Title
This presentation is the property of its rightful owner.
Sponsored Links
1 / 29

Title PowerPoint PPT Presentation


  • 84 Views
  • Uploaded on
  • Presentation posted in: General

Title. Searching for New Physics at the B factories: Measurements of sin2 b at BaBar. Gabriella Sciolla Massachusetts Institute of Technology Representing the BaBar Collaboration Beauty 2005 - Assisi, June 20-24, 2005. BaBar and PEP-II. BaBar detector 4 p collider detector

Download Presentation

Title

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Title

Title

Searching for New Physics at the B factories:

Measurements of sin2b at BaBar

Gabriella Sciolla

Massachusetts Institute of Technology

Representing the BaBar Collaboration

Beauty 2005 - Assisi, June 20-24, 2005


Babar and pep ii

BaBar and PEP-II

  • BaBar detector

    • 4p collider detector

  • PEP-II asymmetricBfactory

    • 9.0 GeV e- beam

    • 3.1 GeV e+ beam

  • Peak luminosity

    • 9.1 x 1033cm-2s-1

  • Integrated luminosity

    • Delivered: >268 fb-1

e+

e+

Most results in this talk are

based on 227 M BB events

Measurements of sin(2b) at BaBar


The beauty of the unitarity triangle

(r,h)

a

b

g

(0,0)

(1,0)

The Beauty of the Unitarity Triangle

Two ways of looking for New Physics:

  • Compare measurement of sides and angles

  • Measure angles in channels with different sensitivity to New Physics

Measurements of sin(2b) at BaBar


The three roads to b

The three roads to b

  • Charmonium modes:

    • J/ψKS, ψ(2S)KS, χc1KS, ηcKS

    • J/ψKL

    • J/ψK*0 (K*0 → KS π0)

  • Open-charm modes:

    • D*+ D*−,D*+ D−, D+ D−

  • Penguin-dominated modes:

    • φK0, K+K−KS,KSKSKS

    • η′KS

    • KSπ0, ωKS,f0(980)KS

Measurements of sin(2b) at BaBar


Cp violation in interference between mixing and decays

mixing

decay

CP violation in interference between mixing and decays

(hf)

  • When only one diagram contributes to the final state:

  • Example: B0 J/YKS:

Measurements of sin(2b) at BaBar


How to measure the cp asymmetry

e+

Flavor tagging

Q=(30.5  0.5)%

Exclusive B

reconstruction

Dz~bgc Dt

Precise Dt determination

How to measure the CP asymmetry

.

e-

B0

e-

U(4S)

m+

B0

p+

p-

m-

Measurements of sin(2b) at BaBar


The golden mode for sin2 b b 0 charmonium k 0

Phys. Rev. Lett. 94, 161803 (2005)

The golden mode for sin2b:B0 charmonium K0

  • Theoretically clean

  • Experimentally clean

  • Relatively large BF (~10-4)

CP sample:

mES[GeV]

DE [MeV]

Measurements of sin(2b) at BaBar


Title

Phys. Rev. Lett. 94, 161803 (2005)

The golden mode for sin2b:CP fit in B charmonium K0

Unbinned maximum likelihood fit to Dt distribution

CP=-1

CP=+1

sin(2b) = 0.722 ± 0.040stat ± 0.023syst

Measurements of sin(2b) at BaBar


Sm test in b 0 charmonium k 0

SM test in B0  charmonium K0

cos(2β)<0

  • Compare sides and angles

    • Both BaBar and Belle results used

  • Ambiguity resolved measuring sign(cos2b) in B0J/YK*

    • cos(2b)=-0.68 excluded at 86.6%CL[PRD 71 (2005)032005]

  • Excellent agreement with constraints from the sides

    • Another SM triumph?

      .

cos(2β)>0

SM test #2:

Compare b in various channels

Measurements of sin(2b) at BaBar

Measurements of angles NOT included in fit


The b ccd trees b 0 open charm

The bccd trees:B0 open charm

  • Tree measures sin2b from bccd transitions

  • Penguin expected to be small in SM (< few %)

    • D*D*: as large as Db = 0.6 [Grossman and Worah, 1997]

u,c,t

New Physics could have large effects

Measurements of sin(2b) at BaBar


The open charm trees recent update b 0 d d

New

The open charm trees: Recent update: B0 D*+D*-

BaBar

Preliminary

  • Vector-vector final state:

    • CP-even and CP-odd admixture

  • Transversity analysis measures fCP-even

CCP+ = +0.06 ± 0.17 ± 0.03

-SCP+ = 0.75 ± 0.25 ± 0.03

fCP+ = (87.54.4 0.7)%

In good agreement with SM

Measurements of sin(2b) at BaBar


The open charm trees b 0 d d

hep-ex/0505092

The open charm trees:B0 D(*)D

Updated

Updated

New

Measurements of sin(2b) at BaBar


The key to new physics the penguin modes

The key to New Physics: The Penguin Modes

Decays dominated by gluonic penguin diagrams

  • The typical example: B0fKS

    • No tree level contributions

    • In SM, top quark dominates the loop: C~0; S~sin2b

  • Impact of New Physics could be significant

    • New particles could participate in the loop  new CPV phases

  • Low branching fractions

    • Measure ACP in as many bsqq penguins as possible!

      • φ K0, K+ K− KS,η′ KS, KS π0, KS KS KS, ω KS,f0(980) KS

NP

SM

Measurements of sin(2b) at BaBar


The golden penguin b 0 f k 0

Phys. Rev. D 71, 091102(R) (2005)

The golden penguin: B0fK0

Combined fKS and fKL fit:

Measurements of sin(2b) at BaBar


Related channel b 0 k k k s

Phys. Rev. D 71, 091102(R) (2005)

Related channel: B0 K+K-KS

  • For non resonant B0K+K-KS decays, hCP = 2 feven- 1

  • feven measured from angular moment analysis of the K+K- system

Measurements of sin(2b) at BaBar


A new golden penguin b 0 k s k s k s

hep-ex/0502013 (accepted by PRL)

A new golden penguin: B0KSKSKS

  • Theoretically clean

    • Penguin dominated CP=+1 eigenstate

  • Experimentally challenging

    • B decay vertex uses KS pseudo-particles and beam spot constraint

Measurements of sin(2b) at BaBar


The silver penguin b 0 h k s

Phys. Rev. Lett. 94, 191802 (2005)

The silver penguin: B0h’KS

  • Relative large BF ~ 6 x 10-5

  • Theoretically less clean than fKS

    • Tree diagram possible

      … but Cabibbo and color suppressed…

    • |DS| =|SYK-SPenguin|~ 0.01QCDFact 0.1SU(3)

Sη′Ks = 0.30± 0.14±0.02

Cη′Ks = −0.21±0.10±0.02

Measurements of sin(2b) at BaBar


The challenging penguins b 0 p 0 k s f 0 k s w k s

hep-ex/0503011 hep-ex/0408095

hep-ex/0503018

The challenging penguins: B0p0KS, f0KS,wKS

  • B0p0KS:

    • dominated by

    • tree contribution are non negligible (DS ~ 0.1 – 0.2)

    • Experimental challenge: BCP decay vertex reconstruction (sDt~1ps)

  • B0f0KS:

    • In SM dominated by

  • B0wKS:

    • In SM dominated by

    • But tree can be relatively large

Measurements of sin(2b) at BaBar


Sin2 b in penguins babar only

“sin2b” in penguins: BaBar only

  • Although each

  • measurement is

  • compatible with J/YKS,

  • a trend is visible

  • h’KS has the most

  • significant shift

  • (~2.9 s if theory

  • uncertainties neglected)

  • … but statistical errors are

  • still large…

Measurements of sin(2b) at BaBar


Sin2 b in penguins babar belle

Statistical fluctuation or

first signs of New Physics?

  • Average of BaBar

  • and Belle results

  • Boxes are SM expected

  • ranges for -hfSf from

  • Beneke, hep-ph/0505075

  • Shift still significant…

SJ/Y- Spenguins > 3 s

“sin2b” in penguins: BaBar + Belle

Measurements of sin(2b) at BaBar


Summary and conclusion

  • Precision measurements of sin2b in many different channels are a powerful probe for New Physics

    • B0 charmonium K0: our calibration point (ssin2b ~ 0.04)

    • B0 open charm: no smoking guns so far

    • B0 penguin modes: intriguing shifts observed

  • New Physics or statistical fluctuations?

    • Time and data will tell…

  • Goals for BaBar luminosity

    • Summer 2006: 500 fb-1

    • Summer 2008: 1 ab-1

Summary and Conclusion

Measurements of sin(2b) at BaBar


Backup slides

Backup slides --------------------------------------------------------------------

Measurements of sin(2b) at BaBar


Transversity analysis

Transversity analysis

  • D*+D*- is not a CP eigenstate

    • sum of L=0, 2 (CP even) and L=1 (CP odd)

  • CP odd fraction Rdetermined by transversity analysis

Measurements of sin(2b) at BaBar


D d analysis

D*D analysis

SM expectations

  • D+D-

  • D*D

Measurements of sin(2b) at BaBar


Cos and sin fits in penguin modes

cos and sin fits in penguin modes

Measurements of sin(2b) at BaBar


The challenging penguins b 0 p 0 k s

hep-ex/0503011

The challenging penguins: B0p0 KS

  • In SM these decays are dominated by

    • tree contribution are non negligible

      • DS ~ 0.1 in model dependent QCD calculations

      • DS ~ 0.2 in SU(3)

  • Experimentally challenging

    • BCP decay vtx from KS and beam spot

    • KS tracks with > 3 SVT: sDt~1ps

  • Unbinned max likelihood fit:

Nsig = 300 ± 23

Measurements of sin(2b) at BaBar


Two more penguins b 0 f 0 k s and b 0 w k s

hep-ex/0408095

hep-ex/0503018

Two more penguins:B0 f0KS and B0 wKS

B0 f0KSdominated by b sss

B0 ωKS : dominated by b → sdd

Tree contamination can be relatively large

Measurements of sin(2b) at BaBar


The other trees recent update b d d

Results presented at Moriond 2005

The Other Trees: Recent update: B  D*+D*-

BaBar

Preliminary

  • Vector-vector final state:

    • CP-even and CP-odd admixture

  • Transversity analysis measures fodd

    • fodd = (12.54.4 0.7)%

CCP+ = +0.04 ± 0.14 ± 0.02

-SCP+ = 0.65 ± 0.26 +0.09-0.07 ± 0.04

 Good agreement with SM

Measurements of sin(2b) at BaBar


Penguins vs tree

Penguins vs tree

Measurements of sin(2b) at BaBar


  • Login