Download presentation

Presentation is loading. Please wait.

Published byAniya Buys Modified over 3 years ago

1
Hadronic B decays involving tensor mesons Hai-Yang Cheng ( 鄭海揚 ) Academia Sinica Properties of tensor mesons QCD factorization Comparison with experiment April 5, 2011 in collaboration with Kwei-Chou Yang 2011 Cross Strait Meeting on Particle Physics and Cosmology

2
22 Even-parity mesons 2 Scalar mesons (J PC = 0 ++ ) Axial-vector mesons 3P13P1 1P11P1 ( J PC =1 ++ ) ( J PC =1 +- ) Kwei-Chou Yang, Nucl. Phys. B776, 187-257 (2007). 1 GeV 1 GeV

3
333 Tensor mesons For J P =2 + tensor mesons 3 P 2 nonet: I=0: f 2 (1270), f’ 2 (1525), I=1/2: K 2 * (1430) I=1: a 2 (1320) close to ideal mixing, f2 5.8 o

4
4 B SM (M=P,V): HYC, Chua, Yang in QCD factorization (’ 06, ’ 08) C.D. Lu et al. in pQCD ( ’ 06, ’ 07, ’ 09) Delepine et al. ( ’ 08) Z. J. Xiao et al. in pQCD ( ’ 08 - ’ 10) B AM: HYC, Yang in QCDF (’ 07) C.D. Lu et al. in pQCD ( ’ 07) B TM: last enterprise

5
5 To study B → TM (M=P,V) decays, we need to know mixing angles decay constants light-cone distribution amplitudes form factors for B → T transition vertex corrections, spectator interactions, annihilation for decay amplitudes HYC, Koike, Yang (’10) HYC, Yang (’10) W. Wang (’10), Yang (’10), Z.G. Wang (’10) Aliev & Shifman ( ’ 82) Braun & Kivel (’01) ISGW (’89,’95), CCH ( ’ 01)

6
6 Decay constants Tensor meson cannot be produced from local V-A current owing to p =0 Can be created from local current involving covariant derivatives with Previous estimates: Aliev & Shifman (’82); Aliev, Azizi, Bashiry (’10) Based on QCD sum rules we obtain (HYC, Koike, Yang, arXiv:1007.3526)

7
77 Form factors for B → T 7 ISGW (Isgur-Scora-Grinstein-Wise) non-relativistic quark model (’89,’95) Covariant light-front quark model (Chua, Hwang, HYC, ’04) Relativistic effects in B-to-light transitions at q 2 =0 are important Large energy effective theory (LEET) (Charles et al. ’99) pQCD approach (W. Wang, arXiv:1008.5326) QCD sum rules (K.C. Yang, arXiv:1010.2144; Z.G. Wang, arXiv:1011.3200)

8
88 Light-cone distribution amplitudes (LCDAs) twist-2: ∥, twist-3: g v, g a, h t, h s twist-4: g 3, h 3 8 C i 3/2 : Gegenbauer polynomial Due to even G-parity, these LCDAs are anti-symmetric under the replacement u→1-u in SU(3) limit first studied by Braun & Kivel (‘01)

9
9 Longitudinal & transverse helicity projectors for tensor mesons: Transverse momentum derivative terms should be included before taking collinear approximation Helicity projectors for vector mesons:

10
10 B → TM in QCDF Apply QCD factorization to B→TM ( Beneke, Buchalla, Neubert, Sachrajda) vertex & penguin spectator int. annihilation

11
Data Previous studies based on naïve or generalized factorization predict rates typically too small by 1-2 orders of magnitude compared to experiment dominated by BaBar, f 2 K modes are due to Belle

12
12 Penguin-dominated B TP

13
13 Beyond naïve factorization, contributions f T defined from local currents involving covariant derivatives can be produced from nonfactorizable contributions such as vertex, penguin and hard spectator corrections B - K 2 *0 vanishes in naïve factorization, while its BR is measured to be ~ 5.6 10 -6 importance of nonfactorizble effects Penguin annihilation is needed in QCDF to account for rates & CP asymmetries TP =0.83, TP = -70 o PT =0.75, PT = -30 o similar to the parameters for B PP

14
14 Penguin-dominated B TP

15
15 B K 2 * , K 2 * ’ Interference between (b) & (c) is constructive for K 2 * ’ and destructive for K 2 * large rate of K 2 * ’ than K 2 * C.S. Kim et al. obtained Br(B K 2 * ’)/Br(B K 2 * ) ~ 45, while it is ~ 2 experimentally. This is because the matrix elements do not have correct chiral limit behavior due to anomaly and should be replaced by

16
16 Tree-dominated B TP

17
17 Penguin-dominated B TV

18
18 Rate puzzle in B K 2 * decays It is naively expected that Experimentally, Br(B K 2 * ) Br(B K 2 * ). This can be accommodated by having penguin annihilation such that (K 2 * ) >> ( K 2 * ). But why ? What is the dynamical origin ?

19
19 Polarization puzzle in charmless B→VV decays Why is f T so sizable ~ 0.5 in penguin-dominated B K * , K * , K *0 0 decays ? In transversity basis 19 A 00 >> A -- >> A ++

20
20 constructive (destructive) interference in A - (A 0 ) ⇒ f L 0.58 NLO corrections alone can lower f L and enhance f T significantly ! Beneke,Rohere,Yang HYC,Yang Although f L is reduced to 60% level, polarization puzzle is not completely resolved as the predicted rate, BR 4.3 10 -6, is too small compared to the data, ~ 10 10 -6 for B →K * Kagan (S-P)(S+P) (S-P)(S+P) penguin annihilation contributes to A -- & A 00 with similar amount

21
21 Polarization puzzle in B K 2 * f L (K 2 *+ ) = 0.56 0.11, f L (K 2 *0 ) = 0.45 0.12, f L (K 2 *+ ) = 0.80 0.10, f L (K 2 *0 ) = 0.901 +0.059 -0.069 f L (K 2 * ) = 0.88, 0.72, 0.48 for A TV = -30 o, -45 o, -60 o, f L (K 2 * )= 0.68, 0.66, 0.64 for A VT = -30 o, -45 o, -60 o In QCDF, f L is very sensitive to the phase A TV for B K 2 * , but not so sensitive to A VT for B K 2 * Why is f T / f L <<1 for B K 2 * and f T /f L 1 for B K 2 * ? Rates & polarization fractions can be accommodated in QCDF BaBar but no dynamical explanation is offered Why is that f T behaves differently in K 2 * and K * ?

22
22 Conclusions Tensor meson cannot be created from local V-A current, but its decay constant can be defined through non-local current or local current with covariant derivative. Some decays e.g. B - K 2 *0 - prohibited in naïve factorization receive sizable nonfactorizable corrections Predictions of QCD factorization in general agree with experiment for B TM (M=P,V), but there remains puzzles to be resolved: rate of K 2 * and polarization of K 2 *

Similar presentations

OK

Run-Hui Li Yonsei University Mainly based on R.H. Li, C.D. Lu, and W. Wang, PRD83:034034.

Run-Hui Li Yonsei University Mainly based on R.H. Li, C.D. Lu, and W. Wang, PRD83:034034.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Resource based view ppt online Emergency dentist appt on your birthday Flexible oled display ppt on tv Ppt on media and communication Ppt on conservation of environment song Ppt on question paper setting Ppt on college management system Ppt on condition based maintenance dod Ppt on australian continent Ppt on series and parallel circuits lessons