1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Question about relativistic energy

  1. May 12, 2005 #1
    A pion at rest ([tex]m_pi = 273m_e[/tex]) decays to a muon (mass = 207[tex]m_e[/tex] 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. jcsd
  3. May 12, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper

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

    [tex] E_{\bar{\nu}_{\mu}}=pc [/tex]

    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.


    P.S.Einstein's formula is [tex] E^{2}=m^{2}c^{4}+\left|\vec{p}\right|^{2}c^{2} [/tex].
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook