First observation of radiative B⁰ → ΦK⁰γ decays and measurements of their time-dependent CP violation

Journal Article · Thu Oct 06 00:00:00 EDT 2011 · Physical Review. D, Particles, Fields, Gravitation and Cosmology

DOI:https://doi.org/10.1103/PhysRevD.84.071101· OSTI ID:1214916

Sahoo, Himansu B.; Browder, Thomas E.; Adachi, I.; Asner, David M.; Aulchenko, V.; Bakich, A. M.; Barberio, E.; Belous, K.; Bhardwaj, V.; Bhuyan, Bipul; Bondar, A.; Bozek, A.; Bracko, Marko; Brovchenko, O.; Chen, A.; Chen, P.; Cheon, B. G.; Cho, K.; Choi, Y.; Dalseno, J. ; Dolezal, Z.; Drasal, Z.; Eidelman, S.; Epifanov, D.; Fast, James E.; Gaur, Vipin; Gabyshev, N.; Haba, J.; Hayasaka, K.; Hayashii, H.; Horii, Y.; Hoshi, Y.; Hou, W. S.; Hsiung, Y. B.; Hyun, H. J.; Iijima, T.; Inami, K.; Ishikawa, A.; Itoh, R.; Iwabuchi, M.; Iwasaki, Y.; Iwashita, T.; Joshi, N. J.; Julius, T.; Kang, J. H.; Kawasaki, T.; Kiesling, C.; Kim, H. J.; Kim, H. O.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, M. J.; Kim, S. K.; Kim, Y. J.; Kinoshita, Kay; Ko, Byeong Rok; Kobayashi, N.; Koblitz, S.; Kodys, P.; Korpar, S.; Krizan, P.; Kuhr, T.; Kumar, R.; Kumita, T.; Kuzmin, A.; Kwon, Y. J.; Lange, J. S.; Lee, M. J.; Lee, S. H.; Li, J.; Li, Y.; Libby, J.; Lim, C. L.; Liu, Z. Q.; Liventsev, Dmitri; Louvot, R.; Matvienko, D.; McOnie, S.; Miyabayashi, K.; Miyata, H.; Miyazaki, Y.; Mizuk, R.; Mohanty, G. B.; Mori, T.; Nakao, M.; Natkaniec, Z.; Ng, C.; Nishida, S.; Nishimura, Kurtis A.; Nitoh, O.; Nozaki, T.; Ohshima, T.; Okuno, S.; Olsen, Stephen L.; Onuki, Y.; Pakhlov, P.; Pakhlova, Galina; Park, C. W.; Park, H. K.; Peng, T.; Pestotnik, Rok; Petric, Marko; Piilonen, Leo E.; Prim, M.; Rohrken, M.; Ryu, S.; Sakai, K.; Sakai, Y.; Sanuki, T.; Schneider, O.; Schwanda, C.; Schwartz, A. J.; Senyo, K.; Seon, O.; Sevior, Martin E.; Shapkin, M.; Shebalin, V.; Shibata, T. A.; Shiu, Jing-Ge; Shwartz, B.; Simon, F.; Smerkol, P.; Sohn, Young-Soo; Sokolov, Anatoly; Solovyeva, Elena; Stanic, S.; Staric, M.; Sumihama, M.; Sumisawa, K.; Sumiyoshi, T.; Suzuki, S.; Tatishvili, Gocha; Teramoto, Y.; Trabelsi, K.; Uchida, M.; Uglov, T.; Unno, Yuji; Uno, S.; Ushiroda, Y.; Vahsen, Sven E.; Varner, Gary; Vinokurova, A.; Watanabe, M.; Watanabe, Y.; Williams, K. M.; Won, Eun Il; Yabsley, B. D.; Yamashita, Y.; Yuan, C. Z.; Yusa, Y.; Zhang, C. C.; Zhang, Z. P.; Zhilich, V.; Zhou, Peng; Zhulanov, V.; Zupanc, A.

We report the first observation of the radiative decay B⁰→ ΦK⁰γ using a data sample of 772 × 10⁶ BB¯ pairs collected at the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e⁺e⁻ collider. We observe a signal of 37 ± 8 events with a significance of 5.4 standard deviations including systematic uncertainties. The measured branching fraction is B(B⁰→ ΦK⁰γ) = (2.74±0.60±0.32)×10⁻⁶, where the uncertainties are statistical and systematic, respectively. We also report the first measurements of time-dependent CP-violation parameters: S _ΦK⁰Sγ = +0.74^⁺0.72 _–1.05(stat)^+0.10 _–0.24(syst) and A _ΦK⁰Sγ = +0.35 ± 0.58(stat)^+0.23 _–0.10(syst). Furthermore, we measure B(B⁺ → ΦK⁺γ) = (2.48 ± 0.30 ± 0.24) × 10⁻⁶, ACP = –0.03 ± 0.11 ± 0.08 and find that the signal is concentrated in the M_ΦK mass region near threshold.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United State)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1214916
• Report Number(s): PNNL-SA-81591; 45392; KA1202033
• Journal Information: Physical Review. D, Particles, Fields, Gravitation and Cosmology, Vol. 84, Issue 7; ISSN 1550-7998: PRVDAQ
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English