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Dark matter and flavor anomalies with vector-like fermions and scalar leptoquark
by Shivaramakrishna Singirala , Suchismita Sahoo and Rukmani Mohanta
Submission summary
| Authors (as registered SciPost users): | Shivaramakrishna Singirala |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202111_00048v1 (pdf) |
| Date submitted: | 2021-11-23 19:22 |
| Submitted by: | Singirala, Shivaramakrishna |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | 16th International Workshop on Tau Lepton Physics (TAU2021) |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Phenomenological |
Abstract
We investigate vector-like fermionic dark matter and flavor anomalies in a simple extension of standard model, with doublet vector-like fermions of quark and lepton type and also a $S_1(\bar{\textbf{3}},\textbf{1},1/3)$ scalar leptoquark. An additional vector-like lepton singlet is included, whose admixture with vector-like lepton doublet plays the role of dark matter and is examined in relic density and direct detection perspective. We utilize the bounds from electroweak precision observables and also constrain the new couplings from the branching ratio and angular observables associated with $b \to sll (\nu_l \bar \nu_l)$, $b \to s \gamma$ decays.
Current status:
Reports on this Submission
Strengths
This paper considers a model to describe relic abundance, direct detection and flavor anomalies.
Weaknesses
A few unanswered questions listed in the report.
Report
The paper ``Dark matter and flavor anomalies with vector-like fermions and
scalar leptoquark'' by Singirala, Sahoo and Mohanta considers new vector-like quark and lepton doublets, lepton singlet and a scalar leptoquark to describe relic abundance, direct detection and flavor anomalies.
I have a few questions regarding the analysis and the model presented in the paper. I am listing them below.
(1) In order to explain the dark matter abundance, the authors use a mixture of the neutral component of the new lepton doublet and lepton singlet. Questions:
(i) in order to plot figure 1, what is the mass of s_1 (scalar leptoquark) the authors have assumed?
(ii) what are the LHC constraints in the parameter space where the authors are showing the direct detection constraints and the observed relic abundance?
The authors should explicitly show the constraints.
(2) The flavor diagrams involve the new particles. Questions:
(i) what are the masses of the particles used to draw figure 3?
(ii) what are the LHC constraints for the couplings and masses the authors used to satisfy the flavor anomalies and constraints in figure 2?
The authors should discuss and add contours of LHC allowed regions in the plot .
(3) Are the values of new couplings and masses used in figure 2 and figure 3 consistent when the authors explain the DM abundance and flavor anomalies constraints?
The authors should discuss it.
(4) Does this spectra of particles emerge from any unifying group scenario? What is the contribution of this model to g-2 of the muon?
The authors should comment.
Before I can recommend this paper for publication, the authors need to respond to these queries satisfactorily.
Requested changes
Mentioned in the report.
Report 1 by Peisi Huang on 2022-1-15 (Invited Report)
Report
In this proceeding, the authors address dark matter and the B-anomalies by extending the Standard Model (SM) with vector-like fermions, and a scalar leptoquark. With new fields assigned with odd $Z_2$ charges, the lightest state is a dark matter candidate. The authors constrain the parameter space by requiring the relic density is consistent with current observation, and the direct detection rates are within the current limit. Then, the authors discuss the possible explanations to B-anomalies using the vector-like fermions and the scalar leptoquark.
I have few questions to the authors,
1) I would expect contributions to muon g-2 from this scenario. How does the contributions to muon g-2 look like in the parameter space that is consistent with everything else?
2) In Fig 1, lower left panel, the authors choose specific values of yl and ylprime. How does the plot change when they go away from those values?
3) The authors never mentioned their choice of parameters for electron-leptoquark-quark couplings. Since it would be essential to $R_K^{(*)}$, and constraints from $B\rightarrow K^{(*)} e e$, I would recommend the authors clarify that part.
4) Few notations are not specified. For example, in Eq. (2), I understand those are the matrix element of the mass matrix, instead of the mass eigenvalues. It will be good clarify that to avoid confusion.