Search for $K^0_S$ invisible decays

BESIII Collaboration; M. Ablikim; M. N. Achasov; P. Adlarson; O. Afedulidis; X. C. Ai; R. Aliberti; A. Amoroso; Q. An; Y. Bai; O. Bakina; I. Balossino; Y. Ban; H. -R. Bao; V. Batozskaya; K. Begzsuren; N. Berger; M. Berlowski; M. Bertani; D. Bettoni; F. Bianchi; E. Bianco; A. Bortone; I. Boyko; R. A. Briere; A. Brueggemann; H. Cai; X. Cai; A. Calcaterra; G. F. Cao; N. Cao; S. A. Cetin; X. Y. Chai; J. F. Chang; G. R. Che; Y. Z. Che; G. Chelkov; C. Chen; C. H. Chen; Chao Chen; G. Chen; H. S. Chen; H. Y. Chen; M. L. Chen; S. J. Chen; S. L. Chen; S. M. Chen; T. Chen; X. R. Chen; X. T. Chen; Y. B. Chen; Y. Q. Chen; Z. J. Chen; S. K. Choi; G. Cibinetto; F. Cossio; J. J. Cui; H. L. Dai; J. P. Dai; A. Dbeyssi; R. E. de Boer; D. Dedovich; C. Q. Deng; Z. Y. Deng; A. Denig; I. Denysenko; M. Destefanis; F. De Mori; B. Ding; X. X. Ding; Y. Ding; J. Dong; L. Y. Dong; M. Y. Dong; X. Dong; M. C. Du; S. X. 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; R. Farinelli; L. Fava; F. Feldbauer; G. Felici; C. Q. Feng; J. H. Feng; Y. T. Feng; M. Fritsch; C. D. Fu; J. L. Fu; Y. W. Fu; H. Gao; X. B. Gao

doi:10.1007/jhep05(2025)092

arXiv · 2501.06426

Search for $K^0_S$ invisible decays

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

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Abstract

Based on $(1.0087\pm0.0044)\times10^{10}$ $J/\psi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ storage ring, we search for $K_{S}^{0}$ invisible decays via the $J/\psi \to \phi K_{S}^{0} K_{S}^{0}$ process. No significant signal is observed, and the upper limit of the branching fraction of these invisible decays is set at 8.4 $\times$ $10^{-4}$ at the 90\% confidence level. This is the first experimental search for $K^0_S$ invisible decays.

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BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, O. Afedulidis, X. C. Ai, R. Aliberti, A. Amoroso, Q. An, Y. Bai, O. Bakina, I. Balossino, Y. Ban, H. -R. Bao, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, H. Cai, X. Cai, A. Calcaterra, G. F. Cao, N. Cao, S. A. Cetin, X. Y. Chai, J. F. Chang, G. R. Che, Y. Z. Che, G. Chelkov, C. Chen, C. H. Chen, Chao Chen, G. Chen, H. S. Chen, H. Y. Chen, M. L. Chen, S. J. Chen, S. L. Chen, S. M. Chen, T. Chen, X. R. Chen, X. T. Chen, Y. B. Chen, Y. Q. Chen, Z. J. Chen, S. K. Choi, G. Cibinetto, F. Cossio, J. J. Cui, H. L. Dai, J. P. Dai, A. Dbeyssi, R. E. de Boer, D. Dedovich, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denysenko, M. Destefanis, F. De Mori, B. Ding, X. X. Ding, Y. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, M. C. Du, S. X. 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, R. Farinelli, L. Fava, F. Feldbauer, G. Felici, C. Q. Feng, J. H. Feng, Y. T. Feng, M. Fritsch, C. D. Fu, J. L. Fu, Y. W. Fu, H. Gao, X. B. Gao. 2025-01-11. Search for $K^0_S$ invisible decays. https://doi.org/10.1007/jhep05(2025)092

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