Jet Reconstruction with charged tracks only in CMS

The performance of jet finding using only charged tracks in CMS has been investigated. Different jet algorithms have been applied to QCD di-jet events, to hadronic tt multi-jet events and on Z+jets events. Results using jets made with tracks only or calorimeter towers are compared for energy response, angular resolution and jet matching to the leading partons. The jet reconstruction performance in the presence of pile-up interactions is presented for the Z+jets sample.Comment: 4 pages, 3 figures, proceedings of Physics at LHC, 29 September - 4 October 2008, Split, Croati

Electroweak Physics at LEP2

The measurements resulting from the analysis of the LEP2 data have brought more strong evidence in support of the standard electroweak model. In particular the LEP2 data has revealed (i) the first determination of the SU(2) gauge bosons self-couplings, (ii) the first direct measurements of the W decay-couplings, and (iii) the current best direct measurement of the W mass.Comment: 5 pages, 3 figures, contribution to the 2005 Lake Louise Winter Institut

First Results of Searches for New Physics at 7 TeV with the CMS detector

First searches for new physics phenomena using the LHC 7 TeV proton-proton collision data collected by the CMS detector in 2010 are reviewed. Results are presented of searches for new physics in events with hadronic jet pairs, and for heavy stable charged particles, including a dedicated search for long-lived particles that stop in the detector and decay in periods between beam crossings.Comment: 8 pages, 11 figures, proceedings of DISCRETE 2010, Symposium on Prospects in the Physics of Discrete Symmetries, 6-11 December 2010, Rome, Ital

The CMS Silicon Strip Tracker

With over 200 square meters of sensitive Silicon and almost 10 million readout channels, the Silicon Strip Tracker of the CMS experiment at the LHC will be the largest Silicon strip detector ever built. The design, construction and expected performance of the CMS Tracker is reviewed in the following.Comment: 8 pages, 8 figures, talk given at XIX EPS NPDC Conference on "New Trends in Nuclear Physics Applications and Technology", September 5-9, 2005 Pavia, Ital

Measurements of the hadronic activity and the electroweak production in events with a Z boson and two jets in proton-proton collisions with the CMS experiment

AbstractThe observation of the electroweak production of a Z boson with two jets in pp collisions at s=8 TeV with the CMS experiment at the CERN LHC is presented, based on a data sample with an integrated luminosity of 19.7 fb-1. The cross section measurement, combining the muon and electron channels, is in agreement with the theoretical expectations. Radiation patterns of selected Z plus two jets events, and the hadronic activity in the rapidity interval between the jets are also measured. These results are of substantial importance in the more general study of vector boson fusion processes, of relevance for Higgs boson searches and for measurements of electroweak gauge couplings and vector boson scattering

Measurements of the hadronic activity and the electroweak production in events with a Z boson and two jets in proton-proton collisions with the CMS experiment

The observation of the electroweak production of a Z boson with two jets in pp collisions at $\sqrt{s} = 8$ TeV with the CMS experiment at the CERN LHC is presented, based on a data sample with an integrated luminosity of 19.7 fb$^{-1}$. The cross section measurement, combining the muon and electron channels, is in agreement with the theoretical expectations. Radiation patterns of selected Z plus two jets events, and the hadronic activity in the rapidity interval between the jets are also measured. These results are of substantial importance in the more general study of vector boson fusion processes, of relevance for Higgs boson searches and for measurements of electroweak gauge couplings and vector boson scattering.Comment: 6 pages, 5 figures, to appear in the proceedings of ICHEP 201

Track Reconstruction Performance in CMS

The expected performance of track reconstruction with LHC events using the CMS silicon tracker is presented. Track finding and fitting is accomplished with Kalman Filter techniques that achieve efficiencies above 99% on single muons with pT>1 GeV/c. Difficulties arise in the context of standard LHC events with a high density of charged particles, where the rate of fake combinatorial tracks is very large for low pT tracks, and nuclear interactions in the tracker material reduce the tracking efficiency for charged hadrons. Recent improvements with the CMS track reconstruction now allow to efficiently reconstruct charged tracks with pT down to few hundred MeV/c and as few as three crossed layers, with a very small fake fraction, by making use of an optimal rejection of fake tracks in conjunction with an iterative tracking procedure.Comment: 4 pages, 3 figures, proceedings of the 11th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD08