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Creating a beam of antiprotons allows to create antineutrons by charge exchange. How does this exchange work? The question pops up after the question "Is there a strong evidence of antineutron existance?"

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HolgerFiedler
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There are lots of possibilities, depending on the energy of the antiproton beam. The hadron spectrum is quite complicated.

Probably the most likely channel is pion production: $$ \bar p \to \bar n + \pi^-. $$ This reaction requires a "spectator" nucleus to exchange energy and momentum with the $\bar p$, and so might be more properly written as $$ A + \bar p \to A^* + \bar n + \pi^- $$ where by $A^*$ I mean that the spectator nucleus might also end up in an excited state. The negative pions will eventually either decay (mostly $\pi^-\to\mu^-+\bar\nu_\mu$) or be captured on another nucleus in a reaction like $$ \pi^- + p \to n. $$ That's not the only available channel: with a spectator nucleus, you can make other antibaryons and mesons, for instance \begin{align} \bar p &\to \bar\Delta + \pi && \text{(which could make $\pi^\pm$ or $\pi^0$)} \\ \bar p &\to \bar\Lambda + K^- \\ \bar p &\to \bar\Sigma + K && \text{(could be a $K^0$ or a $K^-$)} \\ &\vdots \end{align}

Here's a review of low-energy nucleon-antinucleon interactions, which I haven't yet read.

rob
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