First Observation of Λπ+ and Λπ- Signals near the K ¯ N (I=1) Mass Threshold in Λc+ → Λπ+π+π- Decay

Y. Ma, J. Yelton, K. Tanida, I. Adachi, J. K. Ahn, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, Sw Banerjee, P. Behera, K. Belous, J. Bennett, M. Bessner, B. Bhuyan, T. BilkaD. Biswas, A. Bobrov, D. Bodrov, J. Borah, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, D. Červenkov, M. C. Chang, A. Chen, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, S. J. Cho, S. K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Das, G. De Nardo, G. De Pietro, R. Dhamija, F. Di Capua, J. Dingfelder, Z. DoleŽal, T. V. Dong, D. Epifanov, T. Ferber, D. Ferlewicz, B. G. Fulsom, R. Garg, V. Gaur, A. Garmash, A. Giri, P. Goldenzweig, B. Golob, E. Graziani, K. Gudkova, C. Hadjivasiliou, S. Halder, K. Hayasaka, H. Hayashii, M. T. Hedges, W. S. Hou, C. L. Hsu, K. Inami, N. Ipsita, A. Ishikawa, R. Itoh, M. Iwasaki, W. W. Jacobs, E. J. Jang, S. Jia, Y. Jin, A. B. Kaliyar, K. H. Kang, T. Kawasaki, C. Kiesling, C. H. Kim, D. Y. Kim, Y. K. Kim, K. Kinoshita, P. Kodyš, A. Korobov, S. Korpar, E. Kovalenko, P. KriŽan, P. Krokovny, R. Kumar, K. Kumara, Y. J. Kwon, T. Lam, J. S. Lange, S. C. Lee, P. Lewis, L. K. Li, Y. Li, L. Li Gioi, J. Libby, K. Lieret, Y. R. Lin, D. Liventsev, T. Luo, M. Masuda, T. Matsuda, D. Matvienko, S. K. Maurya, F. Meier, M. Merola, F. Metzner, K. Miyabayashi, G. B. Mohanty, R. Mussa, I. Nakamura, T. Nakano, M. Nakao, Z. Natkaniec, A. Natochii, L. Nayak, M. Nayak, N. K. Nisar, S. Nishida, S. Ogawa, H. Ono, P. Oskin, P. Pakhlov, G. Pakhlova, S. Pardi, H. Park, J. Park, S. Patra, S. Paul, R. Pestotnik, L. E. Piilonen, T. Podobnik, E. Prencipe, M. T. Prim, A. Rostomyan, N. Rout, G. Russo, S. Sandilya, L. Santelj, V. Savinov, G. Schnell, J. Schueler, C. Schwanda, Y. Seino, K. Senyo, M. E. Sevior, W. Shan, M. Shapkin, C. Sharma, C. P. Shen, J. G. Shiu, F. Simon, A. Sokolov, E. Solovieva, M. Starič, M. Sumihama, T. Sumiyoshi, W. Sutcliffe, M. Takizawa, U. Tamponi, F. Tenchini, M. Uchida, S. Uehara, T. Uglov, Y. Unno, K. Uno, S. Uno, P. Urquijo, Y. Usov, S. E. Vahsen, R. Van Tonder, G. Varner, A. Vinokurova, A. Vossen, D. Wang, M. Z. Wang, M. Watanabe, S. Watanuki, O. Werbycka, E. Won, X. Xu, B. D. Yabsley, W. Yan, S. B. Yang, J. H. Yin, C. Z. Yuan, L. Yuan, Z. P. Zhang, V. Zhilich, V. Zhukova

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Abstract

Using the data sample of 980 fb-1 collected with the Belle detector operating at the KEKB asymmetric-energy e+e- collider, we present the results of an investigation of the Λπ+ and Λπ- invariant mass distributions looking for substructure in the decay Λc+→Λπ+π+π-. We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Λπ+ (Λπ-) combination a mass of 1434.3±0.6(stat)±0.9(syst) MeV/c2 [1438.5±0.9(stat)±2.5(syst) MeV/c2], an intrinsic width of 11.5±2.8(stat)±5.3(syst) MeV/c2 [33.0±7.5(stat)±23.6(syst) MeV/c2] with a significance of 7.5σ (6.2σ). As these two signals are very close to the K̄N threshold, we also investigate the possibility of a K̄N cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.

Original languageEnglish
Article number151903
JournalPhysical review letters
Volume130
Issue number15
DOIs
Publication statusPublished - 2023 Apr 14

Bibliographical note

Publisher Copyright:
© 2023 authors. Published by the American Physical Society.

ASJC Scopus subject areas

  • General Physics and Astronomy

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