Observation of charmed strange meson pair production in $\Upsilon(2S)$ decays and in $e^{+}e^{-}$ annihilation at $\sqrt{s} = 10.52~ \rm{GeV}$

Author:

Belle Collaboration, B. S. Gao, W. J. Zhu, X. L. Wang, I. Adachi, H. Aihara, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, Sw. Banerjee, M. Bauer, P. Behera, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, T. Bilka, D. Biswas, A. Bobrov, D. Bodrov, A. Bondar, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, D. Červenkov, M. -C. Chang, P. Chang, V. Chekelian, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, S. -K. Choi, Y. Choi, S. Choudhury, D. Cinabro, G. De Nardo, G. De Pietro, R. Dhamija, F. Di Capua, J. Dingfelder, Z. Doležal, T. V. Dong, P. Ecker, T. Ferber, D. Ferlewicz, B. G. Fulsom, V. Gaur, A. Giri, E. Graziani, T. Gu, K. Gudkova, C. Hadjivasiliou, K. Hayasaka, H. Hayashii, S. Hazra, M. T. Hedges, D. Herrmann, W. -S. Hou, C. -L. Hsu, T. Iijima, K. Inami, N. Ipsita, A. Ishikawa, R. Itoh, M. Iwasaki, W. W. Jacobs, E. -J. Jang, S. Jia, Y. Jin, K. K. Joo, T. Kawasaki, C. Kiesling, C. H. Kim, D. Y. Kim, K. -H. Kim, Y. -K. Kim, K. Kinoshita, P. Kodyš, T. Konno, A. Korobov, S. Korpar, P. Križan, M. Kumar, R. Kumar, K. Kumara, A. Kuzmin, Y. -J. Kwon, Y. -T. Lai, S. C. Lee, D. Levit, P. Lewis, L. K. Li, L. Li Gioi, J. Libby, K. Lieret, D. Liventsev, Y. Ma, M. Masuda, T. Matsuda, S. K. Maurya, F. Meier, M. Merola, R. Mizuk, I. Nakamura, M. Nakao, D. Narwal, A. Natochii, L. Nayak, M. Niiyama, N. K. Nisar, S. Nishida, S. Ogawa, P. Pakhlov, G. Pakhlova, S. Pardi, J. Park, S. Patra, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, T. Podobnik, E. Prencipe, M. T. Prim, G. Russo, S. Sandilya, V. Savinov, G. Schnell, C. Schwanda, Y. Seino, K. Senyo, M. E. Sevior, W. Shan, C. Sharma, J. -G. Shiu, B. Shwartz, E. Solovieva, M. Starič, Z. S. Stottler, M. Sumihama, K. Tanida, F. Tenchini, M. Uchida, T. Uglov, Y. Unno, S. Uno, S. E. Vahsen, K. E. Varvell, D. Wang, E. Wang, M. -Z. Wang, S. Watanuki, E. Won, X. Xu, B. D. Yabsley, W. Yan, S. B. Yang, J. H. Yin, Y. Yook, C. Z. Yuan, L. Yuan, V. Zhilich, V. Zhukova

Keyword:

High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex)

journal:

Belle Preprint 2023-12, KEK Preprint 2023-16

date:

2023-08-16 16:00:00

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.

PDF: Observation of charmed strange meson pair production in $\Upsilon(2S)$ decays and in $e^{+}e^{-}$ annihilation at $\sqrt{s} = 10.52~ \rm{GeV}$.pdf