1. May 12, 2005

andrew410

A pion at rest ($$m_pi = 273m_e$$) decays to a muon (mass = 207$$m_e$$ and an antineutrino (mass = 0). Find the kinetic energy of the muon and the energy of the antineutrino in electron volts.

How am I supposed to start this problem? ANy help would be great...thx!

2. May 12, 2005

dextercioby

If the muonic antineutrino has no rest mass,then his energy & rel.momentum vector in modulus are linked through

$$E_{\bar{\nu}_{\mu}}=pc$$

The key point is that both energy (seen as the time component of the energy-momentum 4-vector) and relativistic momentum (seen as the space components of the energy-momentum 4-vector) are conserved.

Daniel.

P.S.Einstein's formula is $$E^{2}=m^{2}c^{4}+\left|\vec{p}\right|^{2}c^{2}$$.