We analyze the dark matter problem in the context of supersymmetric U(1)_{B-L} model. In this model, the lightest neutalino can be the B-L gaugino widetilde {Z}_{B-L} or the extra Higgsinos widetilde{chi}_{1,2} dominated. We compute the thermal relic abundance of these particles and show that, unlike the LSP in MSSM, they can account for the observed relic abundance with no conflict with other phenomenological constraints. The prospects for their direct detection, if they are part of our galactic halo, are also discussed.
Recently, a claim of possible evidence for Dark Matter in data from the Fermi LAT experiment was made by Goodenough and Hooper [8]. We test the Dark Matter properties consistent with their claim in terms of the MSSM by a 24-dimensional parameter scan using nested sampling, excluding all but a very small region of the MSSM. Although this claim is very preliminary, and not made by the Fermi LAT experiment, our scan shows a possible approach for the analysis of future firm evidence from an indirect detection experiment, and its potential for heavily constraining models.
The addition of non-renormalizable terms involving the Higgs fields to the MSSM ameliorates the little hierarchy problem of the MSSM. For neutralino dark matter, new regions for which the relic abundance of the LSP is consistent with WMAP (as the bulk region and the stop coannihilation region) are now permitted. In this framework, we analyze in detail first the direct dark matter detection prospects in a XENON-like experiment; then we study the capability of detecting gamma-rays produced in the annihilation of neutralino LSPs in the FERMI satellite.
Three dark matter direct detection experiments, DAMA, COGENT and CRESST, have reported a possible signal of WIMP interaction corresponding to very light particles, close to the edge of the XENON 100 and CDMS sensitivity. Imposing the latest constraints from colliders, flavour physics, electroweak precision tests and direct and indirect dark matter searches, we show that viable MSSM scenarios with a light neutralino, in agreement with all the present data, are feasible. An analysis of the characteristics of the resulting scenarios will be presented.
In the MSSM, LSP dark matter could arise from the decay of B-balls rather than from thermal relics, with a quite different dependence on the MSSM parameters and a natural correlation with the baryon asymmetry. We discuss the constraints imposed on the properties of B-balls and the MSSM spectrum by experimental constraints and show that B-balls cannot form from an Affleck-Dine condensate with 100% efficiency in the absence of LSP annihilations after they decay. For likely formation efficiencies the LSP and slepton masses are typically constrained to be light. The effects of LSP annihilations af…
In the MSSM, the presence of CP phases can have a significant impact on the neutralino relic abundance. These phase effectsare on the one hand due to shifts in the masses, on the other hand due to modifications of the couplings. Typical variations in Omega h^2 solely from modifications in the couplings are of order 10%-100%.
In this note we briefly review the recent studies of dark matter in the MSSM and its singlet extensions: the NMSSM, the nMSSM, and the general singlet extension. Under the new detection results of CDMS II, XENON, CoGeNT and PAMELA, we find that (i) the latest detection results can exclude a large part of the parameter space which allowed by current collider constraints in these models. The future SuperCDMS and XENON can cover most of the allowed parameter space; (ii) the singlet sector will decouple from the MSSM-like sector in the NMSSM, however, singlet sector makes the nMSSM quite different…
We demonstrate that the recent measurement of the anomalous magnetic moment of the muon and dark matter can be simultaneously explained within the Minimal Supersymmetric Standard Model. Dark matter is a mostly-bino state, with the relic abundance obtained via co-annihilations with either the sleptons or wino. The most interesting regions of parameter space will be tested by the next generation of dark matter direct detection experiments.
We investigate the possibility that both dark matter and the long-standing discrepancy in the anomalous magnetic moment of the muon may be explained within the MSSM. In light of the stringent bounds from direct detection, we argue that the most promising viable scenarios have bino-like dark matter produced via either bino-wino or bino-slepton co-annihilation. We find that the combination of next-generation direct detection experiments and the LHC will be able to probe much of the interesting parameter space, however a future high-energy collider is needed to comprehensively explore this scenar…
With the latest Planck results the dark matter relic density is determined to an unprecedented precision. In order to reduce current theoretical uncertainties in the dark matter relic density prediction, we have calculated next-to-leading order SUSY-QCD corrections to neutralino (co)annihilation processes including Coulomb enhancement effects. We demonstrate that these corrections can have significant impact on the cosmologically favoured MSSM parameter space and are thus of general interest for parameter studies and global fits.
