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arXiv · 2610.26673

Measurement of the relative phase between the strong and electromagnetic amplitudes in $\boldsymbol{J/ψ\to Σ^{+} \barΣ^{-}}$

Abstract

Using 284 pb$^{-1}$ of $e^{+}e^{-}$ collision data collected with the BESIII detector at center-of-mass energies between 3.00 and 3.12 GeV, the relative phase between the strong and electromagnetic interaction amplitudes in the process $J/ψ\to Σ^+ \barΣ^-$ is determined. The relative phase is measured to be $(107.9 \pm 24.9)^{\circ}$ or $(-107.6 \pm 24.3)^{\circ}$, where the uncertainty includes both statistical and systematic sources. This is the first experimental determination of the strong-electromagnetic phase difference in $J/ψ$ decays to a hyperon-antihyperon pair. The branching fraction $\mathcal{B}_{J/ψ\to Σ^+ \barΣ^-}$ is measured to be $(1.14 \pm 0.04)\times 10^{-3}$ for the positive phase solution or $(1.19 \pm 0.04) \times 10^{-3}$ for the negative phase solution. These results provide important input for testing perturbative QCD predictions and studies of SU(3) flavor symmetry.

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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, M. S. Anderson, Y. Bai, O. Bakina, H. R. Bao, X. L. Bao, M. Barbagiovanni, 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, D. Cabiati, 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, E. Di Fiore, X. X. Ding, Y. Ding, Y. X. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, Z. J. Dong, M. C. Du, S. X. Du, Shaoxu 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, Jin Fang, S. S. Fang, W. X. Fang. 2026-10-19. Measurement of the relative phase between the strong and electromagnetic amplitudes in $\boldsymbol{J/ψ\to Σ^{+} \barΣ^{-}}$. https://arxiv.org/abs/2610.26673

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