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Alexander Mazurov
Alexander Mazurov

This document describes a study measuring the fraction of J/ψ mesons originating from Υ(1P), Υ(2P), and Υ(3P) decays as a function of pT(J/ψ) using data collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV. The analysis involves determining yields of J/ψ mesons and yields from Υ decays to J/ψ in different pT bins. Monte Carlo simulations are used to calculate efficiencies and compare data distributions. Results include improved precision on previous LHCb measurements of these fractions and a measurement of the Υ1(3P) mass.

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Production of b at p s =7 and 8 TeV Vanya Belyaev, Concezio Bozzi, Hans Dijkstra, Sasha Mazurov ICHEP approval session 6 June 2014 1/23
Motivation Bound bb states, which can be produced in different spin configurations, are an ideal laboratory for QCD tests. It’s like a hydrogen atom in QCD. States with parallel quark spins (S=1): S-wave state. P-wave b states, composed by 3 spin states b(0;1;2). can be readily produced in the radiative decays of b. b(3P) state recently observed by ATLAS, D0 and LHCb. This study: 1 Measurement of (NS) (N=1, 2, 3) fraction originating from b decays as function of pT(). Provides valuable information on Color-Octet matrix elements. 2 Measurement of b(3P) mass. 2/23
Previous analysis “Production of (1S) mesons from b decays in pp collisions at p s = 1:8 TeV” at CDF, arXiv:hepex/9910025. “Observation of a new b state in radiative transitions to (1S) and (2S) at ATLAS”, arXiv:1112.5154 “Measurement of the fraction of (1S) originating R from b(1P) in pp p collisions at s =7 TeV”, arXiv:1209.0282, L = 32 pb1 “Observation of the b(3P) state at LHCb in pp collisions at p s =7 TeV”, LHCb-CONF-2012-020, R L = 0:9 fb1. 100 90 80 70 60 50 40 30 20 10 6 7 8 9 10 11 12 13 14 15 ¡ (1S) (GeV/c) T p (1P) (%) b (1S) from c ¡ Fraction of 0 LHCb s = 7 TeV 300 LHCb preliminary 250 200 150 100 50 0 0.5 1 1.5 2 2) ) (GeV/c − μ + g ) − m(μ − μ + m(μ Candidates / 20 MeV/c2 0 s = 7 TeV ­1 0.9 fb 0 0.5 1 1.5 2 Pull 4 2 0 ­2 ­4 b(3P) 3/23
In this study The results in this study extend the statistical precision of previous LHCb measurements and add considerably more decays and higher transverse momentum regions. The measurement of (3S) fraction in radiative b(3P) decay was performed for the first time. In each pT() bin calculate: (pp!b(mP)X)Br(b(mP)!(nS) ) (pp!(nS)X) = Nb(mP)!(nS) N(nS) (nS) b(mP)!(nS) for each (nS); n = 1; 2; 3 and b(mP);m = 1; 2; 3 Get N from fits: N from m(+) and Nb! from [m(+ ) m(+)] (for better resolution) Compute efficiency from Monte-Carlo simulation 4/23
Content 1 Datasets 2 Determination of yields 3 Determination of b yields in the following decays: b(1; 2; 3P) ! (1S) b(2; 3P) ! (2S) b(3P) ! (3S) 4 Measuring of b1(3P) mass 5 Monte-Carlo efficiencies 6 Systematic uncertainties 7 Results 5/23
Datasets Full 2011 dataset at p s =7 TeV. R L = 1 fb1 Full 2012 dataset at p s =8 TeV. R L = 2 fb1 Monte-Carlo simulation of b inclusive decays, generated 62 106 events. 6/23
The selection Almost the same cuts as are used in the study “Measurement of production p in pp collisions at s = 2:76 TeV”, arXiv:1402.2539 Description Requirement rapidity 2:0 y 4:5 Track fit quality 2=ndf 4 Track pT 1 GeV=c + vertex probability 0:5% Luminous region jzPVj 0:5m and x2 PV + y2 PV 100mm2 Kullback-Leibler distance 5000 Muon and hadron hypotheses logLh 0 Muon probability ProbNN 0:5 Trigger lines: L0 L0DiMuon HLT1 Hlt1DiMuonHighMass HLT2 HLT2DiMuonB 7/23
The fit model p s = 7 TeV 6 p+ T 12 GeV=c 9 10 11 30000 25000 20000 15000 10000 5000 0 Candidates/(40 MeV=c2) m+ GeV=c2 (1S) (2S) (3S) + transverse momentum intervals, GeV=c 6 – 40 p s = 7 TeV p s = 8 TeV N(1S) 283,300 600 659,600 900 N(2S) 87,500 400 203,300 600 N(3S) 50,420 290 115,300 400015 3 Double Crystal Ball functions for signal yields. Tails’ parameters are fixed from simulation. Exponential function for combinatorial background. 8/23
b selection In this study photons reconstructed using the calorimeter information. Another approach uses photon conversions in e+e pairs—this method has better invariant mass resolution, but requires more statistics. Cuts on : Transverse momentum of pT ( ) 600 MeV=c Polar angle of in the + rest frame cos 0 Confidence level of CL( ) 0:01 Dimuon mass windows: 9 10 11 35000 30000 25000 20000 15000 10000 5000 0 Candidates/(12 MeV=c2) m+ GeV=c2 9/23
b1;2(1; 2; 3P) ! (1S) fit model (1) 10 10.5 1000 800 600 400 200 0 4 2 0 -2 -4 Candidates/(20 MeV=c2) m+ m+ + mPDG (1S) h GeV=c2 i p b(1P) s = 7 TeV b(2P) b1 b2 b(3P) One Crystal Ball (CB) for each b1;2(1P; 2P; 3P) state: 6 CB in total Exclude the study of b0 due to its low radiative branching ratio. Product of exponential and linear combination of polynomials for combinatorial background. 10/23
b1;2(1; 2; 3P) ! (1S) fit model (2) Free parameters: yields and background parameters. Fixed parameter: b1(1P) to the value measured on combined 2011 and 2012 datasets. Linked parameters for b1 and b2 signals: b2(jP) = b1(jP) + mPDG b2(jP), j=1,2 b2(3P) = b1(3P) + mtheory b2(3P) Nb = Nb1 + (1 )Nb2 ( is fixed to 0.5) b2 = b1 Other linked parameters: b1(2P) = b1(1P) + mPDG b1(2P) b1(3P) = b1(1P) + mb1(3P) (mb1(3P) measured in this study) Fixed parameters from MC study: b1(1P), b1(2P) b1(1P) , b1(3P) b1(1P) and n parameters of CB. (1S) transverse momentum intervals, GeV=c 14 – 40 p s = 7 TeV p s = 8 TeV Nb(1P) 2090 80 5070 130 Nb(2P) 450 50 1010 80 Nb(3P) 150 40 220 60 11/23
b fits LHCb p s = 7 TeV 10 10.5 1000 800 600 400 200 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (1S) GeV=c2 LHCb p s = 8 TeV 10 10.5 2500 2000 1500 1000 500 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (1S) GeV=c2 LHCb p s = 7 TeV 10.2 10.4 10.6 10.8 11 250 200 150 100 50 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (2S) GeV=c2 LHCb p s = 7 TeV 10.2 10.4 10.6 10.8 11 600 500 400 300 200 100 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (2S) GeV=c2 LHCb p s = 7 TeV 10.5 10.6 10.7 30 25 20 15 10 5 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (3S) GeV=c2 LHCb p s = 8 TeV 10.5 10.6 10.7 80 70 60 50 40 30 20 10 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (3S) GeV=c2 12/23
