Coincidence Measurement of the Nonmesonic Weak Decay of ^{12}_{Lambda}C

• Main Authors: Kim, M. J, Ajimura, S, Aoki, K, Banu, A, Bhang, H, Fukuda, T, Hashimoto, O, Hwang, J. I, Kameoka, S, Kang, B. H, Kim, E. H, Kim, J. H, Maruta, T, Miura, Y, Miyake, Y, Nagae, T, Nakamura, M, Nakamura, S. N, Noumi, H, Okada, S, Okayasu, Y, Outa, H, Park, H, Saha, P. K, Sato, Y, Sekimoto, M, Shin, S, Takahashi, T, Tamura, H, Tanida, K, Toyoda, A, Tsukada, K, Watanabe, T, Yim, H. J
• Format: Journal Article
• Language: English
• Published: 21.01.2006
• Subjects: Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.nucl-ex/0601029

Phys.Lett. B641 (2006) 28-33 We have measured the angular correlation of the pair nucleons np and nn emitted from the nonmesonic weak decay (NMWD) of ^{12}_{Lambda}C produced via the (pi^+,K^+) reaction in coincidence measurement. The Lambda p -> np and Lambda n -> nn modes were clearly identified by measuring the back-to-back correlation of the emitted nucleon pairs which is the characteristic of two-body kinematics. From the measured nucleon pair numbers N_{nn} and N_{np}, the ratio Gamma_n/Gamma_p of the partial decay widths Gamma_n(Lambda n -> nn) and Gamma_p(Lambda p -> np) of ^{12}_{Lambda}C was extracted to be 0.51+-0.13(stat) +- 0.05(syst); this result is almost free from the ambiguity due to the nuclear final state interaction and 3-body decay process, which were inherent in the previous results. The obtained Gamma_n/Gamma_p ratio of ^{12}_{Lambda}C (p-shell) is close to that of ^5_{Lambda}He (s-shell). The results are consistent with those of recent theoretical calculations.