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arXiv · 1707.00394

Evidence for Isospin Violation and Measurement of $CP$ Asymmetries in $B \to K^{\ast}(892) γ$

T. Horiguchi·A. Ishikawa·H. Yamamoto·I. Adachi·H. Aihara·S. Al Said·D. M. Asner·V. Aulchenko·T. Aushev·R. Ayad·V. Babu·I. Badhrees·A. M. Bakich·V. Bansal·P. Behera·V. Bhardwaj·B. Bhuyan·J. Biswal·A. Bobrov·G. Bonvicini·A. Bozek·M. Bracko·T. E. Browder·D. Cervenkov·V. Chekelian·A. Chen·B. G. Cheon·K. Chilikin·K. Cho·Y. Choi·D. Cinabro·T. Czank·N. Dash·S. Di Carlo·Z. Dolezal·Z. Drasal·D. Dutta·S. Eidelman·D. Epifanov·H. Farhat·J. E. Fast·T. Ferber·B. G. Fulsom·V. Gaur·N. Gabyshev·A. Garmash·M. Gelb·R. Gillard·P. Goldenzweig·B. Golob·Y. Guan·E. Guido·J. Haba·T. Hara·K. Hayasaka·H. Hayashii·M. T. Hedges·T. Higuchi·S. Hirose·W. -S. Hou·T. Iijima·K. Inami·G. Inguglia·R. Itoh·Y. Iwasaki·W. W. Jacobs·I. Jaegle·H. B. Jeon·S. Jia·Y. Jin·D. Joffe·K. K. Joo·T. Julius·K. H. Kang·T. Kawasaki·D. Y. Kim·J. B. Kim·K. T. Kim·M. J. Kim·S. H. Kim·Y. J. Kim·K. Kinoshita·P. Kodys·S. Korpar·D. Kotchetkov·P. Krizan·P. Krokovny·T. Kuhr·R. Kulasiri·R. Kumar·T. Kumita·A. Kuzmin·Y. -J. Kwon·J. S. Lange·C. H. Li·L. Li·L. Li Gioi·J. Libby·D. Liventsev·M. Lubej
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Abstract

We report the first evidence for isospin violation in $B \to K^* γ$ and the first measurement of difference of $CP$ asymmetries between $B^+ \to K^{*+} γ$ and $B^0 \to K^{*0} γ$. This analysis is based on the data sample containing $772 \times 10^6 B\bar{B}$ pairs that was collected with the Belle detector at the KEKB energy-asymmetric $e^+ e^-$ collider. We find evidence for the isospin violation with a significance of 3.1$σ$, $Δ_{0+} = (+6.2 \pm 1.5 ({\rm stat.}) \pm 0.6 ({\rm syst.}) \pm 1.2 (f_{+-}/f_{00}))$\%, where the third uncertainty is due to the uncertainty on the fraction of $B^+B^-$ to $B^0\bar{B}^0$ production in $Υ(4S)$ decays. The measured value is consistent with predictions of the SM. The result for the difference of $CP$ asymmetries is $ΔA_{CP} = (+2.4 \pm 2.8({\rm stat.}) \pm 0.5({\rm syst.}))$\%, consistent with zero. The measured branching fractions and $CP$ asymmetries for charged and neutral $B$ meson decays are the most precise to date. We also calculate the ratio of branching fractions of $B^0 \to K^{*0} γ$ to $B_s^0 \to ϕγ$.

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T. Horiguchi, A. Ishikawa, H. Yamamoto, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Bakich, V. Bansal, P. Behera, V. Bhardwaj, B. Bhuyan, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek, M. Bracko, T. E. Browder, D. Cervenkov, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, K. Cho, Y. Choi, D. Cinabro, T. Czank, N. Dash, S. Di Carlo, Z. Dolezal, Z. Drasal, D. Dutta, S. Eidelman, D. Epifanov, H. Farhat, J. E. Fast, T. Ferber, B. G. Fulsom, V. Gaur, N. Gabyshev, A. Garmash, M. Gelb, R. Gillard, P. Goldenzweig, B. Golob, Y. Guan, E. Guido, J. Haba, T. Hara, K. Hayasaka, H. Hayashii, M. T. Hedges, T. Higuchi, S. Hirose, W. -S. Hou, T. Iijima, K. Inami, G. Inguglia, R. Itoh, Y. Iwasaki, W. W. Jacobs, I. Jaegle, H. B. Jeon, S. Jia, Y. Jin, D. Joffe, K. K. Joo, T. Julius, K. H. Kang, T. Kawasaki, D. Y. Kim, J. B. Kim, K. T. Kim, M. J. Kim, S. H. Kim, Y. J. Kim, K. Kinoshita, P. Kodys, S. Korpar, D. Kotchetkov, P. Krizan, P. Krokovny, T. Kuhr, R. Kulasiri, R. Kumar, T. Kumita, A. Kuzmin, Y. -J. Kwon, J. S. Lange, C. H. Li, L. Li, L. Li Gioi, J. Libby, D. Liventsev, M. Lubej. 2017-10-09. Evidence for Isospin Violation and Measurement of $CP$ Asymmetries in $B \to K^{\ast}(892) γ$. https://doi.org/10.1103/physrevlett.119.191802

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