Here is another one of the four identified tau neutrino interactions from the 2000 data set. From the emulsion data and the spectrometer readings we can see that the neutrino in question interacted in a steel layer with a lead nucleon, forming a tau. The tau then traveled the length of the next emulsion layer to the following steel sheet where it interacted to form a unknown hadron which is indicated by the diverted gray track. The different views of the interaction show the event in several coordinate systems and measuring scales. In this interaction it is particularly interesting to view the event in different coordinate systems. In the picture at the bottom left corner the interaction vertex clearly has 3 product tracks. In the picture in the top right corner, however, the event vertex appears to have only two particle tracks and the tau seems to decay to two daughter particles. What has happened, which is evident in the third figure in the bottom right corner, is that in the second image the tau and hadron tracks from the even vertex are colinear, layed one on top of each other.
Last updated: 6/29/01 comment