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: Neutral meson problem

  1. Oct 16, 2008 #1
    I have been learning about quarks which is really interesting, but i have become confused when it comes to mesons. I have learned the basics of annhilation, particle and anti-particle, etc, but I have learned that neutral mesons, such as the pi neutral meson are made of a quark, (e.g. up), and its corresponding anti-particle, (e.g. anti-up), so why do the particles join together to form the meson, shouldn't the particles annhilate?

    Pi+ meson= up quark, anti-down quark
    Pi neutral meson= up quark, anti-up quark/ down quark, anti-down quark
    Pi- meson= down quark, anti-up quark
  2. jcsd
  3. Oct 16, 2008 #2


    User Avatar
    Homework Helper

    ...apparently this is why we don't see a lot of Pi mesons around on a day to day basis... the lifetime of the Pi is pretty short (or long depending on what you compare it to)...

    The situation is *similar* (I stress similar because the analogy is quite imperfect, yet perhaps helpful) with "positronium" in which a positron and an electron can briefly form a bound state. But, they eventually annihilate.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook