From: ram@zedat.fu-berlin.de   
      
   Anthk NM  wrote or quoted:   
   >Hidden dimensions could explain where mass comes from   
      
     So now you might ask yourself: what exactly is "mass"?   
      
          These days, that kind of question usually comes up in the   
     context of quantum field theory.   
      
          There we use something called a Lagrangian density, which is kind   
     of a pain to write in plain ASCII, but it basically looks like this   
     for a free field (no interactions):   
      
   Lagrange = Psi-bar( i gamma^mu diff_mu - m )Psi.   
      
     In Unicode form, it would be more like:   
      
   𝓛 = 𝛹̅( i 𝛾^𝜇 ∂_𝜇 - m )𝛹.   
      
     Here, the first term (the one before the minus sign) is the "kinetic   
     term", and the second one is the "mass term".   
      
          For fields we already know, this lines up with what we normally   
     mean by mass.   
      
          So if you come across some new kind of field theory that ends   
     up giving you a Lagrangian of this general form, then whatever shows   
     up in place of that "m" is what we call the "mass".   
      
          (The example I picked technically only applies to Dirac fermions,   
     but the same idea works for other kinds of particles too.)   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)