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Physics from Photons at the LHC

by Lucian Harland-Lang

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Submission summary

As Contributors: Lucian Harland-Lang
Preprint link: scipost_202107_00035v1
Date accepted: 2021-10-22
Date submitted: 2021-07-20 17:24
Submitted by: Harland-Lang, Lucian
Submitted to: SciPost Physics Proceedings
Proceedings issue: DIS2021
Academic field: Physics
  • High-Energy Physics - Phenomenology
Approach: Phenomenological


LHC collisions can act as a source of photons in the initial state. This mechanism plays an important role in the production of particles with electroweak couplings, and a precise account of photon-initiated (PI) production at the LHC is a key ingredient in the LHC precision physics programme. I will discuss the possibility of modelling PI processes directly via the structure function approach. This can provide percent level precision in the production cross sections, and is therefore well positioned to account for LHC precision requirements. This formalism in addition allows one to make use of another useful feature of photons, namely that they are colour-singlet and can often be emitted elastically (or quasi-elastically) from the proton. I will discuss recent work on applications of the structure function approach to precision calculations of PI production in the inclusive mode, and to `exclusive' processes with rapidity gaps, which can provide a unique probe of the Standard Model and physics beyond it.

Published as SciPost Phys. Proc. 8, 072 (2022)

Reports on this Submission

Anonymous Report 3 on 2021-9-13 (Invited Report)

  • Cite as: Anonymous, Report on arXiv:scipost_202107_00035v1, delivered 2021-09-13, doi: 10.21468/SciPost.Report.3527


In this contribution to the DIS2021 proceedings an overview over the structure function method for photon-induced processes is given, which allows for predictions with percent level accuracy. Photon-induced processes are accessible at the LHC and are phenomenologically relevant in high precision studies. Key results for different types of processes are shown and put into the context of the field. The manuscript is well written and suitable for publication.

Requested changes

Some minor misprints that could be fixed:

1 - line 79: the sentence starting with 'The total (solid) curve...' doesn't make sense to me.
2 - line 113: 'takes' instead of 'take'?

  • validity: -
  • significance: -
  • originality: -
  • clarity: -
  • formatting: -
  • grammar: -

Author:  Lucian Harland-Lang  on 2021-10-25  [id 1878]

(in reply to Report 3 on 2021-09-13)

I thank the referee for their positive comments. I will account for the minor suggestions in the final paper version.

Anonymous Report 2 on 2021-8-17 (Invited Report)

  • Cite as: Anonymous, Report on arXiv:scipost_202107_00035v1, delivered 2021-08-17, doi: 10.21468/SciPost.Report.3402


The manuscript is a contribution to the proceedings of DIS2021 conference and describe the content of the given talk. The presented results include cross section calculations for inclusive and exclusive photon-induced dilepton production in the structure function approach for proton-proton collisions at the LHC. The framework, that can be considered as the state-of-the-art in precision, is clearly described, relevant references appropriately cited and the significance of the results properly evaluated. The manuscript is within the recommended page limits can thus be recommended for publication as a part of the proceedings in the current form but there are a couple minor suggestion that the Author may consider.

Requested changes

1- Possibly a typo on line 101: than -> then
2- The arXiv links in the References do not work properly

  • validity: high
  • significance: good
  • originality: high
  • clarity: top
  • formatting: excellent
  • grammar: excellent

Author:  Lucian Harland-Lang  on 2021-08-18  [id 1684]

(in reply to Report 2 on 2021-08-17)

Thank you for your positive feedback. I hope the arXiv linking can be resolved at the final submission stage (though I am not sure how to fix that by hand), and I believe 'than' is correct in the context.

Anonymous Report 1 on 2021-8-10 (Invited Report)

  • Cite as: Anonymous, Report on arXiv:scipost_202107_00035v1, delivered 2021-08-10, doi: 10.21468/SciPost.Report.3367


In recent years, the study of photon induced interactions at hadronic colliders  has become a reality and has been used to improve our understanding of hadronic physics. In particular, the study of the dilepton production allows us to probe the Standard Model and search for New Physics. In this contribution the author develops the structure function approach, which will allow us to obtain percent level precision in the production cross sections. The paper is well written and I find this work valuable. In my opinion, it may  be published in the present form.

  • validity: high
  • significance: high
  • originality: high
  • clarity: high
  • formatting: excellent
  • grammar: excellent

Author:  Lucian Harland-Lang  on 2021-08-18  [id 1685]

(in reply to Report 1 on 2021-08-10)

Thank you for your positive feedback.

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