Measurement of the Bs0 production cross section with Bs0→J/ψ Decays in pp collisions at √s=7TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 84:5 (2011)
Abstract:
The Bs0 differential production cross section is measured as functions of the transverse momentum and rapidity in pp collisions at √s=7TeV, using the Bs0→J/ψ decay, and compared with predictions based on perturbative QCD calculations at next-to-leading order. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 40pb -1. The Bs0 is reconstructed from the decays J/ ψ→μ+μ- and →K+K -. The integrated Bs0 cross section times Bs0→J/ψ branching fraction in the range 8Properties of jets measured from tracks in proton-proton collisions at center-of-mass energy √s=7TeV with the ATLAS detector
Physical Review D - Particles, Fields, Gravitation and Cosmology 84:5 (2011)
Search for a Higgs Boson in the Diphoton Final State in p-pbar Collisions at sqrt(s) = 1.96 TeV
(2011)
Testing the jet quenching paradigm with an ultradeep observation of a steadily soft state black hole
Astrophysical Journal Letters 739:1 (2011)
Abstract:
We present ultradeep radio observations with the Expanded Very Large Array of 4U 1957+11, a Galactic black hole (BH) candidate X-ray binary known to exist in a persistent soft X-ray state. We derive a stringent upper limit of 11.4 μJy beam-1 (3σ) at 5-7 GHz, which provides the most rigorous upper limit to date on the presence of jets in a soft state BH X-ray binary (BHXB). X-ray, UV, and optical fluxes obtained within a few weeks of the radio data can be explained by thermal emission from the disk. At this X-ray luminosity, a hard state BHXB that follows the established empirical radio-X-ray correlation would be at least 330-810 times brighter at radio frequencies, depending on the distance to 4U 1957+11. This jet quenching of >2.5 orders of magnitude is greater than some models predict and implies that the jets are prevented from being launched altogether in the soft state. 4U 1957+11 is also more than one order of magnitude fainter than the faintest of the "radio-quiet" population of hard state BHs. In addition, we show that, on average, soft state stellar-mass BHs probably have fainter jets than most active galactic nuclei in a state equivalent to the soft state. These results have implications for the conditions required for powerful, relativistic jets to form and provide a new empirical constraint for time- and accretion mode-dependent jet models, furthering our understanding of jet production and accretion onto BHs. © 2011. The American Astronomical Society. All rights reserved.Measurement of the inclusive jet cross section in pp collisions at √s=7TeV
Physical Review Letters 107:13 (2011)