The Tevatron produces millions of collisions each second in CDF and DZero. The detectors have hardware triggers to decide if a collision is "interesting," that is it contains a candidate event for any one of a number studies. Our dataset contains 48,844 candidate events for a W mass study. There are other datasets to study Z mass, top and b quarks, QCD, etc.
Why don't all the W decays give exactly the same mass? Are all these candidates really Ws? What if we chose only some of these data. How would our choice effect the value of the transverse mass? Work with your classmates. Test the data to see what you can learn. 

Record the best estimate of the W transverse mass from your data analysis. Explain which data you used and why. Check with your classmates and explain any differences between your estimate and theirs.
Compare your graph of the W transverse mass with a graph from CDF. How do your mass values for W and Z compare to the value in the Particle Data Book, http://pdg.lbl.gov/? Explain. 
Assignments: Identifying W 