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:

  1. Z TMass = Z transverse mass or Z mass in a 2-dimensional x-y plane perpendicular to the beam pipe

  2. 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/c2

Z Mass
GeV/c2

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:

  1. Bin the data for each of the two masses.

  2. Make two histograms of the binned masses, one for the transverse mass and one for the mass.

  3. Plot frequency vs. binned masses for each.
Help with data analysis.

What do the histograms tell us?

  1. Read the peaks on the histograms and record the Z transverse mass and the Z mass from these datasets.

  2. Calculate the W mass correction factor, the ratio of the masses (Z Mass)/(Z TMass).

  3. Calculate the W mass: multiply the W transverse mass by the correction factor.

  4. Compare your values for W and Z with those in the Particle Data Book. Explain.

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