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Title: Direct comparison of using a Z-transformation instead of the traditional $Q^2$ for extraction of the proton radius from $e-p$ scattering data

Journal Article · · European Physical Journal. A, Hadrons and Nuclei (Online)
ORCiD logo [1];  [2];  [3]
  1. North Carolina A &T State University, Greensboro, NC (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
  2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  3. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); The Governor’s School for Science and Technology, Hampton, VA (United States)

A discrepancy in the determination of the proton’s charge radius, rp, between muonic hydrogen spectroscopy versus classic atomic spectroscopy and electron scattering data has become known as the proton radius puzzle. Extractions of rp from electron scattering data require determination of the slope of the proton’s charge form factor, $$G$$$^{p}_{E}$$, in the limit of Q2 → 0 through fitting and extrapolation. Some works have presented the Z-transformation fitting technique as the best choice for this type of extraction due to the true functional form of $$G$$$^{p}_{E}$$ being mathematically guaranteed to exist within the parameter-space of the fit function. In this work, we test this claim by examining the mathematical bias and variances introduced by this technique as compared to the more traditional Q2 fits using statistically sampled $$G$$$^{p}_{E}$$ parameterizations with known input radii. Furthermore, our tests conclude that the quality of the Z-transformation technique depends on the range of data used. In the case of new experiments, the fit function and technique should be selected in advance by generating realistic pseudodata and assessing the power of different techniques.

Research Organization:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP); National Science Foundation (NSF)
Grant/Contract Number:
AC02-05CH11231; AC05-06OR23177; PHY-1812421
OSTI ID:
2283949
Report Number(s):
JLAB-PHY-23-3811; DOE/OR/23177-6125
Journal Information:
European Physical Journal. A, Hadrons and Nuclei (Online), Vol. 60, Issue 1; ISSN 1434-601X
Publisher:
Springer NatureCopyright Statement
Country of Publication:
United States
Language:
English

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