In the event that R-Parity conserving supersymmetry (SUSY) is discovered at the LHC, a key issue which will need to be addressed will be the consistency of that signal with astrophysical and non-accelerator constraints on SUSY Dark Matter. This issue is studied for the SPA benchmark model based on measurements of end-points and thresholds in the invariant mass spectra of various combinations of leptons and jets. These measurements are used to constrain the soft SUSY breaking parameters at the electroweak scale in a general MSSM model. Based on these constraints, we assess the accuracy with whi…
A thorough analysis of sneutrinos as dark matter candidates is performed, in different classes of supersymmetric models, as is typically done for the neutralino dark matter. First in the Minimal Supersymmetric Standard Model, sneutrinos are marginally compatible with existing experimental bounds, including direct detection, provided they compose a subdominant component of dark matter. Then supersymmetric models with the inclusion of right-handed fields and lepton number violating terms are presented. These models are perfectly viable: they predict sneutrinos which are compatible with the curre…
Using the latest PandaX limits on light dark matter (DM) with light mediator, we check the implication on the parameter space of the general singlet extension of MSSM (without $Z_3$ symmetry), which can have a sizable DM self-interaction to solve the small-scale structure problem. We find that the PandaX limits can stringently constrain such a paramter space, depending on the coupling $λ$ between the singlet and doublet Higgs fields. For the singlet extension of MSSM with $Z_3$ symmetry, the so-called NMSSM, we also demonstrate the PandaX constraints on its parameter space which gives a light …
In this talk we will discuss how inflation can be embedded within a minimal extension of the Standard Model where the inflaton carries the Standard Model charges. There is no need of an ad-hoc scalar field to be introduced in order to explain the temperature anisotropy of the cosmic microwave background radiation, all the ingredients are present within a minimal supersymmetric Standard Model. For the first time inflaton properties can be directly linked to the particle phenomenology, dark matter, and the baryons of the Standard Model.
We investigate the impact of TeV-scale matter belonging to complete vectorlike multiplets of unified groups on the lightest Higgs boson in the MSSM. We find that consistent with perturbative unification and electroweak precision data the mass m_h can be as large as 160 GeV. These extended MSSM models can also render the little hierarchy problem less severe, but only for lower values of m_h < 125 GeV. We present estimates for the sparticle mass spectrum in these models.
We consider regions of the parameter space of the Minimal Supersymmetric Standard Model (MSSM) with bino-like neutralino dark matter in which a large fraction of the total dark matter annihilation cross section in the present era arises from annihilation to final states with monoenergetic photons. The region of interest is characterized by light sleptons and heavy squarks. We find that it is possible for the branching fraction to final states with monoenergetic photons to be comparable to that for continuum photons, but in those cases the total cross section will be so small that it is unlikel…
We consider the Minimal Supersymmetric Standard Model (MSSM) with varying amounts of non-universality in the soft supersymmetry-breaking contributions to the Higgs scalar masses. In addition to the constrained MSSM (CMSSM) in which these are universal with the soft supersymmetry-breaking contributions to the squark and slepton masses at the input GUT scale, we consider scenarios in which both the Higgs masses are non-universal by the same amount (NUHM1), and scenarios in which they are independently non-universal (NUHM2). As the lightest neutralino is a dark matter candidate, we demand that th…
We examine the case of neutralino dark matter in the focus point region of the MSSM, in which the scalar sparticles are too heavy to be produced at the LHC. Whilst it has been previously asserted that the LHC alone would fail to constrain the properties of the lightest neutralino for such a scenario, we find that one can obtain good predictions of astrophysical quantities such as the relic density, annihilation cross-section and direct search cross-sections by using the shape of the dilepton invariant mass spectrum to constrain neutralino mixing. We demonstrate our technique using a Bayesian a…
