# Presentation: 888757

## B physics from the e+e B factories

- Paul Dauncey, Imperial College London
- on behalf of the BaBar Collaboration

- 2007 Aspen Winter Conference on Particle Physics"New Physics at the Electroweak Scale and New Signals at Hadron Colliders”

- B Physics from the B Factories

- 10 Jan 2007

## Belle and BaBar 

- Belle:   8 GeV e/3.5 GeV e+
- BaBar: 9 GeV e/3.1 GeV e+

- Belle and BaBar

- Very similar detectors; main difference is in PID:
- BaBar: Ring-imaging Cherenkov
- Belle: Threshold Cherenkov and ToF

- BaBar

- Belle

- B Physics from the B Factories

- 10 Jan 2007

## Recorded luminosity

- Y(4S)BB cross section ~1nb

- Total > 1ab1

- KEKB (Belle)

- PEP-II (BaBar)

- B Physics from the B Factories

- 10 Jan 2007

## CKM unitary matrix

- CKM matrix relates weak and mass eigenstates of quarks
- Four physical parameters; fundamental constants of the SM
- Complex elements allow (only source of) CP violation in SM
- Unitary means
- Wolfenstein expansion (A~0.82, , , ) in powers of :

- Only two complex elements to this order; both small ~3

- B Physics from the B Factories

- 10 Jan 2007

## Unitarity triangle

- Represent as “Unitarity Triangle” in complex , plane
- To O(6), use corrected values:                            ,

- Apex is

- B Physics from the B Factories

- 10 Jan 2007

## Example of New Physics in loops

- bsg penguin

- SM

- SUSY: squark, gluino loop with soft breaking term d23

- B0B0 mixing

- SM

- SUSY: squark, gluino loop with soft term d13

- NP can change phase and/or amplitude of loops compared to expectations from measurements of tree processes  inconsistent , 

- B Physics from the B Factories

- 10 Jan 2007

## Measurements of /1

- Phase of Vtd*

- B Physics from the B Factories

- 10 Jan 2007

## CP violation in bccs

- CP violation in bccs

- No Wolfenstein phase

- Two Vtd vertices

- Measurable = relative phase = ei2

- Note: true for any B0 decay with no phase from decay amplitude

- B0

- J/K

- B0

- ei2

- ei0

- ei0

- Two Vtd vertices ei2

- B Physics from the B Factories

- 10 Jan 2007

## Experimental method

- Y(4S) boost  ~0.5

- Time dependent asymmetry = SCPsin(mt)  CCPcos(mt)
- SCP = fCP sin2(fCP= ±1),  CCP “direct” CP violation = 0 for J/K

- Proper time tz/c

- Exclusive B meson vertex reconstruction

- Tag B meson flavour and vertex reconstruction

- B Physics from the B Factories

- 10 Jan 2007

## t time-dependence

- t time-dependence

- t for B0 tag  B0J/K
- t for B0 tag  B0J/K
- Background

- BaBar preliminary, hep-ex/0607107
- Belle preliminary, hep-ex/0608039

**B****0********J/********K****S**

**B****0********J/********K****L**

- Belle
- Preliminary

- Belle
- Preliminary

- B0 tags
- B0 tags

- B0 tags
- B0 tags

- t asymmetry
- J/KL is fCP= +1
- J/KS is fCP= 1

- t oscillation
- Period = B mixing m
- Amplitude = D sin2
- (Dilution D due to mistags; measured experimentally)

- B Physics from the B Factories

- 10 Jan 2007

## World average (HFAG)

- Extracting from sin2 has ambiguities; removed by J/K*, D*D*KS and D0//'/ analyses

- Heavy Flavors Averaging Group
- E.Barberio et al., hep-ex/0603003

- Consistent with zero: no evidence for NP in tree decay

**S****CP**=

- Statistics limited

- B Physics from the B Factories

- 10 Jan 2007

## CP violation in bsss

- CP violation in bsss

- Two Vtd vertices ei2

- Relative phase = ei2

- B0

- K

- B0

- ei2

- ei

- ei

- V*ub vertex ei

- ei

- ei

**+**

- ei2(+

- Overall sin2eff  sin2

- Suppressed

- B Physics from the B Factories

- 10 Jan 2007

## Theoretical estimates of SM offsets

- Mainly positive but large error, sin2eff > sin2

- Small value and error, sin2eff ~ sin2

- Representative theory estimates

- sin2experimental error

- 0.1

- 0.1

- 0.0

- 0.2

- (sin2/1)

- QCDF

- Lazzaro, ICHEP06

- Short distance effect:
- QCDF:
- Beneke, PLB 620, 143 (2005)
- Cheng, Chua, Yang, PRD 73, 014017 (2006)
- pQCD:
- Mishima, Sanda, PRD 72, 114005 (2005)
- SCET:
- Williamson, Zupan, PRD 74, 014003 (2006)
- Long distance effect:
- Cheng, Chua, Soni, PRD 72, 014006 (2005)

