Getting to Higgs
Finding Evidence for W: Z Mass Histograms
Data for 2,012 candidate Z events are in an Excel spreadsheet with the following data as shown in the table below:
 Z TMass = Z transverse mass or Z mass in a 2dimensional xy plane perpendicular to the beam pipe
 Z Mass = Z mass calculated from all three dimensions of momenta

A 
B 
C 
D 
E 
F 

1 
Run No. 
Event No. 
Z TMass GeV/c^{2} 
Z Mass GeV/c^{2} 
Bin Z MT 
Bin Z M 
2 
63977 
63165 
54.40164 
70.40511 


3 
67642 
17809 
55.24385 
87.24314 


We will use this information to determine a correction factor for the W transverse mass based on these Z mass datasets.
Get the data.
To find the W correction factor, we begin by graphing the two Z mass values from our data:
 Bin the data for each of the two masses.
 Make two histograms of the binned masses, one for the transverse mass and one for the mass.
 Plot frequency vs. binned masses for each.
Help with data analysis.
What do the histograms tell us?
 Read the peaks on the histograms and record the Z transverse mass and the Z mass from these datasets.
 Calculate the W mass correction factor, the ratio of the masses (Z Mass)/(Z TMass).
 Calculate the W mass: multiply the W transverse mass by the correction factor.
 Compare your values for W and Z with those in the Particle Data Book. Explain.