Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lepton-Proton Two-Photon Exchange in Chiral Perturbation Theory   We use heavy baryon chiral perturbation theory to evaluate the two-photon
exchange corrections to the low-energy elastic lepton-proton scattering at
next-to-leading order accuracy, i.e., ${\mathcal O}(\alpha, M^{-1})$, including
a non-zero lepton mass. We consider the elastic proton intermediate state in
the two-photon exchange together in the soft photon approximation. The infrared
singular contributions are projected out using dimensional regularization. The
resulting infrared singularity-free two-photon exchange contribution is in good
numerical agreement with existing predictions based on standard diagrammatic
soft photon approximation evaluations.

27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg