20 research outputs found
Scale-Invariant Two Component Dark Matter
We study a scale invariant extension of the standard model which can explain
simultaneously dark matter and the hierarchy problem. In our set-up, we
introduce a scalar and a spinor as two-component dark matter in addition to
scalon field as a mediator. Interesting point about our model is that due to
scale invariant conditions, compared to other two-component dark matter models,
it has lower independent parameters. Possible astrophysical and laboratory
signatures of two-component dark matter candidate are explored and it is shown
that the most contribution of observed relic density of dark matter can be
determined by spinor dark matter. Detectability of these dark matter particles
is studied and the direct and invisible Higgs decay experiments are used to
rule out part of the parameter space of the model. In addition, the dark matter
self-interactions are considered and shown that their contribution saturate
this constraint in the resonant regions.Comment: 22 pages, 14 figure
Conformal vector dark matter and strongly first-order electroweak phase transition
We study a conformal version of the Standard Model (SM), which apart from SM
sector, containing a dark sector with a vector dark matter
candidate and a scalar field (scalon). In this model the dark sector couples to
the SM sector via a Higgs portal. The theory is scale-invariant in lowest
order, therefore the spontaneous symmetry breaking of scale invariance entails
the existence of a scalar particle, scalon, with vanishing zeroth-order mass.
However, one-loop corrections break scale invariance, so they give mass to the
scalon. Because of the scale invariance, our model is subjected to constraints
which remove many of the free parameters. We put constraints to the two
remaining parameters from the Higgs searches at the LHC, dark matter relic
density and dark matter direct detection limits by PandaX-II. The viable mass
region for dark matter is about 1-2 TeV. We also obtain the finite temperature
one-loop effective potential of the model and demonstrate that finite
temperature effects, for the parameter space constrained by dark matter relic
density, induce a strongly first-order electroweak phase transition.Comment: 27 pages, 7 figures, a few clarifications added, references updated,
version published in JHE
Electron Electric Dipole Moment from Lepton Flavor Violation
The general Minimal Supersymmetric Standard Model introduces new sources for
Lepton Flavor Violation (LFV) as well as CP-violation. In this paper, we show
that when both sources are present, the electric dipole moment of the electron,
, receives a contribution from the phase of the trilinear -term of
staus, . For , the value of ,
depending on the ratios of the LFV mass elements, can range between zero and
three orders of magnitude above the present bound. We show that the present
bound on rules out a large portion of the CP-violating and the LFV
parameter space which is consistent with the bounds on the LFV rare decays.
We show that studying the correlation between and the P-odd asymmetry
in helps us to derive a more conclusive bound on
We also discuss the possibility of cancelation among the contributions of
different CP-violating phases to .Comment: 35 pages, 9 figure
Top pair Asymmetries at Hadron colliders with general couplings
Recently it has been shown that measurement of charge asymmetry of top pair
production at LHC excludes any flavor violating vector gauge boson that
could explain Tevatron forward-backward asymmetry (FBA). We consider the
general form of a gauge boson including left-handed, right-handed vector
and tensor couplings to examine FBA and charge asymmetry. To evaluate top pair
asymmetries at Tevatron and LHC, we consider mixing constraints on
flavor changing couplings and show that this model still explain
forward-backward asymmetry at Tevatron and charge asymmetry can not exclude it
in part of parameters space.Comment: 18 pages, 7 figure
The Impact of Kaluza-Klein Excited W Boson on the Single Top at LHC and Comparison with other Models
We study the s-channel single top quark production at the LHC in the context
of extra dimension theories, including the Kaluza-Klein (KK) decomposition. It
is shown that the presence of the first KK excitation of gauge boson can
reduce the total cross section of s-channel single top production considerably
if () for () in
proton-proton collisions. Then the results will be compared with the impacts of
other beyond Standard Model (SM) theories on the cross section of single top
s-channel. The possibility of distinguishing different models via their effects
on the production cross section of the s-channel is discussed.Comment: 23 pages,6 figure
Leptophilic vector dark matter and XENON1T electronic recoil excess
In light of the recently observed electronic recoil in the XENON1T experiment, we revisit the phenomenology of vector dark matter in leptophilic extension of the standard model while, new scalar, vector and spinor fields play the role of mediators. The viable parameter spaces are considered to discuss the possibility of light vector dark matter with mass 2.3 keV and sufficient dark matter relic density. We also study the constraints of the anomalous magnetic moment of the muon, baryon nucleon synthesis and indirect detection experiments on the parameter space of the models