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Production and Properties of Heavy Flavour at CDF

Production and Properties of Heavy Flavour at CDF. Sinéad Farrington On behalf of the CDF collaboration ICHEP 2012, Melbourne. Heavy Flavour Production and Decays. Fragmentation Kaons in association with D mesons Upsilon decay Spin alignment B c Lifetime Fully reconstructed decay.

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Production and Properties of Heavy Flavour at CDF

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  1. Production and Properties of Heavy Flavour at CDF Sinéad Farrington On behalf of the CDF collaboration ICHEP 2012, Melbourne

  2. Heavy Flavour Production and Decays Production and Properties of Heavy Flavour at CDF, Sinead Farrington • Fragmentation • Kaons in association with D mesons • Upsilon decay • Spin alignment • Bc Lifetime • Fully reconstructed decay

  3. Fragmentation CDF Public Note 10704 Production and Properties of Heavy Flavour at CDF, Sinead Farrington

  4. Fragmentation 360 pb-1 Production and Properties of Heavy Flavour at CDF, Sinead Farrington • Quark fragmentation described by phenomenological models • Study charged particle production around heavy quarks • Kaons near Ds(260k) and D+ (140k) both decaying to fp • Bsflavour tagging used similar techniques • D used for fragmentation studies • No known resonance decay to Ds K • Charged D’s do not mix • Select prompt D’s to minimise contamination from B’s

  5. Probing Fragmentation Production and Properties of Heavy Flavour at CDF, Sinead Farrington • Charge correlation between D and K • For Ds • Opposite sign => early in fragmentation chain • Same sign => later in fragmentation chain • For D+ • Random charge correlation

  6. Method Production and Properties of Heavy Flavour at CDF, Sinead Farrington • Take maximum pt tracks in DR=0.7 cone around D candidate • Measure kaon fraction with likelihood fit • Particle ID: time of flight, dE/dx

  7. Compare to Pythia/Herwig Ds D+ Opposite sign Same sign Production and Properties of Heavy Flavour at CDF, Sinead Farrington Pt distribution for early fragmentation kaons better agreement than later steps

  8. Upsilon Spin Alignment Phys. Rev. Lett. 108, 151802 (2012) Production and Properties of Heavy Flavour at CDF, Sinead Farrington

  9. Upsilon Spin-alignment 6.7fb-1 PRL 102,151802 (2009) Production and Properties of Heavy Flavour at CDF, Sinead Farrington • Discrepancies among experimental results • Distribution described by: • Previous measurements: lqonly • Not invariant under change in reference system • Bias could be introduced if acceptance not uniform in j • This measurement: full 3D measurement

  10. Upsilons Production and Properties of Heavy Flavour at CDF, Sinead Farrington • 550k Y(1S), 150k Y(2S), 76k Y(3S) decaying to mm • Background dominated by bb decays to muons • Constrain background by scaling background in displaced (b-enriched) sample by extrapolation from sidebands • Obtain geometric acceptance from MC

  11. Results Production and Properties of Heavy Flavour at CDF, Sinead Farrington • First measurement of Y(3S) parameters • None of the 3 states shows evidence of polarisation • Frame invariance crosschecks performed

  12. Compare with Theory Recent calculations: Significant feed-down from cb states: Production and Properties of Heavy Flavour at CDF, Sinead Farrington Y(1S) parameter: a=lq

  13. Bc Lifetime CDF Public Note 10533 Production and Properties of Heavy Flavour at CDF, Sinead Farrington

  14. BcJ/y p+ 6.7 fb-1 CDF Run II Preliminary Production and Properties of Heavy Flavour at CDF, Sinead Farrington • Bc was discovered at CDF • Short lifetime: b or c can decay or annihilate • Previous lifetime measurements only on partially reconstructed decays • Fully reconstructed decay • Background parameters from sidebands

  15. Method CDF Run II Preliminary CDF Run II Preliminary CDF Run II Preliminary Production and Properties of Heavy Flavour at CDF, Sinead Farrington • B+J/y K+ used as a control sample • Validate • ct Efficiency • biased by cut requiring small pointing angle between decay vector and B momentum vector • Background model • Fitter

  16. Results • Signal • Mass: Gaussian • Decay time: exponential convoluted with resolution • Background • Mass: linear • Decay time: 3 exponential CDF Run II Preliminary Crosscheck: Production and Properties of Heavy Flavour at CDF, Sinead Farrington Fit:

  17. Summary Production and Properties of Heavy Flavour at CDF, Sinead Farrington • Fresh knowledge of fragmentation from our early dataset • Later stages of fragmentation chain not well reproduced by MC • Upsilon polarisationmeasurement • No significant polarisations • Bclifetime measurement • First fully reconstructed decay measurement • Different systematics from previous measurements but in good agreement

  18. Reference Frames Production and Properties of Heavy Flavour at CDF, Sinead Farrington

  19. Crosscheck Production and Properties of Heavy Flavour at CDF, Sinead Farrington

  20. Crosscheck Production and Properties of Heavy Flavour at CDF, Sinead Farrington Frame invariant quantity:

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