spin configurations, is ideal laboratory for QCD tests. ̄ It is like a hydrogen atom in QCD. States with paralell quark spins (S=1): • S-wave ϒ state • P-wave χ b states, composed by 3 spin states χ b(0,1,2) . Can be readily produced in the radiactive decays of ϒ. • χ b (3P) state recently observed by ATLAS, D0 and LHCb Study of χ b production: • Measurement for ϒ(1,2,3S) cross sections in χ b decays as a function of p T (Nϒ) • Measurement of χ b(0,1,3) (3P) mass. • Measured mass • Mass from theory
and χ b (mP), m=1,2,3 • Get N from fits: N ϒ from m(µ+µ-) and N χb→ϒγ from [m(µ+µ- γ) – m(µ+µ-)] (for better resulution) • Compute efficiency ε from Monte-Carlo simulation
Values pT(ϒ) > 14 GeV (in nominal fit) pT(γ) > 0.6 GeV m(χ b ) - m(ϒ(1S)) PDG < 0.2 GeV/c2 χ2 for decay tree fitter in [0, 4] Muons min delta log likelihood > 0 χ b rapidity in [2.5, 4] Use only TOS events (trigger on ϒ): L0 (Muon|DiMuon).*Decision HLT1 (DiMuon|SingleMuonHighPT|MuonTrack).*Decision HLT2 (DiMuon|SingleMuonHighPT).*Decision
+χ b2(2P) χ b1(3P) +χ b2(3P) Signal: 6 Crystall Ball functions Background: e-τx * (c 2 +a 1 x+a 2 x2+a 3 x3) • Fit mean and width of χ b1 (1P) Crystal Ball, and means of χ b1 (2P), χ b (3P) • Use MC to scale all other widths to the χ b1 (1P) width. • Fix means of χ b2 states by using • PDG: mass differences between χ b1 (1P) and χ b2 (1P), χ b1 (2P) and χ b1 (2P) • MC: mass differences between χ b1 (3P) and χ b2 (3P) • For each sum of χ b1 and χ b2 fix a relation: N[χ b1,2 (mP)] = α frac N[χ b1 (mP)] + (1-α frac )N[χ b2 (mP)], m=1,2,3; α frac fixed at 0.5