# Presentation: 942581

## Rare Hadronic B Decays

- John Fry
- Lepton Photon 2003

## Scope of Talk

- To present updated branching fractions (BF) and CP asymmetries  (ACP) for rare (charmless) B decay modes
- To show how BF and ACP are used with theoretical models to put constraints on the Standard Model and to search for New Physics.
**NB:**	All results are preliminary unless referenced.

- John Fry                  Lepton Photon 2003

## How Good is the Standard Model?

- A. H**ö**cker et al, Eur. Phys. Jour.
- C21 (2001) 225, [hep-ph/0104062]

- K [K] and B sectors [md,
- V_ub_ , V_td_ , Sin (2)]
- consistent with each other
- and SM (theory)

- LEP
- Coupling Constants
- CPLEAR
-  T consistent with CP
-  Tight CPT constraint

- John Fry                  Lepton Photon 2003

## Motivation for Rare Decays

**SM is a **_**very**_** good approximation to reality**
**	****Hence**** **
**Need to consider processes where          is small in order to be sensitive to new physics.**
**Hence processes dominated by penguin loops, or CKM**** ****- suppressed decays**

- John Fry                  Lepton Photon 2003

## Procedure

- Compare nature (precise, experimental measurements) with SM (theoretical models) for sensitive quantities.
- Agreement gives an alternative route to (, ) and additional constraints on the unitarity triangle.
- Disagreement means:
- New Physics .... **OR**
- Refinements needed to theoretical calculations ...             ....**AND **Model-independent calculations needed

- John Fry                  Lepton Photon 2003

## The (theoretical) Problem

- How to go from here ...

- to branching fractions and CP asymmetry

- John Fry                  Lepton Photon 2003

## Classes of theoretical calculations

**QCD Factorisation**  (mb >> QCD)
- Amps factorise to LO ( / mb), all orders S
- Naïve factorisation recovered in LO
**Phenomenology**
- Amplitudes of dominant processes related to
-  measured BF and each other via SU(3)
**Model “Independent”**
- Isospin & minimal dynamical assumptions
-    bounds on deviations from SM

- Beneke, Buchalla, Neubert & Sachrajda
- Nucl Phys B606 (2001) 245
- Beneka & Neubert   Hep-ph / 0308039

- Chiang, Rosner  Phys Rev D65 074035
- Chiang et al      Hep-ph / 0307395
- Lipkin  Phys Lett B254 (1991) 247

- Grossman, Ligeti, Nir, Quinn
- Hep-ph / 0303171

- John Fry                  Lepton Photon 2003

## Visualising QCD Factorisation

****

- John Fry                  Lepton Photon 2003

## Pictorial Phenomenology

****

**Leading Order – Naive Factorisation**

- John Fry                  Lepton Photon 2003

## Direct CP Violation

- CP asymmetry occurs if the decay B  f ( and its charge conjugate)
- is mediated by two amplitudes with different strong and weak phases:

- John Fry                  Lepton Photon 2003

## Overview of B Production and Decay

**Inclusive  Reconstruction**** **
**B-Flavor Tagging**

**Exclusive B Meson Reconstruction**
**CP eigenstates**
**Flavor eigenstates**

- John Fry                  Lepton Photon 2003

## Signal Selection

- John Fry                  Lepton Photon 2003

## Discrimination of B and Continuum

- John Fry                  Lepton Photon 2003

## Search for B0 → p pbar @ BaBar

- p

- K e

- Use the DIRC to reject K, , e, 

- Smallest upper-limit BF in B0/Bdecays!

