scholarly journals Dark matter production in association with a single top-quark at the LHC in a two-Higgs-doublet model with a pseudoscalar mediator

2018 ◽  
Vol 21 ◽  
pp. 8-15 ◽  
Author(s):  
Priscilla Pani ◽  
Giacomo Polesello
2021 ◽  
Vol 81 (10) ◽  
Author(s):  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
K. Abeling ◽  
...  

AbstractThis paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a, which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at $$\sqrt{s} = 13$$ s = 13  TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 $$\hbox {fb}^{-1}$$ fb - 1 . No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered.


2007 ◽  
Vol 22 (25n28) ◽  
pp. 2121-2129 ◽  
Author(s):  
XIAO-GANG HE ◽  
HO-CHIN TSAI ◽  
TONG LI ◽  
XUE-QIAN LI

We study possible observational effects of scalar dark matter, the darkon D, in Higgs h and top quark t decay processes, h → DD and t → cDD in the minimal Standard Model (SM) and its two Higgs doublet model (THDM) extension supplemented with a SM singlet darkon scalar field D. We find that the darkon D can have a mass in the range of sub-GeV to several tens of GeV, interesting for LHC and ILC colliders, to produce the required dark matter relic density. In the SM with a darkon, t → cDD only occurs at loop level giving a very small rate, while the rate for Higgs decay h → DD can be large. In THDM III with a darkon, where tree level flavor changing neutral current (FCNC) interaction exists, a sizable rate for t → cDD is also possible.


2018 ◽  
Vol 98 (3) ◽  
Author(s):  
Lei Wang ◽  
Rongle Shi ◽  
Xiao-Fang Han ◽  
Bin Zhu

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Daniel Dercks ◽  
Tania Robens

AbstractIn this work, we use a recast of the Run II search for invisible Higgs decays within Vector Boson Fusion to constrain the parameter space of the Inert Doublet model, a two Higgs doublet model with a dark matter candidate. When including all known theoretical as well as collider constraints, we find that the above can rule out a relatively large part in the $$m_H,\,\lambda _{345}$$mH,λ345 parameter space, for dark scalar masses $$m_H\,\le \,100\,{\mathrm{GeV}}$$mH≤100GeV. Including the latest dark matter constraints, a smaller part of parameter space remains which is solely excluded from the above analysis. We also discuss the sensitivity of monojet searches and multilepton final states from Run II.


2008 ◽  
Vol 23 (32) ◽  
pp. 5159-5172 ◽  
Author(s):  
RENATA JORA ◽  
SHERIF MOUSSA ◽  
SALAH NASRI ◽  
JOSEPH SCHECHTER ◽  
M. NAEEM SHAHID

We study a simple two-Higgs doublet model which reflects, in a phenomenological way, the idea of compositeness for the Higgs sector. It is relatively predictive. In one scenario, it allows for a "hidden" usual Higgs particle in the 100 GeV region and a possible dark matter candidate.


1995 ◽  
Vol 10 (12) ◽  
pp. 967-972 ◽  
Author(s):  
GYE T. PARK

Concentrating on the impact of the very recent top quark discovery, we perform a combined analysis of two strongest constraints on the two-Higgs doublet model, one coming from the recent measurement by CLEO on the inclusive branching ratio of b→sγ decay and the other from the recent LEP data on [Formula: see text] decay. We have included the model predictions for one-loop vertex corrections to [Formula: see text] through εb. We find that the εb constraint excludes most of the less appealing window: tan β≲1 at 95% C.L. for the measured top mass mt=176±8±10 GeV from CDF. Moreover, it excludes tan β≲2 at 95% C.L. for mt≳176 GeV; combined with the b→sγ constraint, only very heavy charged Higgs (≳670 GeV) is allowed by the measured mt from CDF.


2011 ◽  
Vol 26 (25) ◽  
pp. 1869-1879 ◽  
Author(s):  
H. CARDENAS ◽  
J. DUARTE ◽  
J. ALEXIS RODRIGUEZ

The D0 experiment has reported a direct search for a charged Higgs boson produced by [Formula: see text] annihilation and decaying to [Formula: see text] final state, in the 180≤MH+≤300 GeV mass range. The analysis has led to upper limits on the production cross-section in the framework of the two-Higgs doublet model types I, II and III. We compare the predictions of two different scenarios in the framework of the two-Higgs doublet type III to the cross-section limits reported by D0 collaboration, and we obtain constraints on the charged Higgs mass, for the case when the charged Higgs mass is bigger than the top quark mass. Also, searches for the charged Higgs boson with a mass smaller than top quark mass are considered, we discuss the possible limits on the charged Higgs boson mass obtained from measurements of the ratio [Formula: see text] within the two-Higgs doublet model type III.


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