Mass of b1(3P) in b ! (3S) decay LHCb p s = 7 and 8 TeV 10.5 10.6 10.7 100 80 60 40 20 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (3S) GeV=c2 The measured on the combined 2011 and 2012 datasets mb1(3P)=10;510 2 (stat) 6 (syst)MeV=c2 is consistent with the mass measured in another study with converted photons— 10;515:7 3:1 (stat)+1:5 2:1 (syst) MeV=c2 (very preliminary results). ATLAS measured b1 and b2 mass barycenter for mb2 mb1 = 12 MeV=c2 and = 0:5: mb(3P) = 10;530 5 (stat) 9 (syst) MeV=c2 D0: mb(3P) = 10;551 14 (stat) 17 (syst) MeV=c2 13/23
Data— Monte Carlo comparison A comparison of the distribution of the relevant observables used in this analysis was performed on real and simulated data, in order to assess the reliability of Monte Carlo in computing efficiencies 0.06 0.05 0.04 0.03 0.02 0.01 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.06 0.05 0.04 0.03 0.02 0.01 0 pT [(1S)] b(1P) b(2P) b(3P) GeV=c2 pT [b(1P)] b(1P) b(2P) b(3P) GeV=c2 pT [(1S)] GeV=c2 pT [b(2P)] GeV=c2 pT [(1S)] GeV=c2 pT [b(3P)] GeV=c2 b(1P) b(2P) b(3P) 2 of decay tree fitter 2 of decay tree fitter 2 of decay tree fitter 0 0.2 0.4 0.6 0.8 1 0.1 0.08 0.06 0.04 0.02 0.1 0.08 0.06 0.04 0.02 0 0.08 0.06 0.04 0.02 0.06 0.05 0.04 0.03 0.02 0.01 0 0 0.2 0.4 0.6 0.8 1 0.2 0.15 0.1 0.05 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 -0.02 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 0.1 0.08 0.06 0.04 0.02 0 -0.02 0 0.2 0.4 0.6 0.8 1 0 2 4 0 0 2 4 0 0 2 4 -0.02 0 10 20 30 0 10 20 30 0 10 20 30 15 20 25 30 35 0 15 20 25 30 35 0 15 20 25 30 35 0 confidence level confidence level confidence level Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units b(1P) b(2P) b(3P) The agreement is generally very good. 14/23
Monte-Carlo photon reconstruction efficiency b(1P) ! (1S) p s =7 TeV p s =8 TeV b(3P) ! (1S) p s =7 TeV p s =8 TeV b(3P) ! (2S) p s =7 TeV p s =8 TeV 20 30 40 30 25 20 15 10 5 25 20 15 10 5 30 25 20 15 10 5 0 Efficiency, % p(2S) T [ GeV=c] 30 25 20 15 10 5 25 20 15 10 5 25 20 15 10 5 0 b(2P) ! (1S) p s =7 TeV p s =8 TeV b(2P) ! (2S) p s =7 TeV p s =8 TeV b(3P) ! (3S) p s =7 TeV p s =8 TeV 20 25 30 35 40 Efficiency, % p(3S) T [ GeV=c] 10 20 30 40 0 Efficiency, % p(1S) T [ GeV=c] 20 30 40 0 Efficiency, % p(2S) T [ GeV=c] 10 20 30 40 0 Efficiency, % p(1S) T [ GeV=c] 10 20 30 40 0 Efficiency, % p(1S) T [ GeV=c] Photon is more energetic as pT() increases so it is reconstructed more efficiently. 15/23
Systematic uncertainties Since this analysis measures the fraction of (nS) particles originating from b decays, most systematic uncertainties cancel in the ratio and only residual effects need to be taken into account. Systematic uncertainties on the event yields are mostly due to the fit model of and b invariant masses, while the ones on the efficiency are due to the photon reconstruction and the unknown initial polarization of b and particles. The uncertainty related to the fit model estimated by the previous study “Production of Jp = and mesons in pp collisions at s = 8 TeV”, arXiv:1304.6977 Systematic due to photon reconstruction taken from the previous works based on “Study of 0= reconstruction efficiency with 2011 data”, LHCb-INT-2012-001. fraction uncertainties common to all b decays (%) fit model 0:7 reconstruction 3 16/23
