scholarly journals Single-top final states as a probe of top-flavoured dark matter models at the LHC

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Monika Blanke ◽  
Priscilla Pani ◽  
Giacomo Polesello ◽  
Giulia Rovelli
Keyword(s):  
Dark Matter ◽  
Top Quark ◽  
Direct Detection ◽  
Final States ◽  
High Luminosity ◽  
Minimal Flavour Violation ◽  
Single Top ◽  
Discovery Potential ◽  
Flavour Violation ◽  
Flavour Physics

Abstract Models incorporating flavoured dark matter provide an elegant solution to the dark matter problem, evading the tight LHC and direct direction constraints on simple WIMP models. In Dark Minimal Flavour Violation, a simple framework of flavoured dark matter with new sources of flavour violation, the constraints from thermal freeze-out, direct detection experiments, and flavour physics create well-defined benchmark scenarios for these models. We study the LHC phenomenology of four such scenarios, focusing on final states where a single top quark is produced accompanied by no jets, one jet from the fragmentation of light quarks or a b-tagged jet. For each of these signatures we develop a realistic LHC analysis, and we show that the proposed analyses would increase the parameter space coverage for the four benchmarks, compared to existing flavour-conserving LHC analyses. Finally we show the projected discovery potential of the considered signatures for the full LHC statistics at 14 TeV, and for the High Luminosity LHC.

scholarly journals Searching for heavy Higgs in supersymmetric final states at the LHC

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Amit Adhikary ◽  
Biplob Bhattacherjee ◽  
Rohini M. Godbole ◽  
Najimuddin Khan ◽  
Suchita Kulkarni
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Higgs Sector ◽  
Search Strategies ◽  
Final States ◽  
High Luminosity ◽  
The Standard Model ◽  
Extended Higgs Sector ◽  
Flavour Physics

Abstract In this work, we analyse and demonstrate possible strategies to explore extended Higgs sector of the Minimal Supersymmetric Standard Model (MSSM). In particular we concentrate on heavy Higgs decays to electroweakinos. We analyse the Higgs to electroweakino decays in the allowed MSSM parameter space after taking into account 13 TeV LHC searches for supersymmetric particles and phenomenological constraints such as flavour physics, Higgs measurements and dark matter constraints. We explore some novel aspects of these Higgs decays. The final states resulting from Higgs to electroweakino decays will have backgrounds arising from the Standard Model as well as direct electroweakino production at the LHC. We demonstrate explicit kinematical differences between Higgs to electroweakino decays and associated backgrounds. Furthermore, we demonstrate for a few specific example points, optimised analysis search strategies at the high luminosity LHC (HL-LHC) run. Finally, we comment on possible search strategies for heavy Higgs decays to exotic final states, where the lightest chargino is long lived and leads to a disappearing track at the LHC.

scholarly journals Direct detection and CMB constraints on the light dark matter scenario of top quark asymmetry and dijet excess at the Tevatron

2011 ◽  
Vol 84 (3) ◽  
Author(s):  
Andi Hektor ◽  
Gert Hütsi ◽  
Mario Kadastik ◽  
Kristjan Kannike ◽  
Martti Raidal ◽  
...  
Keyword(s):  
Dark Matter ◽  
Top Quark ◽  
Direct Detection

scholarly journals Search for new phenomena with top quark pairs in final states with one lepton, jets, and missing transverse momentum in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Dark Matter ◽  
Transverse Momentum ◽  
Top Quark ◽  
Dark Matter Particle ◽  
Atlas Detector ◽  
Final States ◽  
Quark Pairs ◽  
Missing Transverse Momentum ◽  
Neutralino Mass ◽  
New Phenomena

Abstract A search for new phenomena with top quark pairs in final states with one isolated electron or muon, multiple jets, and large missing transverse momentum is performed. Signal regions are designed to search for two-, three-, and four-body decays of the directly pair-produced supersymmetric partner of the top quark (stop). Additional signal regions are designed specifically to search for spin-0 mediators that are produced in association with a pair of top quarks and decay into a pair of dark-matter particles. The search is performed using the Large Hadron Collider proton-proton collision dataset at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV recorded by the ATLAS detector from 2015 to 2018, corresponding to an integrated luminosity of 139 fb−1. No significant excess above the Standard Model background is observed, and limits at 95% confidence level are set in the stop-neutralino mass plane and as a function of the mediator mass or the dark-matter particle mass. Stops are excluded up to 1200 GeV (710 GeV) in the two-body (three-body) decay scenario. In the four-body scenario stops up to 640 GeV are excluded for a stop-neutralino mass difference of 60 GeV. Scalar and pseudoscalar dark-matter mediators are excluded up to 200 GeV when the coupling strengths of the mediator to Standard Model and dark-matter particles are both equal to one and when the mass of the dark-matter particle is 1 GeV.

