# Presentation: 042319

## CP violation in B decays: Search for Physics beyond the Standard ModelA. JawaheryUniversity of Maryland

**Outline**
**Will cover three sets of measurements that have the potential to reveal effects of physics beyond the SM:**
** “****sin********” measurements in b->s penguin decays**
**Direct CP violation in B decays**
**Polarization effects****: ****Revisit**** ****b->s********L**

## A successful test so far: CP violation in kaonsK,, ’K ) ,CP conserving
observables (Vub, Vcb, md, ms) &    CPV in B decays (sin2
 all fit within the CKM picture with a single CP breaking phase. 

**observables**** ****(Vub, Vcb, ********m****d****, ********m****s****)**** &    ****CPV in B decays**** (sin2******
** ****all fit within the CKM picture with a single CP breaking phase. **
** **

**The CKM Test  (*****covered in Kazuo Abe’s Talk*****)**

_**So, what does this mean for “New Physics” in the flavor sector?**_
** ****From L. Silvestrini’s talk at Lepton-Photon 2005 (Direct quote/copy)**

## Are these effects measurable via CP asymmetries in B decays?

**Are these effects measurable via CP asymmetries in B decays?**
**Again**** borrowing from L. Silvestrini’s talk at Lepton-Photon 2005:**

**Can  alter both the  S and C terms of the time dependent A****cp****(T)**
**Change polarization properties of the final states. **

**SM**

**SM**

**SM**

**SM**

**Significant deviations from the SM expectation for CP asymmetries is possible and detectable with current experiments**
**Failure to see any, will lead to constraints on new mixing angles and new phases**

## f

- B0

- B0

**Within the SM:**

_**The  “sin2**__****__**” Test:  Mixing induced CP violation **_
_**in penguin modes **_**b->sqq**_** **_

- fcp

- Sf~ -cpsin2

- Dominant amplitude (~ same phase as b->ccs

- suppressed amplitude (~

- Expect within SM

**With new physics and new phases, S****f****  could depart from -********cp****sin2******
**The Task: ****Measure**** ********S****f****=-********cp****S****f**** – sin2********search for deviation from zero**

**A Key Question: How well do we know ********S****f ****within the SM?**

**For**** ****f****cp**** =from b->sqq**

## SM expectation

- f

**Within the SM:**

- Dominant amplitude (~ same phase as b->ccs

- suppressed amplitude (~

**  **QCDF calculations**(**Beneke, hep-ph/0505075 Cheng, Chua & Soni, hep-ph/0506268**). **

- SU(2) and SU(3) can also be put to work to connect various CP conserving and CP violating observables--generally much less restrictive- but can improve with data.

- Sf depends on the size and the relative strong phase  of  this “suppressed “ term

## The bsqq penguin decays used in the “sin2”  test

**Need decays into CP eigenstates f****cp ****:**
_**b**__****__**sss:**_** **
**B************s****	**** ****(********cp****=-1)****	**
**B************L****	**** ****(********cp****=+1)****	**
**B********K****+****K****-********s   ****( ********cp****=+1 ****dominates)**
**B********K****+****K****-********L   ****( ********cp****=-1 ****dominates ) ****	**
**B********K****s****K****s****K****s**** **** ****(********cp****=+1) ****	**
**B************’K****s****       (********cp****=-1)****	**
**B************’K****L****       (********cp****=+1)****	**
**B********f****0****K****s**** ****           ****(********cp****=+1)****	**
_**b**__****__**sdd:**_** **
**B********************s****	****(********cp****=-1)****	**** **
**B************s****	****(********cp****=-1)****	**

- Br=8.3+/- 1.1 x10-6

- Br=6.2+/- 0.9 x10-6

- Br=63.2+/- 3.3 x10-6

- Br=1/2(5.5+/-1.0 x10-6 )

- Br=1/2(11.5+/-1.0) x10-6

- Br=1/2(4.7+/-0.6) x10-6

## 232x106 BB’s

- 

**232x10****6**** BB’s**

- The Data:  s, K+K-Ks

- Similarly all other channels are also statistically limited-

##   ~ 2.5 deviation at this point. 

**Simple average:    S****penguins****=0.5 +/- 0.06   vs reference point: ****sin********69+/-0.03**
-   ~ 2.5 deviation at this point.

