Chib status report

Transcript

1. χb status report Sasha Mazurov University of Ferrara (Italy), CERN O&P meeting 23 August 2013 1/16
2. Motivation b¯ b system, which can be produced in different spin configurations, is ideal laboratory for QCD tests. It’s like a hydrogen atom in QCD. Measured mass Mass from theory States with parallel quark spins (S=1): S-wave Υ state. P-wave χb states, composed by 3 spin states χb(1,2,3) . Υ can be readily produced in the radiactive decays of χb. χb (3P) state recently observed by ATLAS, D0 and LHCb. Study of χb production: 1 Measurement for Υ(NS) (N=1, 2, 3) cross sections in χb decays as a function of pT (NΥ) 2 Measurement of χb(0,1,2) (3P) mass. 2/16
3. Content 1 m(χb(3P)) determination 2 Υ(2S) cross section 3 Υ(3S) cross section 3/16
4. χb (3P) mass determination (1) χb(1, 2, 3P) → Υ(1S)γ 0.5 1 0 500 1000 1500 2000 2500 -4 -2 0 2 4 Candidates/(40 MeV/c2) m µ+µ−γ − m µ+µ− GeV/c2 √ s = 8 GeV data. 1 2 3 4 0 100 200 300 400 500 600 700 Candidates pT (γ) [ GeV/c] Background candidates distribution in pT (γ) range (from sPlot). Background can be reduced for χb (2,3P) signal by applying tighter cut on pT (γ) 4/16
5. χb (3P) mass determination (2) pT (γ) > 1.3 GeV/c 0.8 1 1.2 1.4 0 20 40 60 80 100 120 140 160 -4 -2 0 2 4 Candidates/(20 MeV/c2) m µ+µ−γ − m µ+µ− GeV/c2 √ s = 7 GeV data. 0.8 1 1.2 1.4 0 50 100 150 200 250 300 350 -4 -2 0 2 4 Candidates/(20 MeV/c2) m µ+µ−γ − m µ+µ− GeV/c2 √ s = 8 GeV data. √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 795.9 ± 3.1 795.9 ± 2.3 795.9 ± 1.8 795.2 ± 0.6 µχb1(3P) 1047 ± 7 1079 ± 10 1062 ± 6 1055.7 ± 0.7 Nχb(2P) 400 ± 40 850 ± 50 1250 ± 70 Nχb(3P) 169 ± 27 220 ± 40 370 ± 50 B 1560 ± 60 4510 ± 90 6090 ± 110 Bχb(3P) /Nχb(3P) 3.3 ± 0.7 6.1 ± 1.2 5/16
6. χb (3P) mass determination (3) 0 1 2 3 4 5 6 7 8 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Ratio N of primary vertices Normalized distribution of reconstructed primary vertices. Dark blue bar corresponds to √ s = 7 TeV data and light red bar corresponds to √ s = 8 TeV data. 6/16
7. χb (3P) mass determination (4) pT (γ) > 1.3 GeV/c, Npv = 2 0.8 1 1.2 1.4 0 10 20 30 40 50 60 -4 -2 0 2 4 Candidates/(20 MeV/c2) m µ+µ−γ − m µ+µ− GeV/c2 √ s = 7 GeV data. 0.8 1 1.2 1.4 0 20 40 60 80 100 120 140 -4 -2 0 2 4 Candidates/(20 MeV/c2) m µ+µ−γ − m µ+µ− GeV/c2 √ s = 8 GeV data. √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 787 ± 6 794 ± 4 792.2 ± 3.2 795.2 ± 0.6 µχb1(3P) 1069 ± 13 1071 ± 9 1070 ± 7 1055.7 ± 0.7 Nχb(2P) 132 ± 21 311 ± 34 440 ± 40 Nχb(3P) 57 ± 16 134 ± 25 191 ± 30 B 603 ± 35 1610 ± 60 2210 ± 70 Bχb(3P) /Nχb(3P) 3.7 ± 1.3 3.8 ± 0.9 Consistent peak position of χb(3P) signal for 7 TeV and 8 TeV data. 7/16