- Signal Eff = 91%
- Background Eff = 3%

- Total signal efficiency = 37%

- John Fry                  Lepton Photon 2003

## Slide 15

- John Fry                  Lepton Photon 2003

## Slide 16

- John Fry                  Lepton Photon 2003

## Summary of BF (10-6)  for K,  and KK

- Summary of BF (10-6)  for K,  and KK

| Mode | BaBar | Belle | CLEO | Average |
| --- | --- | --- | --- | --- |
| K+ - | 17.9  0.9  0.7 | 18.5  1.0  0.7 | 18.0  2.3  1.2 | 18.1  0.8 |
| K0 + | 17.5  1.8  1.3 | 22.0  1.9  1.1 | 18.8  3.7  2.1 | 19.6  1.5 |
| K+ 0 | 12.8  1.2  1.0 | 12.8  1.4  1.2 | 12.9  2.4  1.2 | 12.8  1.1 |
| K0 0 | 10.4  1.5  0.8 | 12.6  2.4  1.4 | 12.8  4.0  1.7 | 11.2  1.4 |
| + - | 4.7  0.6  0.2 | 4.4  0.6  0.3 | 4.5  1.4  0.5 | 4.6  0.4 |
| + 0 | 5.5  1.0  0.6 | 5.3  1.3  0.5 | 4.6  1.8  0.7 | 5.3  0.8 |
| 0 0 | 2.1  0.6  0.3 | 1.7  0.6  0.3 | < 4.4 | 1.90  0.47 |
| K+ K- | < 0.6 | < 0.7 | < 0.8 | < 0.6 |
| K+ K0 | < 1.3 | < 3.4 | < 3.3 | < 1.3 |
| K0 K0 | < 1.6 | < 3.2 | < 3.3 | < 3.2 |

- John Fry                  Lepton Photon 2003

**HFAG**
- J Smith (Colorado)
- J Alexander (Cornell)

- John Fry                  Lepton Photon 2003

## Belle

**Belle**

**Belle**

**+9.3**
** ****-8.4**

- John Fry                  Lepton Photon 2003

## BaBar 0 0

**BaBar ********0**** ********0**
**Sub to PRL**

- John Fry                  Lepton Photon 2003

## QCD_F:  Ratios of  & K BF’s

- BBNS NPB606 (2001) 245
- Inconsistent ?

- Data (2001)

- Data (2003)

- QCD_F:  Ratios of  & K BF’s

**0.42 ****± 0.11**

- John Fry                  Lepton Photon 2003

## Comparison of BF and ACP with Theory‡

| Mode | BFExp 
(10-6) | BF pQCD
(10-6) | ACP Expt
(%) | ACP pQCD
(%) | ACP QCDF
(%) |
| --- | --- | --- | --- | --- | --- |
| K+- | 18.2 ± 0.8 | 13 – 19 | -9 ± 3† | -13 – -22 | +5 ± 10 |
| K0+ | 19.6 ± 1.5 | 14 – 26 | -1 ± 6 | -0.6 – -1.5 | 0 ± 1 |
| K+0 | 12.8 ± 1.1 | 8 – 14 | 0 ± 7 | -10 – -17 | +7 ± 10 |
| K00 | 11.2 ± 1.4 | 8 – 14 | 3 ± 37 |  | -3 ± 4 |
| +- | 4.55 ± 0.44 | 6 – 11 |  | 16 – 30 | -6 ± 13 |
| +0 | 5.3 ± 0.8 | 2.7 – 4.8 | -7  ± 14 | 0 | -2 ± 5 |
| 00 | 1.90 ± 0.47 | 0.33 – 0.65 |  |  | 45 ± 60 |

- John Fry                  Lepton Photon 2003

## Belle

**Belle**

- John Fry                  Lepton Photon 2003

## CDF

**Disentangling the  B********h+h- contributions (I)**

_**B **_****** **_**h**__**+**__**h**__**-**__** from hadronic trigger**_
**Includes B****d**** ************B****s********KK,**** ****B****s********K**** ********,**** ****and B****d******** ****K******

**Monte-Carlo plot below shows:**
**B****d**** ******** ************************Bs ******** ****K****+****K****-**** B****s**** ******** ****K****±**** ********±****,**** **
**& B****d**** ******** ****K****±**** ********±**** (From Monte-Carlo)**
**all pile up in the same region**

**Must **_**disentangle **_**contributions from each mode **
**To do this we use:**
**-****Kinematical**** ****variable  separation**** ****M******** vs ********=(1-p****1****/p****2****)********q****1 **
**-dE/dx based K and ******** identification**** **

**CDF**

- John Fry                  Lepton Photon 2003

## CDF

**M******** vs a for each B********h****+****h****-**** mode**

**dE/dx calibration using D*****± ******** ****D****0************, **
**D****0 ********K****±********±**** ****(******** from D*  unambiguously distinguishes K, ******** from D****0****)**** **

_**Sanity check: Measure Ratio of Branching Ratios**_
_**CDF :**_** ********(B****d ******** ****************-****)/********(B****d******** ****K****+********-****) = 0.26 ±0.11±0.055, ****PDG:**** **

