## SciPost Submission Page

# Aspects of High Energy Scattering

### by Chris D. White

#### - Published as SciPost Phys. Lect. Notes 13 (2020)

### Submission summary

As Contributors: | Chris White |

Arxiv Link: | https://arxiv.org/abs/1909.05177v2 |

Date accepted: | 2020-01-23 |

Date submitted: | 2020-01-17 |

Submitted by: | White, Chris |

Submitted to: | SciPost Physics Lecture Notes |

Discipline: | Physics |

Subject area: | High-Energy Physics - Theory |

Approach: | Theoretical |

### Abstract

Scattering amplitudes in quantum field theories are of widespread interest, due to a large number of theoretical and phenomenological applications. Much is known about the possible behaviour of amplitudes, that is independent of the details of the underlying theory. This knowledge is often neglected in modern QFT courses, and the aim of these notes - aimed at graduate students - is to redress this. We review the possible singularities that amplitudes can have, before examining the generic behaviour that can arise in the high-energy limit. Finally, we illustrate the results using examples from QCD and gravity.

### Ontology / Topics

See full Ontology or Topics database.Published as SciPost Phys. Lect. Notes 13 (2020)

### Author comments upon resubmission

I am writing to resubmit my lecture notes, following minor revisions at the request of both anonymous referees. My responses to each of them are attached below.

Kind Regards,

Chris White

### List of changes

Response to Report 1:

I thank the referee for their comments, and have made all the requested minor

changes for resubmission.

Response to Report 2:

I thank the referee for their careful reading, and very helpful

suggestions on how to improve the article. A summary of my changes is as follows:

1. I added a reference to Veltman's book in section 2.

2. I have rephrased the discussion of cluster decomposition to remove

this confusion.

3. I have added a discussion at the end of section 2.2 to discuss the

assumption of a mass gap.

4. I have clarified the notation in the caption of figure 3, choosing

to keep letters for particle species, and numbers for 4-momenta. One

reason is that this notation agrees with recent literature on

scattering amplitudes.

5. The referee is strictly speaking correct, although much of the

literature on the Regge limit (including recent studies) uses the terms

"high energy" and "Regge" interchangeably. I have added a clarifying

footnote on p. 19, and hope this does the trick.

6. Please see point 5.

7. The referee is correct about this limitation, which arose due to

the finite length of the lecture notes. I have now added a comment to

address this to the final paragraph of the conclusion, with

references.

8. I have implemented the referee's suggestion.

9. I have added a new introduction to section 4 in line with the

referee's suggestions. Furthermore, I added a clarifying remark at the

end of the first paragraph on p. 30.

### Submission & Refereeing History

## Reports on this Submission

### Anonymous Report 1 on 2020-1-18 Invited Report

### Strengths

The revised manuscript shares all of the many strengths of the original submission, and adds many improvements as well.

### Report

The work is good, thorough, and extremely pedagogical. It will serve as a useful reference to students and researchers alike. It should be published.