Date: October 27, 2009
Time: 12:30 pm - 1:30 pm

Title: "The f(Ds) Puzzle"
Date: Tuesday, October 27, 2009

Time: 12:30 p.m. - 1:30 p.m.
Calendar: Experimental Particle Physics Seminars
Speaker: Andreas Kronfeld
Location: Orange Room
Institution: Fermilab

Recent measurements of the branching fraction for $D_s\to\ell\nu$ disagree with the Standard Model by around $2\sigma$. In this case the key aspect of the Standard Model is the calculation of the decay constant, $f_{D_s}$, with lattice QCD. This talk explains how the lattice QCD calculation(s) are done, and surveys the experimental measurement. Should the discrepancy strengthen again (it was earlier $3.8\sigma$), it would be a signal of new physics. Models that could explain such an effect will also be discussed.