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Upsilon Cross Section: Applied to one p T bin in CDF data. Matthew Jones Purdue University. Recent Developments. Bug fix (actually fixed mid April) improved agreement between CMU and CMX that plagued the results presented in early April Self consistent efficiency definition
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Upsilon Cross Section:Applied to one pT bin in CDF data Matthew Jones Purdue University B Production and Decay Meeting
Recent Developments • Bug fix (actually fixed mid April) • improved agreement between CMU and CMX that plagued the results presented in early April • Self consistent efficiency definition • Constrained using J/ψdecays from μ+SVT dataset • Run dependence in CMP efficiency • Possible evidence for run dependence in ϒ(1S) cross section? • Various cross checks B Production and Decay Meeting
Acceptance Definition • is the acceptance: • Probability that final state is within the fiducial acceptance of the detector • Analysis is performed using CdfMuon objects in data and Monte Carlo • The Monte Carlo actually measures where ≈ B Production and Decay Meeting
Muon Scale Factors • We introduce the muon scale factors so that = • COT hit embedding analysis (CDF Note 6394) gives: • Measure using unbiased leg of J/ψ reconstructed in μ+SVT dataset. • But this leg still has a bias from XFT. • Measure XFT efficiency from unbiased K+ in from the di-muon dataset. B Production and Decay Meeting
XFT Efficiency Matched with XFT track Not matched with XFT track • Only requirement on kaon is that it is found in defTracks and satisfies fiducial cuts: z(R=136 cm) < 155 cm, |z(COT SL)| > 1.5 cm and pT> 3 GeV/c. B Production and Decay Meeting
Muon Efficiency • Require unbiased leg to satisfy fiducial cuts, and to be well within the fiducial acceptance of the muon chambers: • MuonFiducialTool + additional cuts on B Production and Decay Meeting
Muon Efficiency • Muon efficiency for XFT tracks • Scale factors: B Production and Decay Meeting
Muonquality cuts • In addition, require to be compatible with L1 trigger efficiency parameterization… • Which one? • mu.cmu().chsqX()? • mu.cmu().chsqXPosition()? • Methods in MuonUser/StubChisquare.hh? • chsqXPosition() < 9 is essentially fully efficient in both CMU and CMX. • StubChi2Cmu(pt,dx,dphi) < 9: B Production and Decay Meeting
Other efficiencies • Vertex cuts: |z0|<60 cm, |Δz0|<5 cm. • Require generated decays satisfy this cut. • Efficiency measured in CDF notes 7935, 8289: • Radiative losses: • Generate decays with PHOTOS • Fit with single Gaussian as is done in the data • Fitted yield is 90% of the number of decays generated • Should probably also fit using a crystal ball function. B Production and Decay Meeting
CMP Efficiency • Parameterized as a function of 1/pT in 48 “wedges” (24 east + 24 west). • Added an run-dependent scale factor to account for changes in efficiency in some regions. B Production and Decay Meeting
Luminosity Calculation • Most of the data was recorded with DPS triggers. • Effective luminosity retrieved from database using DFCLuminosityTool. • Luminosity put into database was apparently calculated using • Undefined when Pj = 0 in run section j. B Production and Decay Meeting
Extreme example: run 209318 • This was a long 19 hour run with initial luminosity of 40x1030 cm-2s-1… Integrated luminosity = 2.03 pb-1. • Initial prescale = 10 1 after first ½ hour of running. • Integrated luminosity in each 30 second run section varies from 1.5 nb-1 to 0.6 nb-1. • L2 upsilon trigger cross section is about 1.5 nb. • 10% chance of no triggers in a run section at start of run • 40% chance for no triggers in a run section by end of run. • But DFCLuminosityTool returns 0.17 pb-1. B Production and Decay Meeting
Alternative to DFCLuminosityTool • Correlate L2 prescale changes with run sections using • Event number (earlier data) • Time since start of run (later data) • Assumes prescale changes are accurately recorded in the online database • Be careful about runs where there were no prescale changes • Early trigger tables which did not use DPS • LUMI_280 triggers which were always disabled B Production and Decay Meeting
Luminosity Comparison • Most runs agree at the level of 0.25% • No attempt to interpolate within run sections • No difference for unprescaled triggers • Biggest difference for long, low luminosity runs. B Production and Decay Meeting
Results in 8.5-10.5 GeV/c bin Good agreement with results from Run I… maybe just be lucky. B Production and Decay Meeting
Polarization Parameters Background 3S 2S 1S Collins-Soper frame S-channel helicity frame B Production and Decay Meeting
Projections: Collins-Soper frame B Production and Decay Meeting
Projections: S-channel helicity frame B Production and Decay Meeting
Time Dependence? • Better than it was before. • Still not completely consistent with a constant cross section. • Some variation in CMX in early runs could be due to acceptance. • Unlikely to be purely statistical. • How to translate this into a systematic uncertainty? = 23.6/9 35.4 6.0 18.1 17.8 7.8 B Production and Decay Meeting
Summary • Self-consistent definition and measurement of efficiencies and muon scale factors was a useful cross check. • Search for time-dependent effects yielded significantly improved understanding of some effects but no obvious culprit. • Possibly still some time dependence in measured cross sections. • Fit behaves quite well now. • Consider analyzing other pT bins next? B Production and Decay Meeting