Search for the semileptonic decays $D_s^{+}\to K_1(1270{)}^0{e}^{+}\hat{I}{½}_e$ and $D_s^{+}\to b_1(1235{)}^0{e}^{+}\hat{I}{½}_e$

Abstract

By analyzing 7.33\,fb${}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we search for the semileptonic decays $D_s^{+}\to K_1(1270{)}^0{e}^{+}\hat{I}{½}_e$ and $D_s^{+}\to b_1(1235{)}^0{e}^{+}\hat{I}{½}_e$ for the first time. No significant signals are observed for either decay mode. The upper limits on the (product) branching fractions are determined to be $\mathcal{B}[D_s^{+}\to K_1(1270{)}^0{e}^{+}\hat{I}{½}_e]<4.1\times 10^{-4}$ and $\mathcal{B}[D_s^{+}\to b_1(1235{)}^0{e}^{+}\hat{I}{½}_e]\cdot \mathcal{B}[b_1(1235{)}^0\to \ddot{I}‰\ddot{I}{€}^0]<6.4\times 10^{-4}$ at 90\% confidence level.

12 pages,4 figures