Polarization of <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi></mi></mrow><mrow><mi mathvariant="italic">Λ</mi></mrow><mrow><mn>5</mn></mrow></msubsup></mrow><mi>He</mi></math></span> Produced by the <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>(</mo><mrow><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow><mo>,</mo><mrow><msup><mrow><mi mathvariant="italic">K</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow><mo>)</mo></math></span> Reaction

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

doi:10.1103/PhysRevLett.80.3471

Polarization of $_{Λ}^{5} He$ Produced by the $(π^{+}, K^{+})$ Reaction

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

Phys. Rev. Lett. 80, 3471 – Published 20 April 1998

Abstract

We have measured the polarization of $_{Λ}^{5} He$ produced by the $(π^{+} {, K}^{+})$ reaction for the first time by observing the asymmetric emission of its weak decay pions. The large asymmetry parameter of the mesonic decay, which is unique to $_{Λ}^{5} He$ , made the measurement possible. The measurement is consistent with the theoretical prediction by which the mechanism of the hypernuclear polarization was clarified. This technique will open a new field to the spectroscopic study of hypernuclei.