Journal of High Energy Physics (Sep 2021)

Measurement of branching fractions and search for CP violation in D 0 → π + π − η, D 0 → K + K − η, and D 0 → ϕη at Belle

  • The Belle collaboration,
  • L. K. Li,
  • A. J. Schwartz,
  • K. Kinoshita,
  • I. Adachi,
  • H. Aihara,
  • S. Al Said,
  • D. M. Asner,
  • H. Atmacan,
  • V. Aulchenko,
  • T. Aushev,
  • R. Ayad,
  • V. Babu,
  • S. Bahinipati,
  • P. Behera,
  • J. Bennett,
  • M. Bessner,
  • T. Bilka,
  • J. Biswal,
  • A. Bobrov,
  • G. Bonvicini,
  • A. Bozek,
  • M. Bračko,
  • P. Branchini,
  • T. E. Browder,
  • A. Budano,
  • M. Campajola,
  • D. Červenkov,
  • M.-C. Chang,
  • P. Chang,
  • V. Chekelian,
  • A. Chen,
  • Y. Q. Chen,
  • B. G. Cheon,
  • K. Chilikin,
  • H. E. Cho,
  • K. Cho,
  • S.-J. Cho,
  • S.-K. Choi,
  • Y. Choi,
  • S. Choudhury,
  • D. Cinabro,
  • S. Cunliffe,
  • S. Das,
  • N. Dash,
  • G. De Nardo,
  • G. De Pietro,
  • R. Dhamija,
  • F. Di Capua,
  • Z. Doležal,
  • T. V. Dong,
  • S. Eidelman,
  • D. Epifanov,
  • T. Ferber,
  • B. G. Fulsom,
  • R. Garg,
  • V. Gaur,
  • A. Giri,
  • P. Goldenzweig,
  • B. Golob,
  • E. Graziani,
  • T. Gu,
  • Y. Guan,
  • C. Hadjivasiliou,
  • S. Halder,
  • K. Hayasaka,
  • W.-S. Hou,
  • K. Inami,
  • A. Ishikawa,
  • M. Iwasaki,
  • Y. Iwasaki,
  • W. W. Jacobs,
  • E.-J. Jang,
  • S. Jia,
  • Y. Jin,
  • K. K. Joo,
  • K. H. Kang,
  • G. Karyan,
  • C. Kiesling,
  • C. H. Kim,
  • D. Y. Kim,
  • K.-H. Kim,
  • S. H. Kim,
  • Y.-K. Kim,
  • P. Kodyš,
  • T. Konno,
  • A. Korobov,
  • S. Korpar,
  • E. Kovalenko,
  • P. Križan,
  • R. Kroeger,
  • P. Krokovny,
  • T. Kuhr,
  • M. Kumar,
  • K. Kumara,
  • A. Kuzmin,
  • Y.-J. Kwon,
  • K. Lalwani,
  • M. Laurenza,
  • S. C. Lee,
  • C. H. Li,
  • L. Li Gioi,
  • J. Libby,
  • K. Lieret,
  • D. Liventsev,
  • M. Masuda,
  • D. Matvienko,
  • M. Merola,
  • F. Metzner,
  • K. Miyabayashi,
  • R. Mizuk,
  • G. B. Mohanty,
  • T. Mori,
  • M. Nakao,
  • Z. Natkaniec,
  • A. Natochii,
  • L. Nayak,
  • M. Nayak,
  • M. Niiyama,
  • N. K. Nisar,
  • S. Nishida,
  • K. Nishimura,
  • H. Ono,
  • P. Oskin,
  • P. Pakhlov,
  • G. Pakhlova,
  • S. Pardi,
  • S.-H. Park,
  • A. Passeri,
  • S. Paul,
  • T. K. Pedlar,
  • R. Pestotnik,
  • L. E. Piilonen,
  • T. Podobnik,
  • V. Popov,
  • E. Prencipe,
  • M. T. Prim,
  • N. Rout,
  • G. Russo,
  • D. Sahoo,
  • Y. Sakai,
  • S. Sandilya,
  • A. Sangal,
  • L. Santelj,
  • T. Sanuki,
  • V. Savinov,
  • G. Schnell,
  • C. Schwanda,
  • Y. Seino,
  • K. Senyo,
  • M. Shapkin,
  • C. Sharma,
  • C. P. Shen,
  • J.-G. Shiu,
  • B. Shwartz,
  • A. Sokolov,
  • E. Solovieva,
  • M. Starič,
  • Z. S. Stottler,
  • M. Sumihama,
  • T. Sumiyoshi,
  • M. Takizawa,
  • K. Tanida,
  • F. Tenchini,
  • M. Uchida,
  • T. Uglov,
  • Y. Unno,
  • K. Uno,
  • S. Uno,
  • S. E. Vahsen,
  • R. Van Tonder,
  • G. Varner,
  • A. Vinokurova,
  • E. Waheed,
  • C. H. Wang,
  • M.-Z. Wang,
  • P. Wang,
  • X. L. Wang,
  • S. Watanuki,
  • E. Won,
  • B. D. Yabsley,
  • W. B. Yan,
  • S. B. Yang,
  • H. Ye,
  • J. Yelton,
  • J. H. Yin,
  • Y. Yusa,
  • Z. P. Zhang,
  • V. Zhilich,
  • V. Zhukova

