38 research outputs found
Natural SUSY at LHC with Right-Sneutrino LSP
We study an extension of the minimal supersymmetric standard model (MSSM)
with additional right-handed singlet neutrino superfields. While such an
extension incorporates a mechanism for the neutrino mass, it also opens up the
possibility of having the right-sneutrinos () as the lightest
supersymmetric particle (LSP). In this work, we focus on the the viability of
rather small ( GeV) higgsino mass parameter (), an important
ingredient for "naturalness", in the presence of such a LSP. For simplicity, we
assume that the bino and wino mass parameters are much heavier, thus we only
consider (almost) pure and compressed higgsino-like states, with small
gaugino admixture. Considering only prompt decays of the
higgino-like states, especially the lightest chargino, we discuss the
importance of leptonic channels consisting of up to two leptons with large
missing transverse energy to probe this scenario at the Large Hadron Collider
(LHC). Further, we emphasize on how the gaugino mass parameters, although very
heavy, affects the decay of the low-lying higgsino-like states, thus
significantly affecting the proposed signatures at LHC.Comment: matches published versio
Search for a compressed supersymmetric spectrum with a light Gravitino
Presence of the light gravitino as dark matter candidate in a supersymmetric
(SUSY) model opens up interesting collider signatures consisting of one or more
hard photons together with multiple jets and missing transverse energy from the
cascade decay. We investigate such signals at the 13 TeV LHC in presence of
compressed SUSY spectra, consistent with the Higgs mass as well as collider and
dark matter constraints. We analyse and compare the discovery potential in
different benchmark scenarios consisting of both compressed and uncompressed
SUSY spectra, considering different levels of compression and intermediate
decay modes. Our conclusion is that compressed spectra upto 2.5 TeV are likely
to be probed even before the high luminosity run of LHC. Kinematic variables
are also suggested, which offer distinction between compressed and uncompressed
spectra yielding similar event rates for photons + multi-jets + .Comment: 32 pages, 7 figures, 4 tables. Published in JHEP, minor modifications
in text and few references adde
Inflation and Higgs Phenomenology in a Model Unifying the DFSZ Axion with the Majoron
The Two-Higgs-Doublet-Standard Model-Axion-Seesaw-Higgs-Portal inflation
(2hdSMASH) model consisting of two Higgs doublets, a Standard Model (SM)
singlet complex scalar and three SM singlet right-handed neutrinos can embed
axion dark matter, neutrino masses and address inflation. We report on an
investigation of the inflationary aspects of 2hdSMASH and its subsequent impact
on low energy phenomenology. In particular, we identify inflationary directions
for which the parameter values required for successful inflation do not violate
perturbative unitarity and boundedness-from-below conditions. By analyzing the
renormalization-group flow of the parameters we identify the necessary and
sufficient constraints for running all parameters perturbatively and
maintaining stability from the electroweak to the PLANCK scale. We determine
typical benchmark points satisfying theoretical and experimental constraints
which can be potentially probed by future colliders.Comment: 71 pages, 18 figures, 7 table
Natural anomaly-mediation from the landscape with implications for LHC SUSY searches
Supersymmetric models with the anomaly-mediated SUSY breaking (AMSB) arose in
two different settings: 1. extra-dimensional models where SUSY breaking
occurred in a sequestered sector and 2. 4-d models with dynamical SUSY breaking
in a hidden sector where scalars gain masses of order the gravitino mass
m_{3/2} but with gauginos and trilinear soft terms of the AMSB form. Both have
run into serious conflicts with 1. LHC sparticle and Higgs mass constraints, 2.
constraints from wino-like WIMP dark matter searches and 3. bounds from
naturalness. These conflicts may be avoided by introducing minor changes to the
underlying phenomenological models consisting of non-universal bulk scalar
Higgs masses and A-terms, providing a setting for {\it natural
anomaly-mediation} (nAMSB). In nAMSB, the wino is still expected to be the
lightest of the gauginos, but the higgsinos are expected to be the lightest
electroweakinos (EWinos) in accord with naturalness. We examine what sort of
spectra are expected to emerge when nAMSB arises from a string landscape
setting. We explore the LHC phenomenology of nAMSB models via higgsino pair
production and wino pair production. We characterize the dominant LHC
signatures arising from the remaining patch of parameter space which should be
fully testable at high-luminosity LHC via EWino pair production searches.Comment: 37 pages with 27 .png figure
Dark Matter Phenomenology in 2HDMS
The constituents of dark matter are still an unresolved puzzle. Several
Beyond Standard Model (BSM) Physics offer suitable candidates. In this study
here we consider the Two Higgs Doublet model augmented with a
complex scalar singlet (2HDMS) and focus on the dark matter phenomenology
of 2HDMS with the complex scalar singlet as the dark matter candidate.
The parameter space allowed from existing experimental
constraints from dark matter, flavour physics and collider searches has been
studied.
The discovery potential for such a 2HDMS at HL-LHC and at future
colliders has been worked out.Comment: 5 pages, 2 figures, Proceedings of '14th International Conference on
Identification of Dark Matter (IDM2022)
Dark matter phenomenology in Z'2 broken singlet extended 2HDM
Many different approaches have been made to explain the nature of dark matter
(DM), but it remains and unsolved mystery of our universe. In this work we
examine a type II two-Higgs-doublet model extended by a complex singlet
(2HDMS), where the pseudo-scalar component of the singlet acts as a natural DM
candidate. The DM candidate is stabilized by a Z'2 symmetry, which is broken
spontaneously by the singlet acquiring a vacuum expectation value (vev). This
vev in turn causes the scalar component of the singlet to mix with the scalar
components of the two doublets, which results in three scalar Higgs particles.
Additionally we aim to include an excess around 95 GeV, which was observed at
CSM and LEP and can be explained by one of the three scalar Higgs particles.
After introducing the model, we apply experimental and theoretical constraints
and find a viable benchmark point. We then look into the DM phenomenology as
well as collider phenomenology.Comment: 9 pages, 2 figures, 1 tabl