/ nucl-ex arXiv:1703.00623

Missing-mass spectroscopy with the ${}^{6}$Li($\pi^{-}, K^{+}$)X reaction to search for ${}^{6}_{\Lambda}$H

Honda, R. (Osaka U.) ; Agnello, M. (INFN, Turin) ; Ahn, J.K. (Korea U.) ; Ajimura, S. (Osaka U., Res. Ctr. Nucl. Phys.) ; Akazawa, Y. (Tohoku U.) ; Amano, N. (Kyoto U.) ; Aoki, K. (KEK, Tsukuba) ; Bhang, H.C. (Seoul Natl. U., Dept. Phys. Astron.) ; Chiga, N. (Tohoku U.) ; Endo, M. (Osaka U.) ; Evtoukhovitch, P. (Dubna, JINR) ; Feliciello, A. (INFN, Turin) ; Fujioka, H. (Kyoto U.) ; Fukuda, T. (Osaka Electrocommunications U.) ; Hasegawa, S. (JAEA, Ibaraki) ; Hayakawa, S.H. (Osaka U.) ; Hosomi, K. (JAEA, Ibaraki) ; Hwang, S.H. (KRISS, Taejon) ; Ichikawa, Y. (JAEA, Ibaraki) ; Igarashi, Y. (KEK, Tsukuba) ; Imai, K. (JAEA, Ibaraki) ; Ishibashi, N. (Osaka U.) ; Iwasaki, R. (KEK, Tsukuba) ; Joo, C.W. (Seoul Natl. U., Dept. Phys. Astron.) ; Kiuchi, R. (Tokai U., Hiratsuka) ; Lee, J.K. (Pusan Natl. U.) ; Lee, J.Y. (Seoul Natl. U., Dept. Phys. Astron.) ; Matsuda, K. (Osaka U.) ; Matsumoto, Y. (Tohoku U.) ; Matsuoka, K. (Osaka U.) ; Miwa, K. (Tohoku U.) ; Mizoi, Y. (Osaka Electrocommunications U.) ; Moritsu, M. (Osaka U.) ; Nagae, T. (Kyoto U.) ; Nagamiya, S. (JAEA, Ibaraki) ; Nakagawa, M. (Osaka U.) ; Naruki, M. (Kyoto U.) ; Noumi, H. (Osaka U., Res. Ctr. Nucl. Phys.) ; Ota, R. (Osaka U.) ; Roy, B.J. (Bhabha Atomic Res. Ctr.) ; Saha, P.K. (JAEA, Ibaraki) ; Sakaguchi, A. (Osaka U.) ; Sako, H. (JAEA, Ibaraki) ; Samanta, C. (Kentucky U.) ; Samoilov, V. (Dubna, JINR) ; Sasaki, Y. (Tohoku U.) ; Sato, S. (JAEA, Ibaraki) ; Sekimoto, M. (KEK, Tsukuba) ; Shimizu, Y. (Osaka Electrocommunications U.) ; Shiozaki, T. (Tohoku U.) ; Shirotori, K. (Osaka U., Res. Ctr. Nucl. Phys.) ; Soyama, T. (Osaka U.) ; Sugimura, H. (JAEA, Ibaraki) ; Takahashi, T. (KEK, Tsukuba) ; Takahashi, T.N. (Wako, RIKEN) ; Tamura, H. (Tohoku U.) ; Tanabe, K. (Tohoku U.) ; Tanaka, T. (Osaka U.) ; Tanida, K. (JAEA, Ibaraki) ; Tokiyasu, A.O. (Tohoku U., Sendai, ELPH) ; Tsamalaidze, Z. (Dubna, JINR) ; Ukai, M. (KEK, Tsukuba) ; Yamamoto, T.O. (KEK, Tsukuba) ; Yamamoto, Y. (Osaka U., Res. Ctr. Nucl. Phys.) ; Yang, S.B. (Seoul Natl. U., Dept. Phys. Astron.) ; Yoshida, K. (Osaka U.)

Pages: 24

Abstract: We searched for the bound state of the neutron-rich $\Lambda$-hypernucleus ${}^{6}_{\Lambda}$H, using the ${}^{6}$Li($\pi^{-}, K^{+}$)X double charge-exchange reaction at a $\pi^{-}$ beam momentum of 1.2 GeV/c at J-PARC. A total of $1.4 \times 10^{12}$ $\pi^{-}$ was driven onto a ${}^{6}$Li target of 3.5-g/$\rm cm^2$ thickness. No event was observed below the bound threshold, i.e., the mass of ${}^{4}_{\Lambda}$H + 2n, in the missing-mass spectrum of the ${}^{6}$Li($\pi^{-}, K^{+}$)X reaction in the $2^{\circ}$ < $\theta_{\pi K}$ < $20^{\circ}$ angular range. Furthermore, no event was found up to 2.8 MeV/$c^2$ above the bound threshold. We obtained the the double-differential cross section spectra of the ${}^{6}$Li($\pi^{-}, K^{+}$)X reaction in the angular range of $2^{\circ}$ < $\theta_{\pi K}$ < $14^{\circ}$. An upper limit of 0.56 nb/sr (90% C.L.) was obtained for the production cross section of the ${}^{6}_{\Lambda}$H hypernucleus bound state. In addition, not only the bound state region, but also the $\Lambda$ continuum region and part of the $\Sigma^{-}$ quasi-free production region of the ${}^{6}$Li($\pi^{-}, K^{+}$)X reaction, were obtained with high statistics. The present missing-mass spectrum will facilitate the investigation of the $\Sigma^{-}$-nucleus optical potential for $\Sigma^{-}$-${}^{5}$He through spectrum shape analysis.

Web-Page: http://inspirehep.net/record/1515731/files/h6l_count.png; http://inspirehep.net/record/1515731/files/mm_sigmam_v2.png; http://inspirehep.net/record/1515731/files/h6l-div.png; http://inspirehep.net/record/1515731/files/mm_sigmap.png; http://inspirehep.net/record/1515731/files/vtz_v2.png; http://inspirehep.net/record/1515731/files/mm_h6l_all_v4.png; http://inspirehep.net/record/1515731/files/m2_v2.png; http://inspirehep.net/record/1515731/files/k18.png; http://inspirehep.net/record/1515731/files/tmp_de_same.png; http://inspirehep.net/record/1515731/files/eff_vertex.png; http://inspirehep.net/record/1515731/files/eff_sdcin.png; http://inspirehep.net/record/1515731/files/h6l_mm_count.png; http://inspirehep.net/record/1515731/files/integ_h6l.png; http://inspirehep.net/record/1515731/files/beam_through_v2.png; http://inspirehep.net/record/1515731/files/cs_sigmap_cm.png; http://inspirehep.net/record/1515731/files/c12l.png; http://inspirehep.net/record/1515731/files/cs_sigmam_cm.png; http://inspirehep.net/record/1515731/files/arXiv:1703.00623.pdf

Note: 24 pages, 17 figures

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 Record created 2017-04-03, last modified 2017-04-03

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