1 / 13

B s  K + K - lifetime measurement and DG CP / G CP extraction

B s  K + K - lifetime measurement and DG CP / G CP extraction. Mauro Donega DPNC Universite de Geneve Swiss Physical Society annual meeting 13 February 2006. B 0  hh’: Physics motivation. B d,s ->h 1 h 2 = Bd->k  , Bd->  , Bs->KK , Bs->K 

maya
Télécharger la présentation

B s  K + K - lifetime measurement and DG CP / G CP extraction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Mauro Donega BsK+K- lifetime measurement and DGCP/GCP extraction Mauro Donega DPNC Universite de Geneve Swiss Physical Society annual meeting 13 February 2006

  2. Mauro Donega B0hh’: Physics motivation • Bd,s->h1h2= Bd->k, Bd-> ,Bs->KK , Bs->K • Accessible to B factories: Bd->k, Bd->  • Only at TeVatron (until >2007): Bs->KK , Bs-> K • Possible measurements: • Today: • direct CP asymmetry in Bd->k, Bs-> K • (counting experiment) • Future: • CP asymmetry in mixing Bd-> ,Bs->KK • (requires time dependent analysis) • Short term goal: UsingBd->k,Bd-> BR, constrain the relevant hadronic penguin parameters. • Long term goal: combine time-dependent Bd->  and Bs->KK • asymmetries (+other external input) to measure g Tree Penguin PHYSICAL REVIEW D 66, 054009 2002 Physics Letters B 4591999.306–320

  3. Mauro Donega B0hh’: Physics motivation • Bs described as a two states system. • Evolution through Schroedinger equation: • off diagonal terms ->mixing • M12, G12, f = arg(- M12/G12) • What we measure: • Dm = MH –ML ~ 2|M12| DG = GL–GH~ 2| G12 |cos(f) • SM: f ~0 -> CP eigenstates ~ mass eigenstates • Bs-> is predicted to be 95% CP even => ct(Bs->KK) ~1/ GL • Bs->KK lifetime combined with FS (t) can give DG. • Measurement of Bs->KK lifetime can be strongly affected by • new CP violating physics => sensitivity to New Physics _

  4. Mauro Donega CDF B =1.4 T TIME OF FLIGHT TOF: ~100ps resolution, 2sigmaK/ separation for tracks below 1.6 GeV/c (significant improvement of Bs flavor tag effectiveness) COT: large radius (1.4 m) Drift C. • 96 layers, 200ns drift time • Precise PT above 400 MeV/c • Precise 3D tracking in ||<1 (1/PT) ~ 0.1%GeV –1; (hit)~150m • dE/dx info provides >1.4 sigma K/ separation above 2 GeV • SVX-II + ISL: 5 + 1 (2) layers of double-side silicon (3cm < R < 30cm) • Standalone 3D tracking up to ||= 2 • Very good I.P. resolution: ~30m (~20 m with Layer00) LAYER 00:1 layer of radiation-hard silicon at very small radius (1.5 cm) - expected 50 fs proper time resolution inBs Dsp

  5. Mauro Donega Secondary Vertex B Decay Length 35m  33m = 47 m (resolution beam) Lxy Primary Vertex d = impact parameter Fully hadronic decays @ CDF Silicon Vertex Tracker Proper time distribution TOY Pt(trk) >2 GeV/c Pt >5.5 GeV/c 100 m<IP(trk)<1 mm || <1 SVT selection Detector smearing Decay

  6. Mauro Donega Data sample L = 360 pb-1 Bdk Bskk Overlapped Use PID to disentangle them Bd  MC Bs k Bs Bd

  7. Mauro Donega Bdp+p- mass  BdK-p+ Bd K+p- mass mass   BsK+K- mass  Signal fraction separation e   K p Momentum (GeV/c) 2 GeV/c

  8. Mauro Donega Lifetime extraction MC based lifetime extraction (tested on B->Dp decays) Events after trigger+offline cuts = Lifetime MC ev/ev ct error Background described with a template On the right sideband (combinatorial only) =

  9. Mauro Donega Results Fractions Lifetimes

  10. Mauro Donega 5.6 um Systematic uncertainties

  11. Mauro Donega Summary We presented the first measurement of the Bd and Bs in two body charmless decays: ct(Bd) = 452 ± 24(stat) ± 6(syst) mm ct(BsK+K-) = 458 ± 53(stat) ± 6(syst) mm ct(Bd) = 1.51 ± 0.08(stat) ± 0.02(syst) ps ct(BsK+K-) = 1.53 ± 0.18(stat) ± 0.02(syst) ps Using the HFAG 05 data ct(FS) = 441 ± 13 mm DGCP/GCP = -0.08 ± 0.23 (stat) ± 0.03(syst)

  12. Mauro Donega BACKUP

  13. Mauro Donega Other DGCP/GCP measurements Theory prediction = 0.07 ± 0.02 hep-ph 0308029 CDF BsJ/ψΦ = 0.65 ± 0.01 Phys.Rev.Lett.94:101803,2005 This measurement = -0.08 ± 0.23 ± 0.03 HFAG average as of Winter 2005 = 0.31 http://www.slac.stanford.edu/xorg/hfag/results/index.html +0.25 -0.33 +0.10 - 0.11

More Related