I am looking into events within bubble chamber images and have come across a stumbling block. It relates to finding masses of neutral particles within bubble chamber images, specifically the mass of the neutral lambda baryon, with an accepted mass of ~1.116 GeV/c^2.
We are looking into lambda baryon decays into a proton and a negative pion, and have been unsuccessful in finding a method of calculating the lambda's mass. Our supervisor referred us to a method called the "Manchester Alpha Parameter", which involves finding the angles at which the decay products are emitted. However, we can find no mention of this method anywhere online.
I have tried to find other ways of calculating the mass, but they all make comments on the proton's curvature being too small to take reliable measurements from. Are there any methods that I could look into where (by only having access to bubble chamber event images and crude measurement tools i.e. rulers, protractors, etc) we could recover an acceptable mass value for the lambda baryons?