新山　雅之
   所属   京都産業大学  理学部 物理科学科
   職種   教授
発行・発表の年月 2022/06
形態種別 その他
標題 Angular analysis of $B^+ \to ρ^+ρ^0$ decays reconstructed in 2019, 2020, and 2021 Belle II data
執筆形態 その他
著者・共著者 Belle II Collaboration,F. Abudinén,I. Adachi,K. Adamczyk,L. Aggarwal,P. Ahlburg,H. Ahmed,J. K. Ahn,H. Aihara,N. Akopov,A. Aloisio,F. Ameli,L. Andricek,N. Anh Ky,D. M. Asner,H. Atmacan,V. Aulchenko,T. Aushev,V. Aushev,T. Aziz,V. Babu,S. Bacher,H. Bae,S. Baehr,S. Bahinipati,A. M. Bakich,P. Bambade,Sw. Banerjee,S. Bansal,M. Barrett,G. Batignani,J. Baudot,M. Bauer,A. Baur,A. Beaubien,A. Beaulieu,J. Becker,P. K. Behera,J. V. Bennett,E. Bernieri,F. U. Bernlochner,V. Bertacchi,M. Bertemes,E. Bertholet,
概要 We report on a Belle II measurement of the branching fraction
($\mathcal{B}$), longitudinal polarization fraction ($f_L$), and CP asymmetry
($\mathcal{A}_{CP}$) of $B^+\to \rho^+\rho^0$ decays. We reconstruct $B^+\to
\rho^+(\to \pi^+\pi^0(\to \gamma\gamma))\rho^0(\to \pi^+\pi^-)$ decays in a
sample of SuperKEKB electron-positron collisions collected by the Belle II
experiment in 2019, 2020, and 2021 at the $\Upsilon$(4S) resonance and
corresponding to 190 fb$^{-1}$ of integrated luminosity. We fit the
distributions of the difference between expected and observed $B$ candidate
energy, continuum-suppression discriminant, dipion masses, and decay angles of
the selected samples, to determine a signal yield of $345 \pm 31$ events. The
signal yields are corrected for efficiencies determined from simulation and
control data samples to obtain $\mathcal{B}(B^+ \to \rho^+\rho^0) = [23.2^{+\
2.2}_{-\ 2.1} (\rm stat) \pm 2.7 (\rm syst)]\times 10^{-6}$, $f_L = 0.943 ^{+\
0.035}_{-\ 0.033} (\rm stat)\pm 0.027(\rm syst)$, and $\mathcal{A}_{CP}=-0.069
\pm 0.068(\rm stat) \pm 0.060 (\rm syst)$. The results agree with previous
measurements. This is the first measurement of $\mathcal{A}_{CP}$ in $B^+\to
\rho^+\rho^0$ decays reported by Belle II.
PermalinkURL http://arxiv.org/abs/2206.12362v1
researchmap用URL http://arxiv.org/pdf/2206.12362v1