How to turn a proton into neutron by e+p->n?

1. Aug 2, 2008

NERV

how to turn a proton into neutron by e+p-->n?

Just as the topic said,is it possible to turn a proton into a neutron by forcing a electron into the proton?If it's possible,what condition is it required?

2. Aug 3, 2008

ZharAngel

$$n^0 \rightarrow p^+ + e^- + \overline\nu _e$$

Last edited: Aug 3, 2008
3. Aug 3, 2008

humanino

Re: how to turn a proton into neutron by e+p-->n?

Actually it's completely possible provided your electron has enough energy, it will turn itself into a neutrino and the proton into a neutron (via $W^{-}$ exchange, a u becomes a d, both quarks being in the same SU(2) isospin doublet connected by this exchange).

Note that the reaction is as interesting as its final state is daunting.

4. Aug 3, 2008

NERV

Re: how to turn a proton into neutron by e+p-->n?

I know there is a way of electron capture.But,how much energy is it needed?In other words,WHAT CONDITION is the capture reaction required?

5. Aug 3, 2008

humanino

Re: how to turn a proton into neutron by e+p-->n?

Electron capture usually refers to unstable isotope. It's a spontaneous atomic and nuclear process. I was referring to an electron beam on a hydrogen target. But in any case, the energy required will be given by the differences between the masses (and you can neglect the mass of the neutrino !). If you have an electron incident on a free proton, the balance is positive anyway by slightly less than 0.8 MeV.

6. Aug 3, 2008

NERV

Re: how to turn a proton into neutron by e+p-->n?

Thanks a lot.Your quote was what I was answering #2,not for you ^-^.And you seems to have the same idea(to beam hydrogen targets with electrons).