_**Yield for each mode:**_
**B****d ******** **********************
**B****d ******** ****K****±**** ********±**********
**B****s ******** ****K****± ********±**********
**B****s ******** ****K****+****K****-  ********(stat) ********(stat)******
******First observation !**

_**Method works !**_**  Confirmed by Sanity **
**check against ratio of branching ratios**
_**Have first observation of B**__**s **_****** **_**K+K-**_
_**Its a CP Eigenstate: Can use this**_
_**To measure **__****__**s**__** as well !!**_

**CDF**

- John Fry                  Lepton Photon 2003

## Disentangling the  Bh+h- contributions (Blessed CDF results)

** ****ACP(B****d********K******** = ****0.02 ± 0.15(stat) ± 0.017(syst)**
** ****BR(B****d************/BR(B****d********K********=   **
**               ****0.26 ± 0.11(stat) ± 0.055(syst)**
** ****fs X BR(B****s********KK)/fd X BR(B****d********K********) = **
**       ****0.74 ****±**** 0.20(stat) ****±**** 0.22(syst)**
**Yield of ****B****s********KK = 90 ****±****17(stat) ****±****17(syst) events**

- John Fry                  Lepton Photon 2003

## Is Rescattering Important?

- Could modify branching fractions and CP asymmetries in and K decays, complicating extraction of  and 
- KK decays are more sensitive to rescattering
- Could have significant enhancement through (for example) DD or  intermediate states

|  | BaBar | P_QCD* |
| --- | --- | --- |
| K+K- | <0.6 | 0.05 |
| K+K0 | <2.2 | 1.7 |
| K0K0 | <1.6 | 1.8 |

- BF(10-6)

- *Chen and Li, Phys. Rev D63, 014003 (2000)

- John Fry                  Lepton Photon 2003

## BF & ACP for B  , K, , K

| Mode | BF (10-6) (BaBar) | BF (10-6) (Belle) | ACP  % (BaBar) | ACP  % (Belle) |
| --- | --- | --- | --- | --- |
| B0 → ρ+ π-   | 22.6  2.8 | 29.1  6.4 | -11  7  | -38  21  |
| B0 → ρ+ K- | 7.3  1.8 | 15.1  4.1 | 19  18 | 22  23 |
| B0 → ρ0 π0 | < 2.5  | 6.0  3.1 |  |  |
| B+ → ρ+ π0 | 11.0  2.7  |  | 23  17 |  |
| B+ → ρ0 π+ | 9.3  1.3  | 8.0  2.3 | -17  11 |  |
| B+ → ρ0 K+ | < 6.2 | < 12 |  |  |
| B0 → ω K0 | 5.3  1.4 | < 7.6 |  |  |
| B+ → ω K+ | 5.0  1.1 | 6.7  1.4 | -5  16 | 6  20 |
| B0 → ω π0 | < 3 |  |  |  |
| B+ → ω π+ | 5.4  1.1 | 5.9  1.5 | 4  17 | 48  23 |

- John Fry                  Lepton Photon 2003

## Belle  B  , K

**Belle  B ******** ********, K**

**K****+**

******+**

**K****S**

- John Fry                  Lepton Photon 2003

## BaBar:   B  K Dalitz Plot

- BaBar:*   *B  K Dalitz Plot

| B+  K*0(892)+,          K*0K+ - | 10.3±1.2+1.0 |
| --- | --- |
| B+  f0(980)K+, f0 + | 9.2±1.2+2.1 |
| B+  c0 K+, c0 + | 1.46±0.35±0.12 |
| B+  D0+, D0 K+ - | 184.6±3.2±9.7 |
| B+higher K*0+, K*0K+- | 25.1±2.0+11.0 |
| B+  0(770)K+, 0 + | < 6.2 |
| B+  K+ - + (non resonant) | < 17 |
| B+  higher fK+, f + | <12 |

**-5.7**

**-2.6**

**-2.7**

**K*****0****(892)**

**K*****0****(higher)**

**D****0**

**ρ****0**

-  **f****0****(980)**

******c0**

**56.4 fb****-1**

**Branching Fractions 10**** -6**

- John Fry                  Lepton Photon 2003

## Belle:   Dalitz Plot Amplitude Analysis

- 140 fb-1 B+  K+K+K- (Signal 1400) and K++ - (Signal 2584)
- Resonances:
- K++ -      K*(890), K*(1430), (770), c0(3400), f0(980), X(1350)
- K+K+K-      (1020),  C0(3400), X(1500)
- Background parameterisation – fitted with large (7*) sideband sample