Systematic uncertainties— Polarization The polarization is expected to be small. “Measurement of the (1S), p Y2S and (3S) polarizations in pp collisions at s = 7 TeV”, arXiv:1209.2922. The uncertainty related to the unknown polarization of b mesons was estimated using the prescription described in the LHCb paper “Measurement of the relative rate of prompt c0, c1 and c2 production at p s = 7TeV” (thanks to Edwige Tournefier) that is based on the analytical calculations in HERA “Production of the Charmonium States and p c1 c2 in Proton Nucleus Interactions at s = 41.6-GeV” In the previous study the uncertainty due to polarization is dominated 20%. This study shows that this uncertanty is less than 9%. 17/23
Summary of systematic uncertainties T Summary of fraction systematic uncertainties (%) (maximum deviations that were found in pbins): b fit model b polarization b(1P) ! (1S) +4:3 5:8 +5:1 4:0 b(2P) ! (1S) +4:8 6:2 +5:8 6:8 b(3P) ! (1S) +19:6 16:6 +6:9 6:7 b(2P) ! (2S) +2:3 7:0 +8:7 7:8 b(3P) ! (2S) +19:7 19:9 +4:5 4:2 b(3P) ! (3S) +20:9 27:6 +6:4 7:5 18/23
fractions in b ! decays p s =7 TeV p s =8 TeV b(1P) ! (1S) b(2P) ! (1S) b(3P) ! (1S) 10 20 30 40 50 45 40 35 30 25 20 15 10 5 0 (1S) fraction, % p(1S) T [ GeV=c] p s =7 TeV p s =8 TeV b(2P) ! (2S) b(3P) ! (2S) 10 20 30 40 60 50 40 30 20 10 0 (2S) fraction, % p(2S) T [ GeV=c] p s =7 TeV p s =8 TeV b(3P) ! (3S) 10 20 30 40 100 90 80 70 60 50 40 30 20 10 0 (3S) fraction, % p(3S) T [ GeV=c] Outer error bars show statistical and systematics errors, inner error bars — only statistical errors. Unexpected huge fraction of (3S) ( 50%) originated from b(3P) 19/23
(1S) fractions in b(1P) ! (1S) decays In agreement with the previous LHCb result. b(1P) ! (1S) p s =7 TeV p s =8 TeV p s =7 TeV (2010) 10 20 30 40 50 45 40 35 30 25 20 15 10 5 0 (1S) fraction, % p(1S) T [ GeV=c] Outer error bars show statistical and systematics errors, inner error bars — only statistical errors. 20/23
Summary Measured fractions of (1; 2; 3S) originated from b decays. About 40% of come from b, with mild dependence on transverse momentum. The measurement of (3S) fraction in radiative b(3P) decay was performed for the first time. This analysis improves significantly the statistical precision of the previous work and adds more decays and transverse momentum regions. Measured mass of b(3P) is 10; 510 2 (stat) 6 (stat) MeV=c2, consistent with another determination which uses converted photons. Request approval to go to paper Thanks to our referees Mikhail Shapkin and Olivier Deschamps Documentation: TWiki page Analysis Note: LHCb-ANA-2014-004 Paper draft available 21/23
Backup 22/23
yields as function of pT 106 105 104 103 102 (1S) p s =7 TeV p s =8 TeV 0 10 20 30 40 50 106 105 104 103 102 (3S) 0 10 20 30 40 50 106 105 104 103 (2S) 0 10 20 30 40 50 102 Events pT() [ GeV=c] Events pT() [ GeV=c] Events pT() [ GeV=c] p s =7 TeV p s =8 TeV p s =7 TeV p s =8 TeV Yields normalized by bin width and luminosity. The small difference between 7 and 8 TeV data is due to the production cross-sections, which are expected to be about 10% larger. 23/23

