학술논문
Observation of charmed strange meson pair production in $\Upsilon(2S)$ decays and in $e^{+}e^{-}$ annihilation at $\sqrt{s} = 10.52~ \rm{GeV}$
Document Type
Working Paper
Author
Belle Collaboration; Gao, B. S.; Zhu, W. J.; Wang, X. L.; Adachi, I.; Aihara, H.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Ayad, R.; Babu, V.; Banerjee, Sw.; Bauer, M.; Behera, P.; Belous, K.; Bennett, J.; Bessner, M.; Bhardwaj, V.; Bilka, T.; Biswas, D.; Bobrov, A.; Bodrov, D.; Bondar, A.; Bozek, A.; Bračko, M.; Branchini, P.; Browder, T. E.; Budano, A.; Červenkov, D.; Chang, M. -C.; Chang, P.; Chekelian, V.; Cheon, B. G.; Chilikin, K.; Cho, H. E.; Cho, K.; Choi, S. -K.; Choi, Y.; Choudhury, S.; Cinabro, D.; De Nardo, G.; De Pietro, G.; Dhamija, R.; Di Capua, F.; Dingfelder, J.; Doležal, Z.; Dong, T. V.; Ecker, P.; Ferber, T.; Ferlewicz, D.; Fulsom, B. G.; Gaur, V.; Giri, A.; Graziani, E.; Gu, T.; Gudkova, K.; Hadjivasiliou, C.; Hayasaka, K.; Hayashii, H.; Hazra, S.; Hedges, M. T.; Herrmann, D.; Hou, W. -S.; Hsu, C. -L.; Iijima, T.; Inami, K.; Ipsita, N.; Ishikawa, A.; Itoh, R.; Iwasaki, M.; Jacobs, W. W.; Jang, E. -J.; Jia, S.; Jin, Y.; Joo, K. K.; Kawasaki, T.; Kiesling, C.; Kim, C. H.; Kim, D. Y.; Kim, K. -H.; Kim, Y. -K.; Kinoshita, K.; Kodyš, P.; Konno, T.; Korobov, A.; Korpar, S.; Križan, P.; Kumar, M.; Kumar, R.; Kumara, K.; Kuzmin, A.; Kwon, Y. -J.; Lai, Y. -T.; Lee, S. C.; Levit, D.; Lewis, P.; Li, L. K.; Gioi, L. Li; Libby, J.; Lieret, K.; Liventsev, D.; Ma, Y.; Masuda, M.; Matsuda, T.; Maurya, S. K.; Meier, F.; Merola, M.; Mizuk, R.; Nakamura, I.; Nakao, M.; Narwal, D.; Natochii, A.; Nayak, L.; Niiyama, M.; Nisar, N. K.; Nishida, S.; Ogawa, S.; Pakhlov, P.; Pakhlova, G.; Pardi, S.; Park, J.; Patra, S.; Paul, S.; Pedlar, T. K.; Pestotnik, R.; Piilonen, L. E.; Podobnik, T.; Prencipe, E.; Prim, M. T.; Russo, G.; Sandilya, S.; Savinov, V.; Schnell, G.; Schwanda, C.; Seino, Y.; Senyo, K.; Sevior, M. E.; Shan, W.; Sharma, C.; Shiu, J. -G.; Shwartz, B.; Solovieva, E.; Starič, M.; Stottler, Z. S.; Sumihama, M.; Tanida, K.; Tenchini, F.; Uchida, M.; Uglov, T.; Unno, Y.; Uno, S.; Vahsen, S. E.; Varvell, K. E.; Wang, D.; Wang, E.; Wang, M. -Z.; Watanuki, S.; Won, E.; Xu, X.; Yabsley, B. D.; Yan, W.; Yang, S. B.; Yin, J. H.; Yook, Y.; Yuan, C. Z.; Yuan, L.; Zhilich, V.; Zhukova, V.
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Subject
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Abstract
We observe the process $\Upsilon(2S)\to D_s^{(*)+} D_{sJ}^{-}$ and continuum production $e^+e^- \to D_s^{(*)+} D_{sJ}^- $ at $\sqrt{s} = 10.52$ GeV (and their charge conjugates) using the data samples collected by the Belle detector at KEKB, where $D_{sJ}^-$ is $D_{s1}(2536)^-$ or $D^{*}_{s2}(2573)^-$. Both $D_{sJ}^-$ states are identified through their decay into $\bar{K}\bar{D}^{(*)}$. We measure the products of branching fractions ${\cal B}(\Upsilon(2S) \to D_{s}^{(*)+} D_{sJ}^-) {\cal B}(D_{sJ}^-\to \bar{K} \bar{D}^{(*)})$ and the Born cross sections $\sigma^{\rm Born}(e^+e^- \to D_{s}^{(*)+} D_{sJ}^-) {\cal B}(D_{sJ}^-\to \bar{K} \bar{D}^{(*)})$, and then compare the ratios $R_1 \equiv {\cal B}(\Upsilon(2S)\to D_{s}^{(*)+} D_{sJ}^-)/{\cal B}(\Upsilon(2S)\to\mu^{+}\mu^-)$ for $\Upsilon(2S)$ decays and $R_2 \equiv \sigma^{\rm Born}(e^+e^-\to D_{s}^{(*)+}D_{sJ}^-)/\sigma^{\rm Born}(e^+e^-\to \mu^{+}\mu^-)$ for continuum production. We obtain $R_1/R_2 = 9.7\pm 2.3 \pm 1.1$, $6.8 \pm 2.1 \pm 0.8$, $10.2 \pm 3.3 \pm 2.5$, and $3.4 \pm 2.1 \pm 0.5$ for the $D_s^+ D_{s1}(2536)^-$, $D_s^{*+} D_{s1}(2536)^-$, $D_s^+ D_{s2}^{*}(2573)^{-}$, and $D_s^{*+} D_{s2}^{*}(2573)^{-}$ final states in the $D_{sJ}^-\to K^{-} \bar{D}^{(*)0}$ modes, respectively. Therefore, the strong decay is expected to dominate in the $\Upsilon(2S)\to D_{s}^{(*)+}D_{sJ}^-$ processes. We also measure the ratios of branching fractions ${\cal B}(D_{s1}(2536)^-\to K_S^0 D^{*}(2010)^{-})/{\cal B}(D_{s1}(2536)^-\to K^{-} D^{*}(2007)^0) = 0.48 \pm 0.07 \pm 0.02$ and ${\cal B}(D_{s2}^{*}(2573)^- \to K_S^0 D^-)/{\cal B}(D_{s2}^{*}(2573)^- \to K^{-}D^0) = 0.49 \pm 0.10 \pm 0.02$, which are consistent with isospin symmetry. The second ratio is the first measurement of this quantity. Here, the first uncertainties are statistical and the second are systematic.