (6.6 0.2)*10-4 158 (7.9 0.6)*10-4 80_120 90000 3878 (1.9 0.1) *10-3 163 (1.8 0.1)*10-3 120_170 70000 4314 (3.8 0.1)*10-3 286 (4.1 0.2)*10-3 170_230 40000 3403 (7.2 0.2)*10-3 276 (7.0 0.4)*10-3 230_300 20000 2125 (1.1 0.0)*10-2 199 (1.0 0.1)*10-2 300_380 243983 33606 (1.9 0.0)*10-2 4051 (1.70.0)*10-2 380_470 5000 774 (2.4 0.2)*10-2 117 ( 2.30.2)*10-2

Trigger Rate at 1033 μPt >3GeV μPt >4GeV μPt >5GeV 0_15 ( 21.511.0) (11.6 7.2) ( 2.42.1) (0.9 1.0) (0.3 0.5) 15_20 ( 18.03.0) ( 12.62.3) (5.4 1.2) (2.30.6) (1.0 0.3) 20_30 ( 25.71.9) (18.6 1.9) ( 11.61.3) ( 6.40.6) (3.1 0.4) 30_50 ( 23.41.6) (18.7 1.6) (12.3 0.9) ( 7.30.6) (4.5 0.5) 50_80 ( 13.90.4) (11.3 0.4) ( 8.60.2) (6.1 0.2) ( 4.00.2) 80_120 ( 5.60.3) (4.7 0.3) ( 3.80.3) (2.8 0.1) (2.1 0.1) 120_170 (1.9 0.0) (1.6 0.5) ( 1.30.0) (1.0 0.0) (0.8 0.0) 170_230 (0.7 0.0) (0.6 0.0) (0.4 0.0) (0.3 0.0) 230_300 ( 0.20.0) (0.2 0.0) (0.1 0.0) 300_380 380_470 (0.0 0.0) ( 0.00.0) Total (111 11.7) ( 80.18.0) (46.3 2.9) ( 27.51.5) ( 16.30.9)

Isolation could not separate QCD and B hadron

J/ψ mass window can be used to reduce the HLT rates 2 windows : small [3.0, 3.2] large [2.9, 3.3]

Mass of di-muons from QCD

QCD J/ψmass window (small) efficiency Dataset σ(mb) Total No. of events jm03b_qcd_15_20 → jm03b_qcd_380 470 895,971 No. of events dimuon (μPt>3GeV) within [3.0,3.2] = 64

QCD HLT rates with small window at 1033 μPt>3GeV (Hz) And 3.0<Mass<3.2GeV (Hz) 0_15 ( 21.511.0) ( 0.26  0.13) 15_20 ( 18.03.0) (0.22  0.04) 20_30 ( 25.71.9) (0.31  0.02) 30_50 ( 23.41.6) ( 0.28  0.02) 50_80 ( 13.90.4) ( 0.17  0.00) 80_120 ( 5.60.3) (0.07  0.00) 120_170 (1.9 0.0) (0.02  0.00) 170_230 (0.7 0.0) (0.01  0.00) 230_300 (0.3 0.0) (0.00  0.00) 300_380 (0.1 0.0) ( 0.00  0.00) 380_470 (0.0 0.0) Total (111 11.7) ( 1.34  0.14)

W+jets HLT rates at 1033 μPt>3GeV & 3.0<Mass<3.2 GeV 0_20 (3.318 0.336)*10-5 20_50 (2.142  0.126)*10-5 50_85 (1.554  0.042)*10-5 85_150 (1.428  0.042)*10-5 150_250 (4.62  0.00)*10-6 250_400 (1.554 0.084)*10-6 Total (9.06  0.01) *10-5 (Hz)

Z+jets HLT rates with small window at 1033 μPt>3GeV & 3.0<Mass<3.2 GeV 0_20 (7.58 0.14) *10-5 20_50 (1.67 0.08) *10-5 50_85 (0.59 0.00) *10-5 85_150 (0.27 0.00) *10-5 150_250 (0.08 0.00) *10-5 250_400 (0.03 0.00) *10-5 Total (1.022  0.16) *10-4 (Hz)

Other channels Small window sum 1.55±0.15 Hz μPt>3GeV & 3.0<Mass<3.2 GeV bbbar→ μμ+ X 0.0058  0.00166 (Hz) ccbar→ μμ+ X 0.0075  0.00036 (Hz) prompt J/ψ → μμ 0.1675  0.00036 (Hz) B+ → J/ ψ (μμ)+X 0.0316  0.00009 (Hz) Bs → J/ ψ (μμ)+ X 0.0101  0.00003 (Hz) B0 → J/ ψ (μμ)+ X 0.0338  0.00006 (Hz) Λb → J/ ψ (μμ)+X 0.0122  0.00003 (Hz) Small window sum 1.55±0.15 Hz

QCD HLT rates with large window at 1033 Data μPt>3GeV & 2.9<Mass<3.3GeV 0_15 ( 0.36  0.18) 15_20 ( 0.30  0.06) 20_30 ( 0.43  0.03) 30_50 ( 0.39  0.03) 50_80 ( 0.23  0.01) 80_120 ( 0.10  0.01) 120_170 ( 0.03  0.00) 170_230 ( 0.01  0.00) 230_300 ( 0.00  0.00) 300_380 380_470 Total ( 1.85  0.19) (Hz)

Large mass window Large window sum 2.14±0.20 Hz Data μPt>3GeV & 2.9<Mass<3.3GeV bbbar→ μμ+ X 0.0134  0.00254 (Hz) ccbar→ μμ+ X 0.0153  0.00051 (Hz) prompt J/ψ → μμ+ X 0.1696  0.00036 (Hz) B+ → μμ+X 0.0320  0.00009 (Hz) Bs → μμ+ X 0.0102  0.00003 (Hz) B0 → μμ+ X 0.0342  0.00006 (Hz) Λb → μμ+X 0.0124  0.00004 (Hz) Total ( 0.2871  0.0026) (Hz) Large window sum 2.14±0.20 Hz

Preliminary suggestion Dimuon trigger for the first 1/fb data collection: L<1032 pT>3GeV L>1032, pT>7GeV or pT>3GeV & J/ψ mass window increasing the trigger rate by about 2Hz @1033

Outlook Study the J/ψ→μ+μ- trigger with CSA06 data in the CMSSW framework Consider the trigger efficiency for B hadrons and prompt J/ψ Consider timing