Register to reply

Beta plus decay: mass balance?

by Chem.Stud.
Tags: balance, beta, decay, mass
Share this thread:
Chem.Stud.
#1
Aug13-13, 09:49 AM
P: 27
Hi:

I am taking a radiochemistry class, and I am confused by beta plus decay.

(1) p --> n + positron + electron-neutrino

The mass of a proton is less than the mass of a neutron. In addition, the neutrino has mass as does the positron.

(2) E = mc2

There must be come sort of balance, must there not? Mass cannot be created unless energy is consumed. So where does the nuclei get the energy from to convert a single proton into three different particles, one of which has a larger mass than the proton itself?

I hope I have made my confusion understandable. Also, my macbook would not let me use the greek characters or sub- and superscript.

Sincerely,
Anders
Phys.Org News Partner Physics news on Phys.org
Physicists unlock nature of high-temperature superconductivity
Serial time-encoded amplified microscopy for ultrafast imaging based on multi-wavelength laser
Measuring the smallest magnets: Physicists measured magnetic interactions between single electrons
SteamKing
#2
Aug13-13, 10:13 AM
Emeritus
Sci Advisor
HW Helper
Thanks
PF Gold
P: 6,321
The beta-plus decay cannot occur in a single proton due to the need for energy to be supplied from some external source.

See: http://en.wikipedia.org/wiki/Beta_decay

In heavier nuclei, beta-plus decay can occur if the original nucleus has a higher binding energy than the nucleus which remains after the emission of the beta-plus particle.
Chem.Stud.
#3
Aug13-13, 10:17 AM
P: 27
Ahh, that makes sense. Thank you for your help.


Register to reply

Related Discussions
Beta- decay and mass deficit Advanced Physics Homework 0
Beta decay mass condition High Energy, Nuclear, Particle Physics 8
Mass/charge balance of Beta decay/nuclear reactions Introductory Physics Homework 1
Beta decay of neutron gives a quark mass of Proton (uud) and e- much less than udd High Energy, Nuclear, Particle Physics 17
Boson and electron mass and speed in beta decay High Energy, Nuclear, Particle Physics 1