Reconstruction of Chirp Mass in the Search of Compact Binaries

Excess energy method is used in searches of gravitational waves (GWs) produced from sources with poorly modeled characteristics. It identifies GW events by searching for a coincidence appearance of excess energy in a GW detector network. While it is sensitive to a wide range of signal morphologies, the energy outliers can be populated by background noise events (background), thereby reducing the statistical confidence of a true signal. However, if the physics of the source is partially understood, weak model dependent constraints can be imposed to suppress the background. This letter presents a novel idea of using the reconstructed chirp mass along with two goodness of fit parameters for suppressing background when search is focused on GW produced from the compact binary coalescence

Regression of Environmental Noise in LIGO Data

We address the problem of noise regression in the output of gravitational-wave (GW) interferometers, using data from the physical environmental monitors (PEM). The objective of the regression analysis is to predict environmental noise in the gravitational-wave channel from the PEM measurements. One of the most promising regression method is based on the construction of Wiener-Kolmogorov filters. Using this method, the seismic noise cancellation from the LIGO GW channel has already been performed. In the presented approach the Wiener-Kolmogorov method has been extended, incorporating banks of Wiener filters in the time-frequency domain, multi-channel analysis and regulation schemes, which greatly enhance the versatility of the regression analysis. Also we presents the first results on regression of the bi-coherent noise in the LIGO data

The role of interference in unraveling the ZZ-couplings of the newly discovered boson at the LHC

We present a general procedure for measuring the tensor structure of the coupling of the scalar Higgs-like boson recently discovered at the LHC to two Z bosons, including the effects of interference among different operators. To motivate our concern with this interference, we explore the parameter space of the couplings in the effective theory describing these interactions and illustrate the effects of interference on the differential dilepton mass distributions. Kinematic discriminants for performing coupling measurements that utilize the effects of interference are developed and described. We present projections for the sensitivity of coupling measurements that use these discriminants in future LHC operation in a variety of physics scenarios.Comment: 29 pages, 9 Figure

The CMS Discovery Potential of Supersymmetry within mSugra with two same sign muons

A detailed study of the same-sign muon signature within the mSUGRA model was performed. Selection criteria based on the missing transverse energy in the events and the jet and muon transverse momenta are applied to select the data sample. An excess of SUSY events over the standard model background processes can be statistically significant for many benchmark points for an integrated luminosity of less than 10 fb/sup -1detailed detector simulation, trigger emulation and reconstruction were performed

Performance of the WaveBurst algorithm on LIGO data

In this paper we describe the performance of the WaveBurst algorithm which was designed for detection of gravitational wave bursts in interferometric data. The performance of the algorithm was evaluated on the test data set collected during the second LIGO Scientific run. We have measured the false alarm rate of the algorithm as a function of the threshold and estimated its detection efficiency for simulated burst waveforms.Comment: proceedings of GWDAW, 2003 conference, 13 pages, 6 figure

Constraint Likelihood analysis for a network of gravitational wave detectors

We propose a coherent method for the detection and reconstruction of gravitational wave signals for a network of interferometric detectors. The method is derived using the likelihood functional for unknown signal waveforms. In the standard approach, the global maximum of the likelihood over the space of waveforms is used as the detection statistic. We identify a problem with this approach. In the case of an aligned pair of detectors, the detection statistic depends on the cross-correlation between the detectors as expected, but this dependence dissappears even for infinitesimally small misalignments. We solve the problem by applying constraints on thelikelihood functional and obtain a new class of statistics. The resulting method can be applied to the data from a network consisting of any number of detectors with arbitrary detector orientations. The method allows us reconstruction of the source coordinates and the waveforms of two polarization components of a gravitational wave. We study the performance of the method with numerical simulation and find the reconstruction of the source coordinates to be more accurate than in the standard approach.Comment: 13 pages, 6 figure

Precision studies of the Higgs boson decay channel H -> ZZ -> 4l with MEKD

The importance of the H -> ZZ -> 4l "golden" channel was shown by its major role in the discovery, by the ATLAS and CMS collaborations, of a Higgs-like boson with mass near 125 GeV. We analyze the discrimination power of the matrix element method both for separating the signal from the irreducible ZZ background and for distinguishing various spin and parity hypotheses describing a signal in this channel. We show that the proper treatment of interference effects associated with permutations of identical leptons in the four electron and four muon final states plays an important role in achieving the best sensitivity in measuring the properties of the newly discovered boson. We provide a code, MEKD, that calculates kinematic discriminants based on the full leading order matrix elements and which will aid experimentalists and phenomenologists in their continuing studies of the H -> ZZ -> 4l channel.Comment: Major revision: added new sections discussing spin/ parity determination and the importance of using the full matrix element for the same flavor final state (involving both pairings of the leptons). Also added new functionality, including the most general couplings of a spin-0 or spin-2 boson to gluons and Zs, to the publicly-available code, MEKD, presented in this paper. 43 pages, 15 figure

Fast algorithm for track segment and hit reconstruction in the CMS Cathode Strip Chambers

In this note, we propose an algorithm for fast and efficient track segment reconstruction in Cathode Strip Chambers used by CMS experiment for muon detection in the forward direction. The algorithm is designed to be CPU-efficient and is targeted for High Level Trigger (HLT, online reconstructed events pre-selection) purposes. The segment finding efficiency and the spatial resolution attainable with the proposed algorithm as well as the required CPU time are benchmarked using the MTCC data and found to surpass the HLT requirements

Measuring Muon Reconstruction Efficiency from Data

We suggest a method of measuring the global muon reconstruction efficiency epsilon directly from data, which largely alleviates uncertainties associated with our ability to monitor and reproduce in Monte Carlo simulation all details of the underlying detector performance. With the data corresponding to an integrated luminosity L = 10 fb^-1, the precision of measuring epsilon for muons in the P_T range of 10-100~GeV will be better than 1%