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Chib paper approval

  • 1. Production of b at p s =7 and 8 TeV Vanya Belyaev, Concezio Bozzi, Hans Dijkstra, Sasha Mazurov ICHEP approval session 6 June 2014 1/23
  • 2. Motivation Bound bb states, which can be produced in different spin configurations, are an ideal laboratory for QCD tests. It’s like a hydrogen atom in QCD. States with parallel quark spins (S=1): S-wave state. P-wave b states, composed by 3 spin states b(0;1;2). can be readily produced in the radiative decays of b. b(3P) state recently observed by ATLAS, D0 and LHCb. This study: 1 Measurement of (NS) (N=1, 2, 3) fraction originating from b decays as function of pT(). Provides valuable information on Color-Octet matrix elements. 2 Measurement of b(3P) mass. 2/23
  • 3. Previous analysis “Production of (1S) mesons from b decays in pp collisions at p s = 1:8 TeV” at CDF, arXiv:hepex/9910025. “Observation of a new b state in radiative transitions to (1S) and (2S) at ATLAS”, arXiv:1112.5154 “Measurement of the fraction of (1S) originating R from b(1P) in pp p collisions at s =7 TeV”, arXiv:1209.0282, L = 32 pb1 “Observation of the b(3P) state at LHCb in pp collisions at p s =7 TeV”, LHCb-CONF-2012-020, R L = 0:9 fb1. 100 90 80 70 60 50 40 30 20 10 6 7 8 9 10 11 12 13 14 15 ¡ (1S) (GeV/c) T p (1P) (%) b (1S) from c ¡ Fraction of 0 LHCb s = 7 TeV 300 LHCb preliminary 250 200 150 100 50 0 0.5 1 1.5 2 2) ) (GeV/c − μ + g ) − m(μ − μ + m(μ Candidates / 20 MeV/c2 0 s = 7 TeV ­1 0.9 fb 0 0.5 1 1.5 2 Pull 4 2 0 ­2 ­4 b(3P) 3/23
  • 4. In this study The results in this study extend the statistical precision of previous LHCb measurements and add considerably more decays and higher transverse momentum regions. The measurement of (3S) fraction in radiative b(3P) decay was performed for the first time. In each pT() bin calculate: (pp!b(mP)X)Br(b(mP)!(nS) ) (pp!(nS)X) = Nb(mP)!(nS) N(nS) (nS) b(mP)!(nS) for each (nS); n = 1; 2; 3 and b(mP);m = 1; 2; 3 Get N from fits: N from m(+) and Nb! from [m(+ ) m(+)] (for better resolution) Compute efficiency from Monte-Carlo simulation 4/23
  • 5. Content 1 Datasets 2 Determination of yields 3 Determination of b yields in the following decays: b(1; 2; 3P) ! (1S) b(2; 3P) ! (2S) b(3P) ! (3S) 4 Measuring of b1(3P) mass 5 Monte-Carlo efficiencies 6 Systematic uncertainties 7 Results 5/23
  • 6. Datasets Full 2011 dataset at p s =7 TeV. R L = 1 fb1 Full 2012 dataset at p s =8 TeV. R L = 2 fb1 Monte-Carlo simulation of b inclusive decays, generated 62 106 events. 6/23
  • 7. The selection Almost the same cuts as are used in the study “Measurement of production p in pp collisions at s = 2:76 TeV”, arXiv:1402.2539 Description Requirement rapidity 2:0 y 4:5 Track fit quality 2=ndf 4 Track pT 1 GeV=c + vertex probability 0:5% Luminous region jzPVj 0:5m and x2 PV + y2 PV 100mm2 Kullback-Leibler distance 5000 Muon and hadron hypotheses logLh 0 Muon probability ProbNN 0:5 Trigger lines: L0 L0DiMuon HLT1 Hlt1DiMuonHighMass HLT2 HLT2DiMuonB 7/23
