scholarly journals Electroweak phase transitions with BSM fermions

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Martin Gabelmann ◽  
M. Margarete Mühlleitner ◽  
Jonas Müller
Keyword(s):  
Standard Model ◽  
Degrees Of Freedom ◽  
Higgs Doublet ◽  
Beyond The Standard Model ◽  
Electroweak Phase Transition ◽  
The Standard Model ◽  
Light Scalar ◽  
Doublet Model ◽  
Split Supersymmetry ◽  
The Impact

Abstract We study the impact of additional beyond-the-Standard Model (BSM) fermions, charged under the Standard Model (SM) SU(2)L ⊗ U(1)Y gauge group, on the electroweak phase transition (EWPT) in a 2-Higgs-Doublet-Model (2HDM) of type II. We find that the strength of the EWPT can be enhanced by about 40% compared to the default 2HDM. Therefore, additional light fermions are a useful tool to weaken the tension between increasing mass constraints on BSM scalars and the requirement of additional light scalar degrees of freedom to accommodate a strong first order EWPT. The findings are of particular interest for a variety of (non-minimal) split supersymmetry scenarios which necessarily introduce additional light fermion degrees of freedom.

ONE LOOP-INDUCED WZH COUPLING IN THE TWO HIGGS DOUBLET MODEL

1989 ◽  
Vol 04 (28) ◽  
pp. 2757-2766 ◽  
Author(s):  
THOMAS G. RIZZO
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Tree Level ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Charged Higgs ◽  
Doublet Model ◽  
The One ◽  
Two Higgs Doublet Model

Although absent at the tree level in models with only doublet and singlet Higgs representations, the WZH coupling can be induced at the one-loop level. We examine the size of this induced coupling in the two Higgs doublet model due to fermion as well as Higgs/gauge boson loops. Such couplings could provide a new mechanism for charged Higgs production at colliders and are ‘backgrounds’ to new physics beyond the Standard Model. We find, however, that these couplings are very weak for all regions of the parameter space explored.

scholarly journals Higgs searches beyond the Standard Model

2014 ◽  
Vol 31 ◽  
pp. 1460288 ◽  
Author(s):  
R. Mankel ◽  
Keyword(s):  
Standard Model ◽  
Higgs Sector ◽  
Higgs Doublet ◽  
Higgs Bosons ◽  
Supersymmetric Model ◽  
Beyond The Standard Model ◽  
Model Interpretation ◽  
The Standard Model ◽  
Extended Higgs Sectors ◽  
Minimal Supersymmetric Model

While the existence of a Higgs boson with a mass near 125 GeV has been clearly established, the detailed structure of the entire Higgs sector is yet unclear. Besides the Standard Model interpretation, various possibilities for extended Higgs sectors are being considered. The minimal supersymmetric extension (MSSM) features two Higgs doublets resulting in five physical Higgs bosons, which are subject to direct searches. Alternatively, more generic Two-Higgs Doublet models (2HDM) are used for the interpretation of results. The Next-to-Minimal Supersymmetric Model (NMSSM) has a more complex Higgs sector with seven physical states. Also exotic Higgs bosons decaying to invisible final states are considered. This article summarizes recent findings based on results from collider experiments.

scholarly journals Constraining extended scalar sectors at the LHC and beyond

2018 ◽  
Vol 33 (10n11) ◽  
pp. 1830007 ◽  
Author(s):  
Agnieszka Ilnicka ◽  
Tania Robens ◽  
Tim Stefaniak
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Standard Model ◽  
Parameter Space ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Doublet Model ◽  
Inert Doublet Model ◽  
Scalar Sector ◽  
Scalar Singlet

We give a brief overview of beyond the Standard Model (BSM) theories with an extended scalar sector and their phenomenological status in the light of recent experimental results. We discuss the relevant theoretical and experimental constraints, and show their impact on the allowed parameter space of two specific models: the real scalar singlet extension of the Standard Model (SM) and the Inert Doublet Model. We emphasize the importance of the LHC measurements, both the direct searches for additional scalar bosons, as well as the precise measurements of properties of the Higgs boson of mass 125 GeV. We show the complementarity of these measurements to electroweak and dark matter observables.

scholarly journals The dark phases of the N2HDM

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Isabell Engeln ◽  
Pedro Ferreira ◽  
M. Margarete Mühlleitner ◽  
Rui Santos ◽  
Jonas Wittbrodt
Keyword(s):  
Dark Matter ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Hadron Collider ◽  
Higgs Doublet ◽  
Tree Level ◽  
Vacuum Structure ◽  
The Standard Model ◽  
Doublet Model ◽  
Specific Phase

