Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Dlarah on 19/08/2008 02:22:19

Title: How can a neutron decay into a proton and an electron?
Post by: Dlarah on 19/08/2008 02:22:19

This question might sound stupid,and it might have been dealt with, but I'll ask anyway. In the case of betides this happens N>P+e+Ve  (Neutron becomes a proton and emitts an electron and an anti-neutrino). A proton is made of two up-quarks and one down-quark, a neutron is made of one up-quark and two down-quarks. The real question is, how can a neutron decay into a proton and an electron? Are neutrons made of electrons? And does the down-quark have more mass than the up-quark?

Title: Re: How can a neutron decay into a proton and an electron?
Post by: DoctorBeaver on 19/08/2008 11:25:04

To answer the last 2 questions first - no, a neutron is not made of electrons. You answered that question yourself by saying that a neutron is made of 1 up & 2 down quarks. As for mass, an up quark is 3MeV,a down quark is 7MeV, an electron is 0.5MeV, and neutrinos are massless.

There are 2 types of Beta decay. B- is where an electron is emitted, and B+ where it is a positron.

In B- decay, a down quark is converted to an up quark by emitting a W- boson. The W- boson then decays into an electron and an anti-neutrino.

B+ decay cannot occur by itself as it requires energy input. It can only occur between 2 nuclei where the binding energy of 1 is lower than that of the other.

Title: Re: How can a neutron decay into a proton and an electron?
Post by: Dlarah on 20/08/2008 16:03:21

Thank you bery much DoctorBeaver. The answer was very good and appreciated; I understand the concept better now.