Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Proton Radius from Electron Scattering Data   [Background] The proton charge radius extracted from recent muonic hydrogen
Lamb shift measurements is significantly smaller than that extracted from
atomic hydrogen and electron scattering measurements.
  [Purpose] In an attempt to understand the discrepancy, we review
high-precision electron scattering results from Mainz, Jefferson Lab, Saskatoon
and Stanford.
  [Method] We make use of stepwise regression techniques using the $F$-test as
well as the Akaike information criterion to systematically determine the
predictive variables to use for a given set and range of electron scattering
data as well as to provide multivariate error estimates.
  [Results] Starting with the precision, low four-momentum transfer ($Q^2$)
data from Mainz (1980) and Saskatoon (1974), we find that a stepwise regression
of the Maclaurin series using the $F$-test as well as the Akaike information
criterion justify using a linear extrapolation which yields a value for the
proton radius that is consistent with the result obtained from muonic hydrogen
measurements. Applying the same Maclaurin series and statistical criteria to
the 2014 Rosenbluth results on $G_E$ from Mainz, we again find that the
stepwise regression tends to favor a radius consistent with the muonic hydrogen
radius but produces results that are extremely sensitive to the range of data
included in the fit. Making use of the high-$Q^2$ data on $G_E$ to select
functions which extrapolate to high $Q^2$, we find that a Pad\'e ($N=M=1$)
statistical model works remarkably well, as does a dipole function with a 0.84
fm radius, $G_E(Q^2) = ( 1 + Q^2/0.66\,\mathrm{GeV}^2)^{-2}$.
  [Conclusions] From this statistical analysis, we conclude that the electron
scattering result and the muonic hydrogen result are consistent. It is the
atomic hydrogen results that are the outliers.

21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc