# Why isn't Higgs coupling considered a fifth fundamental force?

When I first learned about the four fundamental forces of nature, I assumed that they were just the only four kind of interactions there were. But after learning a little field theory, there are many other kinds of couplings, even in the standard model. So why isn't the Yukawa Higgs coupling considered a fifth fundamental force? To be a fundamental force, does there need to be a gauge boson mediating it?

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I think you're more or less right; what have been (sociologically) canonized as the fundamental forces (minus gravity) roughly correspond to the factors $U(1)$, $SU(2)$, and $SU(3)$ in the famous "$U(1)\times SU(2)\times SU(3)$" gauge symmetry of the standard model. But this is really a historical question, in my opinion. – j.c. Nov 18 '10 at 18:40
Uhm... how about: maybe because it wasn't observed yet? I think that is a pretty serious blow to anything trying to call itself fundamental :-) – Marek Nov 18 '10 at 18:58
Doesn't look like this has been mentioned yet: intuitively, forces are vectors and impart momentum, whereas the Higgs field is a scalar field that generates mass. If a fundamental interaction isn't mediated by a gauge boson, then it loses it's most force-like quality of being a vector field. – David H Mar 28 at 4:09