January+7-January+14

January 7
Today, I arrived at 3:35, and as a group we discussed our progress thus far in isolating cosmic rays. We narrowed our discoveries to four main criteria: 1. (Phi 1 + Phi 2) or (Eta 1 + Eta 2) should cancel each other out. The detector reads the single cosmic ray as a two-particle event, separating it into parts 1 and 2. Phi and Eta 1 and 2 are read being opposites due to the linear trajectory of the cosmic ray. 2. The Phi values of a cosmic ray should fall below around 1/2 pi and above around -1/2 pi. 3. (E1+E2)/M should be equal to about 1. Regarding the equation E^2=m^2+p^2, the momentum of a cosmic ray is read as zero by the detector for similar reasons that phi and eta sums are read as zero (straight line trajectory, momentum is read as equal and opposite in "parts" 1 and 2) 4. The mass of a cosmic ray should be above 40 GeV based on many scatterplots, histograms, etc.

We discussed an additional criterion to use to isolate the cosmic rays. We began discussing the charges of particles, represented in our data by Q. (If Q is positive, the particle is positively charged). We predict that the value of Q1*Q2 would be negative for cosmic rays. This is because the detector assumes the two particles (that are actually one cosmic ray) are oppositely charged. Multiplying two unlike charges results in a negative value, whereas multiplying two like charges results in a positive (+*+=+, -*-=+).

When I plotted Q1*Q2 against Event Number, the majority of the particles were negative, with the exception of a few positive values.

I highlighted these values so that I might be able to see if they meet the 40 GeV requirement for cosmic rays.



All of the particles that were highlighted as having a positive Q1*Q2 value are also less than 40 GeV. Because of this, I can assume it is reasonable to cut out any positive Q1*Q2 values as not being cosmic rays.