## Precision Measurement of the $e^{+}e^{-}~\rightarrow~Λ_{c}^{+} \barΛ_{c}^{-}$ Cross Section Near Threshold

Ablikim, M. ; Achasov, M. N. ; Ahmed, S. ; Albrecht, M. ; Alekseev, M. ; Amoroso, A. ; An, F. F. ; An, Q. ; Bai, J. Z. ; Bai, Y. ; Bakina, O. ; Ferroli, R. Baldini ; Ban, Y. ; Bennett, D. W. ; Bennett, J. V. ; Berger, N. ; Bertani, M. ; Bettoni, D. ; Bian, J. M. ; Bianchi, F. ; Boger, E. ; Boyko, I. ; Briere, R. A. ; Cai, H. ; Cai, X.

The Born cross section of the $e^{+}e^{-}~\rightarrow~Λ_{c}^{+} \barΛ_{c}^{-}$ process is measured with unprecedented precision using data collected with the BESIII detector at $\sqrt{s}$=4574.5, 45580.0, 4590.0 and 4599.5 MeV. The non-zero cross section near the $\Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}$ production threshold is discerned. At center-of-mass energies $\sqrt{s}$=4574.5 and 4599.5 MeV, the higher statistics data enable us to measure the $\Lambda_{c}$ polar angle distributions. From these, the ratio between the $\Lambda_{c}$ electric and magnetic form factors ($|G_{E}/G_{M}|$) is measured for the first time. They are found to be 1.14±0.14±0.07 and 1.23±0.05±0.03 respectively, where the first uncertainties are statistical and the second are systematic.

Publication Date:
Mar 29 2018
Date Submitted:
Jul 01 2019
Pagination:
132001
ISSN:
0031-9007
Citation:
Physical Review Letters
120
13
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