학술논문
Search for $C\!P$ violation and measurement of branching fractions and decay asymmetry parameters for $\Lambda_c^+\to\Lambda h^+$ and $\Lambda_c^+\to\Sigma^{0} h^+$ ($h\!=\!K,\,\pi$)
Document Type
Working Paper
Author
Belle Collaboration; Li, L. K.; Shan, W.; Kinoshita, K.; Adachi, I.; Aihara, H.; Asner, D. M.; Atmacan, H.; Aushev, T.; Babu, V.; Bahinipati, S.; Banerjee, Sw.; Behera, P.; Bennett, J.; Bessner, M.; Bhardwaj, V.; Bhuyan, B.; Bilka, T.; Bobrov, A.; Bodrov, D.; Borah, J.; Bračko, M.; Branchini, P.; Budano, A.; Campajola, M.; Červenkov, D.; Chang, M. -C.; Chang, P.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chilikin, K.; Cho, H. E.; Cho, K.; Cho, S. -J.; Choi, S. -K.; Choi, Y.; Choudhury, S.; Cinabro, D.; Dash, N.; De Nardo, G.; De Pietro, G.; Dhamija, R.; Di Capua, F.; Doležal, Z.; Dong, T. V.; Epifanov, D.; Ferber, T.; Frey, A.; Fulsom, B. G.; Gaur, V.; Garmash, A.; Giri, A.; Goldenzweig, P.; Gong, G.; Graziani, E.; Gu, T.; Guan, Y.; Gudkova, K.; Hadjivasiliou, C.; Hayasaka, K.; Hayashii, H.; Hedges, M. T.; Hou, W. -S.; Hsu, C. -L.; Inami, K.; Ishikawa, A.; Itoh, R.; Jacobs, W. W.; Jang, E. -J.; Ji, Q. P.; Jia, S.; Jin, Y.; Joo, K. K.; Kiesling, C.; Kim, C. H.; Kim, D. Y.; Kim, K. -H.; Kodyš, P.; Konno, T.; Korobov, A.; Korpar, S.; Kovalenko, E.; Krokovny, P.; Kuhr, T.; Kumar, R.; Kumara, K.; Kuzmin, A.; Kwon, Y. -J.; Lai, Y. -T.; Lam, T.; Lange, J. S.; Lee, S. C.; Li, J.; Li, S. X.; Li, Y.; Li, Y. B.; Gioi, L. Li; Libby, J.; Lieret, K.; Masuda, M.; Maurya, S. K.; Merola, M.; Metzner, F.; Miyabayashi, K.; Mizuk, R.; Mussa, R.; Nakao, M.; Natkaniec, Z.; Natochii, A.; Nayak, L.; Nayak, M.; Niiyama, M.; Nisar, N. K.; Nishida, S.; Ogawa, S.; Ono, H.; Oskin, P.; Pakhlova, G.; Pardi, S.; Park, H.; Park, S. -H.; Passeri, A.; Patra, S.; Paul, S.; Pedlar, T. K.; Pestotnik, R.; Piilonen, L. E.; Podobnik, T.; Prencipe, E.; Prim, M. T.; Rostomyan, A.; Rout, N.; Russo, G.; Sahoo, D.; Sakai, Y.; Sandilya, S.; Sangal, A.; Savinov, V.; Schnell, G.; Schueler, J.; Schwanda, C.; Schwartz, A. J.; Seino, Y.; Senyo, K.; Sevior, M. E.; Shapkin, M.; Sharma, C.; Shen, C. P.; Shiu, J. -G.; Singh, J. B.; Sokolov, A.; Solovieva, E.; Starič, M.; Sumihama, M.; Sumisawa, K.; Sumiyoshi, T.; Sutcliffe, W.; Takizawa, M.; Tamponi, U.; Tanida, K.; Tenchini, F.; Uchida, M.; Uglov, T.; Unno, Y.; Uno, S.; Usov, Y.; Vahsen, S. E.; van Tonder, R.; Varner, G.; Vinokurova, A.; Vossen, A.; Waheed, E.; Wang, E.; Wang, X. L.; Watanabe, M.; Watanuki, S.; Werbycka, O.; Won, E.; Xu, X.; Yabsley, B. D.; Yan, W.; Yang, S. B.; Yelton, J.; Yin, J. H.; Yook, Y.; Yuan, C. Z.; Zhang, Z. P.; Zhilich, V.; Zhukova, V.
Source
Science Bulletin 68 (2023) 583
Subject
Language
Abstract
We report a study of $\Lambda_c^+\to\Lambda h^+$ and $\Lambda_c^+\to\Sigma^{0} h^+$ ($h\!=\!K,\,\pi$) decays based on a data sample of 980~${\rm fb}^{-1}$ collected with the Belle detector at the KEKB energy-asymmetric $e^+e^-$ collider. The first results of direct $C\!P$ asymmetry in two-body singly Cabibbo-suppressed (SCS) decays of charmed baryons are measured, $A_{C\!P}^{\rm{dir}}(\Lambda_c^+\to\Lambda K^+)\!=\!+0.021\pm0.026\pm0.001$ and $A_{C\!P}^{\rm{dir}}(\Lambda_c^+\to\Sigma^0K^+)\!=\!+0.025\pm0.054\pm0.004$. We also make the most precise measurement of the decay asymmetry parameters ($\alpha$) for the four modes of interest and search for $C\!P$ violation via the $\alpha$-induced $C\!P$ asymmetry ($A_{C\!P}^{\alpha}$). We measure $A_{C\!P}^{\alpha}(\Lambda_c^+\to\Lambda K^+)\!=\!{-0.023\pm0.086\pm0.071}$ and $A_{C\!P}^{\alpha}(\Lambda_c^+\to\Sigma^0K^+)\!=\!{+0.08\pm 0.35\pm 0.14}$, which are the first $A_{C\!P}^{\alpha}$ results for SCS decays of charmed baryons. We search for $\Lambda$-hyperon $C\!P$ violation in $\Lambda_c^+\to(\Lambda,\,\Sigma^0)\pi^+$ and find $A_{C\!P}^{\alpha}(\Lambda\to p\pi^{-})\!=\!{+0.013\pm0.007\pm0.011}$. This is the first time that hyperon $C\!P$ violation has been measured via Cabibbo-favored charm decays. No evidence of baryon $C\!P$ violation is found. We also obtain the most precise branching fractions for two SCS $\Lambda_c^+$ decays, $\mathcal{B}(\Lambda_c^+\to\Lambda K^+)\!=\!(6.57\pm0.17\pm0.11\pm0.35)\times10^{-4}$ and $\mathcal{B}(\Lambda_c^+\to\Sigma^0K^+)\!=\!(3.58\pm0.19\pm0.06\pm0.19)\times10^{-4}$. The first uncertainties are statistical and the second systematic, while the third uncertainties come from the uncertainties on the world average branching fractions of $\Lambda_c^+\to(\Lambda,\,\Sigma^0)\pi^+$.
Comment: 15 pages, 9 figures, accepted for publication as an article in the Science Bulletin
Comment: 15 pages, 9 figures, accepted for publication as an article in the Science Bulletin