# A massive force carrying particle? The weak nuclear force, the W boson has mass?

1. Jul 15, 2010

### filegraphy

I was looking at the list of the force carrying particles and all of their masses read zero other than the W boson of the weak nuclear force.

Q: Does the W boson travel at the speed of light even if it is massive? (I am guessing not)
Q: If the W boson is massive then it emits other gauge bosons in a gravitational field. How can this be? A boson emit other bosons?
Q: Does the W boson have spin or charge?

Thank you for answering.

2. Jul 15, 2010

### mathman

3. Jul 16, 2010

### the_house

The Z boson also has mass.

No, a W boson will not travel at the speed of light.

I don't really want to talk about gravitons, but a W boson has electric charge and so it couples directly to photons (see the next question). So there's no problem with a boson emitting other bosons.

The W is a spin 1 particle with electric charge of +1 or -1. See the pdf that mathman linked to for more details.

4. Jul 16, 2010

### ansgar

why not, it is virtual and does not satisfy E^2 = P^2 + M^2

5. Jul 16, 2010

### tom.stoer

The W-boson need not be a virtual particle; it is only a particle with a rather short lifetime; but in that sense even neutrons are only virtual particles.

A virtual particle does not have a velocity at all. A virtual particle is not a single particle but a "bunch of all particles possible in momentum space" with an "integral over momentum space".

6. Jul 16, 2010

### filegraphy

Thank you all for the answers. That makes sense that the W and Z bosons cannot travel at the speed of light because there fore would require infinte amount of energy to get it to that speed causing it to have an infinite amount of mass.

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