Title: Robust extraction of the proton charge radius from electron-proton scattering data

Abstract

Background: Extracting the proton charge radius from electron scattering data requires determining the slope of the charge form factor at Q² 15 of zero. But as experimental data never reach that limit, numerous methods for making the extraction have been proposed, though often the functions are determined after seeing the data which can lead to confirmation bias. Purpose: To find functional forms that will allow for a robust extraction of the input radius for a wide variety of functional forms in order to have confidence in the extraction from upcoming low Q² experimental data such as the Jefferson Lab PRad experiment. Method: We create a general framework for inputting form-factor functions as well as various fitting functions. The input form factors are used to generate pseudo-data with fluctuations intended to mimic the binning and random uncertainty of a given set of real data. All combinations of input functions and fit functions can then be tested repeatedly against regenerated pseudo-data. Since the input radius is known, this allows us to find those functions that are robust for radius extractions in an objective fashion. Results: For the range and uncertainty of the PRad data, we find that a two-parameter rational function, amore » two-parameter continued fraction and the second order polynomial expansion of z can extract the input radius regardless of the input charge form factor function that is used. Conclusions: We have created an easily expandable framework to search for functional forms that allow for a robust extraction of the radius from a given binning and uncertainty of pseudo-data generated from a wide variety of trial functions. This method has enabled a successful search for the best functional forms to extract the radius from the upcoming PRad data, and can be used for other experiments.« less

Authors:

Yan, Xuefei ^[1]; Higinbotham, Douglas W. ^[2]; Dutta, Dipangkar ^[3]; Gao, Haiyan ^[4]; Gasparian, Ashot ^[5]; Khandaker, Mahbub A. ^[6]; Liyanage, Nilanga ^[7]; Pasyuk, Eugene ^[2]; Peng, Chao ^[1]; Xiong, Weizhi ^[1]

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+ Show Author Affiliations

1. Duke Univ., Durham, NC (United States); triangle Univ. Nuclear Lab., Durham, NC (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
3. Mississippi State Univ., Mississippi State, MS (United States)
4. Duke Univ., Durham, NC (United States); triangle Univ. Nuclear Lab., Durham, NC (United States); Duke Kunchan Univ., Jiangsu (China)
5. North Carolina A & T State Univ., Greensboro, NC (United States)
6. Idaho State Univ., Pocatello, ID (United States)
7. Univ. of Virginia, Charlottesville, VA (United States)

Publication Date:

Tue Aug 21 00:00:00 EDT 2018

Research Org.:

Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mississippi State Univ., Mississippi State, MS (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Nuclear Physics (NP)

OSTI Identifier:

1466730

Alternate Identifier(s):

OSTI ID: 1465610; OSTI ID: 1599330

Report Number(s):

JLAB-PHY-18-2655; DOE/OR/23177-4361; arXiv:1803.01629
Journal ID: ISSN 2469-9985; PRVCAN

Grant/Contract Number:  

AC05-060R23177; FG02-03ER41231; FG02-07ER41528

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review C

Additional Journal Information:

Journal Volume: 98; Journal Issue: 2; Journal ID: ISSN 2469-9985

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

73 NUCLEAR PHYSICS AND RADIATION PHYSICS