8. χb (3P) mass determination (5) pT (γ) > 1.3 GeV/c Npv = 1 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 797 ± 4 794 ± 4 795.2 ± 2.8 795.2 ± 0.6 µχb1(3P) 1041 ± 10 1061 ± 19 1047 ± 10 1055.7 ± 0.7 Nχb(2P) 150 ± 20 239 ± 26 396 ± 33 Nχb(3P) 47 ± 13 58 ± 18 106 ± 22 B 340 ± 28 780 ± 40 1110 ± 50 Bχb(2P) /Nχb(2P) 1.55 ± 0.33 1.78 ± 0.30 1.79 ± 0.23 Bχb(3P) /Nχb(3P) 2.4 ± 0.9 4.9 ± 1.9 3.5 ± 0.9 Npv > 2 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 803 ± 7 799 ± 4 799.9 ± 3.2 795.2 ± 0.6 µχb1(3P) 1041 ± 11 1100 ± 50 1049 ± 15 1055.7 ± 0.7 Nχb(2P) 91 ± 18 304 ± 31 390 ± 40 Nχb(3P) 54 ± 14 23 ± 20 75 ± 27 B 426 ± 30 1620 ± 50 2050 ± 60 Bχb(2P) /Nχb(2P) 2.6 ± 0.7 2.14 ± 0.32 2.9 ± 0.4 Bχb(3P) /Nχb(3P) 2.7 ± 1.0 17 ± 17 8.7 ± 3.5 8/16
9. χb (3P) mass determination (6) Npv <= 2 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 796.8 ± 3.5 793.5 ± 2.6 794.6 ± 2.1 795.2 ± 0.6 µχb1(3P) 1054 ± 8 1071 ± 9 1063 ± 6 1055.7 ± 0.7 Nχb(2P) 266 ± 28 530 ± 40 800 ± 50 Nχb(3P) 97 ± 19 176 ± 29 274 ± 35 B 840 ± 40 2120 ± 70 2950 ± 80 Bχb(2P) /Nχb(2P) 1.95 ± 0.31 1.97 ± 0.22 2.00 ± 0.18 Bχb(3P) /Nχb(3P) 2.9 ± 0.8 3.8 ± 0.8 3.4 ± 0.6 Npv <= 3 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 798.6 ± 3.4 795.2 ± 2.2 796.2 ± 1.8 795.2 ± 0.6 µχb1(3P) 1049 ± 6 1071 ± 9 1058 ± 5 1055.7 ± 0.7 Nχb(2P) 332 ± 32 730 ± 50 1090 ± 60 Nχb(3P) 143 ± 23 212 ± 34 350 ± 40 B 1120 ± 50 3080 ± 80 4190 ± 90 Bχb(2P) /Nχb(2P) 2.06 ± 0.29 2.01 ± 0.19 1.90 ± 0.15 Bχb(3P) /Nχb(3P) 2.6 ± 0.6 4.5 ± 0.9 4.0 ± 0.6 9/16
10. χb (3P) mass determination. hSPD cuts 2011, 2012 0 200 400 600 800 0 0.01 0.02 0.03 0.04 0.05 0.06 Ratio SPD hits (hSPD) hSPD < 300 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 795 ± 4 792.5 ± 2.9 793.3 ± 2.3 795.2 ± 0.6 µχb1(3P) 1056 ± 9 1069 ± 10 1063 ± 7 1055.7 ± 0.7 Nχb(2P) 201 ± 22 375 ± 31 580 ± 40 Nχb(3P) 78 ± 15 108 ± 21 186 ± 26 B 445 ± 32 1030 ± 50 1470 ± 60 Bχb(2P) /Nχb(2P) 1.36 ± 0.26 1.54 ± 0.21 1.50 ± 0.16 Bχb(3P) /Nχb(3P) 2.0 ± 0.6 3.1 ± 0.8 2.6 ± 0.5 hSPD < 400 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 795.1 ± 3.4 793.0 ± 2.3 793.7 ± 1.9 795.2 ± 0.6 µχb1(3P) 1055 ± 8 1073 ± 9 