B s k k lifetime measurement and dg cp g cp extraction
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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 

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

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B s k k lifetime measurement and dg cp g cp extraction

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


B 0 hh physics motivation

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


B 0 hh physics motivation1

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

_


B s k k lifetime measurement and dg cp g cp extraction

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


Fully hadronic decays @ cdf

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


Data sample

Mauro Donega

Data sample

L = 360 pb-1

Bdk

Bskk

Overlapped

Use PID to disentangle them

Bd 

MC

Bs k

Bs

Bd


Signal fraction separation

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


Lifetime extraction

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) =


Results

Mauro Donega

Results

Fractions

Lifetimes


Systematic uncertainties

Mauro Donega

5.6 um

Systematic uncertainties


Summary

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)


Backup

Mauro Donega

BACKUP


Other dg cp g cp measurements

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


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