  • 8. The fit model p s = 7 TeV 6 p+ T 12 GeV=c 9 10 11 30000 25000 20000 15000 10000 5000 0 Candidates/(40 MeV=c2) m+ GeV=c2 (1S) (2S) (3S) + transverse momentum intervals, GeV=c 6 – 40 p s = 7 TeV p s = 8 TeV N(1S) 283,300 600 659,600 900 N(2S) 87,500 400 203,300 600 N(3S) 50,420 290 115,300 400015 3 Double Crystal Ball functions for signal yields. Tails’ parameters are fixed from simulation. Exponential function for combinatorial background. 8/23
  • 9. b selection In this study photons reconstructed using the calorimeter information. Another approach uses photon conversions in e+e pairs—this method has better invariant mass resolution, but requires more statistics. Cuts on : Transverse momentum of pT ( ) 600 MeV=c Polar angle of in the + rest frame cos 0 Confidence level of CL( ) 0:01 Dimuon mass windows: 9 10 11 35000 30000 25000 20000 15000 10000 5000 0 Candidates/(12 MeV=c2) m+ GeV=c2 9/23
  • 10. b1;2(1; 2; 3P) ! (1S) fit model (1) 10 10.5 1000 800 600 400 200 0 4 2 0 -2 -4 Candidates/(20 MeV=c2) m+ m+ + mPDG (1S) h GeV=c2 i p b(1P) s = 7 TeV b(2P) b1 b2 b(3P) One Crystal Ball (CB) for each b1;2(1P; 2P; 3P) state: 6 CB in total Exclude the study of b0 due to its low radiative branching ratio. Product of exponential and linear combination of polynomials for combinatorial background. 10/23
  • 11. b1;2(1; 2; 3P) ! (1S) fit model (2) Free parameters: yields and background parameters. Fixed parameter: b1(1P) to the value measured on combined 2011 and 2012 datasets. Linked parameters for b1 and b2 signals: b2(jP) = b1(jP) + mPDG b2(jP), j=1,2 b2(3P) = b1(3P) + mtheory b2(3P) Nb = Nb1 + (1 )Nb2 ( is fixed to 0.5) b2 = b1 Other linked parameters: b1(2P) = b1(1P) + mPDG b1(2P) b1(3P) = b1(1P) + mb1(3P) (mb1(3P) measured in this study) Fixed parameters from MC study: b1(1P), b1(2P) b1(1P) , b1(3P) b1(1P) and n parameters of CB. (1S) transverse momentum intervals, GeV=c 14 – 40 p s = 7 TeV p s = 8 TeV Nb(1P) 2090 80 5070 130 Nb(2P) 450 50 1010 80 Nb(3P) 150 40 220 60 11/23
  • 12. b fits LHCb p s = 7 TeV 10 10.5 1000 800 600 400 200 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (1S) GeV=c2 LHCb p s = 8 TeV 10 10.5 2500 2000 1500 1000 500 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (1S) GeV=c2 LHCb p s = 7 TeV 10.2 10.4 10.6 10.8 11 250 200 150 100 50 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (2S) GeV=c2 LHCb p s = 7 TeV 10.2 10.4 10.6 10.8 11 600 500 400 300 200 100 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (2S) GeV=c2 LHCb p s = 7 TeV 10.5 10.6 10.7 30 25 20 15 10 5 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (3S) GeV=c2 LHCb p s = 8 TeV 10.5 10.6 10.7 80 70 60 50 40 30 20 10 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (3S) GeV=c2 12/23
