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!

What guarantees the electron mass

  1. Mar 14, 2014 #1
    I am just wondering in pair production, what is the physics that determine the mass of the electrons? Why can't the electron get more mass than the positron or the other way round?
  2. jcsd
  3. Mar 14, 2014 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    This is a bit puzzling. Maybe you should explain why, in a pair production, you think electrons can have variable masses.

    Please note that the mass of a bare electron is well-defined. A bare particle, having a mass different than an electron, is no longer an electron. We either call it a muon, or we have discovered a new particle.

  4. Mar 14, 2014 #3


    User Avatar

    Staff: Mentor

    The mass of fundamental particles is simply an intrinsic property, much like charge and spin.
  5. Mar 14, 2014 #4


    User Avatar
    Science Advisor

    The mass of the electron is something we measure from experiment. I don't believe there is any good theory for predicting the mass. We observe in bubble chambers and the like that the positron charge to mass ratio is the same as the electron charge to mass ratio. It's possible that there is some small difference in masses, but there's no compelling reason to believe so.
  6. Mar 15, 2014 #5
    The positron must have the same mass and opposite charge to the electron by CPT symmetry.

    There are (incomplete) theories that attempt to explain the masses of the electron and other fermions.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook