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Hitting two BSM particles with one lepton-jet: search for a top partner decaying to a dark photon, resulting in a lepton-jet

by K. du Plessis, M. M. Flores, D. Kar, S. Sinha, H. van der Schyf

This is not the latest submitted version.

Submission summary

As Contributors: Deepak Kar · Sukanya Sinha
Arxiv Link: (pdf)
Date submitted: 2022-05-10 08:15
Submitted by: Kar, Deepak
Submitted to: SciPost Physics
Academic field: Physics
  • High-Energy Physics - Phenomenology
Approach: Phenomenological


A maverick top partner model, decaying to a dark photon was suggested. The dark photon decays to two overlapping electrons for dark photon masses of $\approx 100$ GeV, and results in a so-called lepton-jet. The event includes a top quark as well, which results in events with two boosted objects, one heavy and the other light. We propose a search strategy exploiting the unique signal topology. We show that for a set of kinematic selections, both in hadronic and leptonic decay channel of the SM top quark, almost all background can be eliminated, leaving enough signal events up to top partner mass of about 3 TeV for the search to be viable at the LHC.

Current status:
Has been resubmitted

Author comments upon resubmission

We thanks the referee for their careful review of the paper, and we have addressed all the comments in this new draft. A detailed point by point response is posted as well.

List of changes

* Expanded the theory section with details of the model, parameter choices and references
* Added a projected sensitivity study for the proposed search
* Clarified the analysis section with specific labels for different types of jets used
* Fixed typos, a few of which caused confusion

Reports on this Submission

Anonymous Report 1 on 2022-6-20 (Invited Report)


The authors have completed a thorough collider study of an interesting signal.


Minor typos/language.


The authors have addressed all my concerns. The manuscript is much clearer, and the authors make a strong case that this is an interesting signal to look at.

After addressing my minor requested changes below, the paper is ready to be published.

Requested changes

1. In the Introduction the authors state "This leads to the conjecture of the existence of a new gauge boson that would mediate this dark force, analogous to the role of the photon in Quantum Electrodynamics. For this reason, the new gauge boson is referred to in literature as the dark photon..." However, I believe the dark photon is referred to as a dark photon because its leading interactions in the small mixing limit is the QED current. There are other models with U(1) dark sector forces called "Dark-Zs" because they can interact with the weak neutral current as well. For example see arXiv:1203.2947.

2. In the third paragraph on page 10 there's a statement "highest invariant pT" Do the authors mean just pT?

3. In Fig. 6, the wording on before and after m/pT cuts and the placement of "(right)" are a little confusing.

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

Author:  Deepak Kar  on 2022-06-22  [id 2600]

(in reply to Report 1 on 2022-06-20)

Dear referee,

Thank you for your follow up. We have included your suggestion for the introduction text, fixed the caption in Fig 6, and just used pair pT to avoid confusion in the new version.

Deepak for the authors

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