- B Physics from the B Factories

- 10 Jan 2007

## BKS and B'KS

- Belle preliminary, hep-ex/0608039
- BaBar preliminary, hep-ex/0607112
- BaBar preliminary, hep-ex/0609052

- BKS: B.F. = (4.3±0.6)×106

- B'KS: B.F. = (3.4±0.2)×105

- Even with small rates,
- clear CP violation observed in penguin decays

- Belle
- Preliminary

- Belle
- Preliminary

**B********K****S**

**B********'****K****S**

- BaBar
- Preliminary

- B Physics from the B Factories

- 10 Jan 2007

## Comparison to bccs

- Comparison to bccs

- sin2 from J/K

- B Physics from the B Factories

- 10 Jan 2007

## Measurements of /2

- 

- B Physics from the B Factories

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## CP violation in charmless modes

- Two Vtd vertices ei2

- Relative phase = ei2(ei2() = ei2

- B0

- 

- B0

- ei2

- ei

- ei

- Vtd vertex ei

- ei(+

- ei(+

**+**

- ei2(+

- Overall sin2eff  sin2

- Suppressed

- V*ub vertex ei

- E.g. B0

- B Physics from the B Factories

- 10 Jan 2007

## Penguin corrections

| + | 5.2±0.2 | + |  23±4 |
| --- | --- | --- | --- |
| +0 | 5.7±0.4 | +0 |  18±3 |
| 00 | 1.3±0.2 | 00 | 1.2±0.5 |

- Penguin correction cleaner for than largest penguin contribution is in00 or 00

- SM correction for penguin from first principles difficult
- Use isospin or SU(3) relations with input from data
- Other  and modes; 00, +0, 00, +0

- Branching fractions (×106)

- Zupan, hep-ph/0701004

- Amplitude Penguin/Tree

- Isospin
- SU(3)

- B Physics from the B Factories

- 10 Jan 2007

## Bdecays

- BaBar preliminary; hep-ex/0607106

- Belle preliminary; hep-ex/0608035

- B0 tags

- B0 tags

- BellePreliminary

- B0 tags
- B0 tags

- Direct CP

- CCP  0    SCP = (1CCP2)sin2eff

- B Physics from the B Factories

- 10 Jan 2007

## Bdecay results

- Belle and BaBar only marginally in agreement

- Bayesian and frequentist interpretations give quantitively different conclusions

- UTFit,
- M.Bona et al.,
- hep-ph/0606167

- CKMFitter,
- J.Charles et al.,
- Eur.Phys.J.C41, 1 (2005)

- Including +0, 00 isospin analysis

- Primarily Bayesian

- Primarily frequentist

- SCP= (1CCP2)sin2eff

- B Physics from the B Factories

- 10 Jan 2007

## Bdecays

- Bdecays

- BaBar preliminary; hep-ex/0607098

- Belle; Phys.Rev.Lett.96, 171801 (2006)

- Belle

- Direct CP consistent with zero

- B Physics from the B Factories

- 10 Jan 2007

## Bdecay results

- Including +0, 00 isospin analysis

- Small CP violation: restricts eff ~ 90 or 0/180

- SCP= (1CCP2)sin2eff

- B Physics from the B Factories

- 10 Jan 2007

## Overall result, including 

- Combined: = [93+119]

- Indirect: = [100+57]

**CL=0.683**

- Other solutions disfavoured

- B Physics from the B Factories

- 10 Jan 2007

## Measurements of /3

- Phase of Vub*

- B Physics from the B Factories

- 10 Jan 2007

## CP violation in DK modes

- Relative phase = ei

- B+

- D0K+

- ei

- ei

- V*ub vertex ei

- E.g. B+D0 /D0K+

- D0K+

- D0/D0 CP state (GLW)
- D0/D0K+/K+, CA/DCS (ADS)
- D0/D0KS+, Dalitz (GGSZ)

- D decays do not involve Vub or Vtd: no contribution to phase

- GLW: Gronau, London, Wyler (2001)
- ADS: Atwood, Dunietz, Soni (1997)
- GGSZ: Giri, Grossman, Soffer, Zupan (2003)

- ei

- ei

- B±  no time dependence; extract  from rates and CP asymmetries

- B Physics from the B Factories

- 10 Jan 2007

## The GGSZ method

- BaBar preliminary; hep-ex/0607104
- Belle; Phys.Rev.D 73, 172009 (2006)

- Belle

- Belle

- Map out Dalitz plot from all D0 decays

- B+

- B

- Look for deviations in B±D0K± plots

- B Physics from the B Factories

- 10 Jan 2007

## Results from GGSZ method

- rB is ratio of D/D amplitudes = 0.16±0.07
- B is D/D relative (strong) phase
- Different rB, B for each mode D(*)K(*)

