Observation of Transverse Λ/Λ[over ¯] Hyperon Polarization in e^{+}e^{-} Annihilation at Belle.

/ Authors

Y. Guan, A. Vossen, I. Adachi, K. Adamczyk, J. Ahn, H. Aihara, S. Al Said, D. Asner, H. Atmacan, V. Aulchenko

and 197 more authors

T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. Bakich, V. Bansal, P. Behera, C. Beleño, M. Berger, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek, M. Bračko, T. Browder, L. Cao, D. Červenkov, P. Chang, V. Chekelian, A. Chen, B. Cheon, K. Chilikin, K. Cho, S. Choi, Y. Choi, D. Cinabro, S. Cunliffe, N. Dash, S. Di Carlo, J. Dingfelder, Z. Doležal, T. Dong, Z. Drasal, S. Eidelman, D. Epifanov, J. Fast, T. Ferber, B. Fulsom, R. Garg, V. Gaur, N. Gabyshev, A. Garmash, M. Gelb, A. Giri, P. Goldenzweig, B. Golob, E. Guido, J. Haba, K. Hayasaka, H. Hayashii, S. Hirose, W. Hou, T. Iijima, K. Inami, G. Inguglia, A. Ishikawa, R. Itoh, M. Iwasaki, Y. Iwasaki, W. Jacobs, I. Jaegle, H. Jeon, S. Jia, Y. Jin, D. Joffe, K. Joo, T. Julius, K. Kang, T. Kawasaki, C. Kiesling, D. Kim, H. Kim, J. Kim, K. Kim, S. Kim, K. Kinoshita, P. Kodys, S. Korpar, D. Kotchetkov, P. Križan, R. Kroeger, P. Krokovny, T. Kuhr, R. Kulasiri, A. Kuzmin, Y. Kwon, J. Lange, I. Lee, S. Lee, L. Li, Y. Li, L. Li Gioi, J. Libby, D. Liventsev, M. Lubej, T. Luo, M. Masuda, T. Matsuda, D. Matvienko, M. Merola, H. Miyata, R. Mizuk, G. Mohanty, H. Moon, Takashi Mori, R. Mussa, M. Nakao, T. Nanut, K. Nath, Z. Natkaniec, M. Nayak, M. Niiyama, N. Nisar, S. Nishida, S. Ogawa, S. Okuno, H. Ono, P. Pakhlov, G. Pakhlova, B. Pal, S. Pardi, H. Park, S. Paul, T. Pedlar, R. Pestotnik, L. Piilonen, V. Popov, E. Prencipe, A. Rabusov, A. Rostomyan, G. Russo, D. Sahoo, Y. Sakai, M. Salehi, S. Sandilya, L. Santelj, T. Sanuki, V. Savinov, O. Schneider, G. Schnell, C. Schwanda, R. Seidl, Y. Seino, K. Senyo, O. Seon, M. Sevior, V. Shebalin, C. Shen, T. Shibata, J. Shiu, F. Simon, A. Sokolov, E. Solovieva, M. Starič, J. Strube, M. Sumihama, T. Sumiyoshi, W. Sutcliffe, K. Suzuki, M. Takizawa, U. Tamponi, K. Tanida, F. Tenchini, M. Uchida, T. Uglov, Y. Unno, S. Uno, P. Urquijo, Y. Usov, S. Vahsen, C. Van Hulse, R. van Tonder, G. Varner, A. Vinokurova, V. Vorobyev, E. Waheed, B. Wang, C. Wang, M. Wang, P. Wang, X. Wang, S. Watanuki, E. Widmann, E. Won, H. Ye, J. Yelton, J. Yin, C. Yuan, Y. Yusa, Z. Zhang, V. Zhilich, V. Zhukova, V. Zhulanov, A. Zupanc

/ Abstract

We report the first observation of the spontaneous polarization of Λ and Λ[over ¯] hyperons transverse to the production plane in e^{+}e^{-} annihilation, which is attributed to the effect arising from a polarizing fragmentation function. For inclusive Λ/Λ[over ¯] production, we also report results with subtracted feed-down contributions from Σ^{0} and charm. This measurement uses a dataset of 800.4 fb^{-1} collected by the Belle experiment at or near a center-of-mass energy of 10.58 GeV. We observe a significant polarization that rises with the fractional energy carried by the Λ/Λ[over ¯] hyperon.

Journal: Physical review letters

DOI: 10.1103/PhysRevLett.122.042001