Special Lagrangians, stable bundles and mean curvature flow

We make a conjecture about mean curvature flow of Lagrangian submanifolds of Calabi-Yau manifolds, expanding on \cite{Th}. We give new results about the stability condition, and propose a Jordan-H\"older-type decomposition of (special) Lagrangians. The main results are the uniqueness of special Lagrangians in hamiltonian deformation classes of Lagrangians, under mild conditions, and a proof of the conjecture in some cases with symmetry: mean curvature flow converging to Shapere-Vafa's examples of SLags.Comment: 36 pages, 4 figures. Minor referee's correction

A Classification and Analysis of Higgs-flavor Models

A classification is given of Higgs-flavor models. In these models, there are several Higgs doublets in an irreducible multiplet R_{Phi} of a non-abelian symmetry G_{Phi}, under which the quarks and leptons do not transform (thus giving minimal flavor-changing for the fermions). It is found that different G_{Phi} and R_{Phi} lead to very distinctive spectra of the extra Higgs doublets, including different numbers of "sequential Higgs" and of "inert Higgs" that could play the role of dark matter, different mass relations, and different patterns of SU(2)_L-breaking splittings within the Higgs doublets.Comment: 35 page

Improving estimates of the number of fake leptons and other mis-reconstructed objects in hadron collider events: BoB's your UNCLE. (Previously "The Matrix Method Reloaded")

We consider current and alternative approaches to setting limits on new physics signals having backgrounds from misidentified objects; for example jets misidentified as leptons, b-jets or photons. Many ATLAS and CMS analyses have used a heuristic matrix method for estimating the background contribution from such sources. We demonstrate that the matrix method suffers from statistical shortcomings that can adversely affect its ability to set robust limits. A rigorous alternative method is discussed, and is seen to produce fake rate estimates and limits with better qualities, but is found to be too costly to use. Having investigated the nature of the approximations used to derive the matrix method, we propose a third strategy that is seen to marry the speed of the matrix method to the performance and physicality of the more rigorous approach.Comment: v1 :11 pages, 5 figures. v2: title change requested by referee, and other corrections/clarifications found during review. v3: final tweaks suggested during review + move from revtex to jhep styl

Interplay of Spin and Orbital Angular Momentum in the Proton

We derive the consequences of the Myhrer-Thomas explanation of the proton spin problem for the distribution of orbital angular momentum on the valence and sea quarks. After QCD evolution these results are found to be in very good agreement with both recent lattice QCD calculations and the experimental constraints from Hermes and JLab