Exclusive proton asymmetry measurement in non-mesonic weak decay of polarized 5_Lambda_He
Nuclear Experiment
2007-05-23 v1
Abstract
The asymmetry parameter alpha_p^NM for a proton exclusively emitted in the Lambda p -> np process was, for the first time, measured in the non-mesonic weak decay of a polarized 5_La,bda_He hypernucleus by selecting the proton-neutron pairs emitted in the back-to-back kinematics. The highly polarized 5_Lambda_He was abundantly produced with the (pi+,K+) reaction at 1.05GeV/c in the scattering angular range of +-15$ degrees. The obtained value alpha_p^NM=0.31+-0.22, as well as that for inclusive protons, alpha_p^NM=0.11+-0.08+-0.04, largely contradicts recent theoretical values of around -0.6, although these calculations well reproduce the branching ratios of non-mesonic weak decay.
Keywords
Cite
@article{arxiv.nucl-ex/0509016,
title = {Exclusive proton asymmetry measurement in non-mesonic weak decay of polarized 5_Lambda_He},
author = {T. Maruta 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 B. H. Kang and E. H. Kim and J. H. Kim and M. J. Kim 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/0509016},
year = {2007}
}
Comments
4pages, 2 figures, submitted to Physical Review Letters