- Signal parameterisation – fix masses, widths except X, f0

- Fit to signal + background and determine amplitudes and phases

- John Fry                  Lepton Photon 2003

## Slide 32

- John Fry                  Lepton Photon 2003

## Belle DP Mass and Helicity Projections K

- Belle DP Mass and Helicity Projections K

- John Fry                  Lepton Photon 2003

## Belle  Branching Fractions from Dalitz Plot

**Belle ** Branching Fractions from Dalitz Plot

- John Fry                  Lepton Photon 2003

**HFAG**
**J Smith (Colorado)**
**J Alexander (Cornell)**

- John Fry                  Lepton Photon 2003

## Longitudinal Polarisation   B → V V

- fL = L / 
- 100% Pol  CP even
- Expect:   fL ~ 1 – O(M2V/M2B)

- John Fry                  Lepton Photon 2003

## Belle

**Belle**
**B ******** ********+**** ********0**

- John Fry                  Lepton Photon 2003

## B → ρ ρ and ρ K* [BaBar & Belle]

| (Errors approximated) | BF (10-6) | ACP % | Long. Poln % |
| --- | --- | --- | --- |
| B0→ ρ0 ρ0 | < 2.1 (90 % CL) |  |  |
| B0→ ρ+ ρ- | 27 ± 7 ± 6 |  | 99 ± 7 ± 3 |
| B+→ ρ+ ρ0
Belle | 22.5 ± 5.7 ± 5.8
31.7 ± 7.1 ± 6.7 | -19 ± 23 ± 3
0 ± 22 ± 3 | 97 ± 7 ± 4
95 ± 11 ± 2 |
| B+→ ρ0 K*+ | 10.6 ± 3.0 ± 2.4 | 20 ± 32 ± 4 | 96 ± 15 ± 4 |

-  CP asymmetries consistent with zero
-  Polarisation in agreement with expectation

- John Fry                  Lepton Photon 2003

## Why we need Theorists

**K****0********+**

******+********0**

| Mode | CKM | (fdecay)2 | Ratio | Exp Ratio | BF (10-6) |
| --- | --- | --- | --- | --- | --- |
| K0+ | 1 | 1 | 1 | 1 | 19.6 |
| K*0+ | 1 | 1.85 | 1.85 | 0.65 | 12.7 |
| +0 | 2 | 0.66 | 0.03 | 0.27 | 5.3 |
| +0 | 2 | 1.71 | 0.085 | 0.46 | 9.1 |
| +0 | 2 | 2.9 | 0.145 | 1.35 | 26.4 |

**The VPSTE effect**    (Form factor corrections at 40% level)

- John Fry                  Lepton Photon 2003

## The unique decays B  0 0 and 0 0

**BF give model-independent**
**limits to the CP angle ******

- John Fry                  Lepton Photon 2003

## B   K(*)  BaBar & Belle

**q**

**q**

***s***

***s***

-   u

- u

**B****+,0**

****

**K****(*)**

| Mode | BF (10-6) | ACP (%) | Polarisation  % |
| --- | --- | --- | --- |
|  K0 | 7.6 ± 1.4      9.0 ± 2.2 |  |  |
|  K+ | 10.0 ± 1.0    9.4 ± 1.3 | 4 ± 9      1 ± 13 |  |
|  K*0 | 11.2 ± 1.5    10.0 ± 1.8 | 4 ± 12    7 ± 16 | 65 ± 7    43 ± 10 |
|  K*+ | 12.7 ± 2.4    6.7 ± 2.2 | 16 ± 17   -13 ± 31 | 46 ± 12 |

-  Expect similar BF all modes
-  BF(+) < 4 10-7  [90% CL]
- No indication for rescattering – as KK
- Polarisation unexpectedly small

- John Fry                  Lepton Photon 2003

## Belle

**Belle**

- John Fry                  Lepton Photon 2003

## BR(B±K±) at CDF 

- BR(B±K±) /BR(B±J/K±) = 0.0068 ±0.0021 (*stat*.) ± 0.0007 (*syst.*)
- Using PDG 2002 for BR(B±J/K±):
- BR(B±K±) = (6.9 ± 2.1 (*stat*.) ± 0.8 (*syst.*)) x 10-6

