Theory Seminar

KEK 素粒子原子核研究所・理論セミナー

TITLE Determining the photon polarization of the $b\to s\gamma$ using the $B\to K_1(1270)\gamma\to(K\pi\pi)\gamma$ decay
(英語 / in English)
SPEAKER Dr. Andrey Tayduganov
Orsay, IPN & Orsay, LPT
DATE: November 04 (Fri.) 13:30 − 14:30
PLACE: 4th building 1F, Seminar Hall


Recently the radiative $B$ decay to the strange axial-vector mesons, $B\to K_1(1270) \gamma$, has been observed with rather large rate. This process is particularly interesting as the subsequent $K_1$ decay into its three body final state allows to determine the polarization of the gamma, which is mostly left- (right-)handed for $\overline{B} (B)$ in the SM while various new physics models predict additional right- (left-)handed components. A new method is proposed to determine the polarization, exploiting the full Dalitz plot distribution, which seems to reduce strongly the statistical errors. In order to obtain a theoretical prediction for this polarization measurement, it is necessary to understand the hadronic $K_1 \to K \pi \pi$ decay channel and its uncertainties. The strong decays of the $K_1$ mesons, namely the partial wave amplitudes as well as their relative phases, are revisited in the framework of the $^3P_0$ quark-pair-creation model. Then, the result on the sensitivity of the $B\to K_1(1270) \gamma$ process to the photon polarization is presented.