Dark matter is examined within the ``golden region'' of the Minimal Supersymmetric Standard Model. This region satisfies experimental constraints, including a lower bound on the Higgs mass of 114 GeV, and minimizes fine-tuning of the Z boson mass. Here we impose additional constraints (particularly due to experimental bounds on $b\to s γ$). Then we find the properties of the Dark Matter in this region. Neutralinos with a relic density that provides the amount of dark matter required by cosmological data are shown to consist of a predominant gaugino (rather than higgsino) fraction. In addition,…
We study the complementarity between dark matter experiments (direct detection and indirect detections) and accelerator facilities (the CERN LHC and a $\sqrt{s}= 1$ TeV $e^+e^-$ Linear Collider) in the framework of the constrained Minimal Supersymmetric Standard Model (MSSM). We show how non--universality in the scalar and gaugino sectors can affect the experimental prospects to discover the supersymmetric particles. The future experiments will cover a large part of the parameter space of the MSSM favored by WMAP constraint on the relic density, but there still exist some regions beyond reach …
Positron excess upto energies $\sim$350 GeV has been observed by AMS-02 result and it is consistent with the positron excess observed by PAMELA upto 100 GeV. There is no observed excess of anti-protons over the expected CR background. We propose a leptophilic dark matter with an $U(1)_{L_μ-L_τ}$ gauge extension of MSSM. The dark matter is an admixture of the $L_μ-L_τ$ gaugino and fermionic partners of the extra $SU(2)$ singlet Higgs boson, which break the $L_μ-L_τ$ symmetry. We construct the SM$\otimes U(1)_{ L_μ-L_τ}$ SUSY model which provides the correct relic density of dark matter and is c…
We apply the perturbative grand unification due to renormalization to distinguish TeV-scale relics of supersymmetric $\rm{SO}(10)$ scenarios. With rational theoretical constraints taken into account, we find that for the breaking pattern of either $\rm{SU}(5)$ or Pati-Salam only extra matter $\mathbf{16}$ supermultiplet of $SO(10)$ can appear at TeV scale, apart from MSSM spectrum.
The standard model (SM) of particle physics is for the last three decades a very successful description of the properties and interactions of all known elementary particles. Currently, it is again probed with the first collisions at the Large Hadron Collider (LHC). It is widely expected that new physics will be detected at the LHC and the SM has to be extended. The most exhaustive analyzed extension of the SM is supersymmetry (SUSY). SUSY can not only solve intrinsic problems of the SM like the hierarchy problem, but it also postulates new particles which might explain the nature of dark matte…
The LEP experiments give a lower bound on the neutralino mass of about 46 GeV which, however, relies on a supersymmetric grand unification relation. Dropping this assumption, the experimental lower bound on the neutralino mass vanishes completely. Recent analyses suggest, however, that in the minimal supersymmetric standard model (MSSM), a light neutralino dark matter candidate has a lower bound on its mass of about 7 GeV. In light of this, we investigate the mass sensitivity at the ILC for very light neutralinos. We study slepton pair production, followed by the decay of the sleptons to a lep…
We show that present experimental constraints on B_s -> mu+ mu- decay and the CDMS upper limit on the cold dark matter elastic scattering cross section already have significant impact on the parameter space of the minimal supersymmetric extension of the Standard Model (MSSM) with non-universal supersymmetry-breaking scalar masses for the Higgs multiplets (NUHM). The relaxation of scalar universality in the MSSM allows the possibility of a relatively light mass M_A for the pseudoscalar Higgs boson. The present upper limit on B_s -> mu+ mu- already excludes much of the scope for this possibility…
Extending the Higgs sector of the MSSM by the addition of a gauge singlet scalar field can remedy the mu problem. We explore the implications of extended models for both the spectrum of the neutralinos and the cascade decays of the neutralinos and charginos. Extra steps due to light decoupled neutralinos in the cascade decays of both neutralinos and charginos allow an excess of trilepton events compared to the MSSM and the existence of events with higher lepton multiplicity. Additionally, displaced vertices of the chi_2^0 due to small decay widths in some models may be observable.
