118779045
Constraining the flavor changing Higgs couplings to the top-quark at the LHC
A bstractWe study the flavor-changing couplings of the Higgs-boson with the top-quark using the processes: (a) pp → tt, (b) pp→t¯j$$ pp\to \overline{t}j $$, and, (c) pp→t¯jh$$ pp\to \overline{t}jh $$ at the LHC in light of current discovery of a 126 GeV Higgs-Boson. Sensitivities for the flavor-changing couplings are estimated using the LHC data that was collected until spring 2013. It is found that the process (c) is the most capable of yielding the best upper bound on the flavor-changing couplings with 2σ level sensitivities of |ξtc2 + ξtu2|1/2 ≲ 7.3 × 10− 3 and ≲2 .9 ×10−3 resulting from t → blνl, h → jj with the 7 TeV and 8 TeV centre-of-mass energies respectively using existing data from the LHC. The corresponding bounds from h→bb¯$$ h\to b\overline{b} $$ are worse by a factor of about 1.8.
207846098
Right sneutrinos in a supergravity model and the signals of a stable stop at the Large Hadron Collider
197440770
CP violating anomalous top-quark couplings at the Large Hadron Collider
In this talk, I review the T-odd correlations induced by CP violating anomalous top-quark couplings at both production and decay level in the process gg --> t t_bar --> (b mu+ nu_mu) (b_bar mu-nu_mu_bar). In addition I will also focus on experimental sensitivities corresponding to the anomalous couplings at the LHC.
14302099
Right-chiral sneutrinos and long-lived staus: Event characteristics at the CERN Large Hadron Collider
We investigate the signals of a supersymmetric scenario where the lighter tau-sneutrino is the lightest supersymmetric particle, while the lighter stau-state is the next lightest. We confirm that such a scenario can be motivated within the framework of minimal supergravity, with just the addition of a right-chiral neutrino superfield. Such a spectrum leads to rather unusual signals of supersymmetry, showing stable tracks of the stau in the muon chambers. We have studied two types of signals, namely (a) two or more hard jets and two stau tracks, and (b) hard jets with two muons and two stau tracks. We demonstrate that the stau tracks can be distinguished from the muonic ones through proper kinematic cuts which also enable one to remove all standard model backgrounds.
8775045
The Impossibility of heavy neutrino dark matter in the Littlest Higgs Model with T-parity: Constraints from direct search
We consider the Littlest Higgs Model with T-parity (LHT), in the parameter region where a heavy neutrino is the lightest T-odd particle (LTP). Having emphasized that this corresponds to a sizable region in the parameter space of the theory, we show that both the Cryogenic Dark Matter Search (CDMS) and Xenon10 experiments disallow the entire region where the masses of the new particles in LHT can lie within several TeV. Therefore, any observation of the signals of a heavy neutrino LTP is likely to seriously reopen the issue of cold dark matter in the universe.
119107758
Peccei-Quinn violating minimal supergravity and a 126 GeV Higgs boson
In a Peccei-Quinn extension of supergravity the h --> \gamma\gamma detection rate can be significantly enhanced due to the reduction of the total Higgs decay width. To assess the viability of various Peccei-Quinn extensions of minimal supergravity we perform a Bayesian analysis on three such scenarios. The main constraints on these models come from the currently observed Higgs boson like state by the Large Hadron Collider and from the WMAP observation of dark matter abundance. Our comparative study reveals that under these constraints the PQ violating scenarios with axino dark matter are clearly preferred over the minimal supegravity model with the lightest neutralino as a dark matter candidate.
123004962
Flavour degrees of freedom and the transition temperature in QCD
We study the finite temperature transition in QCD with four flavours of dynamical quarks. Our simulation is performed on an 8×16 3 lattice for quarks of mass ma=0.01. At the coupling β c =5.15, we find long-lived metastable states, as well as an abrupt change in the entropy density, suggesting a first order phase transition. Using presently available results from corresponding calculations of the hadron masses and the chiral condensate, this gives us a transition temperature T c ≅100 MeV, which is a factor two lower than the transition temperature found in quenched QCD.
124737204
Thermalization of quarkonia at energies available at the CERN Large Hadron Collider
We argue that the relative yields of $\Upsilon$ states observed at the LHC can be understood as bottomonium states coming to early thermal equilibrium and then freezing out. The bottomonium freezeout temperature is approximately 250 MeV. We examine its systematics as a function of centrality. We remark on the interesting differences seen by the CMS and ALICE experiments in the charmonium sector.
118446008
The QCD Critical Point: Marching towards continuum
Abstract We present results of our simulations of QCD with two light dynamical quarks on a 32 3 × 8 lattice at a current quark mass tuned to have the Goldstone pion mass of about 230 MeV. Employing the Taylor expansion method we proposed earlier, we estimate the radius of convergence of the series for the baryonic susceptibility by using terms up to eighth order. Together with our earlier results, corresponding to the same physical parameters but on coarser lattices at respectively 1.33 times and twice the lattice cut-off ( a ), we were able to attempt a march towards the continuum limit.
41160767
Chiral dynamics in QCD at finite chemical potential
We present the renormalized Taylor expansion of the chiral condensate with chemical potential. The relation with the Taylor coefficients of meson susceptibilities and the quark mass dependence of the quark number susceptibilities are obtained through chiral Ward identities and Maxwell relations. The continuum limit is obtained in quenched and two flavor QCD. In N{sub f}=2 QCD, the quadratic response coefficients of the chiral condensate to chemical potential indicate that pion fluctuations decrease at finite chemical potential toward the critical end point. We discuss how these observables can be used to test other features of the QCD phase diagram.
123608845
Sign-Posting the Phase Diagram of QCD
The good agreement between lattice predictions and data for the shape of the distribution of event-by-event fluctuations of the baryon number is discussed. Such comparisons can give fine probes of thermalization, and can be used to provide a direct determination of the crossover temperature of QCD, Tc. The logic of these comparisons and the systematics involved are discussed. The same methods can be used to further explore the phase diagram.