Exclusive measurement of the nonmesonic weak decay of the Λ5He hypernucleus - art. no. 062301

被引：63

作者：

Kang, BH ^{[1
]}

Bhang, H

Kim, EH

Kim, JH

Kim, MJ

Yim, HJ

Ajimura, S

Miyake, Y

Aoki, K

Nagae, T

Noumi, H

Outa, H

Saha, PK

Sato, Y

Sekimoto, M

Toyoda, A

Banu, A

Fukuda, T

Hashimoto, O

Kameoka, S

Miura, Y

Nakamura, SN

Okayasu, Y

Takahashi, T

Tamura, H

Tsukada, K

Watanabe, T

Hwang, JI

Maruta, T

Nakamura, M

Okada, S

Park, H

Tanida, K

机构：

[1] Seoul Natl Univ, Dept Phys, Seoul 151742, South Korea

[2] Osaka Univ, Dept Phys, Toyonaka, Osaka 5600043, Japan

[3] KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan

[4] GSI Darmstadt, D-64291 Darmstadt, Germany

[5] Osaka Electrocommun Univ, Phys Lab, Neyagawa, Osaka 5728530, Japan

[6] Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan

[7] Ewha Womans Univ, Dept Phys, Seoul 120750, South Korea

[8] Univ Tokyo, Dept Phys, Tokyo 1130033, Japan

[9] Tokyo Inst Technol, Dept Phys, Ookayama 1528551, Japan

[10] Korea Res Inst Stand & Sci, Taejon 305600, South Korea

[11] RIKEN, Wako Inst, Wako, Saitama 3510198, Japan

来源：

PHYSICAL REVIEW LETTERS | 2006年 / 96卷 / 06期

关键词：

D O I：

10.1103/PhysRevLett.96.062301

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay of He-5(Lambda) formed via the Li-6(pi(+),K+) reaction. The energies of the 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 weak reactions of Lambda p -> np and Lambda n -> nn, respectively. The ratio of the nucleon pair numbers was N-nn/N-np=0.45 +/- 0.11(stat)+/- 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 and/or direct-quark exchange picture.

引用

页数：4

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