Rubin-LSST

Abstract:

A measurement of inclusive W and Z production cross sections in pp collisions at √s = 7TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb-1. The measured inclusive cross sections are σ(pp → WX) × ß(W → lν) = 10.31 × 0.02 (stat.) × 0.09 (syst.) × 0.10 (th.) × 0.41 (lumi.) nb and σ(pp → ZX) x B(Z → l +l- = 0.974 × 0.007 (stat.) × 0.007 (syst.) × 0.018 (th.) × 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are (σ(pp → WX) × B(W → lv))/(σ(pp → ZX) × B(Z → l+l-)) = 10.54 × 0.07 (stat.) × 0.08 (syst.) × 0.16 (th.) and (σ(pp → W+X) × B(W+ → l+ν))/(σ(pp → W-X) × B(W- → l-v̄)) = 1.421×0.006 (stat.) ×0.014 (syst.) ×0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions. Copyright CERN.

Abstract:

A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at √s=7TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1.14fb-1. In this search, a kinematic variable αT is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found. Exclusion limits in the parameter space of the constrained minimal supersymmetric extension of the standard model are set. In this model, squark masses below 1.1 TeV are excluded at 95% C.L. Gluino masses below 1.1 TeV are also ruled out at 95% C.L. for values of the universal scalar mass parameter below 500 GeV. © 2011 CERN.

Abstract:

A subset of microquasars exhibits high peculiar velocity with respect to the local standard of rest due to the kicks they receive when being born in supernovae. The interaction between the radio plasma released by microquasar jets from such high-velocity binaries with the interstellar medium must lead to the production of trails and bow shocks similar to what is observed in narrow-angle tailed radio galaxies and pulsar wind nebulae. We present a set of numerical simulations of this interaction that illuminate the long-term dynamical evolution and the observational properties of these microquasar bow-shock nebulae and trails. We find that this interaction always produces a structure that consists of a bow shock, a trailing neck, and an expanding bubble. Using our simulations to model emission, we predict that the shock surrounding the bubble and the neck should be visible in Hα emission, the interior of the bubble should be visible in synchrotron radio emission, and only the bow shock is likely to be detectable in X-ray emission. We construct an analytic model for the evolution of the neck and bubble shape and compare this model with observations of the X-ray binary SAX J1712.6-3739. © 2011. The American Astronomical Society. All rights reserved.