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arXiv · 2601.07617

Amplitude analysis and branching fraction measurement of $J/\psi \to \Lambda\bar{\Sigma}^0\eta +\mathrm{c.c}$

BESIII Collaboration·M. Ablikim·M. N. Achasov·P. Adlarson·X. C. Ai·C. S. Akondi·R. Aliberti·A. Amoroso·Q. An·Y. H. An·Y. Bai·O. Bakina·Y. Ban·H. -R. Bao·X. L. Bao·V. Batozskaya·K. Begzsuren·N. Berger·M. Berlowski·M. B. Bertani·D. Bettoni·F. Bianchi·E. Bianco·A. Bortone·I. Boyko·R. A. Briere·A. Brueggemann·H. Cai·M. H. Cai·X. Cai·A. Calcaterra·G. F. Cao·N. Cao·S. A. Cetin·X. Y. Chai·J. F. Chang·T. T. Chang·G. R. Che·Y. Z. Che·C. H. Chen·Chao Chen·G. Chen·H. S. Chen·H. Y. Chen·M. L. Chen·S. J. Chen·S. M. Chen·T. Chen·W. Chen·X. R. Chen·X. T. Chen·X. Y. Chen·Y. B. Chen·Y. Q. Chen·Z. K. Chen·J. Cheng·L. N. Cheng·S. K. Choi·X. Chu·G. Cibinetto·F. Cossio·J. Cottee-Meldrum·H. L. Dai·J. P. Dai·X. C. Dai·A. Dbeyssi·R. E. de Boer·D. Dedovich·C. Q. Deng·Z. Y. Deng·A. Denig·I. Denisenko·M. Destefanis·F. De Mori·X. X. Ding·Y. Ding·Y. X. Ding·J. Dong·L. Y. Dong·M. Y. Dong·X. Dong·M. C. Du·S. X. Du·X. L. Du·Y. Q. Du·Y. Y. Duan·Z. H. Duan·P. Egorov·G. F. Fan·J. J. Fan·Y. H. Fan·J. Fang·S. S. Fang·W. X. Fang·Y. Q. Fang·L. Fava·F. Feldbauer·G. Felici·C. Q. Feng·J. H. Feng
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Abstract

Based on a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events collected with the BESIII detector, a partial-wave analysis of $ J/\psi \to \Lambda \bar{ \Sigma }^0\eta +\mathrm{c.c} $ is performed for the first time. The dominant contributions are found to be excited $\Lambda$ states with $J^P=1/2^-$ and $J^P=1/2^+$ in the $\eta\Lambda$ mass spectra. The measured masses and widths are $M=1668.8\pm3.1\pm21.2$ MeV/$c^2$ and $\Gamma=52.7\pm4.2\pm17.8$ MeV for the $\Lambda(1670)$, and $M=1881.5\pm16.5\pm20.3$ MeV/$c^2$ and $\Gamma=82.4\pm18.2\pm8.9$ MeV for the $\Lambda(1810)$, respectively. The branching fraction is determined to be $ \mathcal{B}(J/\psi \to \Lambda \bar{ \Sigma }^0\eta +\mathrm{c.c}) $ = $(3.44 \pm 0.11 \pm 0.13) \times 10^{-5}$. The first uncertainties are statistical and the second systematic.

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BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. H. An, Y. Bai, O. Bakina, Y. Ban, H. -R. Bao, X. L. Bao, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, H. Cai, M. H. Cai, X. Cai, A. Calcaterra, G. F. Cao, N. Cao, S. A. Cetin, X. Y. Chai, J. F. Chang, T. T. Chang, G. R. Che, Y. Z. Che, C. H. Chen, Chao Chen, G. Chen, H. S. Chen, H. Y. Chen, M. L. Chen, S. J. Chen, S. M. Chen, T. Chen, W. Chen, X. R. Chen, X. T. Chen, X. Y. Chen, Y. B. Chen, Y. Q. Chen, Z. K. Chen, J. Cheng, L. N. Cheng, S. K. Choi, X. Chu, G. Cibinetto, F. Cossio, J. Cottee-Meldrum, H. L. Dai, J. P. Dai, X. C. Dai, A. Dbeyssi, R. E. de Boer, D. Dedovich, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De Mori, X. X. Ding, Y. Ding, Y. X. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, M. C. Du, S. X. Du, X. L. Du, Y. Q. Du, Y. Y. Duan, Z. H. Duan, P. Egorov, G. F. Fan, J. J. Fan, Y. H. Fan, J. Fang, S. S. Fang, W. X. Fang, Y. Q. Fang, L. Fava, F. Feldbauer, G. Felici, C. Q. Feng, J. H. Feng. 2026-01-12. Amplitude analysis and branching fraction measurement of $J/\psi \to \Lambda\bar{\Sigma}^0\eta +\mathrm{c.c}$. https://doi.org/10.1103/njqp-5kg6

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