1065 ± 6 1055.7 ± 0.7 Nχb(2P) 273 ± 27 580 ± 40 850 ± 50 Nχb(3P) 102 ± 19 167 ± 27 269 ± 33 B 730 ± 40 1860 ± 60 2590 ± 70 Bχb(2P) /Nχb(2P) 1.74 ± 0.27 1.62 ± 0.18 1.72 ± 0.15 Bχb(3P) /Nχb(3P) 2.6 ± 0.7 3.5 ± 0.7 3.1 ± 0.5 hSPD < 600 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 797.7 ± 3.2 794.2 ± 2.2 795.3 ± 1.8 795.2 ± 0.6 µχb1(3P) 1050 ± 7 1072 ± 9 1061 ± 6 1055.7 ± 0.7 Nχb(2P) 336 ± 32 770 ± 50 1110 ± 60 Nχb(3P) 136 ± 23 206 ± 34 340 ± 40 B 1130 ± 50 3170 ± 80 4300 ± 90 Bχb(2P) /Nχb(2P) 2.04 ± 0.29 1.94 ± 0.18 2.03 ± 0.16 Bχb(3P) /Nχb(3P) 2.8 ± 0.6 4.7 ± 0.9 3.9 ± 0.6 10/16
11. χb (3P) mass determination. Number of tracks. 2011, 2012 0 50 100 150 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 Ratio Number of tracks (nLong) nLong < 40 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 795 ± 4 791.8 ± 2.8 792.8 ± 2.3 795.2 ± 0.6 µχb1(3P) 1056 ± 9 1073 ± 11 1067 ± 7 1055.7 ± 0.7 Nχb(2P) 215 ± 23 396 ± 32 590 ± 40 Nχb(3P) 87 ± 16 91 ± 20 176 ± 27 B 456 ± 33 1080 ± 50 1550 ± 60 Bχb(2P) /Nχb(2P) 1.46 ± 0.26 1.64 ± 0.22 1.49 ± 0.16 Bχb(3P) /Nχb(3P) 2.0 ± 0.6 3.2 ± 0.9 3.1 ± 0.6 nLong < 70 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 797.1 ± 3.2 793.5 ± 2.3 794.6 ± 1.8 795.2 ± 0.6 µχb1(3P) 1056 ± 7 1073 ± 9 1065 ± 6 1055.7 ± 0.7 Nχb(2P) 326 ± 30 680 ± 40 1010 ± 50 Nχb(3P) 129 ± 21 182 ± 30 310 ± 40 B 940 ± 50 2420 ± 70 3360 ± 80 Bχb(2P) /Nχb(2P) 1.76 ± 0.25 1.77 ± 0.18 1.78 ± 0.15 Bχb(3P) /Nχb(3P) 2.5 ± 0.6 4.0 ± 0.8 3.4 ± 0.5 nLong < 100 √ s = 7 TeV √ s = 8 TeV √ s = 7 and 8 TeV PDG µχb1(2P) 798.1 ± 3.2 793.7 ± 2.2 795.1 ± 1.8 795.2 ± 0.6 µχb1(3P) 1050 ± 6 1076 ± 9 1062 ± 6 1055.7 ± 0.7 Nχb(2P) 343 ± 33 770 ± 50 1120 ± 60 Nχb(3P) 144 ± 23 206 ± 34 350 ± 40 B 1140 ± 50 3150 ± 80 4280 ± 90 Bχb(2P) /Nχb(2P) 2.09 ± 0.29 1.90 ± 0.18 2.10 ± 0.16 Bχb(3P) /Nχb(3P) 2.7 ± 0.6 4.6 ± 0.9 3.8 ± 0.6 11/16
12. Υ(2S) cross section(1) χb(2, 3P) → Y (2S) 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 400 -4 -2 0 2 4 Candidates/(20 MeV/c2) 18 < pΥ (2S) T < 22 GeV/c √ s = 8 GeV m µ+µ−γ − m µ+µ− GeV/c2 √ s =7 TeV Υ(2S) transverse momentum interval in GeV/c 18 — 22 22 — 30 Nχb(2P) 146 ± 23 67 ± 17 Nχb(3P) 24 ± 13 23 ± 10 B 1410 ± 40 683 ± 32 µχb1(2P) , MeV/c2 223.2 ± 2.8 234 ± 4 µχb1(3P) , MeV/c2 529 ± 13 482 ± 11 σχb1(2P) , MeV/c2 12.1 11.5 σχb1(3P) /σχb1(2P) , MeV/c2 1.7 1.9 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 -4 -2 0 2 4 Candidates/(20 MeV/c2) 22 < pΥ (2S) T < 30 GeV/c √ s = 8 GeV m µ+µ−γ − m µ+µ− GeV/c2 √ s =8 TeV Υ(2S) transverse momentum interval in GeV/c 18 — 22 22 — 30 Nχb(2P) 350 ± 40 242 ± 27 Nχb(3P) 54 ± 23 32 ± 15 B 3720 ± 70 1600 ± 50 µχb1(2P) , MeV/c2 226.6 ± 1.9 229.2 ± 1.7 µχb1(3P) , MeV/c2 497 ± 10 468 ± 13 σχb1(2P) , MeV/c2 12.1 11.5 σχb1(3P) /σχb1(2P) , MeV/c2 1.7 1.9 12/16
