Precise nuclear measurements give clues to astronomical X-ray bursts (Forwarded)

{{Date: Mon, 14 Jul 2003 10:57:24 -0400
From: Andrew Yee
For example, arsenic-67 can capture a proton to become selenium-68. ...
Some nuclides, like selenium-68, can't absorb an incoming proton as
quickly as others can. The reaction must "wait" for the nucleus to
absorb a proton -- which may take up to 30 minutes, a relative
eternity -- or for the neutron to decay to a proton, called beta
decay, to convert the nuclide into one with a more favorable capture
rate.}}

That's bad English. You were talking about capture of a proton, not a
neutron, so the phrase "the neutron" has no meaning here.

{{A beta-decay, for example, converts the selenium-68 nucleus into
arsenic-68.}}

But in that case the captured proton decays to a neutron.
I wonder if some proofreader thought "neutrons decay to protons, not
vice versa, so let me correct the text" without thinking that in the
high energy state we're talking about electrons and positrons and gamma
rays are flying all over the place providing enough energy to push a
proton up the energy hill to "decay" to a neutron?

By the way, one or the other (p - n, or n - p), I can't remember
which, is called "inverse" beta decay, right? Yeah:
http://scienceworld.wolfram.com/phys...BetaDecay.html
Inverse Beta Decay
The recombination of a proton p and an electron e to produce a neutron
n and electron neutrino [iimg327.gif]
So that's a second typo in the posted article.
More confirmation:
http://classweb.howardcc.edu/astrono...15/tsld059.htm
In this process, which occurs at a significant rate only under
conditions of very high pressure, a proton and an electron are
forced together, forming a neutron and a neutrino. Energy is
absorbed in the process, rather than being produced.
Yup, that sounds like the conditions on the surface of a neutron star
during this runaway thermonuclear fusion event.