Units of Vx() and Vy() within TParticle class

Dear Root users,

Within root’s own Pythia tutorial, I am using the command ‘part->Vx();’ and ‘part->Vy()’ to get the x and y of the production vertices of particles within the TParticle class. I was wondering if anyone knows what the units are of the numbers being returned by this command. In general: what are the units of distance which are mostly being used within particle physics?

Best regards,



The units are provided by Pythia. These are mm for distances and GeV/c for momentum. See for example
Particle::xProd() in the Pythia8 documentation, http://home.thep.lu.se/~torbjorn/pythia81html/Welcome.html


Hi Lorenzo,

So to conclude, I should have done a better job at searching the internet…
Thanks for helping me in spite of that.