Andy Beretvas

More than expected

CDF observes approximately 740 events in the muon decay mode. CDF looked for a signature of three muons, the mass of two oppositely charged muons being consistent with that of the J/ψ particle.

Estimated and observed distribution for our algorithm, which is used to identify WW events. High values of NN indicate a more signal-like event. In a recent measurement, the CDF experiment studied in detail events with two massive W vector bosons produced with associated jets (a spray of particles resulting from an energetic quark or gluon). These types of events are widely considered to be a window for looking for physics beyond the Standard Model. Each W can decay into a… More »

This plot shows the forward-backward asymmetry in bottom quark production at the Tevatron as a function of the mass of the bottom-antibottom system compared to predictions with and without axigluons. When a top-antitop quark pair is produced at the Tevatron, does the top quark go more often in the direction of the collision beam’s proton or antiproton? Early measures of the forward-backward asymmetry — the difference in direction between an outgoing pair of particles relative to the incoming colliding particles… More »

Comparison of expected and observed distributions of both Z invariant masses. The region CDF looked at contained only seven events (inside the blue lines). While the production of a single W or Z boson in particle collisions at the Tevatron happened quite often and has been a reference for precise electroweak measurements, a pair of such bosons was produced less frequently. Scientists predict that, in collisions between protons and antiprotons, a ZZ boson pair is produced only once for every… More »