TY - JOUR
T1 - Measurements of the Electric and Magnetic Form Factors of the Neutron for Timelike Momentum Transfer
AU - BESIII Collaboration
AU - Ablikim, M.
AU - Achasov, M. N.
AU - Kalantar-Nayestanaki, N.
AU - Kappert, R.
AU - Kavatsyuk, M.
AU - Messchendorp, J.
AU - Rodin, V.
N1 - Funding Information:
The BESIII Collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by the National Key R&D Program of China under Contracts No. 2020YFA0406400, No. 2020YFA0406300; National Natural Science Foundation of China (NSFC) under Contracts No. 11635010, No. 11735014, No. 11805124, No. 11835012, No. 11935015, No. 11935016, No. 11935018, No. 11961141012, No. 12022510, No. 12025502, No. 12035009, No. 12035013, No. 12061131003, No. 12122509, No. 12192260, No. 12192261, No. 12192262, No. 12192263, No. 12192264, No. 12192265, No. 12221005; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the CAS Center for Excellence in Particle Physics (CCEPP); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contract No. U1832207; CAS Key Research Program of Frontier Sciences under Contracts No. QYZDJ-SSW-SLH003, No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; Guangdong Major Project of Basic and Applied Basic Research No. 2020B0301030008; Science and Technology Program of Guangzhou (No. 2019050001); The Double First-Class university project foundation of USTC; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; ERC under Contract No. 758462; European Union’s Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement under Contract No. 894790; German Research Foundation DFG under Contracts Nos. 443159800, 455635585, Collaborative Research Center CRC 1044, FOR5327, GRK 2149; Istituto Nazionale di Fisica Nucleare, Italy; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Research Foundation of Korea under Contract No. NRF-2022R1A2C1092335; National Science and Technology fund; National Science Research and Innovation Fund (NSRF) via the Program Management Unit for Human Resources and Institutional Development, Research and Innovation under Contract No. B16F640076; Polish National Science Centre under Contract No. 2019/35/O/ST2/02907; Suranaree University of Technology (SUT), Thailand Science Research and Innovation (TSRI), and National Science Research and Innovation Fund (NSRF) under Contract No. 160355; The Royal Society, UK under Contract No. DH160214; The Swedish Research Council; U.S. Department of Energy under Contract No. DE-FG02-05ER41374.
Publisher Copyright:
© 2023 authors. Published by the American Physical Society.
PY - 2023/4/14
Y1 - 2023/4/14
N2 - We present the first measurements of the electric and magnetic form factors of the neutron in the timelike (positive q2) region as function of four-momentum transfer. We explored the differential cross sections of the reaction e+e-→n¯n with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of 354.6 pb-1 in total at twelve center-of-mass energies between s=2.0-2.95 GeV. A relative uncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at s=2.3935 GeV. Our results are comparable in accuracy to those from electron scattering in the comparable spacelike region of four-momentum transfer. The electromagnetic form factor ratio Rem|GE|/|GM| is within the uncertainties close to unity. We compare our result on |GE| and |GM| to recent model predictions, and the measurements in the spacelike region to test the analyticity of electromagnetic form factors.
AB - We present the first measurements of the electric and magnetic form factors of the neutron in the timelike (positive q2) region as function of four-momentum transfer. We explored the differential cross sections of the reaction e+e-→n¯n with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of 354.6 pb-1 in total at twelve center-of-mass energies between s=2.0-2.95 GeV. A relative uncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at s=2.3935 GeV. Our results are comparable in accuracy to those from electron scattering in the comparable spacelike region of four-momentum transfer. The electromagnetic form factor ratio Rem|GE|/|GM| is within the uncertainties close to unity. We compare our result on |GE| and |GM| to recent model predictions, and the measurements in the spacelike region to test the analyticity of electromagnetic form factors.
UR - http://www.scopus.com/inward/record.url?scp=85153779550&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.130.151905
DO - 10.1103/PhysRevLett.130.151905
M3 - Article
C2 - 37115883
SN - 0031-9007
VL - 130
JO - Physical Review Letters
JF - Physical Review Letters
IS - 15
M1 - 151905
ER -