- Express in terms of measurables from B±

******B******

******B****+******

****

- BaBar preliminary; hep-ex/0607104
- Belle; PRD 73, 112009 (2006)

- B Physics from the B Factories

- 10 Jan 2007

## Overall result

- Indirect: = [59+94]

- Combined: = [62+3824 ]

- B Physics from the B Factories

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## Measurements of Ru

- Error on Ru dominated by error on |Vub|

- B Physics from the B Factories

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## Semileptonic bu decays

- Semileptonic bu decays

- In principle, simple measurement of rate  |Vub|2
- But huge rate of semileptonic bc to remove
- Inclusive BXul+l
- Use high momentum lepton (“endpoint”), Xu mass (or both)
- Need to correct for missing parts of spectra
- Exclusive B0/+/0l+l
- Correct B+ decays for lifetime difference
- Need to include form factor f+(q2=ml2) for B transition

- B Physics from the B Factories

- 10 Jan 2007

## Vub inclusive summary

- Representative theory example (BLNP)

- BLNP: Lange, Neubert, Paz (2005)
- DGE: Anderson, Gardi (2006)
- LLR: Leibovich, Low, Rothstein (2006)

- Room for some experimental statistical improvement

- B Physics from the B Factories

- 10 Jan 2007

## Vub exclusive summary

- Measured branching fractions (all 2006)

- Using theoretical form factors

- Experiments starting to measure form factor shape from data; allows elimination of some theory models

- Theoretical errors dominate

- Will still need form factor normalisation from theory

- B Physics from the B Factories

- 10 Jan 2007

## Vub vs. sin2/1

- Model independent NP in B mixing
- Add new amplitude to SM

- Limits amplitudes to at most ~50% of SM

- Direct:   sin2/1 = 0.67±0.03
- Indirect: sin2/1 = 0.76±0.04
- Difference:           = 0.09±0.05
- Not statistically significant, but...

-  modifies  to +dNP

- B Physics from the B Factories

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## Measurements of Rt

- Error on Rt dominated by error on |Vtd|

-     Not covered here
- B mixing; new ms
- See talk by P. Gutierrez
- bs and d rates
- See talk by S. Robertson

- B Physics from the B Factories

- 10 Jan 2007

## Overall CKM agreement

- Conclusion is the same:
- All measurements agree with SM picture of CKM matrix within errors

- Frequentist

- Bayesian

- B Physics from the B Factories

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## Trees versus loops

- Loops

- Trees

- B Physics from the B Factories

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## Trees versus loops

- Consistent within errors

- Trees

- Loops

- B Physics from the B Factories

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## Prospects for the future

- Both aiming for around 1ab1 each over next two years
- Some measurements are clearly statistics limited
- Sin2/1 bccs vs. bsss comparison
- All angle measurements
- Vub is mainly theory limited
- Some experimental improvements possible
- Theory error can be reduced but with substantial work
- More data also brings new techniques and decay modes
- Improvements better than N can be expected
- The Tevatron and LHC may also help us out 

- B Physics from the B Factories

- 10 Jan 2007

## Conclusions

- NP must be correction, not alternative, to SM in flavour sector
- Little room for any NP in trees; possible in loops
- Items to watch...
- Vub vs. sin2/1  (NP in B0 mixing loop?)
- sin2/1 in bccs vs. bsss  (NP in bsg penguin loop?)
- ...but neither is significant at this stage
- More data will help and will come
- More likely to limit NP through loops than discover it
- NP in flavor sector is constrained
- Flavor physics must be considered in any NP model building

- B Physics from the B Factories

- 10 Jan 2007

- Backup slides

- B Physics from the B Factories

- 10 Jan 2007

## Isospin analysis for , 

- Assuming isospin symmetry between amplitudes

- Flipping triangles gives four-fold ambiguity in solution

- B Physics from the B Factories

- 10 Jan 2007

## Results from GLW, ADS methods

- GLW

- ADS

- CP+

- CP

- CP+

- CP+

- CP

- CP

- No significant CP± differences

- Most rates consistent with zero so few measured asymmetries

- AADS=0.22±0.63

- B Physics from the B Factories

- 10 Jan 2007

## Results from GGSZ method

- rB is ratio of D/D amplitudes and B the relative (strong) phases

- Express in terms of measurables from B±

- B+

- B

- B± difference
- due to 

- B Physics from the B Factories

- 10 Jan 2007

## Angles versus sides

- Consistent

- Angles

- Sides

- B Physics from the B Factories

- 10 Jan 2007

## sin2 vs. time (BaBar only)

- 1/N

- B Physics from the B Factories

- 10 Jan 2007