Charmless B Decays to Vector-Vector (Tensor) Zijin Guo (on behalf of - PowerPoint PPT Presentation

1 Charmless B Decays to Vector-Vector (Tensor) Zijin Guo (on behalf of the BABAR Collaboration) Johns Hopkins University PHENO 2008 Sym PHENO 2008 Symposium posium Madison, April 29 th th , 2008 Madison, April 29 , 2008

2 OUTLINE � Introduction � Angular Distributions � B → ϕ K *0 , ϕ K 2 *0 , ϕ K *+ – � B → K *0 K *0 , K *0 K *0 � Summary

Producing and Detecting B Mesons at BABAR 3 E cm = 10.58 GeV – use 384 million BB pairs – in B → ϕ K * and K * K * analyses BABAR Detector Experiment ended 04/07/2008 433 fb -1 at Y(4S) 475 M BB pairs PEP-II

Why Study B → Vector-Vector Decays 4 • Interest in “penguin” dominated modes, e.g. B → ϕ K * Standard Model (V-A): expected |A 0 | |A + | |A - | λ =0 λ =+1 λ =-1 λ ≡ Vector meson helicity b → s Surprise: for ϕ K *+ and ϕ K *0 , |A 0 | 2 ~ 50% |A 0 |~|A ± |, but |A + |>>|A - | or |A - |>>|A + | (?) • Possible New Physics in loop amplitude: – if separate B and B: 12 measurements 6 |A i |, 5 arg(A i /A j ), 1 phase

V-V ANGULAR DISTRIBUTIONS 5 B B has spin 0 ⇒ no orbital angular momentum projection θ 1 and θ 2 are the helicity angles; Φ is the angle between the decay plane normals • Measure amplitudes from the full angular dependence; Define Transversity Amplitudes

B → ϕ K *0 and ϕ K *+ 6 • Estimate parameters using Maximum Likelihood Fit (polarization, strong phase, weak phase difference, …) • Full angular analysis in B → ϕ K * (possible since high luminosity → enough data) B 0 → ϕ (K π ) 0 0 (1430) 0 & non-resonant) Significant (K π ) 0 *0 : K π S-wave (includes K * - interference ⇒ resolve ( φ || , φ ⊥ ) mathematical ambiguity cf. B → J/ ψ K π ( BABAR) PRD 71, 032005 (2005) B + → ϕ K* +

Polarization and CP Results in B → ϕ K *0 and ϕ K *+ 7 PRL 98, 051801(2007), PRL 99, 201802(2007) • 12 measurements • 6 CP-asymmetries reject ambiguous solution consistent with 0 using the K π mass dependence new approach to CP of the S-A 0 relative phase (weak phase of A + ) (Wigner Causality)

8 Vector-Tensor and Spectroscopy in B 0 → ϕ (K π ) 0 PRL 98, 051801 (2007) ? PRD 76, 051103 (2007) Vector-Tensor puzzle: f L ( ϕ K * 2 ) ~ 1 Vector-Vector: Vector-Tensor:

– Observation of B 0 → K *0 K *0 and 9 Search for B 0 → K *0 K *0 • Charmless penguin decay - provide insight into the polarization puzzle b → d - test factorization models - could be used to help constrain the angles α and γ electroweak gluonic - Previous experimental results (BF): < 22 x 10 -6 (CLEO2, PRL 88, 021802 ) - BF theoretical predictions - Longitudinal polarization predictions NPB 774, 64 (2007) • B 0 → K *0 K *0 : SM suppressed decay BF < 37 x 10 -6 (CLEO2, PRL 88, 021802)

10 10 BABAR PRL 100, 081801 (2008) low statistics ⇒ measure f L only – • B 0 → K *0 K *0 : Beneke et al. consistent f L = BF in reasonable agreement with theoretical predictions • B 0 → K *0 K *0 : UL < 0.41 x 10 -6 (@90% CL) 2 orders of magnitude more stringent than previous measmt.

B → VK * : Experiment-Theory Comparison 11 11 (SU 3 ) * B eneke, R ohrer, and Y ang, NPB 774, 64 (2007)

SUMMARY 12 12 • Polarization Puzzle: strong or weak interaction effect ? in B → ϕ K *0 , ϕ K *+ (puzzle) in B → ρ K *0 (|A + |>>|A - | or |A - |>>|A + | (?)) – in B → ϕ K 2 * (1430) 0 , K *0 K *0 (not consistent with above) • Possible Solutions to Explain A + Annihilation mechanism Rescattering mechanism (FSI) no generally accepted solution

13 13 Possible New Physics in Polarization Scalar interaction Supersymmetry