Abstract We discuss the dark phases of the Next-to-2-Higgs Doublet model. The model is an extension of the Standard Model with an extra doublet and an extra singlet that has four distinct CP-conserving phases, three of which provide dark matter candidates. We discuss in detail the vacuum structure of the different phases and the issue of stability at tree-level of each phase. Taking into account the most relevant experimental and theoretical constraints, we found that there are combinations of measurements at the Large Hadron Collider that could single out a specific phase. The measurement of h125 → γγ together with the discovery of a new scalar with specific rates to τ+τ− or γγ could exclude some phases and point to a specific phase.

scholarly journals Detailed study of the Λb → Λcτν̄τ decay

2018 ◽  
Vol 33 (29) ◽  
pp. 1850169 ◽  
Author(s):  
E. Di Salvo ◽  
F. Fontanelli ◽  
Z. J. Ajaltouni
Keyword(s):  
Standard Model ◽  
Semileptonic Decay ◽  
Form Factors ◽  
Higgs Doublet ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Left Handed ◽  
The Standard Model ◽  
Analogous Formula ◽  
Two Higgs Doublet Model

We examine in detail the semileptonic decay [Formula: see text], which may confirm previous hints, from the analogous [Formula: see text] decay, of a new physics beyond the Standard Model. First of all, starting from rather general assumptions, we predict the partial width of the decay. Then we analyze the effects of five possible new physics interactions, adopting in each case five different form factors. In particular, for each term beyond the Standard Model, we find some constraints on the strength and phase of the coupling, which we combine with those found by other authors in analyzing the analogous semileptonic decays of [Formula: see text]. Our analysis involves some dimensionless quantities, substantially independent of the form factor, but which, owing to the constraints, turn out to be strongly sensitive to the kind of nonstandard interaction. We also introduce a criterion thanks to which one can discriminate among the various new physics terms: the left-handed current and the two-Higgs-doublet model appear privileged, with a neat preference for the former interaction. Finally, we suggest a differential observable that could, in principle, help to distinguish between the two cases.

Implementation of the CMS-EXO-19-002 search in the MadAnalysis 5 framework (physics beyond the Standard Model with multilepton final states; 137 fb−1)

2021 ◽  
Vol 36 (01) ◽  
pp. 2141012
Author(s):  
Eric Conte ◽  
Robin Ducrocq
Keyword(s):  
Standard Model ◽  
Beyond The Standard Model ◽  
Final States ◽  
Text Data ◽  
Proton Proton ◽  
Original Analysis ◽  
The Standard Model ◽  
Light Scalar ◽  
Charged Leptons ◽  
Proton Proton Collisions

In this paper, we present the MadAnalysis 5 implementation of the CMS-EXO-19-002 analysis, probing an excess of events featuring multiple charged leptons in LHC proton–proton collisions at [Formula: see text]. The original analysis is based on data acquired by the CMS detector during the 2016–2018 campaign, which corresponds to an integrated luminosity of 137 fb[Formula: see text]. Data have been tested against hypothetical extensions of the Standard Model where additional leptons can stem from new heavy fermion decays or from new light scalar/pseudoscalar decays. The CMS selection has been fully implemented in the MadAnalysis 5 platform and successfully validated by reproducing official results in the form of signal distributions at the end of the selection.

scholarly journals Higgs searches beyond the Standard Model

2014 ◽  
Vol 29 (24) ◽  
pp. 1430057
Author(s):  
R. Mankel ◽  
Keyword(s):  
Standard Model ◽  
Higgs Sector ◽  
Higgs Doublet ◽  
Higgs Bosons ◽  
Supersymmetric Model ◽  
Beyond The Standard Model ◽  
Model Interpretation ◽  
The Standard Model ◽  
Extended Higgs Sectors ◽  
Minimal Supersymmetric Model

While the existence of a Higgs boson with a mass near 125 GeV has been clearly established, the detailed structure of the entire Higgs sector is yet unclear. Besides the Standard Model interpretation, various possibilities for extended Higgs sectors are being considered. The minimal supersymmetric extension (MSSM) features two Higgs doublets resulting in five physical Higgs bosons, which are subject to direct searches. Alternatively, more generic Two-Higgs Doublet models (2HDM) are used for the interpretation of results. The Next-to-Minimal Supersymmetric Model (NMSSM) has a more complex Higgs sector with seven physical states. Also exotic Higgs bosons decaying to invisible final states are considered. This article summarizes recent findings based on results from collider experiments.

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