  • 13. Mass of b1(3P) in b ! (3S) decay LHCb p s = 7 and 8 TeV 10.5 10.6 10.7 100 80 60 40 20 0 Candidates/(20 MeV=c2) m+ m+ + mPDG (3S) GeV=c2 The measured on the combined 2011 and 2012 datasets mb1(3P)=10;510 2 (stat) 6 (syst)MeV=c2 is consistent with the mass measured in another study with converted photons— 10;515:7 3:1 (stat)+1:5 2:1 (syst) MeV=c2 (very preliminary results). ATLAS measured b1 and b2 mass barycenter for mb2 mb1 = 12 MeV=c2 and = 0:5: mb(3P) = 10;530 5 (stat) 9 (syst) MeV=c2 D0: mb(3P) = 10;551 14 (stat) 17 (syst) MeV=c2 13/23
  • 14. Data— Monte Carlo comparison A comparison of the distribution of the relevant observables used in this analysis was performed on real and simulated data, in order to assess the reliability of Monte Carlo in computing efficiencies 0.06 0.05 0.04 0.03 0.02 0.01 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.06 0.05 0.04 0.03 0.02 0.01 0 pT [(1S)] b(1P) b(2P) b(3P) GeV=c2 pT [b(1P)] b(1P) b(2P) b(3P) GeV=c2 pT [(1S)] GeV=c2 pT [b(2P)] GeV=c2 pT [(1S)] GeV=c2 pT [b(3P)] GeV=c2 b(1P) b(2P) b(3P) 2 of decay tree fitter 2 of decay tree fitter 2 of decay tree fitter 0 0.2 0.4 0.6 0.8 1 0.1 0.08 0.06 0.04 0.02 0.1 0.08 0.06 0.04 0.02 0 0.08 0.06 0.04 0.02 0.06 0.05 0.04 0.03 0.02 0.01 0 0 0.2 0.4 0.6 0.8 1 0.2 0.15 0.1 0.05 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 -0.02 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 0.1 0.08 0.06 0.04 0.02 0 -0.02 0 0.2 0.4 0.6 0.8 1 0 2 4 0 0 2 4 0 0 2 4 -0.02 0 10 20 30 0 10 20 30 0 10 20 30 15 20 25 30 35 0 15 20 25 30 35 0 15 20 25 30 35 0 confidence level confidence level confidence level Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units Arbitrary units b(1P) b(2P) b(3P) The agreement is generally very good. 14/23
  • 15. Monte-Carlo photon reconstruction efficiency b(1P) ! (1S) p s =7 TeV p s =8 TeV b(3P) ! (1S) p s =7 TeV p s =8 TeV b(3P) ! (2S) p s =7 TeV p s =8 TeV 20 30 40 30 25 20 15 10 5 25 20 15 10 5 30 25 20 15 10 5 0 Efficiency, % p(2S) T [ GeV=c] 30 25 20 15 10 5 25 20 15 10 5 25 20 15 10 5 0 b(2P) ! (1S) p s =7 TeV p s =8 TeV b(2P) ! (2S) p s =7 TeV p s =8 TeV b(3P) ! (3S) p s =7 TeV p s =8 TeV 20 25 30 35 40 Efficiency, % p(3S) T [ GeV=c] 10 20 30 40 0 Efficiency, % p(1S) T [ GeV=c] 20 30 40 0 Efficiency, % p(2S) T [ GeV=c] 10 20 30 40 0 Efficiency, % p(1S) T [ GeV=c] 10 20 30 40 0 Efficiency, % p(1S) T [ GeV=c] Photon is more energetic as pT() increases so it is reconstructed more efficiently. 15/23
  • 16. Systematic uncertainties Since this analysis measures the fraction of (nS) particles originating from b decays, most systematic uncertainties cancel in the ratio and only residual effects need to be taken into account. Systematic uncertainties on the event yields are mostly due to the fit model of and b invariant masses, while the ones on the efficiency are due to the photon reconstruction and the unknown initial polarization of b and particles. The uncertainty related to the fit model estimated by the previous study “Production of Jp = and mesons in pp collisions at s = 8 TeV”, arXiv:1304.6977 Systematic due to photon reconstruction taken from the previous works based on “Study of 0= reconstruction efficiency with 2011 data”, LHCb-INT-2012-001. fraction uncertainties common to all b decays (%) fit model 0:7 reconstruction 3 16/23
