Pion off-shell electromagnetic form factors: Data extraction and model analysis
Abstract
We investigate the pion electromagnetic half-off-shell form factors, which parametrize the matrix element of the charged pion electromagnetic current with one leg off mass shell and the other leg on mass shell, using an exactly solvable manifestly covariant model of a (3 + 1)-dimensional fermion field theory. The model provides a three-dimensional imaging of the two off-shell pion form factors $$F_1$$ and $$F_2$$ as a function of ($Q^2, t$), which are related to each other, satisfying the Ward-Takahashi identity. The normalization of the renormalized charge form factor $$F_1$$ is fixed by $$F_1$$ ($$Q^2 = 0 , t = m^2_ π)$$ = 1, while the other form factor $$F_2$$ vanishes; i.e., $$F_2 (Q^2, t = m^2_π$$) = 0 for any value of $Q^2$ due to the time-reversal invariance of the strong interaction. We define the new form factor $$g(Q^ 2, t) = F_2(Q^2, t)/(t – m^2_π)$$ and find that $g(Q^2, t)$ can be measurable in the on-mass-shell limit. In particular, $$g(Q^2 = 0, t = m^2_π)$$ is related with the pion charge radius. We also compare our form factors with the data extracted from the pion electroproduction reaction for both the off-shell region ($$\mathcal{t}$$ < 0) and the on-shell limit ($$t → m^2_ π$$).
- Authors:
- Publication Date:
- Research Org.:
- North Carolina State Univ., Raleigh, NC (United States); Univ. of California, Oakland, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Org.:
- USDOE Office of Science (SC); National Research Foundation of Korea (NRF); Coordination for the Improvement of Higher Education Personnel (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP)
- OSTI Identifier:
- 1580179
- Alternate Identifier(s):
- OSTI ID: 1800101
- Grant/Contract Number:
- FG02-03ER41260; AC02-05CH11231; NRF-2017R1D1A1B03033129; 308025/2015-6; 308486/2015-3; PVE 401322/2014-9
- Resource Type:
- Published Article
- Journal Name:
- Physical Review D
- Additional Journal Information:
- Journal Name: Physical Review D Journal Volume: 100 Journal Issue: 11; Journal ID: ISSN 2470-0010
- Publisher:
- American Physical Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Astronomy & Astrophysics; Physics
Citation Formats
Choi, Ho-Meoyng, Frederico, T., Ji, Chueng-Ryong, and de Melo, J. P. B. C. Pion off-shell electromagnetic form factors: Data extraction and model analysis. United States: N. p., 2019.
Web. doi:10.1103/PhysRevD.100.116020.
Choi, Ho-Meoyng, Frederico, T., Ji, Chueng-Ryong, & de Melo, J. P. B. C. Pion off-shell electromagnetic form factors: Data extraction and model analysis. United States. https://doi.org/10.1103/PhysRevD.100.116020
Choi, Ho-Meoyng, Frederico, T., Ji, Chueng-Ryong, and de Melo, J. P. B. C. Mon .
"Pion off-shell electromagnetic form factors: Data extraction and model analysis". United States. https://doi.org/10.1103/PhysRevD.100.116020.
@article{osti_1580179,
title = {Pion off-shell electromagnetic form factors: Data extraction and model analysis},
author = {Choi, Ho-Meoyng and Frederico, T. and Ji, Chueng-Ryong and de Melo, J. P. B. C.},
abstractNote = {We investigate the pion electromagnetic half-off-shell form factors, which parametrize the matrix element of the charged pion electromagnetic current with one leg off mass shell and the other leg on mass shell, using an exactly solvable manifestly covariant model of a (3 + 1)-dimensional fermion field theory. The model provides a three-dimensional imaging of the two off-shell pion form factors $F_1$ and $F_2$ as a function of ($Q^2, t$), which are related to each other, satisfying the Ward-Takahashi identity. The normalization of the renormalized charge form factor $F_1$ is fixed by $F_1$ ($Q^2 = 0 , t = m^2_ π)$ = 1, while the other form factor $F_2$ vanishes; i.e., $F_2 (Q^2, t = m^2_π$) = 0 for any value of $Q^2$ due to the time-reversal invariance of the strong interaction. We define the new form factor $g(Q^ 2, t) = F_2(Q^2, t)/(t – m^2_π)$ and find that $g(Q^2, t)$ can be measurable in the on-mass-shell limit. In particular, $g(Q^2 = 0, t = m^2_π)$ is related with the pion charge radius. We also compare our form factors with the data extracted from the pion electroproduction reaction for both the off-shell region ($\mathcal{t}$ < 0) and the on-shell limit ($t → m^2_ π$).},
doi = {10.1103/PhysRevD.100.116020},
journal = {Physical Review D},
number = 11,
volume = 100,
place = {United States},
year = {2019},
month = {12}
}
https://doi.org/10.1103/PhysRevD.100.116020
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