SciPost Submission Page
Dark Matter in Anomaly-Free Gauge Extensions
by Martin Bauer, Sascha Diefenbacher, Tilman Plehn, Michael Russell, Daniel A. Camargo
This is not the latest submitted version.
Submission summary
| Authors (as registered SciPost users): | Martin Bauer · Sascha Diefenbacher · Tilman Plehn |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/1805.01904v2 (pdf) |
| Date submitted: | May 29, 2018, 2 a.m. |
| Submitted by: | Martin Bauer |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
A consistent model for vector mediators to dark matter needs to be anomaly-free and include a scalar mode from mass generation. For the leading U(1) extensions we review the structure and constraints, including kinetic mixing at loop level. The thermal relic density suggests that the vector and scalar masses are similar. For the LHC we combine a $Z'$ shape analysis with mono-jets. For the latter, we find that a shape analysis offers significant improvement over existing cut-and-count approaches. Direct detection limits strongly constrain the kinetic mixing angle and we propose a $\ell^+\ell^- E_T$ search strategy based on the scalar mediator.
Current status:
Reports on this Submission
Report #2 by Anonymous (Referee 2) on 2018-7-5 (Invited Report)
- Cite as: Anonymous, Report on arXiv:1805.01904v2, delivered 2018-07-05, doi: 10.21468/SciPost.Report.527
Strengths
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The main topic of the paper (dark matter in gauge extended models) is interesting.
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The discussion of the mono-jet shape analysis (and its comparison with the cut and count analysis) and of the possibility to establish the link between a $Z^\prime$ and dark matter (even in the presence of $Z^\prime$ decays to invisible neutrinos) is novel and interesting.
Weaknesses
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The discussion of the several bounds (Secs. 4, 5) is not particularly novel and it mainly summarizes many results already reported in the literature.
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The presentation of the $U(1)_{B-L}$ model is rather misleading: the authors drop this model after an initial short discussion.
Report
Requested changes
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The presentation would improve if the authors shorten a bit the discussion of the models in Secs. 2,3 and of the bounds in Secs. 4,5 since these sections are not particularly novel.
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At the end of Sec.4, the authors should change the discussion of the LHC $Z\to4\mu$ bound. As shown in their Ref. 34 (1406.2332) and Ref. 19 (1511.04107), as well as in the corresponding CMS analysis http://inspirehep.net/record/1676064/files/EXO-18-008-pas.pdf the $Z\to4\mu$ search can be more powerful than the trident bound in certain regions of parameter space.
Report #1 by Anonymous (Referee 1) on 2018-6-28 (Invited Report)
- Cite as: Anonymous, Report on arXiv:1805.01904v2, delivered 2018-06-28, doi: 10.21468/SciPost.Report.517
Strengths
Weaknesses
There are a few minor weaknesses in the presentation of the results and I invite the authors to address these issues.
1-The information density of the paper at hand is quite high (which of course is not necessarily a weaknesses, see above), however the readability of the paper would strongly profit moving some of the detailed derivations to appendices. I invite the authors to implement such changes, as detailed below.
2- The Introduction is partly hard to comprehend. For example I do not understand the relevance of the abrupt sentence "Even if we model our dark matter candidate after the supersymmetric neutralino..."
3- The paper introduces three U(1) models, however very early on in the discussion of relevant limits, one of them turns out to be basically excluded (the B-L model) and the authors state: "This is why at this stage we will drop the U(1)B−L gauge group (and any other group with gauged electrons) from our analysis.". Still, later on again constraints for the B-L are discussed.
4- I do not understand how the program MATRIX is used in the analysis at hand. The authors state: "We compute the Z′ production cross section with MadGraph5 [43], accounting for higher order corrections using Matrix ". To the best of my knowledge the MATRIX Monte Carlo does not provide predictions in any Z' model.
5- There are several typos in the manuscript, starting from the very first sentence: "The nature of dark matter is one the great mysteries", amongst others also including "This setup is by trivially free of anomalies" on page 4 and "the the" on page 15, "gauge bosons the LHC production cross section" on page 17.
Report
Requested changes
Following the listed weaknesses above I suggest to
1- Streamline Indoduction
2- Move detailed derivations to appendices, in particular from Section 2.
3- Sections 2 & 3 should be merged, they both discuss the phenomenology and motivation for the three models.
4- Already in this new Section 2 (see above) it should be mentioned that the B-L is basically excluded. In fact I don't necessarily see the point this model is discussed in great detail including several Figures.
5- The use of the code MATRIX should be clarified.
6- At the beginning of Section 6 the authors state: "We follow two strategies to establish the Z′ as a dark matter mediator: a profile analysis of the di-lepton mass peak [63] and a combination with the mono-jet signal." In fact there is a third signatures being discussed in Section 6.3.
7- The authors should state clearly that a realistic uncertainty estimate of the proposed shape analysis is highly non-trivially due to the nature how the monojet backgrounds are constrained.
8- Fix typos