Determination of the Σ^{+} Timelike Electromagnetic Form Factors

• Published in: Physical review letters 2024-02, Vol.132 (8), p.081904-081904, Article 081904
• Main Authors: Ablikim, M, Achasov, M N, Adlarson, P, Ai, X C, Aliberti, R, Amoroso, A, An, M R, An, Q, Bai, Y, Bakina, O, Balossino, I, Ban, Y, Batozskaya, V, Begzsuren, K, Berger, N, Berlowski, M, Bertani, M, Bettoni, D, Bianchi, F, Bianco, E, Bortone, A, Boyko, I, Briere, R A, Brueggemann, A, Cai, H, Cai, X, Calcaterra, A, Cao, G F, Cao, N, Cetin, S A, Chang, J F, Chang, T T, Chang, W L, Che, G R, Chelkov, G, Chen, C, Chen, Chao, Chen, G, Chen, H S, Chen, M L, Chen, S J, Chen, S M, Chen, T, Chen, X R, Chen, X T, Chen, Y B, Chen, Y Q, Chen, Z J, Cheng, W S, Choi, S K, Chu, X, Cibinetto, G, Coen, S C, Cossio, F, Cui, J J, Dai, H L, Dai, J P, Dbeyssi, A, de Boer, R E, Dedovich, D, Deng, Z Y, Denig, A, Denysenko, I, Destefanis, M, De Mori, F, Ding, B, Ding, X X, Ding, Y, Dong, J, Dong, L Y, Dong, M Y, Dong, X, Du, M C, Du, S X, Duan, Z H, Egorov, P, Fan, Y H Y, Fan, Y L, Fang, J, Fang, S S, Fang, W X, Fang, Y, Farinelli, R, Fava, L, Feldbauer, F, Felici, G, Feng, C Q, Feng, J H, Fischer, K, Fritsch, M, Fritzsch, C, Fu, C D, Fu, J L, Fu, Y W, Gao, H, Gao, Y N, Gao, Yang, Garbolino, S, Garzia, I
• Format: Article
• Language: English
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.132.081904

Based on data samples collected with the BESIII detector at the BEPCII collider, the process e^{+}e^{-}→Σ^{+}Σ[over ¯]^{-} is studied at center-of-mass energies sqrt[s]=2.3960, 2.6454, and 2.9000 GeV. Using a fully differential angular description of the final state particles, both the relative magnitude and phase information of the Σ^{+} electromagnetic form factors in the timelike region are extracted. The relative phase between the electric and magnetic form factors is determined to be sinΔΦ=-0.67±0.29(stat)±0.18(syst) at sqrt[s]=2.3960  GeV, ΔΦ=55°±19°(stat)±14°(syst) at sqrt[s]=2.6454  GeV, and 78°±22°(stat)±9°(syst) at sqrt[s]=2.9000  GeV. For the first time, the phase of the hyperon electromagnetic form factors is explored in a wide range of four-momentum transfer. The evolution of the phase along with four-momentum transfer is an important input for understanding its asymptotic behavior and the dynamics of baryons.