Measurement of R and search for new heavy quarks in e+e- annihilation at 50 and 52 GeV centre-of-mass energies

H. Yoshida, Y. Chiba, I. Endo, I. Hayashibara, T. Ohsugi, A. Taketani, R. Tanaka, K. Amako, Y. Arai, H. Boerner, M. Fukawa, Y. Fukushima, N. Ishihara, J. Kanzaki, T. Kondo, K. Maehata, T. Matsui, S. Odaka, K. Ogawa, T. OhamaH. Sakamoto, M. Sakuda, J. Shirai, T. Sumiyoshi, F. Suekane, Y. Teramoto, F. Takasaki, T. Tsuboyama, S. Uehara, Y. Unno, M. Wake, Y. Watase, Y. Yamada, Y. Noguchi, A. Ono, Y. Homma, Y. Hojyo, H. Sakae, Y. Hemmi, R. Kikuchi, K. Kubo, H. Kurashige, K. Miyake, T. Nakamura, N. Sasao, N. Tamura, K. Tobimatsu, J. Haba, T. Kamitani, N. Kanematsu, Y. Nagashima, H. Osabe, S. Sakamoto, S. Sugimoto, Y. Suzuki, A. Tsukamoto, T. Yamashita, K. Abe, M. Higuchi, Y. Hoshi, M. Sato, T. Emura, M. Chiba, T. Fukui, T. Hirose, Y. Nakagawa, M. Minami, H. Saito, M. Wakai, T. Watanabe, T. Yamagata, Y. Asano, T. Koseki, S. Mori, M. Sakano, M. Shioden, Y. Takada, Y. Ikegami, I. Nakano, M. Daigo

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Abstract

The total cross section for the process of the e+e- annihilation into hadrons has been measured at the centre-of-mass energies of 50 GeV and 52 GeV and a search has been made for new heavy quarks. The ratios R = σ(e+e- → hadrons)/σpoint(e+e- → μ+μ-) obtained are 4.4±0.5 at 50 GeV and 4.7±0.3 at 52 GeV, respectively. An additional systematic uncertainty is 10%. From the event shape analysis we found no evidence for a new quark with charge 2 3e.

Original languageEnglish
Pages (from-to)570-576
Number of pages7
JournalPhysics Letters B
Volume198
Issue number4
DOIs
Publication statusPublished - Dec 3 1987
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

Cite this

Yoshida, H., Chiba, Y., Endo, I., Hayashibara, I., Ohsugi, T., Taketani, A., ... Daigo, M. (1987). Measurement of R and search for new heavy quarks in e+e- annihilation at 50 and 52 GeV centre-of-mass energies. Physics Letters B, 198(4), 570-576. https://doi.org/10.1016/0370-2693(87)90920-8