
#1
Jul1709, 03:22 PM

P: 173

How can a down quark emit a W when decaying if the boson is much heavier than the quark or even the whole neutron?
Actually, the three quarks together make ~10 MeV, but the neutron is said to be ~939 MeV, so there is 929 MeV missing, i though that W bosons made it up, but then i realized that the bosons mass is said to be ~80 GeV, witch is much more than missing. And gluons are said to be massless. 



#2
Jul1709, 04:49 PM

Mentor
P: 11,232

The W is a virtual particle in this case. Virtual particles are "off the mass shell," that is, they don't satisfy the massenergymomentum relationship for real particles, [itex]E^2 = (pc)^2 + (mc^2)^2[/itex]. Alternatively, people sometimes say that virtual particles can very briefly violate conservation of energy by "hiding" behind the uncertainty principle.




#3
Jul1709, 05:29 PM

P: 2,828




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