scholarly journals Constraints on coloured scalars from global fits

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Otto Eberhardt ◽  
Víctor Miralles ◽  
Antonio Pich
Keyword(s):  
Top Quark ◽  
Scalar Potential ◽  
Higgs Doublet ◽  
Model Parameters ◽  
Simple Extension ◽  
Minimal Flavour Violation ◽  
Yukawa Couplings ◽  
Flavour Violation ◽  
The One ◽  
Potential Parameters

Abstract We consider a simple extension of the electroweak theory, incorporating one SU(2)L doublet of colour-octet scalars with Yukawa couplings satisfying the principle of minimal flavour violation. Using the HEPfit package, we perform a global fit to the available data, including all relevant theoretical constraints, and extract the current bounds on the model parameters. Coloured scalars with masses below 1.05 TeV are already excluded, provided they are not fermiophobic. The mass splittings among the different (charged and CP-even and CP-odd neutral) scalars are restricted to be smaller than 20 GeV. Moreover, for scalar masses smaller than 1.5 TeV, the Yukawa coupling of the coloured scalar multiplet to the top quark cannot exceed the one of the SM Higgs doublet by more than 80%. These conclusions are quite generic and apply in more general frameworks (without fine tunings). The theoretical requirements of perturbative unitarity and vacuum stability enforce relevant constraints on the quartic scalar potential parameters that are not yet experimentally tested.

scholarly journals Dark matter within the minimal flavour violation ansatz

2013 ◽  
Vol 722 (1-3) ◽  
pp. 135-143 ◽  
Author(s):  
Laura Lopez-Honorez ◽  
Luca Merlo
Keyword(s):  
Dark Matter ◽  
Minimal Flavour Violation ◽  
Flavour Violation

scholarly journals A relatively light, highly bino-like dark matter in the Z3-symmetric NMSSM and recent LHC searches

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Waleed Abdallah ◽  
AseshKrishna Datta ◽  
Subhojit Roy
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Top Quark ◽  
Direct Detection ◽  
Mass Parameter ◽  
Supersymmetric Particle ◽  
Detection Rates ◽  
Realistic Situation

Abstract A highly bino-like Dark Matter (DM), which is the Lightest Supersymmetric Particle (LSP), could be motivated by the stringent upper bounds on the DM direct detection rates. This is especially so when its mass is around or below 100 GeV for which such a bound tends to get most severe. Requiring not so large a higgsino mass parameter, that would render the scenario reasonably ‘natural’, prompts such a bino-like state to be relatively light. In the Minimal Supersymmetric Standard Model (MSSM), in the absence of comparably light scalars, such an excitation, if it has to be a thermal relic, is unable to meet the stringent experimental upper bound on its abundance unless its self-annihilation hits a funnel involving either the Z-boson or the Standard Model (SM)-like Higgs boson. We demonstrate that, in such a realistic situation, a highly bino-like DM of the popular Z3-symmetric Next-to-Minimal Supersymmetric Standard Model (NMSSM) is viable over an extended range of its mass, from our targeted maximum in the vicinity of the mass of the top quark down to about 30 GeV. This is facilitated by the presence of comparably light singlet-like states that could serve as funnel (scalars) and/or coannihilating (singlino) states even as the bino-like LSP receives a minimal (but optimal) tempering triggered by suitably light higgsino states that, in the first place, evade stringent lower bounds on their masses that can be derived from the Large Hadron Collider (LHC) experiments only in the presence of a lighter singlino-like state. An involved set of blind spot conditions is derived for the DM direct detection rates by considering for the very first time the augmented system of neutralinos comprising of the bino, the higgsinos and the singlino which highlights the important roles played by the NMSSM parameters ‘λ’ and tan β in delivering a richer phenomenology.

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