Branching Fractions and CP Asymmetries in Two-Body Nonleptonic Charmless b-Hadron Decays

Relative branching fractions of B^0_d,s -> h^+ h^'- decays (where h, h' = K or pi) and the direct CP asymmetry A_CP in the B^0_d -> K^+ pi^- mode are measured with 179 +- 11 pb^-1 of data collected at sqrt{s} = 1.96 TeV using the CDF II detector at the Fermilab Tevatron ppbar collider. The first branching-fraction measurement of a B^0_s meson to two pseudoscalars, Br(B^0_s -> K^+ K^-), and a search for the baryon mode Lambda^0_b -> p^+ h^- are also presented, in addition to branching-fraction limits on the rare channels B^0_s -> K^+ pi^-, B^0_d -> K^+ K^-, and B^0_s -> pi^+ pi^-.Comment: 4 pages, LaTeX, 1 eps figure; Invited talk presented at the 2004 Annual Meeting of the Division of Particles and Fields (DPF) of the American Physical Society (APS), Riverside, CA, August 27-31, 2004; to be published in the International Journal of Modern Physics A (IJMPA

Measurements of αs\alpha_s in pppp Collisions at the LHC

The coupling of the strong force, $\alpha_s$, is deemed to be a fundamental parameter of Nature, and, beyond the quark masses, constitutes the only free parameter in the QCD Lagrangian. Provided is an overview of CERN Large Hadron Collider (LHC) measurements of $\alpha_s(M_Z)$ evaluated at the $Z$-boson mass and of the running of $\alpha_s(Q)$ as a function of energy-momentum transfer $Q$. The measurements were performed by the ATLAS and CMS Collaborations using proton-proton ($pp$) collisions with centre-of-mass energies of 7 TeV and data samples with time-integrated luminosities up to 5 fb$^{-1}$. Four different categories of observable were used in the described extractions of $\alpha_s$: inclusive jet cross sections, 3-jet to 2-jet inclusive cross-section ratios, 3-jet mass cross sections, and top-quark pair production cross sections. These results, which include the first NNLO measurement of $\alpha_s$ at a hadron collider and the first determinations of $\alpha_s$ at energy scales above 1 TeV, are consistent with each other, with the world-average value, and with QCD predictions of their running with $Q$.Comment: Invited talk presented at CIPANP2015 (Twelfth Conference on the Intersections of Particle and Nuclear Physics, Vail, Colorado, USA, 19 - 24 May 2015); 13 pages, LaTeX, 13 PDF figure

Preface : CAA 2010: Computer assisted assessment: supporting student learning

The Preface for the first special issue for the International Journal of e-Assessment highlights the role of the assessment for learning agenda. It also points to papers within the special issue which relate to: (a) Overcoming the barriers to supporting student learning with computer-assisted assessment; (b) Marking and computer-assisted assessment; (c) Harnessing the technology to improve efficiency and pedagogy. The papers in this issue stress the general recognition that times are changing and that assessment needs to become embedded in the teaching/learning cycle and not purely as a checking device for the awarding institution. These papers encourage us to rise to the challenge of developing more sophisticated computer-assisted assessment systems that support student learning and there is still a lot to do

A short note on a Bernstein-Bezier basis for the pyramid

We introduce a Bernstein-Bezier basis for the pyramid, whose restriction to the face reduces to the Bernstein-Bezier basis on the triangle or quadrilateral. The basis satisfies the standard positivity and partition of unity properties common to Bernstein polynomials, and spans the same space as non-polynomial pyramid bases in the literature.Comment: Submitte

Patch-recovery filters for curvature in discontinuous Galerkin-based level-set methods

In two-phase flow simulations, a difficult issue is usually the treatment of surface tension effects. These cause a pressure jump that is proportional to the curvature of the interface separating the two fluids. Since the evaluation of the curvature incorporates second derivatives, it is prone to numerical instabilities. Within this work, the interface is described by a level-set method based on a discontinuous Galerkin discretization. In order to stabilize the evaluation of the curvature, a patch-recovery operation is employed. There are numerous ways in which this filtering operation can be applied in the whole process of curvature computation. Therefore, an extensive numerical study is performed to identify optimal settings for the patch-recovery operations with respect to computational cost and accuracy.Comment: 25 pages, 8 figures, submitted to Communications in Computational Physic