Observation of $D^0\to ρ^0γ$ and search for $CP$ violation in radiative charm decays
Creators: name: Belle Collaboration
name: Nanut, T.
name: Zupanc, A.
name: Adachi, I.
name: Aihara, H.
name: Said, S. Al
name: Asner, D. M.
name: Aulchenko, V.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Badhrees, I.
name: Bakich, A. M.
name: Bansal, V.
name: Behera, P.
name: Bhardwaj, V.
name: Biswal, J.
name: Bondar, A.
name: Bozek, A.
name: Bračko, M.
name: Browder, T. E.
name: Červenkov, D.
name: Chekelian, V.
name: Chen, A.
name: Cheon, B. G.
name: Chistov, R.
name: Cho, K.
name: Choi, S. -K.
name: Choi, Y.
name: Cinabro, D.
name: Dash, N.
name: Di Carlo, S.
name: Dutta, D.
name: Eidelman, S.
name: Farhat, H.
name: Fast, J. E.
name: Ferber, T.
name: Fulsom, B. G.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Gillard, R.
name: Goldenzweig, P.
name: Hayasaka, K.
name: Hayashii, H.
name: Hou, W. -S.
name: Iijima, T.
name: Inami, K.
name: Inguglia, G.
name: Ishikawa, A.
name: Iwasaki, Y.
name: Jacobs, W. W.
name: Jaegle, I.
name: Joffe, D.
name: Joo, K. K.
name: Julius, T.
name: Kaliyar, A. B.
name: Kang, K. H.
name: Kawasaki, T.
name: Kim, D. Y.
name: Kim, J. B.
name: Kim, K. T.
name: Kim, M. J.
name: Kim, S. H.
name: Kinoshita, K.
name: Kodyš, P.
name: Krokovny, P.
name: Kuhr, T.
name: Kulasiri, R.
name: Kuzmin, A.
name: Kwon, Y. -J.
name: Lange, J. S.
name: Lee, I. S.
name: Li, C. H.
name: Li, L.
name: Li, Y.
name: Gioi, L. Li
name: Libby, J.
name: Liventsev, D.
name: Lubej, M.
name: Masuda, M.
name: Matsuda, T.
name: Matvienko, D.
name: Miyabayashi, K.
name: Miyata, H.
name: Mizuk, R.
name: Mohanty, G. B.
name: Moon, H. K.
name: Nath, K. J.
name: Nayak, M.
name: Nisar, N. K.
name: Nishida, S.
name: Ogawa, S.
name: Okuno, S.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pal, B.
name: Park, C. -S.
name: Park, C. W.
name: Park, H.
name: Paul, S.
name: Pedlar, T. K.
name: Pesántez, L.
name: Pestotnik, R.
name: Petrič, M.
name: Piilonen, L. E.
name: Prasanth, K.
name: Pulvermacher, C.
name: Rauch, J.
name: Ritter, M.
name: Rostomyan, A.
name: Sandilya, S.
name: Sanuki, T.
name: Sato, Y.
name: Savinov, V.
name: Schlüter, T.
name: Schneider, O.
name: Schnell, G.
name: Schwanda, C.
name: Schwartz, A. J.
name: Seino, Y.
name: Senyo, K.
name: Seon, O.
name: Sevior, M. E.
name: Shebalin, V.
name: Shen, C. P.
name: Shibata, T. -A.
name: Shiu, J. -G.
name: Shwartz, B.
name: Solovieva, E.
name: Stanič, S.
name: Starič, M.
name: Strube, J. F.
name: Stypula, J.
name: Sumiyoshi, T.
name: Takizawa, M.
name: Tamponi, U.
name: Tenchini, F.
name: Trabelsi, K.
name: Uchida, M.
name: Uno, S.
name: Ushiroda, Y.
name: Varner, G.
name: Vinokurova, A.
name: Vorobyev, V.
name: Vossen, A.
name: Wang, C. H.
name: Wang, M. -Z.
name: Wang, P.
name: Watanabe, Y.
name: Widmann, E.
name: Won, E.
name: Yamaoka, J.
name: Yamashita, Y.
name: Yelton, J.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
name: Zhulanov, V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

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