**QCD factorization calculation of ********S**

## Tests with Direct CP violations

_**   **_

**Direct CP violation results when several diagrams, with different cp conserving  and cp breaking phases contributing to the same final state, interfere:**

- +

**E.g. B********K********:   **

**********************************************************************..******

**A contributing diagram from “New Physics” can alter A****cp**** from the SM values. Need predictions of A****cp**** within SM- Again rely on QCDF or PQCD, or exploit symmetries (SU2, SU3 etc) to connect A****cp**** in different modes and derive sum rules- to be tested.**

##  So far the only confirmed case for  direct CP violation in B decays

** ****So far the only confirmed case for  direct CP violation in B decays**

**A****cp****(B****0********K********************0.115+/- 0.018**

**Within SM: Expect  ****A****cp********b->s**************

## Observation of direct CP violation in B0K+-   

**HFAG Average**

- -0.115+/- 0.018

- BaBar 2004

- New Belle Result:
- -0.113+/- 0.022+/- 0.008

**232x10****6**** BB’s**

- superweak is really out; Strong phases are non-zero in these decays- one more challenge  for QCD to explain quantitatively.

## 		(Needs more data)

**A****cp****(B****0********K****+********-****) = ****-0.115+/- 0.018**
**A****cp****(B****0********K****0********0****) = ****+0.02+/- 0.13**
**A****cp****(B****+********K****+********0****) = ****+0.04+/- 0.04**
**A****cp****(B****+********K****0********+****) = ****-0.02+/- 0.04**
**Naive expectation: **** **
**The test fails– New Physics or too naïve?**

- A more accurate sum rule relation derived based on SU(2) and SU(3) relations- (M. Gronau hep-ph/0508047)
- To satisfy this relation requires: (accounting for  & br. differences)
-  **A****expected****cp****(B****0********K****0********0****) = ****-0.17+/- 0.06**  vs measured **A****cp****(B****0********K****0********0****) = ****+0.02+/- 0.13** .
- 		**(****Needs more data)**

**Within the SM,   direct A****cp****’s  for all B->K********modes are related-**

## Polarization effects- Revisit bs

**EW:b********s********b********sl****+****l****-**

**Measured rate consistent with SM:**
**BF(b****→****s********)****TH ****  = 3.57 ****± ****0.30 x 10****-4**** (SM NLO)**
**BF(b****→****s********)****EXP**** = 3.54 ****± ****0.30 x 10****-4**** (HFAG) **
**(See Jeff Richman’s talk this conf.)**

- **New physics contributions can result in mixed polarization for ******** (& non-zero direct CPV)**

**But there is more info in this process:**** ****In the SM:**
**b************s****L ************left-handed)**
**Direct CP violation – ****nearly zero**

## The value of SK* as a NP observable  depends on SM uncertainties -  recent work based on QCDF/SCET, considering the impact of bsg) set  SK* -  (Grinstein, Grossman, Ligeti, Pirjol PRD 71, 011504(2005), Grinstein, Pirjol, hep-ph/0510104)

- Probing the polarization via Time-dependent CP violation in bsdecays

**The value of S****K********* as a NP observable  depends on SM uncertainties -  recent work based on QCDF/SCET, considering the impact of **bsg) set  **S****K************* -  ***(**Grinstein, Grossman, Ligeti, Pirjol PRD 71, 011504(2005), Grinstein, Pirjol, hep-ph/0510104*)

- (A. Atwood,  M. Gronau & A. Soni (1997))

**Within SM**

## SM:SK* ~ 0.1

**B********K*(890)**with **K*********K****0**** ****************K****0 **** ********Ks**************with r~****x10-6

- SK*** =-0.21 +/- 0.40 +/- 0.05**
- CK*** = -0.40 +/- 0.23 +/- 0.04**

- SKs** =-0.21 +/- 0.40 +/- 0.05**
- CK** = -0.40 +/- 0.23 +/- 0.03**

- SK*** =0.01 +/- 0.51 +/- 0.11**
- CK*** = -0.11 +/- 0.33 +/- 0.09**

- HFAG Average: SK*** =-0.13 +/- 0.32    **CK*** = -0.31 +/0.19**

- SM:SK* ~ 0.1

**275 M BB’s**

**Needs much  more data**

**232x10****6**** BB’s**

## Summary & Outlook

- Uncertainties in most Direct CP asymmetries  to follow sqrt(n)  to ~1% level.

**BaBar & Belle  are aiming for around 1 ab****-1**** of data each by 2008**

- Penguin CPV errors in 2008

**Together with the CKM unitarity tests, this could soon either lead to signs of Physics beyond the SM In the flavor sector (a 2  to 3 ******** deviation from the SM is present now) , and/or to  a precisely constrained charged current sector of the Electroweak theory as a reference point for future searches for New Physics****.**