We consider the effect of CP violating phases in the MSSM on the relic density of the lightest supersymmetric particle (LSP). In particular, we find that the upper limits on the LSP mass are relaxed when phases in the MSSM are allowed to take non-zero values when the LSP is predominantly a gaugino (bino). Previous limits of $\mb \la 250$ GeV for $Ωh^2 < 0.25$ can be relaxed to $\mb \la 650$ GeV. We also consider the additional constraints imposed by the neutron and electron electric dipole moments induced by these phases. Though there is some restriction on the phases, the bino mass may still …
In order to meet the requirement of BBN, the right handed neutrino is added to the singlet Higgs sector in the GNMSSM. The spectrum and Feynman rules are calculated. the dark matter phenomenology is also studied. In case of $ł\sim 0$, the singlet sector can give perfect explanation of relic abundance of dark matter and small cosmological structure simulations. The BBN constraints on the light mediator can be easily solved by decaying to the right handed neutrino. When the $ł_N$ is at the order of $\mathcal{O}(0.1)$, the mass of the mediator can be constrained to several MeV
Supersymmetric (SUSY) extension of the Standard Model (SM) is a primary candidate for new physics beyond the SM. If SUSY breaking scale is very low, for example, the multi-TeV range, and the SUSY breaking sector, except for the goldstino (gravitino), is decoupled from the low energy spectrum, the hidden sector effect in the minimal SUSY SM (MSSM) is well described by employing the goldstino chiral superfield ($X$) with the nilpotent condition of $X^2=0$. Although this so-called "nonlinear MSSM" (NL-MSSM) provides a variety of interesting phenomenologies, there is a cosmological problem that th…
We consider a class of $U(1)^\prime$-extended MSSM in which the $U(1)^{\prime}$ symmetry is broken by vacuum expectation values (VEVs) of four MSSM singlet fields. While one MSSM singlet field interacts with the MSSM Higgs fields, three of them interact only with each other in forming a secluded sector. Assigning universal $U(1)^{\prime}$ charges for three families, the anomaly cancellation condition requires exotic fields which are assumed to be heavy and decoupled. We discuss a variety of $U(1)^{\prime}$ charge assignments and anomaly cancellation, $Z^{\prime}/Z$ hierarchy, neutralinos, char…
We discuss the possibilities for the direct detection of neutralino dark matter via elastic scattering in variants of the minimal supersymmetric extension of the Standard Model (MSSM) with non-universal supersymmetry-breaking contributions to the Higgs masses, which may be either equal (NUHM1) or independent (NUHM2). We compare the ranges found in the NUHM1 and NUHM2 with that found in the MSSM with universal supersymmetry-breaking contributions to all scalar masses, the CMSSM. We find that both the NUHM1 and NUHM2 offer the possibility of larger spin-independent dark matter scattering cross s…
The region of low neutralino masses as low as (5-10) GeV has attracted attention recently due to the possibility of excess events above background in dark matter detectors. An analysis of spin independent neutralino-proton cross sections $\SI$ which includes this low mass region is given. The analysis is done in MSSM with radiative electroweak symmetry breaking (REWSB). It is found that cross sections as large as $10^{-40}$ cm$^2$ can be accommodated in MSSM within the REWSB framework. However, inclusion of sparticle mass limits from current experiments, as well as lower limits on the Higgs se…
We investigate the parameter space of a supersymmetric model with an extended U(1) gauge symmetry in which the RH sneutrino is a thermal dark matter candidate. In this scenario, annihilation of RH sneutrinos proceeds mainly through Higgs or Z' exchange. We find that sneutrinos in the mass range from 50GeV to more than 1 TeV can be consistent with both the WMAP limit and the direct detection upper limits. Powerful constraints from new gauge boson searches at the LHC as well as from $ΔM_s$ are incorporated. Depending on the choice of the U(1) charge, these scenarios will be further probe by dire…
This letter presents new results on the combined sensitivity of the LHC and underground dark matter search experiments to the lightest neutralino as WIMP candidate in the minimal Supersymmetric extension of the Standard Model. We show that monojet searches significantly extend the sensitivity to the neutralino mass in scenarios where scalar quarks are nearly degenerate in mass with it. The inclusion of the latest bound by the LUX experiment on the neutralino-nucleon spin-independent scattering cross section expands this sensitivity further, highlighting the remarkable complementarity of jets/$…
The constraints imposed on the Minimal Supersymmetric Standard Model (MSSM) parameter space by the Large Hadron Collider (LHC) Higgs mass limit and gluino mass lower bound are revisited. We also analyze the thermal relic abundance of lightest neutralino, which is the Lightest Supersymmetric Particle (LSP). We show that the combined LHC and relic abundance constraints rule out most of the MSSM parameter space except a very narrow region with very large $\tan β~(\sim 50)$. Within this region, we emphasize that the spin-independent scattering cross section of the LSP with a proton is less than th…
We study phenomenological aspects of the MSSM with extra U(1) gauge symmetry. We find that the lightest Higgs boson mass can be increased up to 125 GeV, without introducing a large SUSY scale or large A-terms, in the frameworks of the CMSSM and gauge mediated SUSY breaking (GMSB) models. This scenario can simultaneously explain the discrepancy of the muon anomalous magnetic moment (muon g-2) at the 1 sigma level, in both of the frameworks, U(1)-extended CMSSM/GMSB models. In the CMSSM case, the dark matter abundance can also be explained.
