Observation of $D^0\to {\rho }^0\gamma$ and Search for $CP$ Violation in Radiative Charm Decays

Journal Article · Tue Jan 31 00:00:00 EST 2017 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.118.051801· OSTI ID:1594365

Nanut, T.; Zupanc, A.; Adachi, I.; Aihara, H.; Al Said, S.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Ayad, R.; Babu, V.; Badhrees, I.; Bakich, A. M.; Bansal, V.; Behera, P.; Bhardwaj, V.; Biswal, J.; Bondar, A.; Bozek, A.; Bračko, M.; Browder, T. E. ; Červenkov, D.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chistov, R.; Cho, K.; Choi, S. -K.; Choi, Y.; Cinabro, D.; Dash, N.; Di Carlo, S.; Doležal, Z.; Dutta, D.; Eidelman, S.; Farhat, H.; Fast, J. E.; Ferber, T.; Fulsom, B. G.; Gaur, V.; Gabyshev, N.; Garmash, A.; Gillard, R.; Goldenzweig, P.; Golob, B.; Hayasaka, K.; Hayashii, H.; Hou, W. -S.; Iijima, T.; Inami, K.; Inguglia, G.; Ishikawa, A.; Iwasaki, Y.; Jacobs, W. W.; Jaegle, I.; Joffe, D.; Joo, K. K.; Julius, T.; Kaliyar, A. B.; Kang, K. H.; Kawasaki, T.; Kim, D. Y.; Kim, J. B.; Kim, K. T.; Kim, M. J.; Kim, S. H.; Kinoshita, K.; Kodyš, P.; Korpar, S.; Krokovny, P.; Kuhr, T.; Kulasiri, R.; Kuzmin, A.; Kwon, Y. -J.; Lange, J. S.; Lee, I. S.; Li, C. H.; Li, L.; Li, Y.; Li Gioi, L.; Libby, J.; Liventsev, D.; Lubej, M.; Masuda, M.; Matsuda, T.; Matvienko, D.; Miyabayashi, K.; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Moon, H. K.; Nakao, M.; Nath, K. J.; Nayak, M.; Nisar, N. K.; Nishida, S.; Ogawa, S.; Okuno, S.; Pakhlov, P.; Pakhlova, G.; Pal, B.; Park, C. -S.; Park, C. W.; Park, H.; Paul, S.; Pedlar, T. K.; Pesántez, L.; Pestotnik, R.; Petrič, M.; Piilonen, L. E.; Prasanth, K.; Pulvermacher, C.; Rauch, J.; Ritter, M.; Rostomyan, A.; Sakai, Y.; Sandilya, S.; Santelj, L.; Sanuki, T.; Sato, Y.; Savinov, V.; Schlüter, T.; Schneider, O.; Schnell, G.; Schwanda, C.; Schwartz, A. J.; Seino, Y.; Senyo, K.; Seon, O.; Sevior, M. E.; Shebalin, V.; Shen, C. P.; Shibata, T. -A.; Shiu, J. -G.; Shwartz, B.; Solovieva, E.; Stanič, S.; Starič, M.; Strube, J. F.; Stypula, J.; Sumiyoshi, T.; Takizawa, M.; Tamponi, U.; Tenchini, F.; Trabelsi, K.; Uchida, M.; Uno, S.; Ushiroda, Y.; Varner, G.; Vinokurova, A.; Vorobyev, V.; Vossen, A.; Wang, C. H.; Wang, M. -Z.; Wang, P.; Watanabe, Y.; Widmann, E.; Won, E.; Yamaoka, J.; Yamashita, Y.; Yelton, J.; Zhang, Z. P.; Zhilich, V.; Zhukova, V.; Zhulanov, V.

Here, we discuss the first observation of the radiative charm decay $D^0\to {\rho }^0\gamma$ and the first search for $CP$ violation in decays $D^0\to {\rho }^0\gamma$, $\phi \gamma$, and ${\overline{K}}^{*0}\left(892\right)\gamma$, using a data sample of $943{\mathrm{fb}}^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The branching fraction is measured to be $\mathcal{B}(D^0\to {\rho }^0\gamma )=(1.77\pm 0.30\pm 0.07)\times {10}^{-5}$, where the first uncertainty is statistical and the second is systematic. The obtained $CP$ asymmetries ${\mathcal{A}}_{CP}(D^0\to {\rho }^0\gamma )=+0.056\pm 0.152\pm 0.006$, ${\mathcal{A}}_{CP}(D^0\to \phi \gamma )=-0.094\pm 0.066\pm 0.001$, and ${\mathcal{A}}_{CP}(D^0\to {\overline{K}}^{*0}\gamma )=-0.003\pm 0.020\pm 0.000$ are consistent with no $CP$ violation. Furthermore, we present an improved measurement of the branching fractions $\mathcal{B}(D^0\to \phi \gamma )=(2.76\pm 0.19\pm 0.10)\times {10}^{-5}$ and $\mathcal{B}(D^0\to {\overline{K}}^{*0}\gamma )=(4.66\pm 0.21\pm 0.21)\times {10}^{-4}$.

• Research Organization: Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Univ. of Hawaii, Honolulu, HI (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); National Science Foundation (NSF)
• Contributing Organization: Belle Collaboration
• Grant/Contract Number: SC0009973; SC0010504
• OSTI ID: 1594365
• Alternate ID(s): OSTI ID: 1341935
• Journal Information: Physical Review Letters, Vol. 118, Issue 5; ISSN 0031-9007
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

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