- John Fry                  Lepton Photon 2003

## B  (')K(*) and ('),   BaBar and Belle

| Mode | BF (10-6)
Belle          BaBar |  |
| --- | --- | --- |
|  K+ | 5.3 ± 1.9 | 2.8 ± 0.8 |
|  K0 |  | < 4.6 |
| ' K+ | 78 ± 11 | 76.9 ± 5.6 |
| ' K0 | 68 ± 13 | 55.4 ± 6.6 |
|  + | 5.4 ± 2.1 | 4.2 ± 1.0 |
| ' + | < 7 | 2.8 ± 1.3
3.4  |
|  0 | < 5.5 |  |

| Mode | BF (10-6)
Belle          BaBar |  |
| --- | --- | --- |
|  K*+ | 26.5 ± 8.4 | 25.7 ± 4.2 |
|  K*0 | 16.5 ± 4.8 | 19.0 ± 2.6 |
| ' K*+ | < 90 | < 12 |
| ' K*0 | < 20 | < 6.4 |
|  + | < 6.2 | 10.5 ± 3.4
4.8  |
| ' + |  | 14.0 ± 5.4
3.8  |
| ' 0 | < 14 |  |

- John Fry                  Lepton Photon 2003

## Theoretical background: (') K, K * modes

- Similarly for *K *0, *K **0 except no external tree

- Flavour singlet diagram:
- Also important for *K**

- CKM suppressed

- H Lipkin  Phys Lett B254 (1991) 247

- John Fry                  Lepton Photon 2003

## Slide 46

- John Fry                  Lepton Photon 2003

## B  (')K(*) and ,   BaBar and Belle

| Mode | ACP (%)
Belle        BaBar |  |
| --- | --- | --- |
|  K+ |  | -32 ± 22 |
|  K0 |  |  |
| ' K+ | -2 ± 7 | 4 ± 5 |
| ' K0 |  |  |
|  + |  | -51 ± 20 |

| Mode | ACP (%)
Belle        BaBar |  |
| --- | --- | --- |
|  K*+ |  | 15 ± 14 |
|  K*0 |  | 3 ± 11 |
| ' K*+ |  |  |
| ' K*0 |  |  |
|  + |  | 6 ± 29 |

- John Fry                  Lepton Photon 2003

**HFAG**
**J Smith (Colorado)**
**J Alexander (Cornell)**

- John Fry                  Lepton Photon 2003

**HFAG**
**J Smith (Colorado)**
**J Alexander (Cornell)**

- John Fry                  Lepton Photon 2003

## How does theory stack up?

- Good phenomenological understanding of Branching Fractions for 2-body PP and PV decays
- [Chiang et al hep-ph/0307395; Beneke et al hep-ph/0308039; Keum et al hep-ph/0306004]
- Factorisation models give insight into dynamics, but:
- BF for 0 0 looks to be in disagreement with all predictions
- BF for K, ' K,  K* final states underestimated in QCDF
- [Annihilation contribution may be too large Aleksan et al, hep-ph/0301165]
- Asymmetry data is not yet precise enough to test models
- There is still a considerable role for model-independent theoretical calculations

- John Fry                  Lepton Photon 2003

## When is it safe to claim New Physics?

- For B0  KS, 'KS, K+K-KS we expect to measure:
- 	S = sin(2) + ,  C = ,  where  = O (2)
- If S and C are measured precisely (S, C << 2 = 0.05)
- Claim new physics if:  |C| > 5, or |S- sin(2)| > 5
****** ****might be enhanced:**	Grossman bounds  using isospin

- relations and ratios of  BFs.
- (K+K-KS)  0.2, ('KS)  0.5
- 	GLNQ     Hep-ph / 0303171
- Must measure  20 BFs precisely
- to improver the limit on !

- u-amplitude might be large

- John Fry                  Lepton Photon 2003

## Summary – What have we learned?

- Precision measurements of branching fractions are testing factorisation models – to destruction??
- Precise measts of ACP will enable further tests of models. Is there a hint of a signal in K+- ?
- B K, K*,'K, 'K* are now almost understood, but polarisation << 100% in K* is a puzzle
- Measuring the BF for 0 0 is a triumph, but the value is surprisingly high.  Increased focus on 00 for | - eff|
- Measurement of many more decay modes is needed to make model-independent tests of NP meaningful
- The expected increase in luminosity of the B Factories promises a continuing, rich harvest of physics

- John Fry                  Lepton Photon 2003