Exclusive Measurement of the Nonmesonic Weak Decay of ^{5}_{\Lambda}He Hypernucleus
Abstract
We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay (NMWD) of ^{5}_{\Lambda}He formed via the ^{6}Li(\pi^+,K^+) reaction. The energies of two nucleons and the pair number distributions in the opening angle between them were measured. In both np and nn pairs, we observed a clean back-to-back correlation coming from the two-body decay of \Lambda p --> n p and \Lambda n --> n n, respectively. The ratio of the nucleon pair numbers was N_{nn}/N_{np}=0.45 \pm 0.11(stat)\pm 0.03(syst) in the kinematic region of cos(theta_{NN}) < -0.8. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of \Gamma(\Lambda p --> np)/\Gamma(\Lambda n --> nn). The ratio is consistent with recent theoretical calculations based on the heavy meson/direct quark exchange picture.
Keywords
Cite
@article{arxiv.nucl-ex/0509015,
title = {Exclusive Measurement of the Nonmesonic Weak Decay of ^{5}_{\Lambda}He Hypernucleus},
author = {B. H. Kang and S. Ajimura and K. Aoki and A. Banu and H. Bhang and T. Fukuda and O. Hashimoto and J. I. Hwang and S. Kameoka and E. H. Kim and J. H. Kim and M. J. Kim and T. Maruta and Y. Miura and Y. Miyake and T. Nagae and M. Nakamura and S. N. Nakamura and H. Noumi and S. Okada and Y. Okayasu and H. Outa and H. Park and P. K. Saha and Y. Sato and M. Sekimoto and T. Takahashi and H. Tamura and K. Tanida and A. Toyoda and K. Tsukada and T. Watanabe and H. J. Yim},
journal= {arXiv preprint arXiv:nucl-ex/0509015},
year = {2016}
}
Comments
Submitted to Phys. Rev. lett., 4 pages, 3 figures