We study the collider phenomenology of dark matter pair production at the LHC in simplified dark matter models and in the MSSM. Among the large space of dark matter models, we focus on two particular models where a fermionic dark matter candidate interacts with the Standard Model via the exchange of either a vector mediator in the s-channel or coloured scalar mediators in the t-channel. We find that the simplified models are capable of reproducing the predictions of the MSSM to some extent in simplified supersymmetric scenarios, but lack the complexity to descibe the complete theory over the f…
We discuss the constraints on Supersymmetry in the Higgs sector arising from LHC searches, rare B decays and dark matter direct detection experiments. We show that constraints derived on the mass of the lightest h0 and the CP-odd A0 bosons from these searches are covering a broader fraction of the SUSY parameter space compared to searches for strongly interacting supersymmetric particle partners. We discuss the implications of a mass determination in the range 123 < Mh < 127 GeV, inspired by the intriguing hints reported by the ATLAS and CMS collaborations, as well as those of a non-observatio…
We present the dark matter (DM) extension (by N) of the minimal supersymmetric standard model to give the recent trend of the high energy positron spectrum of the PAMELA/HEAT experiments. If the trend survives by future experiments, the MSSM needs to be extended. Here, we minimally extend the MSSM with one more DM component N together with a heavy lepton E, and introduce the coupling e_R E_R^c N_R. This coupling naturally appears in the flipped SU(5) GUT models. This N_{DM}MSSM contains the discrete symmetry Z_6, and for some parameter ranges there result two DM components. For the MSSM fields…
We study thermal neutralino dark matter in an effective field theory extension of the MSSM, called "Beyond the MSSM" (BMSSM) in Dine, Seiberg and Thomas (2007). In this class of effective field theories, the field content of the MSSM is unchanged, but the little hierarchy problem is alleviated by allowing small corrections to the Higgs/higgsino part of the Lagrangian. We perform parameter scans and compute the dark matter relic density. The light Higgsino LSP scenario is modified the most; we find new regions of parameter space compared to the standard MSSM. This involves interesting interplay…
In this thesis we use the Effective Field Theory approach for supersymmetric theories, applied to two experimental domains : the search for the Higgs bosons at colliders and the Dark Matter observables. The reason for introducing an effective approach in the Higgs physics is that the simple supersymmetric extension of the Standard Model (the MSSM) is known to have a tightly constrained Higgs sector, in particular with a lightest Higgs mass difficult to raise without introducing some fine-tuning. Many specific expansions (as the NMSSM for instance) allow for a richer Higgs sector. In this case …
Recently we examined a large number of points in a 19-dimensional parameter subspace of the CP-conserving MSSM with Minimal Flavor Violation. We determined whether each of these points satisfied existing theoretical, experimental, and observational constraints. Here we discuss the properties of the parameter space points allowed by existing data that are relevant for dark matter searches.
