Systematic uncertainties of the top background in the H->WW channel

The ttbar process is one of the main backgrounds for the H->WW->lnulnu signal search. The simulation of this background as well as an estimation of its contribution to the total systematic error for this Higgs search will be studied in detail. For this, the predictions of the PYTHIA, HERWIG, TopREX and MC@NLO Monte Carlos are compared in order to estimate the effect of different showering programs and of the spin correlations. Furthermore, the question of how to include NLO corrections will be addressed and the simulation of single top background at NLO discussed. In order to extrapolate the ttbar background to the Higgs signal region, once data is available, different normalization methods will be proposed and compared. The experimental uncertainties coming from different normalization processes will be estimated using a full CMS simulation

Energy Resolution Performance of the CMS Electromagnetic Calorimeter

The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals

Standard Model Higgs Discovery Potential of CMS in the H→WW→lνlνH \to WW\to l\nu l\nu channel

The Standard Model Higgs discovery potential of CMS in the H->WW->lnulnu channel is presented. The results are based on a full detector simulation and include the last theoretical developments for background and signal simulation. A first estimate of the expected systematics is also performed. If the Standard Model Higgs has a mass between 150GeV and 180GeV, it should be discovered with more than 5sigma significance with a luminosity of 10fb-1

Standard Model Higgs Discovery Potential of CMS in H→WW→lνlνH \to WW \to l\nu l\nu Channel

The discovery potential of the CMS detector for the Standard Model Higgs boson in the H->WW->lnulnu channel is assessed using a full detector simulation. Sources of systematic uncertainties as well as methods to determine backgrounds from data are discussed. If the Standard Model Higgs boson has a mass between 150GeV and 180GeV, it should be observed with a significance of more than 5 sigma with a luminosity of about 10fb-1

Les Houches Physics at TeV Colliders 2005, Standard Model and Higgs working group: Summary report

This Report summarises the activities of the "SM and Higgs" working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 2-20 May, 2005. On the one hand, we performed a variety of experimental and theoretical studies on standard candles (such as W, Z, and ttbar production), treating them either as proper signals of known physics, or as backgrounds to unknown physics; we also addressed issues relevant to those non-perturbative or semi-perturbative ingredients, such as Parton Density Functions and Underlying Events, whose understanding will be crucial for a proper simulation of the actual events taking place in the detectors. On the other hand, several channels for the production of the Higgs, or involving the Higgs, have been considered in some detail. The report is structured into four main parts. The first one deals with Standard Model physics, except the Higgs. A variety of arguments are treated here, from full simulation of processes constituting a background to Higgs production, to studies of uncertainties due to PDFs and to extrapolations of models for underlying events, from small-$x$ issues to electroweak corrections which may play a role in vector boson physics. The second part of the report treats Higgs physics from the point of view of the signal. In the third part, reviews are presented on the current status of multi-leg, next-to-leading order and of next-to-next-to-leading order QCD computations. Finally, the fourth part deals with the use of Monte Carlos for simulation of LHC physics

Energy Resolution of the Barrel of the CMS Electromagnetic Calorimeter

The energy resolution of the barrel part of the CMS Electromagnetic Calorimeter has been studied using electrons of 20 to 250 GeV in a test beam. The incident electron's energy was reconstructed by summing the energy measured in arrays of 3x3 or 5x5 channels. There was no significant amount of correlated noise observed within these arrays. For electrons incident at the centre of the studied 3x3 arrays of crystals, the mean stochastic term was measured to be 2.8% and the mean constant term to be 0.3%. The amount of the incident electron's energy which is contained within the array depends on its position of incidence. The variation of the containment with position is corrected for using the distribution of the measured energy within the array. For uniform illumination of a crystal with 120 GeV electrons a resolution of 0.5% was achieved. The energy resolution meets the design goal for the detector

Results of the first performance tests of the CMS electromagnetic calorimeter

CMS ECALPerformance tests of some aspects of the CMS ECAL were carried out on modules of the "barrel" sub-system in 2002 and 2003. A brief test with high energy electron beams was made in late 2003 to validate prototypes of the new Very Front End electronics. The final versions of the monitoring and cooling systems, and of the high and low voltage regulation were used in these tests. The results are consistent with the performance targets including those for noise and overall energy resolution, required to fulfil the physics programme of CMS at the LHC

Track Reconstruction with Cosmic Ray Data at the Tracker Integration Facility

The subsystems of the CMS silicon strip tracker were integrated and commissioned at the Tracker Integration Facility (TIF) in the period from November 2006 to July 2007. As part of the commissioning, large samples of cosmic ray data were recorded under various running conditions in the absence of a magnetic field. Cosmic rays detected by scintillation counters were used to trigger the readout of up to 15\,\% of the final silicon strip detector, and over 4.7~million events were recorded. This document describes the cosmic track reconstruction and presents results on the performance of track and hit reconstruction as from dedicated analyses