Model Unspecific Search in CMS

We present the results of a model independent analysis, which systematically scans the data taken by CMS for deviations from the Standard Model predictions. Due to the minimal theoretical bias this approach is sensitive to a variety of models for new physics. Events with at least one electron or muon are classified according to their content of reconstructed objects (muons, electrons, photons, jets and missing transverse energy). A broad scan of three kinematic distributions in those classes is performed by identifying deviations from Standard Model expectations, accounting for systematic uncertainties.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 2 pages, 3 figur

Some aspects of hadron-hadron collisions in high energy interactions (Bs mixing oscillations in semileptonic decay at D0 experiment)

In this thesis, we report the study on one such particle called the B{sub s}{sup 0} meson made up of a bottom and a strange quark. B{sub s}{sup 0} mesons are currently produced in a great numbers only at the Tevatron and we report a study done to measure the mixing parameter {Delta}m{sub s} between the B{sub s}{sup 0} meson and its anti-particle {bar B}{sub s}{sup 0}. Mixing is the ability of a very few neutral mesons to change from their particle to their antiparticle and vice versa. Until recently there existed only a lower limit on this measurement, here we report an upper bound and a most probable value for the mixing parameter. In the following chapter, we discuss the theoretical motivation behind this study. The measurement technique and the different factors that effect the measurement are also given. In Chapter 3, we provide an overview of the experimental setup needed to perform the study. In Chapter 4, we present a new initial state flavor tagging algorithm using electrons and measurement of the B{sub d}{sup 0} mixing parameter {Delta}m{sub d} with the new technique. Details of the combined initial state tagging used in the B{sub s}{sup 0} mixing study are also given. A detailed description of the B{sub s}{sup 0} mixing analysis and the results are covered in Chapter 5. And finally the results from all the three channels and a bound on the mixing parameter are presented in Chapter 6

Hadron energy response of the Iron Calorimeter detector at the India-based Neutrino Observatory

The results of a Monte Carlo simulation study of the hadron energy response for the magnetized Iron CALorimeter detector, ICAL, proposed to be located at the India-based Neutrino Observatory (INO) is presented. Using a GEANT4 modeling of the detector ICAL, interactions of atmospheric neutrinos with target nuclei are simulated. The detector response to hadrons propagating through it is investigated using the hadron hit multiplicity in the active detector elements. The detector response to charged pions of fixed energy is studied first, followed by the average response to the hadrons produced in atmospheric neutrino interactions using events simulated with the NUANCE event generator. The shape of the hit distribution is observed to fit the Vavilov distribution, which reduces to a Gaussian at high energies. In terms of the parameters of this distribution, we present the hadron energy resolution as a function of hadron energy, and the calibration of hadron energy as a function of the hit multiplicity. The energy resolution for hadrons is found to be in the range 85% (for 1GeV) -- 36% (for 15 GeV).Comment: 14 pages, 10 figures (24 eps files