13. Υ(2S) cross section (2) √ s =7 TeV, √ s =8 TeV 20 25 30 15 20 25 30 35 40 Fraction(%) χb(2P) pT (Υ (2S)) [ GeV/c] √ s =7 TeV Υ(2S) transverse momentum interval in GeV/c 18 — 22 22 — 30 Nχb(2P) 146 ± 23 67 ± 17 Nχb(2P) 24 ± 13 23 ± 10 NΥ(2S) 2750 ± 60 1480 ± 50 εχb(2P) (%) 15.1 ± 1.8 22.2 ± 3.5 εχb(3P) (%) 22 ± 4 22 ± 7 Fraction χb(2P) (%) 35 ± 7 20 ± 6 Fraction χb(3P) (%) 4.0 ± 2.4 7 ± 4 20 25 30 2 3 4 5 6 7 8 9 10 Fraction(%) χb(3P) pT (Υ (2S)) [ GeV/c] √ s =8 TeV Υ(2S) transverse momentum interval in GeV/c 18 — 22 22 — 30 Nχb(2P) 350 ± 40 242 ± 27 Nχb(2P) 54 ± 23 32 ± 15 NΥ(2S) 6590 ± 100 3590 ± 80 εχb(2P) (%) 15.1 ± 1.8 22.2 ± 3.5 εχb(3P) (%) 22 ± 4 22 ± 7 Fraction χb(2P) (%) 35 ± 6 30 ± 6 Fraction χb(3P) (%) 3.8 ± 1.8 4.2 ± 2.3 13/16
14. Υ(3S) cross section (1) χb(3P) → Y (3S) 0.1 0.2 0.3 0.4 0 2 4 6 8 10 12 14 16 18 20 22 -4 -2 0 2 4 Candidates/(20 MeV/c2) 27 < pΥ (2S) T < 40 GeV/c √ s = 7 GeV m µ+µ−γ − m µ+µ− GeV/c2 √ s =7 TeV Υ(3S) transverse momentum interval in GeV/c 27 — 40 Nχb(3P) 39 ± 9 B 116 ± 13 µχb1(3P) , MeV/c2 157.0 ± 2.6 σχb1(3P) , MeV/c2 8.2 0.1 0.2 0.3 0.4 0 10 20 30 40 50 60 -4 -2 0 2 4 Candidates/(20 MeV/c2) 27 < pΥ (2S) T < 40 GeV/c √ s = 8 GeV m µ+µ−γ − m µ+µ− GeV/c2 √ s =8 TeV Υ(3S) transverse momentum interval in GeV/c 27 — 40 Nχb(3P) 99 ± 15 B 378 ± 23 µχb1(3P) , MeV/c2 150.3 ± 2.0 σχb1(3P) , MeV/c2 8.2 14/16
15. Υ(3S) cross section (2) √ s =7 TeV, √ s =8 TeV 30 35 40 30 40 50 60 70 80 90 100 Fraction(%) χb(3P) pT (Υ (3S)) [ GeV/c] √ s =7 TeV Υ(3S) transverse momentum interval in GeV/c 27 — 40 Nχb(3P) 39 ± 9 NΥ(3S) 419 ± 29 εχb(3P) (%) 13 ± 6 Fraction χb(3P) (%) 70 ± 40 √ s =8 TeV Υ(3S) transverse momentum interval in GeV/c 27 — 40 Nχb(3P) 99 ± 15 NΥ(3S) 1310 ± 50 εχb(3P) (%) 13 ± 6 Fraction χb(3P) (%) 58 ± 29 15/16
16. Summary Measured cross-sections for Υ(1, 2, 3S) (need to fix m(χb (3P)) in fits) Measured mass of χb(3P) TODO Generate more Monte-Carlo events Measure systematic uncertainties Analysis note draft: https://twiki.cern.ch/twiki/bin/viewauth/LHCbPhysics/ChiB2fb (not ready for review yet) 16/16