1-loop SQCD corrections to the decay of top-squarks to charm and neutralino in the generic MSSM

In this article we calculate the 1-loop supersymmetric QCD (SQCD) corrections to the decay $\tilde u_1\to c \tilde\chi^0_1$ in the MSSM with generic flavour structure. This decay mode is phenomenologically important if the mass difference between the lightest squark $\tilde u_1$ (which is assumed to be mainly stop-like) and the neutralino LSP $\tilde \chi^0_1$ is smaller than the top mass. In such a scenario $\tilde u_1\to t \tilde\chi^0_1$ is kinematically not allowed and searches for $\tilde u_1\to W b \tilde\chi^0_1$ and $\tilde u_1\to c \tilde\chi^0_1$ are performed. A large decay rate for $\tilde u_1\to c \tilde\chi^0_1$ can weaken the LHC bounds from $\tilde u_1\to W b \chi^0_1$ which are usually obtained under the assumption ${\rm Br}[\tilde u_1\to W b \chi^0_1]=100\%$. We find the SQCD corrections enhance $\Gamma[\tilde u_1\to c \tilde\chi^0_1]$ by approximately 10\% if the flavour-violation originates from bilinear terms. If flavour-violation originates from trilinear terms, the effect can be $\pm 50\%$ or more, depending on the sign of $A^t$. We note that connecting a theory of SUSY breaking to LHC observables, the shift from the $\overline{\rm DR}$ to the on-shell mass is numerically very important for light stop decays.Comment: 25 pages, 7 figure

The MSSM without Gluinos; an Effective Field Theory for the Stop Sector

In this article we study the MSSM with stops and Higgs scalars much lighter than gluinos and squarks of the first two generations. In this setup, one should use an effective field theory with partial supersymmetry in which the gluino and heavy squarks are integrated out in order to connect SUSY parameters (given at a high scale) to observables in the stop sector. In the construction of this effective theory, valid below the gluino mass scale, we take into account $O(\alpha_3)$ and $O(Y_{t,b}^2)$ effects and calculate the matching as well as the renormalization group evolution. As a result, the running of the parameters for the stop sector is modified with respect to the full MSSM and SUSY relations between parameters are broken. We show that for some couplings sizable numerical differences exist between the effective field theory approach and the naive calculation based on the MSSM running.Comment: 14 pages, 2 figure

B physics Beyond the Standard Model at One Loop: Complete Renormalization Group Evolution below the Electroweak Scale

General analyses of $B$-physics processes beyond the Standard Model require accounting for operator mixing in the renormalization-group evolution from the matching scale down to the typical scale of $B$ physics. For this purpose the anomalous dimensions of the full set of local dimension-six operators beyond the Standard Model are needed. We present here for the first time a complete and non-redundant set of dimension-six operators relevant for $B$-meson mixing and decay, together with the complete one-loop anomalous dimensions in QCD and QED. These results are an important step towards the automation of general New Physics analyses.Comment: 37 pages, 3 figures + ancillary mathematica package. Version published in JHEP, with a corrected list of lepton-number-violating operator

Silence, Rape and Politics in 'Measure for Measure': Close Readings in Theatre History.

Post print version of article deposited in accordance with SHERPA RoMEO guidelines. Copyright © 2008, Johns Hopkins University Press. This article first appeared in Shakespeare Bulletin Vol.27 pp 1-23. Reprinted with permission by The Johns Hopkins University Press.Ever since John Barton, in 1970, deliberately gave Measure for Measure an ‘open’ ending, the indeterminacy of the play’s conclusion has been widely recognised. It forms the crucial problem investigated by Philip McGuire’s chapter on the play in Speechless Dialect: Shakespeare’s Open Silences (1984), in which he analysed the six distinct ‘open silences’ that punctuate the last Act. This article revisists McGuire’s work in the light of more recent developments in theatre history and performance studies and investigates the relationship between rape, silence and politics in Act Five of Measure for Measure. Combining a reappraisal of Isabella’s silences in the light of Tiffany Stern’s work on actors’ parts with a theoretically self-conscious application of close reading techniques to archival records of a range of RSC performances (reviews, promptbooks, photographs, archival video recordings, actors’ and directors’ comments), I show how Isabella’s silent body in performance generates political meanings that can only be decoded through detailed attention to the performance text and its relation to its historical context