In this paper, we discuss the MSSM extended with one vector-like lepton doublets $L$-$\overline{L}$ and one right-handed neutrino $N$. The neutral vecotor-like sneutrino can be a candidate of dark matter. In order to avoid the interaction with the necleons by exchanging a $Z$-boson, the mass splitting between the real part and the imaginary part of the sneutrino field is needed. Compared with the MSSM sneutrino dark matter, the mass splitting between the vector-like sneutrino field can be more naturally acquired without large A-terms and constraints on the neutralino masses. We have also calcu…
The electroweak phase transition (EWPT) in the secluded-$U(1)'$-extended MSSM (sMSSM) is studied. Using the effective potential at zero and finite temperatures, we search for the non-MSSM-like EWPT in which the light stop mass is larger than the top quark mass. Scanning the parameters relevant to the EWPT, the upper limits of the Higgs boson masses, which are consistent with the strong first order EWPT, are derived. For the lightest CP-even and -odd Higgs bosons, we find $m_{H_1}<160$ GeV and $m_{A_1}<250$ GeV, respectively. In the sMSSM, the tree-level CP violation is possible by the complex …
The prediction of neutralino dark matter is generally regarded as one of the successes of the Minimal Supersymmetric Standard Model (MSSM). However the successful regions of parameter space allowed by WMAP and collider constraints are quite restricted. We discuss fine-tuning with respect to both dark matter and Electroweak Symmetry Breaking (EWSB) and explore regions of MSSM parameter space with non-universal gaugino and third family scalar masses in which neutralino dark matter may be implemented naturally. In particular allowing non-universal gauginos opens up the bulk region that allows Bin…
Spurred by the discovery of a boson resonance at the LHC as the result of the search for the Standard Model Higgs, we pursue our investigation of the properties and signatures of Higgses in an effective supersymmetric scenario that goes beyond the usual MSSM. Such scenarios were first introduced to alleviate the naturalness problem of the MSSM Higgs and are found to have a very rich phenomenology that allows departures from the Standard Model in the production rate of the Higgs in many of the search channels. We now include the constraints from flavour observables in particular the rare decays…
The possibility of identification of an observable CMS $μ^+ μ^-$ excess at 28 GeV in the channel $pp\to μ^+ μ^- b \bar b$ at $\sqrt{s}$=8 TeV and 13 TeV as a manifestation of one of the minimal supersymmetric standard model (MSSM) Higgs bosons is investigated. The MSSM parametric scenarios in the regime of large threshold corrections involving low-mass CP-odd scalar, a 125 GeV CP-even scalar and other Higgs bosons with suitable masses are found, where the alignment limit conditions for the Higgs couplings are respected. Perturbative unitarity bounds and constraints on the electroweak vacuum st…
The left-handed sneutrino in the Minimal Supersymmetric Standard Model (MSSM) has been ruled out as a viable thermal dark matter candidate, due to conflicting constraints from direct detection experiments and from the measurement of the dark matter relic density. The intrinsic fine-tuning problem of the MSSM, however, motivates an extension with a new U(1)' gauge symmetry. We show that in the U(1)'-extended MSSM the right-handed sneutrino becomes a good thermal dark matter candidate. We identify two generic parameter space regions where the combined constraints from relic density determination…
The flat directions LLe and udd within the minimal supersymmetric Standard Model provide all the necessary ingredients for a successful inflation with the right amplitude of the scalar density perturbations, negligible gravity waves and the spectral tilt within 2σobserved range 0.92 \leq n_s \leq 1.0. In this paper we explore the available parameter space for inflation in conjunction with a thermal cold dark matter abundance within the minimal supergravity model. Remarkably for the inflaton, which is a combination of squarks and sleptons, there is a stau-neutralino coannihilation region below …
We examine the issue of fine tuning in the MSSM with GUT-scale boundary conditions. We identify specific unification patterns and mass relations that can lead to a significant lowering of the fine tuning due to gauginos, scalars, and the μ parameter, relative to the simplest unification conditions. We focus on a phenomenologically interesting region that is favored by the Higgs mass and the relic density where the dark matter is a nearly pure higgsino with mass given by μ~1 TeV while the scalars and gauginos have masses in the multi-TeV regime. There, we find that the fine tuning can be reduce…
It has recently been pointed out that a component of the observed gamma ray emission in the low-latitudes of Fermi Bubble has a spectral shape that can be explained by a 10 GeV dark matter (DM) annihilating to tau leptons with a cross-section of 2 x 10^{-27} cm^3/s. Motivated by this possibility, we revisit the annihilation of a 10 GeV neutralino DM in the MSSM via stau exchange. The required stau masses and mixing, consistent with LEP direct search and electroweak precision constraints, are correlated with a possible enhancement of the Higgs decay rate to two photons. We also explore the impl…
New analysis of the heavy, neutral MSSM Higgs bosons H and A production at the Photon Collider is presented for M_A = 200, 250, 300 and 350 GeV in the parameter range corresponding to the so called "LHC wedge" and beyond. The expected precision of the cross section measurement for the process gamma+gamma->A,H->b+bbar and the "discovery reach" of the Photon Collider are compared for different MSSM scenarios. The analysis takes into account all relevant theoretical and experimental issues which could affect the measurement. For MSSM Higgs bosons A and H, for M_A = 200-350 GeV and tan(beta)=7, th…
Weak scale supersymmetry (SUSY) remains a prime explanation for the radiative stability of the Higgs field. A natural account of the Higgs boson mass, however, strongly favors extensions of the Minimal Supersymmetric Standard Model (MSSM). A plausible option is to introduce a new supersymmetric sector coupled to the MSSM Higgs fields, whose associated states resolve the little hierarchy problem between the third generation squark masses and the weak scale. SUSY also accomodates a weakly interacting cold dark matter (DM) candidate in the form of a stable neutralino. In minimal realizations, the…
We study neutralino dark matter within a semi-realistic type I string model, where supersymmetry breaking arises from F-terms of moduli fields parameterised in terms of Goldstino angles, which automatically gives rise to non-universal soft third sfamily and gaugino masses. We study the fine-tuning sensitivities for dark matter and electroweak symmetry breaking across the parameter space of the type I string model, and compare the results to a similar analysis in the non-universal MSSM. Within the type I string model we find that neutralino dark matter can be naturally implemented in the $\stau…
We perform a Bayesian model selection analysis in the the R-parity conserving MSSM to compare two different assumptions: whether the lightest neutralinos make all or only part of the cold dark matter. This corresponds to either imposing full WMAP relic density limits or just its upper bound for constraining the MSSM parameters. We consider several realisations of the MSSM, namely, three GUT-scale SUSY breaking scenarios with a handful of parameters corresponding to the CMSSM, anomaly mediation and the large volume string scenarios as well as the weak-scale 25-parameter phenomenological MSSM (p…
In this work we explore a lepton flavor violation effect induced at one loop for a flavor structure in an extended minimal standard supersymmetric model, considering an ansatz for the trilinear term. In particular we find a finite expression which will show the impact of this phenomena in the $h\to μτ$ decay, produced by a mixing in the trilinear coupling of the soft supersymmetric Lagrangian.
We investigate electric dipole moments (EDMs) in a CP-violating minimal supersymmetric standard model with the Bino-like neutralino dark matter (DM) annihilating through the heavy Higgs funnel. Motivated by the current experimental results, in particular, the measured mass of the standard model-like Higgs boson, we consider a mass spectrum with stop masses of about 10 TeV. For the other sfermions, we consider masses of about 100 TeV. We show that CP-violating phases of the order of ten degrees in gaugino and Higgsino mass parameters are consistent with the current bound by EDMs of the electron…
Low-energy supersymmetric models such as MSSM, NMSSM and MSSM with vectorlike fermion are consistent with perturbative unification. While the non-minimal extensions naturally explain Higgs mass and dark matter in the low energy region, it is unclear how seriously they are constrained in the ultraviolet region. Our study shows that $i)$, In the case of embedding MSSM into $\rm{SU}(5)$, the fit to SM fermion masses requires a singlet $S$, which leads to unviable embedding of NMSSM into $\rm{SU}(5)$ because such $S$ feeds singlet $N$ a mass of order unification scale as well. $ii)$, Similar resul…
As discussed recently by Hooper and Tait, the singlino-like dark matter in the Minimal Supersymmetric Standard Model (MSSM) extended by a singlet Higgs superfield can give a perfect explanation for both the relic density and the Pamela result through the Sommerfeld-enhanced annihilation into singlet Higgs bosons ($a$ or $h$ followed by $h->a a$) with $a$ being light enough to decay dominantly to muons or electrons. In this work we analyze the parameter space required by such a dark matter explanation and also consider the constraints from the LEP experiments. We find that although the light si…
