Studies of e +e −→ γγ and γγγ reactions

• Published in: Physics letters. B 1992-06, Vol.284 (1), p.144-150
• Main Authors: Shimozawa, K., Fujimoto, J., Abe, T., Adachi, I., Doser, M., Enomoto, R., Fujii, H., Fujii, K., Fujii, T., Fujio, N., Fujiwara, N., Harigae, K., Hayashii, H., Hori, S., Howell, B., Iida, N., Ikeda, H., Itoh, R., Iwasaki, H., Kajikawa, R., Kamae, T., Kato, S., Kato, Y., Kawabata, S., Kichimi, H., Kishida, T., Kobayashi, M., Koltick, D., Levine, I., Miyabayashi, K., Miyamoto, A., Muramatsu, K., Nagai, K., Nagira, T., Nakagawa, N., Nakajima, M., Nakano, E., Nakayama, M., Nishioka, H., Nitoh, O., Noguchi, S., Ochiai, F., Ohkura, M., Ohnishi, Y., Okuno, H., Okusawa, T., Sakai, E., Shimonaka, A., Shirahashi, A., Sugiyama, A., Suzuki, S., Tachibana, N., Takahashi, K., Takahashi, T., Takamure, H., Tanimori, T., Tauchi, T., Teramoto, Y., Tsukamoto, T., Uno, S., Watanabe, Y., Yamamoto, A., Yamamoto, S., Yamauchi, M.
• Format: Article
• Language: English
• Subjects: Classical and quantum physics: mechanics and fields; Exact sciences and technology; General theory of scattering; Physics
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(92)91940-B

We have measured the cross section for γγ production with the TOPAZ detector in the energy region √ s=50.0–61.4 GeV. The observed cross section for γγ production integrated over |cos θ| ⩽ 0.77 is 50.2±0.8±2.2 pb at 〈√ s〉=57.6 GeV and the ratio of this value to the QED prediction is 1.01±0.02±0.04. The angular distribution is in good agreement with the QED predictions, thereby setting limits on the compositeness scales, Λ L+R +=168 GeV, Λ L+R −=97 GeV, Λ L,R=141 GeV, Λ L,R −=81 GeV, and Λ L−R ±=68 GeV, at the 95% confidence level. The reaction e +e −→ γγγ was also studied and was found consistent with the QED prediction.