Measurement of Zγ production in pp̄ collisions at √s=1.96TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:3 (2010)
Abstract:
The production rate and kinematics of photons produced in association with Z bosons are studied using 2fb-1 of pp̄ collision data collected at the Collider Detector at Fermilab. The cross section for pp̄→"+-γ+X (where the leptons " are either muons or electrons with dilepton mass M>40GeV/c2, and where the photon has transverse energy ETγ>7GeV and is well separated from the leptons) is 4.6±0.2(stat)±0.3(syst)±0.3(lum)pb, which is consistent with standard model expectations. We use the photon ET distribution from Zγ events where the Z has decayed to μ+μ -, e+e-, or νν̄ to set limits on anomalous (non standard model) trilinear couplings between photons and Z bosons. © 2010 The American Physical Society.Search for the production of scalar bottom quarks in pp collisions at square root(s) = 1.96 TeV.
Phys Rev Lett 105:8 (2010) 081802
Abstract:
We report on a search for direct scalar bottom quark (sbottom) pair production in pp collisions at square root(s) = 1.96 TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a collider detector at Fermilab Run II data sample corresponding to 2.65 fb(-1) of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70 GeV/c2, sbottom masses up to 230 GeV/c2 are excluded at 95% confidence level.Search for the production of scalar bottom quarks in pp̄ collisions at √s=1.96TeV
Physical Review Letters 105:8 (2010)
Abstract:
We report on a search for direct scalar bottom quark (sbottom) pair production in pp̄ collisions at √s=1.96TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a collider detector at Fermilab Run II data sample corresponding to 2.65fb-1 of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70GeV/c2, sbottom masses up to 230GeV/c2 are excluded at 95% confidence level. © 2010 The American Physical Society.Ultracold atoms in an optical lattice with dynamically variable periodicity
Physical Review A - Atomic, Molecular, and Optical Physics 82:2 (2010)
Abstract:
The use of a dynamic "accordion" lattice with ultracold atoms is demonstrated. Ultracold atoms of Rb87 are trapped in a two-dimensional optical lattice, and the spacing of the lattice is then increased in both directions from 2.2 to 5.5 μm. Atoms remain bound for expansion times as short as a few milliseconds, and the experimentally measured minimum ramp time is found to agree well with numerical calculations. This technique allows an experiment such as quantum simulations to be performed with a lattice spacing smaller than the resolution limit of the imaging system, while allowing imaging of the atoms at individual lattice sites by subsequent expansion of the optical lattice. © 2010 The American Physical Society.Studying the underlying event in Drell-Yan and high transverse momentum jet production at the Tevatron
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:3 (2010)