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 2021/09
形態種別 その他
標題 Angular analysis of $B^+ \to ρ^+ρ^0$ decays reconstructed in 2019-2020 Belle II data
執筆形態 その他
著者・共著者 Belle II collaboration,F. Abudinén,I. Adachi,R. Adak,K. Adamczyk,P. Ahlburg,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,S. Baehr,S. Bahinipati,A. M. Bakich,P. Bambade,Sw. Banerjee,S. Bansal,M. Barrett,G. Batignani,J. Baudot,A. Beaulieu,J. Becker,P. K. Behera,M. Bender,J. V. Bennett,E. Bernieri,F. U. Bernlochner,M. Bertemes,E. Bertholet,M. Bessner,S. Bettarini,V. Bhardwaj,B. Bhuyan,F. Bia
概要 We report on the first Belle II measurement of the branching fraction
($\mathcal{B}$) and longitudinal polarization fraction ($f_L$) 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 and
2020 at the $\Upsilon$(4S) resonance and corresponding to $62.8$ fb$^{-1}$ of
integrated luminosity. We fit the distributions of the difference between
expected and observed $B$ candidate energy, continuum-suppression variable,
dipion masses, and angular distributions of the resulting samples, to determine
a signal yield of $104\pm16$ events. The signal yields are corrected for
efficiencies determined from simulation and control data samples to obtain
$\mathcal{B}(B^+ \to \rho^+\rho^0) = [20.6 \pm 3.2(\rm stat) \pm 4.0(\rm
syst)]\times 10^{-6}$, and $f_L(B^+ \to \rho^+\rho^0) = 0.936
^{+0.049}_{-0.041}(\rm stat)\pm 0.021(\rm syst)$. This first Belle II $B^+ \to
\rho^+\rho^0$ angular analysis yields results compatible with previous
determinations, and indicates Belle II performance superior to early Belle
results.
PermalinkURL http://arxiv.org/abs/2109.11456v2
researchmap用URL http://arxiv.org/pdf/2109.11456v2