Resonant Effect for Breit–Wheeler Process in the Field of an X-ray Pulsar
Gregory Vereshchagin
Round 1
Reviewer 1 Report
The paper discusses resonant Breit-Wheeler process in external field. The author perform standard QED calculations of the process and consider typical parameters of X-ray pulsars to justify the choice of photon energies. The work is generally sound and interesting for astrophysicists and theoreticians working on particle interactions in external fields.
There are several points which should be addressed before the paper can be reconsidered for publication:
- The width of the resonance should be estimated at least for the typical parameters under consideration. The authors claim the excess of the resonant cross section over the non-resonant one about 12 orders of magnitude, but it possibly implies extremely narrow width. Similar effect exists for light-by-light scattering, probably it could be mentioned. Can the cross section be cast in the Breit-Wigner form?
- Are the conditions (18) necessary for the process, or just convenient for calculations? It should be explained better.
- Why the threshold energy after eq. (23) is 100 MeV? Where does this number come from? How does it correlate with the estimate used after eq. (1)?
- In the end of Sec. 4 the authors discuss production of positrons with energy 100 GeV, observed in excess and discussed in Ref. [3]. Why the energies of photons are so special? What is the mechanism the authors envision to produce GeV photons around X-ray pulsars? This should be discussed in order to justify their claim.
- The authors should add the reference to the paper R. Ruffini, G.V. Vereshchagin and S.-S. Xue, Physics Reports, 487 (2010) 1-140 about astrophysical significance of the B-W process, alongside to the review paper by Di Piazza et al.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Minor but obvious typos should be addressed, such as (not least):
- below line 46, "1-100 KeV", "10^11 - 10^13 V/cm", similar typos at other places;
- below line 56, Equation (9) should be (4) instead.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors have undertaken necessary revision. The paper can now be accepted for publication.
