We show that in studies of light quark- and gluon-initiated jet discrimination, it is important to include the information on softer reconstructed jets (associated jets) around a primary hard jet. This is particularly relevant while adopting a small
radius parameter for reconstructing hadronic jets. The probability of having an associated jet as a function of the primary jet transverse momentum ($p_T$) and radius, the minimum associated jet $p_T$ and the association radius is computed upto next-to-double logarithmic accuracy (NDLA), and the predictions are compared with results from Herwig++, Pythia6 and Pythia8 Monte Carlos (MC). We demonstrate the improvement in quark-gluon discrimination on using the associated jet rate variable with the help of a multivariate analysis. The associated jet rates are found to be only mildly sensitive to the choice of parton shower and hadronization algorithms, as well as to the effects of initial state radiation and underlying event. In addition, the number of $k_T$ subjets of an anti-$k_T$ jet is found to be an observable that leads to a rather uniform prediction across different MCs, broadly being in agreement with predictions in NDLA, as compared to the often used number of charged tracks observable.
We discuss the indirect detection of the wino dark matter utilizing gamma-ray observations of dwarf spheroidal galaxies (dSphs). After carefully reviewing current limits with particular attention to astrophysical uncertainties, we show prospects of t
he wino mass limit in future gamma-ray observation by the Fermi-LAT and the GAMMA-400 telescopes. We find that the improvement of the so-called $J$-factor of both the classical and the ultra-faint dSphs will play a crucial role to cover whole mass range of the wino dark matter. For example, with $delta (log_{10}J) = 0.1$ for both the classical and the ultra-faint dSphs, whole wino dark matter mass range can be covered by 15 years and 10 years data at the Fermi-LAT and GAMMA-400 telescopes, respectively.
We discuss both MSSM and NMSSM scenarios in which the lightest Higgs boson with $m_h=98$~GeV is consistent with the small excess ($sim 2.3 sigma$) observed at the LEP in $e^+ e^-rightarrow Zh$, with $h rightarrow b {bar b}$ process and the heavier Hi
ggs boson of mass close to 125~GeV as the observed candidate of the SM Higgs like particle at the LHC. We show the allowed regions in the non-decoupling Higgs zone of MSSM parameter space which are consistent with several low energy constraints coming from heavy flavour physics, latest experimental data on Higgs signals and lower limit on superparticle masses from 7~TeV and 8~TeV LHC run. We also implement the constraints from the relic density of the cold dark matter as obtained from the recent PLANCK data. Additionally, we discuss the possibility of observing the light Higgs boson of mass 98~GeV at the 14~TeV LHC run via $pp rightarrow V h$, with $h rightarrow b bar b$ using the technique of jet substructure. Our analysis shows that at 14~TeV LHC run with 300 ${rm fb}^{-1}$ luminosity the signal efficiency of such a light Higgs boson is at most 2.5$sigma$. Finally, we make a comment on the prospect of proposed $e^+ e^-$ ILC to discover/exclude this light Higgs boson.
Top polarization is an important probe of new physics that couples to the top sector, and which may be discovered at the 14 TeV LHC. Taking the example of the MSSM, we argue that top polarization measurements can put a constraint on the soft supersym
metry breaking parameter A_t. In light of the recent discovery of a Higgs-like boson of mass ~125 GeV, a large A_t is a prediction of many supersymmetric models. To this end, we develop a *detector level* analysis methodology for extracting polarization information from hadronic tops using boosted jet substructure. We show that with 100 fb^(-1) of data, left and right 600 GeV stops can be distinguished to 4sigma, and 800 GeV stops can be distinguished to 3sigma.
The recent Belle and BaBar measurements of the branching ratio of $B^+ to tau^+ u_tau$ indicate a significant deviation from the Standard Model prediction. We demonstrate that this measurement has a serious impact on models with minimal flavor viola
tion involving a charged Higgs boson, ruling out a large portion of the currently-allowed parameter space. In the constrained minimal supersymmetric standard model, this creates a tension between the measurements of $B^+ to tau^+ u_tau$ and the anomalous magnetic moment of the muon, unless $tanbeta$ is small, $mu > 0$, and $A_0$ takes a large negative value. In fact, a very small region of the parameter space of this model, with small values of $m_0$ and $m_{1/2}$, survives all the constraints at 95% C.L.. It is remarkable that this specific region is still consistent with the lightest supersymmetric particle as the dark matter. Moreover, it predicts observable SUSY signals in the early runs of the LHC, even perhaps at 7 TeV. We also show that a consistent explanation for the deviation of the $B^+ to tau^+ u_tau$ branching ratio from the Standard Model can be achieved in a non-universal Higgs mass model, which could also predict early signals of supersymmetry at the LHC.
