De-excitation gamma-rays from the s-hole state in 15N associated with proton decay in 16O

K. Kobayashi; H. Akimune; H. Ejiri; H. Fujimura; M. Fujiwara; K. Hara; K. Y. Hara; T. Ishikawa; M. Itoh; Y. Itow; T. Kawabata; M. Nakamura; H. Sakaguchi; Y. Sakemi; M. Shiozawa; H. Takeda; Y. Totsuka; H. Toyokawa; M. Uchida; T. Yamada; Y. Yasuda; H. P. Yoshida; M. Yosoi; R. G. T. Zegers

arXiv · nucl-ex/0604006

De-excitation gamma-rays from the s-hole state in 15N associated with proton decay in 16O

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Abstract

We have measured de-excitation gamma-rays from the s-hole state in 15N produced via the 16O(p,2p)15N reaction in relation to the study of the nucleon decay and the neutrino neutral-current interaction in water Cherenkov detectors. In the excitation-energy region of the s-hole state between 16 MeV and 40 MeV in 15N, the branching ratio of emitting gamma-rays with the energies at more-than-6 MeV are found to be 15.6+-1.3+0.6-1.0%. Taking into account the spectroscopic factor of the s-hole state, the total emission probability is found to be 3.1%. This is about 1/10 compared with the emission probability of the 6.32 MeV gamma-ray from the 3/2- p-hole state in 15N. Moreover, we searched for a 15.1 MeV gamma-ray from the 12C 1+ state which may be populated after the particle-decay of the s-hole state in 15N. Such a high energy gamma-ray from the hole state would provide a new method to search for mode-independent nucleon decay even if the emission probability is small. No significant signal is found within a statistical uncertainty.

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K. Kobayashi, H. Akimune, H. Ejiri, H. Fujimura, M. Fujiwara, K. Hara, K. Y. Hara, T. Ishikawa, M. Itoh, Y. Itow, T. Kawabata, M. Nakamura, H. Sakaguchi, Y. Sakemi, M. Shiozawa, H. Takeda, Y. Totsuka, H. Toyokawa, M. Uchida, T. Yamada, Y. Yasuda, H. P. Yoshida, M. Yosoi, R. G. T. Zegers. 2006-04-10. De-excitation gamma-rays from the s-hole state in 15N associated with proton decay in 16O. https://arxiv.org/abs/nucl-ex/0604006

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