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Measurements of isospin asymmetry and difference of direct C P asymmetries in inclusive B → X s γ decays

2019; American Physical Society; Volume: 99; Issue: 3 Linguagem: Inglês

10.1103/physrevd.99.032012

2470-0037

S. Watanuki, A. Ishikawa, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Bakich, V. Bansal, P. K. Behera, C. Beleño, M. Berger, V. Bhardwaj, B. Bhuyan, T. Bilka, J. P. Biswal, A. Bobrov, G. Bonvicini, A. Bożek, M. Bračko, T. E. Browder, L. Cao, D. Červenkov, P. Chang, B. G. Cheon, K. Chilikin, K. Cho, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, S. Di Carlo, J. Dingfelder, T. V. Dong, S. Eidelman, D. Epifanov, J. Fast, T. Ferber, A. Frey, B. G. Fulsom, V. Gaur, N. Gabyshev, A. Garmash, Michael H. Gelb, A. Giri, P. Goldenzweig, Y. Guan, E. Guido, J. Haba, K. Hayasaka, H. Hayashii, W.-S. Hou, T. Iijima, K. Inami, G. Inguglia, R. Itoh, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, I. Jaeglé, H. B. Jeon, S. Jia, Yao Jin, K. K. Joo, T. Julius, G. Karyan, T. Kawasaki, C. Kiesling, D. Y. Kim, J. B. Kim, S. H. Kim, K. Kinoshita, P. Kodyš, S. Korpar, D. Kotchetkov, P. Križan, R. Kroeger, P. Krokovny, T. Kuhr, R. Kumar, A. Kuzmin, Y.-J. Kwon, I. S. Lee, S. C. Lee, L. K. Li, Y. B. Li, L. Li Gioi, J. Libby, D. Liventsev, M. Lubej, T. Luo, M. Masuda, T. Matsuda, M. Merola, K. Miyabayashi, H. Miyata, R. Mizuk, G. B. Mohanty, T. Mori, M. Nakao, T. Nanut, K. J. Nath, M. Niiyama, S. Nishida, K. Nishimura, K. Ogawa, S. Ogawa, S. Okuno, H. Ono, W. Ostrowicz, P. Pakhlov, G. Pakhlova, B. Pal, H. Park, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, E. Prencipe, M. Ritter, A. Rostomyan, G. Russo, Y. Sakai, S. Sandilya, L. Šantelj, V. Savinov, O. Schneider, G. Schnell, J. Schueler, C. Schwanda, A. J. Schwartz, Y. Seino, K. Senyo, O. Seon, V. Shebalin, T.-A. Shibata, J.-G. Shiu, B. Shwartz, A. Sokolov, E. Solovieva, S. Stanič, M. Starič, T. Sumiyoshi, W. Sutcliffe, M. Takizawa, K. Tanida, N. Taniguchi, F. Tenchini, M. Uchida, T. Uglov, Y. Unno, S. Uno, S. Vahsen, C. Van Hulse, R. van Tonder, G. Varner, K. E. Varvell, A. Vossen, B. Wang, C. H. Wang, M.-Z. Wang, P. Wang, M. Watanabe, E. Widmann, E. Won, H. Ye, J. H. Yin, Y. Yusa, S. Zakharov, Z. P. Zhang, V. Zhilich, V. Zhukova, V. Zhulanov, A. Zupanc,

Quantum Chromodynamics and Particle Interactions

We report measurements of isospin asymmetry ${\mathrm{\ensuremath{\Delta}}}_{0\ensuremath{-}}$ and difference of direct $CP$ asymmetries $\mathrm{\ensuremath{\Delta}}{A}_{CP}$ between charged and neutral $B\ensuremath{\rightarrow}{X}_{s}\ensuremath{\gamma}$ decays. This analysis is based on the data sample containing $772\ifmmode\times\else\texttimes\fi{}{10}^{6}B\overline{B}$ pairs that was collected with the Belle detector at the KEKB energy-asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ collider. Using a sum-of-exclusive technique with invariant ${X}_{s}$ mass up to $2.8\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, we obtain ${\mathrm{\ensuremath{\Delta}}}_{0\ensuremath{-}}=[\ensuremath{-}0.48\ifmmode\pm\else\textpm\fi{}1.49(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.97(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}1.15({f}_{+\ensuremath{-}}/{f}_{00})]%$ and $\mathrm{\ensuremath{\Delta}}{A}_{CP}=[+3.69\ifmmode\pm\else\textpm\fi{}2.65(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.76(\mathrm{syst})]%$, where the last uncertainty for ${\mathrm{\ensuremath{\Delta}}}_{0\ensuremath{-}}$ is due to the uncertainty on the production ratio of ${B}^{+}{B}^{\ensuremath{-}}$ to ${B}^{0}{\overline{B}}^{0}$ in $\mathrm{\ensuremath{\Upsilon}}(4S)$ decays. The measured value of ${\mathrm{\ensuremath{\Delta}}}_{0\ensuremath{-}}$ is consistent with zero, allowing us to constrain the resolved photon contribution in the $B\ensuremath{\rightarrow}{X}_{s}\ensuremath{\gamma}$, and improve the branching fraction prediction. The result for $\mathrm{\ensuremath{\Delta}}{A}_{CP}$ is consistent with the prediction of the SM. We also measure the direct $CP$ asymmetries for charged and neutral $B\ensuremath{\rightarrow}{X}_{s}\ensuremath{\gamma}$ decays. All the measurements are the most precise to date.