Observation of H Λ4 hyperhydrogen by decay-pion spectroscopy in electron scattering

A. Esser, S. Nagao, F. Schulz, P. Achenbach, C. Ayerbe Gayoso, R. Böhm, O. Borodina, D. Bosnar, V. Bozkurt, L. Debenjak, M. O. Distler, I. Friščić, Y. Fujii, T. Gogami, O. Hashimoto, S. Hirose, H. Kanda, M. Kaneta, E. Kim, Y. KohlJ. Kusaka, A. Margaryan, H. Merkel, M. Mihovilovič, U. Müller, S. N. Nakamura, J. Pochodzalla, C. Rappold, J. Reinhold, T. R. Saito, A. Sanchez Lorente, S. Sánchez Majos, B. S. Schlimme, M. Schoth, C. Sfienti, S. Širca, L. Tang, M. Thiel, K. Tsukada, A. Weber, K. Yoshida

研究成果: Article査読

60 被引用数 (Scopus)


At the Mainz Microtron MAMI, the first high-resolution pion spectroscopy from decays of strange systems was performed by electron scattering off a Be9 target in order to study the Λ binding energy of light hypernuclei. Positively charged kaons were detected by a short-orbit spectrometer with a broad momentum acceptance at 0° forward angles with respect to the beam, efficiently tagging the production of strangeness in the target nucleus. Coincidentally, negatively charged decay pions were detected by two independent high-resolution spectrometers. About 103 pionic weak decays of hyperfragments and hyperons were observed. The pion momentum distribution shows a monochromatic peak at pπ≈133MeV/c, corresponding to the unique signature for the two-body decay of hyperhydrogen HΛ4→He4+π-, stopped inside the target. Its Λ binding energy was determined to be BΛ=2.12±0.01(stat)±0.09(syst)MeV with respect to the H3+Λ mass.

ジャーナルPhysical review letters
出版ステータスPublished - 2015 6 9

ASJC Scopus subject areas

  • 物理学および天文学(全般)


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