(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

This should be quite a simple problem, i'm tying myself in knots with it though regardless. Anyway,

An electron of energy 9.0 GeV and a positron of energy E collide head on to produce a B meson and an anti B meson (B nought mesons), each with a mass of 5.3 GeV/c^2 . What is the minimum positron energy required to produce the B Meson pair? (You may neglect the rest mass energies of the electron and the positron).

2. Relevant equations

Invarience of the interval? Lorentx transforms for energy and momentum?

3. The attempt at a solution

Obviously not a linear subtraction (I wish). In the CM (ZM/COM) frame, it seems to me that the electron and the positron have equal energies, E, where E= 5.3GeV

Their momenta are equal and opposite, and the value for the invarient of the whole system is 4*(5.3 GeV)^2

gamme = g

If I then use E' = g(E - vp) and take p to be zero as the unprimed frame is the cm frame, I can work out the velocity - but then I get stuck, and I'm a bit dubious about this wole last step. (The idea would then be to transform the total energy by the same amount and subtract the 9 from it)

Any help would be greatly appreciated, as would any quicker (non 4 vector based please because this is first year undergrad stuff), methods.

Thanks

Cpfoxhunt

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Special Rel Colliding Particles Problem

**Physics Forums | Science Articles, Homework Help, Discussion**