  • 17. Systematic uncertainties— Polarization The polarization is expected to be small. “Measurement of the (1S), p Y2S and (3S) polarizations in pp collisions at s = 7 TeV”, arXiv:1209.2922. The uncertainty related to the unknown polarization of b mesons was estimated using the prescription described in the LHCb paper “Measurement of the relative rate of prompt c0, c1 and c2 production at p s = 7TeV” (thanks to Edwige Tournefier) that is based on the analytical calculations in HERA “Production of the Charmonium States and p c1 c2 in Proton Nucleus Interactions at s = 41.6-GeV” In the previous study the uncertainty due to polarization is dominated 20%. This study shows that this uncertanty is less than 9%. 17/23
  • 18. Summary of systematic uncertainties T Summary of fraction systematic uncertainties (%) (maximum deviations that were found in pbins): b fit model b polarization b(1P) ! (1S) +4:3 5:8 +5:1 4:0 b(2P) ! (1S) +4:8 6:2 +5:8 6:8 b(3P) ! (1S) +19:6 16:6 +6:9 6:7 b(2P) ! (2S) +2:3 7:0 +8:7 7:8 b(3P) ! (2S) +19:7 19:9 +4:5 4:2 b(3P) ! (3S) +20:9 27:6 +6:4 7:5 18/23
  • 19. fractions in b ! decays p s =7 TeV p s =8 TeV b(1P) ! (1S) b(2P) ! (1S) b(3P) ! (1S) 10 20 30 40 50 45 40 35 30 25 20 15 10 5 0 (1S) fraction, % p(1S) T [ GeV=c] p s =7 TeV p s =8 TeV b(2P) ! (2S) b(3P) ! (2S) 10 20 30 40 60 50 40 30 20 10 0 (2S) fraction, % p(2S) T [ GeV=c] p s =7 TeV p s =8 TeV b(3P) ! (3S) 10 20 30 40 100 90 80 70 60 50 40 30 20 10 0 (3S) fraction, % p(3S) T [ GeV=c] Outer error bars show statistical and systematics errors, inner error bars — only statistical errors. Unexpected huge fraction of (3S) ( 50%) originated from b(3P) 19/23
  • 20. (1S) fractions in b(1P) ! (1S) decays In agreement with the previous LHCb result. b(1P) ! (1S) p s =7 TeV p s =8 TeV p s =7 TeV (2010) 10 20 30 40 50 45 40 35 30 25 20 15 10 5 0 (1S) fraction, % p(1S) T [ GeV=c] Outer error bars show statistical and systematics errors, inner error bars — only statistical errors. 20/23
  • 21. Summary Measured fractions of (1; 2; 3S) originated from b decays. About 40% of come from b, with mild dependence on transverse momentum. The measurement of (3S) fraction in radiative b(3P) decay was performed for the first time. This analysis improves significantly the statistical precision of the previous work and adds more decays and transverse momentum regions. Measured mass of b(3P) is 10; 510 2 (stat) 6 (stat) MeV=c2, consistent with another determination which uses converted photons. Request approval to go to paper Thanks to our referees Mikhail Shapkin and Olivier Deschamps Documentation: TWiki page Analysis Note: LHCb-ANA-2014-004 Paper draft available 21/23
  • 23. yields as function of pT 106 105 104 103 102 (1S) p s =7 TeV p s =8 TeV 0 10 20 30 40 50 106 105 104 103 102 (3S) 0 10 20 30 40 50 106 105 104 103 (2S) 0 10 20 30 40 50 102 Events pT() [ GeV=c] Events pT() [ GeV=c] Events pT() [ GeV=c] p s =7 TeV p s =8 TeV p s =7 TeV p s =8 TeV Yields normalized by bin width and luminosity. The small difference between 7 and 8 TeV data is due to the production cross-sections, which are expected to be about 10% larger. 23/23