Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Integral of d3p

  1. Oct 5, 2013 #1
    I was recently told that the integral for a 3-momentum d^3p = 4∏∫p^2 dp

    But I dunno what how is this integtal done.

    Any help?
  2. jcsd
  3. Oct 5, 2013 #2


    User Avatar
    Science Advisor
    Gold Member

    This integral was done in spherical coordinates
    [itex]\int dxdydz = \int r^{2}sin(\theta)dr d\theta d\phi[/itex]
    if what you're integrating over does not depend on [itex]\theta[/itex] or [itex]\phi[/itex], then you can integrate over those variables giving you an additional factor of [itex]4 \pi[/itex]. Thus
    [itex]\int dxdydz = 4\pi \int r^{2}d r[/itex].

    I expect d^3p is shorthand for dp_{x}dp_{y}dp_{z}.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook