Asymmetry in the Nonmesonic Weak Decay of Polarized <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow></mrow><mrow><mi mathvariant="italic">Λ</mi></mrow><mrow><mn>5</mn></mrow></msubsup></mrow><mi>He</mi></math></span> Hypernuclei

S. Ajimura; K. Ikeda; M. Ishikawa; T. Kishimoto; A. Okusu; N. Shinkai; Y. Tanaka; H. Ejiri; T. Nakano; K. Manabe; T. Nagae; H. Noumi; M. Sekimoto; T. Shibata; O. Hashimoto; K. Maeda; T. Takahashi; T. Hasegawa; H. Bhang; Y. D. Kim; H. Park; M. Youn

doi:10.1103/PhysRevLett.84.4052

Asymmetry in the Nonmesonic Weak Decay of Polarized $_{Λ}^{5} He$ Hypernuclei

S. Ajimura, K. Ikeda, M. Ishikawa, T. Kishimoto, A. Okusu, N. Shinkai, Y. Tanaka, H. Ejiri, T. Nakano, K. Manabe, T. Nagae, H. Noumi, M. Sekimoto, T. Shibata, O. Hashimoto, K. Maeda, T. Takahashi, T. Hasegawa, H. Bhang, Y. D. Kim, H. Park, and M. Youn

Phys. Rev. Lett. 84, 4052 – Published 1 May 2000

Abstract

We have measured the asymmetric emission of protons from the nonmesonic decay of polarized $_{Λ}^{5} He$ produced by the $(π^{+} {, K}^{+})$ reaction. $_{Λ}^{5} He$ is an $s$ -shell hypernucleus and its polarization is due to the $Λ$ . One expects to obtain direct information on the elementary weak $\vec{Λ} p \to np$ process. The asymmetry parameter has been determined to be $0.24 \pm 0.22$ . The implication of the result is discussed.