Using the chargino-neutralino and slepton search results from the LHC in conjunction with the WMAP/PLANCK and (g − 2) µ data, we constrain several generic pMSSM models with decoupled strongly interacting sparticles, heavier Higgs bosons and characterized by different hierarchies among the EW sparticles. We find that some of them are already under pressure and this number increases if bounds from direct detection experiments like LUX are taken into account, keeping in mind the associated uncertainties. The XENON1T experiment is likely to scrutinize the remaining models closely. Analysing models with heavy squarks, a light gluino along with widely different EW sectors, we show that the limits on m g are not likely to be below 1.1 TeV, if a multichannel analysis of the LHC data is performed. Using this light gluino scenario we further illustrate that in future LHC experiments the models with different EW sectors can be distinguished from each other by the relative sizes of the n-leptons + m-jets + E / T signals for different choices of n.

As a sequel to our earlier work on wino-dominatedχ ± 1 andχ 0 2 (wino models), we focus on the pMSSM models whereχ ± 1 ,χ 0 2 andχ 0 3 are either higgsino dominated (higgsino models) or admixtures of significant amount of higgsino and wino components (mixed models), with or without light sleptons. The LHC constraints in the trilepton channel are significantly weaker even in the presence of light sleptons, especially in the higgsino models, compared to those mostly studied by the LHC collaborations with wino-dominated χ ± 1 andχ 0 2 . The modesχ 0 3 ,χ 0 2 →χ 0 1 h with large branching ratios (BRs) are more common in the higgsino models and may produce spectacular signal in the LHC Run-II. In a variety of higgsino and mixed models we have delineated the allowed parameter space due to the LHC constraints, the observed Dark Matter (DM) relic density of the universe, which gets contributions from many novel DM producing mechanisms i.e., the annihilation/coannihilation processes that lead to the correct range of relic density, and the precise measurement of the anomalous magnetic moment of the muon. In the higgsino models many new DM producing mechanisms, which are not allowed in the wino models, open up. We have also explored the prospects of direct and indirect detection of DM in the context of the LUX and IceCube experiments respectively. In an extended model having only light gluinos in addition to the electroweak sparticles, the gluinos decay into final states with multiple taggable b-jets with very large BRs. As a consequence, the existing ATLAS data in the 0l + jets (3b) + E / T channel provide the best limit on mg (≈ 1.3 TeV). Several novel signatures of higgsino models for LHC Run-II and ILC have been identified.

In this work we study the collider phenomenology of a compressed supersymmetric model with the gluino (g) and the lightest neutralino (χ 0 1 ). All other sparticles are assumed to be heavy. We consider gluino pair production at the 14 TeV LHC and present the mass reach of the gluino as a function of mass splitting between the gluino and the lightest neutralino. We find that the gluino mass below 1 TeV can be excluded at 95% C.L. with an integrated luminosity of 100 fb −1 for the extreme degenerate case where the mass separation between the gluino and the lightest neutralino is about 20 GeV. On the other hand, the lower bound on the mass of the gluino increases to 1.2-1.3 TeV if the mass splitting between the gluino andχ 0 1 is about 200 GeV. This result shows that for a degenerate gluino, the current mass limit may approximately extend up to 400-500 GeV at the 14 TeV LHC.The constrained minimal supersymmetric standard model (cMSSM) [1] is one of the supersymmetric (SUSY) models which draws much attention to the particle physics community due to its small number of parameters which make this model highly predictive. For this reason, two major collaborations of the LHC, ATLAS and CMS, have searched for the cMSSM from the very beginning of the LHC run in many different final states. In the R-parity conserving model, SUSY particles (sparticles) are produced in pairs and the lightest supersymmetric particle (LSP) must be stable. In most of the cases, the lightest neutralino (χ 0 1 ), being the LSP can be a good candidate for cold dark matter. The generic signature of a SUSY search is comprised of multijets þ leptons þ large amount of missing transverse energy (E T ) which arises due to cascade decays of squarks and gluino into jets, leptons andχ 0 1 . Hereχ 0 1 is the primary source of E T which escapes the detector like neutrinos.In cMSSM, the gluino is generally much heavier than the LSP (mg ∼ 6m~χ0 1 ) and jets produced from the decay ofg, i.e.,g → qqχ 0i are very energetic resulting in signatures having a sufficient amount of E T as well as effective mass (M eff ). Here M eff is defined as the scalar sum of P T of jets, P T of leptons (wherever leptons are present) and E T . These two kinematic variables ðE T ; M eff Þ can be efficiently used to discriminate SUSY signals from the SM backgrounds. The CMS [2] and ATLAS [3] Collaborations have searched for SUSY in the jets þ leptons þ E T channel and in the absence of a significant excess of signal events over the SM backgrounds, they put stringent bounds on the masses of squarks and the gluino in the framework of cMSSM using 7=8 TeV data. For example, with an integrated luminosity ðLÞ ¼ 20.3 fb −1 , equal masses of squarks and gluino are excluded below 1.7 TeV in the cMSSM scenario from 8 TeV LHC data [3]. 1

The bj6 ET signal at the ongoing LHC experiments is simulated with PYTHIA in the minimal supergravity (mSUGRA) and other models of supersymmetry (SUSY) breaking. Special attention is given to the compatibility of this signature with the low mass neutralino dark matter (LMNDM) scenario consistent with the Wilkinson Microwave Anisotropy Probe data. In the mSUGRA model the above signal as well as the LMNDM scenario are strongly disfavored due to the constraints from the ongoing SUSY searches at the LHC. This tension, however, originates from the model dependent correlations among the parameters in the strong and electroweak sectors of mSUGRA. That there is no serious conflict between the LMNDM scenario and the LHC data is demonstrated by constructing generic phenomenological models such that the strong sector is unconstrained or mildly constrained by the existing LHC data and parameters in the electroweak sector, unrelated to the strong sector, yield dark matter relic density consistent with the Wilkinson Microwave Anisotropy Probe data. The proposed models, fairly insensitive to the conventional SUSY searches in the jets þ 6 E T and other channels, yield observable signal in the suggested channel for L * 1 fb À1 of data. They are also consistent with the LMNDM scenario and can be tested by the direct dark matter search experiments in the near future. Some of these models can be realized by nonuniversal scalar and gaugino masses at the grand unified theory scale.

We propose the signal 1b + 1l + N j + E T along with appropriate selection criteria for the LHC 7 TeV run, where the number of jets (N j ) is ≥ 2 or 4. These signals can complement the canonical Jets + E T signature since they are sensitive to the trilinear soft breaking parameter (A 0 ) and low values of the parameter tanβ in the minimal supergravity (mSUGRA) model. A large region of this mSUGRA parameter space within the reach of the ongoing experiments at the LHC is disfavoured by the bound on the lightest Higgs boson mass (m h ≥ 114.4 GeV) unless A 0 has moderate to large negative values. Interestingly part of this parameter space with A 0 = 0 is also consistent with the observed dark matter relic density. A natural consequence of large A 0 is the existence of a light top squark ( t 1 ). The proposed signals primarily stem from direct t 1 t * 1 production and/org →t 1 t, if all squark-gluino events are considered. A thorough analysis of the signals and the corresponding backgrounds are presented using the event generator Pythia. We finally compare the signal size for A 0 = 0 and A 0 = 0.PACS no:12.60.Jv, 95.35.+d, 13.85.-t, 04.65.+e 1 nabanita@iiserkol.ac.in 2 arghyac@iiserkol.ac.in 3 adatta@iiserkol.ac.in 1