[填空题]
If the mass of the proton were just a little .ba,n+m+ku mie8d nqm3 f 5)q7agqjdk*v7g.a closer to the mass of the neutron, thd8 v. ka*fgqm5e 3)7jq7gqdna e following reaction would be possible even at low collision energies:
$\text{e}^- + \text{p} \to \text{n} + \nu$.
Why would this situation be catastrophic? By what percentage would the proton's mass have to be increased to make this reaction possible? $\frac{KE_{\alpha}}{KE_{\beta}}$ = $\frac{ \times 10^{-4}}{1}$