DOI
https://doi.org/10.1007/JHEP09(2021)075
Journal volume & issue
Vol. 2021, no. 9
pp. 1 – 25

Abstract

Read online

Abstract We measure the branching fractions and CP asymmetries for the singly Cabibbo-suppressed decays D 0 → π + π − η, D 0 → K + K − η, and D 0 → ϕη, using 980 fb −1 of data from the Belle experiment at the KEKB e + e − collider. We obtain B D 0 → π + π − η = 1.22 ± 0.02 stat ± 0.02 syst ± 0.03 B ref × 10 − 3 , B D 0 → K + K − η = 1.80 − 0.06 + 0.07 stat ± 0.04 syst ± 0.05 B ref × 10 − 4 , B D 0 → ϕη = 1.84 ± 0.09 stat ± 0.06 syst ± 0.05 B ref × 10 − 4 , $$ {\displaystyle \begin{array}{c}\mathcal{B}\left({D}^0\to {\pi}^{+}{\pi}^{-}\eta \right)=\left[1.22\pm 0.02\left(\mathrm{stat}\right)\pm 0.02\left(\mathrm{syst}\right)\pm 0.03\left({\mathcal{B}}_{\mathrm{ref}}\right)\right]\times {10}^{-3},\\ {}\mathcal{B}\left({D}^0\to {K}^{+}{K}^{-}\eta \right)=\left[{1.80}_{-0.06}^{+0.07}\left(\mathrm{stat}\right)\pm 0.04\left(\mathrm{syst}\right)\pm 0.05\left({\mathcal{B}}_{\mathrm{ref}}\right)\right]\times {10}^{-4},\\ {}\mathcal{B}\left({D}^0\to \phi \eta \right)=\left[1.84\pm 0.09\left(\mathrm{stat}\right)\pm 0.06\left(\mathrm{syst}\right)\pm 0.05\left({\mathcal{B}}_{\mathrm{ref}}\right)\right]\times {10}^{-4},\end{array}} $$ where the third uncertainty ( B $$ \mathcal{B} $$ ref) is from the uncertainty in the branching fraction of the reference mode D 0 → K − π + η. The color-suppressed decay D 0 → ϕη is observed for the first time, with very high significance. The results for the CP asymmetries are A CP D 0 π + π − η = 0.9 ± 1.2 stat ± 0.5 syst % , A CP D 0 → K + K − η = − 1.4 ± 3.3 stat ± 1.1 syst % , ACP D 0 → ϕη = − 1.9 ± 4.4 stat ± 0.6 syst % . $$ {\displaystyle \begin{array}{c}{A}_{CP}\left({D}^0\ {\pi}^{+}{\pi}^{-}\eta \right)=\left[0.9\pm 1.2\left(\mathrm{stat}\right)\pm 0.5\left(\mathrm{syst}\right)\right]\%,\\ {}{A}_{CP}\left({D}^0\to {K}^{+}{K}^{-}\eta \right)=\left[-1.4\pm 3.3\left(\mathrm{stat}\right)\pm 1.1\left(\mathrm{syst}\right)\right]\%,\\ {} ACP\ \left({D}^0\to \phi \eta \right)=\left[-1.9\pm 4.4\left(\mathrm{stat}\right)\pm 0.6\left(\mathrm{syst}\right)\right]\%.\end{array}} $$ The results for D 0 → π + π − η are a significant improvement over previous results. The branching fraction and A CP results for D 0 → K + K − η, and the ACP result for D 0 → ϕη, are the first such measurements. No evidence for CP violation is found in any of these decays.

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