High Energy Physics Seminars

I will first analytically show a simple, yet subtle "invariance" of two-body decay kinematics for the case of a massless daughter and a mother particle which is unpolarized and has a generic boost distribution in the laboratory frame. Namely, the laboratory frame energy distribution of the massless decay product has a peak, whose location is identical to the (fixed) energy of that particle in the rest frame of the corresponding mother particle. As a proof of principle of the usefulness of this observation, I will then apply it for measuring the mass of the top quark at the LHC, using simulated data and including experimental effects. Finally, I will show how it can be used to measure all the superpartner masses in a cascade decay chain of the gluino.