A parsec scale X-ray extended structure from the X-ray binary Circinus X-1
Monthly Notices of the Royal Astronomical Society: Letters 397:1 (2009)
Abstract:
We present the results of the analysis of two Chandra observations of Circinus X-1 performed in 2007, for a total exposure time of ~50 ks. The source was observed with the High Resolution Camera during a long X-ray low-flux state of the source. Cir X-1 is an accreting neutron star binary system that exhibits ultra-relativistic arcsec-scale radio jets and an extended arcmin-scale radio nebula. Furthermore, a recent paper has shown an X-ray excess on arcmin-scale prominent on the side of the receding radio jet. In our images, we clearly detect X-ray structures on both the side of the receding and the approaching radio jet. The X-ray emission is consistent with a synchrotron origin. Our detection is consistent with neutron star binaries being as efficient as black hole binaries in producing X-ray outflows, despite their shallower gravitational potential. © 2009 The Authors. Journal compilation © 2009 RAS.Search for narrow resonances lighter than Υ mesons
European Physical Journal C 62:2 (2009) 319-326
Abstract:
We report a search for narrow resonances, produced in p p̄ collisions at √ s=1.96 TeV, that decay into muon pairs with invariant mass between 6.3 and 9.0 GeV/c 2. The data, collected with the CDF II detector at the Fermilab Tevatron collider, correspond to an integrated luminosity of 630 pb -1. We use the dimuon invariant mass distribution to set 90% upper credible limits of about 1% to the ratio of the production cross section times muonic branching fraction of possible narrow resonances to that of the Υ(1S) meson. © 2009 Springer-Verlag.Search for WW and WZ production in lepton plus jets final state at CDF
Physical Review D - Particles, Fields, Gravitation and Cosmology 79:11 (2009)
Abstract:
We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in s=1.96TeV pp̄ collisions at the Fermilab Tevatron, using data corresponding to 1.2fb-1 of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of σWW×BR(W→ν,W→jets)+σWZ×BR(W→ ν ,Z→jets)<2.88pb, which is consistent with the standard model next-to-leading-order cross section calculation for this decay channel of 2.09±0.12pb. © 2009 The American Physical Society.Erratum: Measurement of the inclusive jet cross section at the Fermilab Tevatron pp̄ collider using a cone-based jet algorithm (Physical Review D (2008) 78 (052006))
Physical Review D - Particles, Fields, Gravitation and Cosmology 79:11 (2009)
Linking jet emission and X-ray properties in the peculiar neutron star X-ray binary Circinus X-1
(2009)