Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Complete Measurement of the Λ Electromagnetic Form Factors. / The BESIII Collaboration.
в: Physical Review Letters, Том 123, № 12, 122003, 20.09.2019.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Complete Measurement of the Λ Electromagnetic Form Factors
AU - BESIII Collaboration
AU - Ablikim, M.
AU - Achasov, M. N.
AU - Adlarson, P.
AU - Ahmed, S.
AU - Albrecht, M.
AU - Alekseev, M.
AU - Amoroso, A.
AU - An, F. F.
AU - An, Q.
AU - Bai, Y.
AU - Bakina, O.
AU - Baldini Ferroli, R.
AU - Ban, Y.
AU - Begzsuren, K.
AU - Bennett, J. V.
AU - Berger, N.
AU - Bertani, M.
AU - Bettoni, D.
AU - Bianchi, F.
AU - Biernat, J.
AU - Bloms, J.
AU - Boyko, I.
AU - Briere, R. A.
AU - Cai, H.
AU - Cai, X.
AU - Calcaterra, A.
AU - Cao, G. F.
AU - Cao, N.
AU - Cetin, S. A.
AU - Chai, J.
AU - Chang, J. F.
AU - Chang, W. L.
AU - Chelkov, G.
AU - Chen, D. Y.
AU - Chen, G.
AU - Chen, H. S.
AU - Chen, J. C.
AU - Chen, M. L.
AU - Chen, S. J.
AU - Chen, Y. B.
AU - Cheng, W.
AU - Cibinetto, G.
AU - Cossio, F.
AU - Cui, X. F.
AU - Dai, H. L.
AU - Dai, J. P.
AU - Dai, X. C.
AU - Dbeyssi, A.
AU - Muchnoi, N. Yu
AU - Nikolaev, I. B.
N1 - Publisher Copyright: © 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP . Copyright: Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/9/20
Y1 - 2019/9/20
N2 - The exclusive process e+e-→ΛΛ̄, with Λ→pπ- and Λ̄→p̄π+, has been studied at s=2.396 GeV for measurement of the timelike Λ electric and magnetic form factors, GE and GM. A data sample, corresponding to an integrated luminosity of 66.9 pb-1, was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R=|GE/GM| and, for the first time for any baryon, the relative phase Δφ=φE-φM. The resulting values are R=0.96±0.14(stat)±0.02(syst) and Δφ=37°±12°(stat)±6°(syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter αΛ=0.750±0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be σ=118.7±5.3(stat)±5.1(syst) pb, which corresponds to an effective form factor of |G|=0.123±0.003(stat)±0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.
AB - The exclusive process e+e-→ΛΛ̄, with Λ→pπ- and Λ̄→p̄π+, has been studied at s=2.396 GeV for measurement of the timelike Λ electric and magnetic form factors, GE and GM. A data sample, corresponding to an integrated luminosity of 66.9 pb-1, was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R=|GE/GM| and, for the first time for any baryon, the relative phase Δφ=φE-φM. The resulting values are R=0.96±0.14(stat)±0.02(syst) and Δφ=37°±12°(stat)±6°(syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter αΛ=0.750±0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be σ=118.7±5.3(stat)±5.1(syst) pb, which corresponds to an effective form factor of |G|=0.123±0.003(stat)±0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.
KW - OBSERVABLES
UR - http://www.scopus.com/inward/record.url?scp=85072785332&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.123.122003
DO - 10.1103/PhysRevLett.123.122003
M3 - Article
C2 - 31633986
AN - SCOPUS:85072785332
VL - 123
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 12
M1 - 122003
ER -
ID: 23380033