B d s h 1 h 2 br cp asymmetries and lifetimes
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B d,s ->h 1 h 2 : BR, CP asymmetries, and lifetimes. . . S. Budroni, S. Donati, M. Donega’ , S. Giagu, M. Morello, G. Punzi, D. Tonelli CDF Collaboration Meeting February 3, 2006. Notes: 6175, 6356, 6357, 6453, 7066, 7978, 8057

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B d,s ->h 1 h 2 : BR, CP asymmetries, and lifetimes

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B d s h 1 h 2 br cp asymmetries and lifetimes

Bd,s->h1h2: BR, CP asymmetries,and lifetimes

S. Budroni, S. Donati, M. Donega’, S. Giagu,

M. Morello, G. Punzi, D. Tonelli

CDF Collaboration Meeting February 3, 2006

Notes: 6175, 6356, 6357, 6453, 7066, 7978, 8057

(+linked notes on dE/dx calibrations and isolation studies)

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Physics motivations

Physics motivations

  • 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

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Physics motivation cont d

Physics motivation (cont’d)

  • 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

_

Mauro Donega’ - CDF collaboration meeting February 3, 2006


B d s h 1 h 2 br cp asymmetries and lifetimes

Two groups:

BR, ACP andLifetimes

worked on the same

data sample:

Ideal x-check of the

common results !

Signal

extraction

DATA

Optimized

sample

Fitter

Kinematics+PID+Lifetimes

Fitter

Kinematics+PID

Raw

fractions

Acceptance

corrections

BR and ACP

Lifetimes

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Data and mc samples

Data and MC samples

Dataset: xbpp0d ~355 pb^-1 (BPAK good run list applied)

Triggers:

B_PIPI

B_PIPI_HIGH_PT (~7% of the total)

MonteCarlo: BMC framework 5.3.4

Simulated the four signal modes:

Bd->Kp, Bd->pp, Bs->KK, Bs->Kp

Reconstruction:

CharmMods – 5.3.4

Track refit with L00

Primary vtx from beamline

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Signal extraction

Signal extraction

Optimization performed independently by the two groups

Lead to similar set of cuts:

S/B~ 2

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Background mass description

Background mass description

B->hh signals

to be disentangled

Bd/s/K

Include Bd/s/K in the

mass description (little bias to the lifetimes,

included as systematic

uncertainty)

combinatorial

Lifetimes

  • Fit combinatorial bkg

  • Shape

  • fraction

BR ACP

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Disentangling the signal fractions

Disentangling the signal fractions

Bdp+p-

e

mass

BdK-p+

Bd K+p-

K

mass

mass

p

BsK+K-

mass

2

Momentum

(GeV/c)

BPAK calibrations

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Extract the lifetimes

Extract the lifetimes

MC based lifetime extraction (tested on B->Dp decays CDF7386)

Events after trigger+offline cuts

=

Lifetime MC

ev/ev ct error

Background described with a template

On the right sideband (combinatorial only) =

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Raw fractions results

Raw fractions results

Lifetimes

BR, ACP

Compatible results !

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Br acp

BR ACP

=XXX ± 0.039 (stat) ± 0.013(syst)

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Lifetimes results

mass

z1

ct (cm)

a

p1+p2

z2

Lifetimes results

In agreement with world average 460 ± 4 um

ct(Bd)floating ct(Bd)PDG constrained

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Systematic uncertainties

Lifetimes

BR ACP

5.6 um

0.013

Systematic uncertainties

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Status 360 pb 1 and plans 1 fb 1

Status (360 pb-1) and Plans (1 fb-1)

  • Status:

  • BR and ACP pre-blessed on January 26th, 2006

  • Lifetime measurement blessed on January 26th, 2006

  • Plans:

  • Bless BR and ACP 360 pb-1and move to 1 fb-1

  • Lifetimes move to 1 fb-1:

  • Data skimming + MC production (in progress)

  • dE/dx calibrations (~done)

Mauro Donega’ - CDF collaboration meeting February 3, 2006


Summary

Summary

The charmless two body B decay sample is

Extremely Rich !

And leads to world class B physics measurements.

We are upgrading the BR and ACP measurements and

for the first time we measured the lifetimes on 360 pb-1:

ct (Bd) = 452 ± 24 ± 6 um

ct (BsK+K-) = 458 ± 53 ± 6 um

DG(CP) / G (CP) = -0.08 ± 0.23 ± 0.03

Mauro Donega’ - CDF collaboration meeting February 3, 2006


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