It should normally only take 10-15 minutes for an artifact to propagate to Maven Central after the staging repositories have been released in Sonatype OSSRH. If the artifacts do not show up on the browse view at http://search.maven.org/#browse, then there might be something broken with the index that powers this view.
I asked Sonatype support about this, and luckily, the artifacts are still available in Maven Central, even if they do not show up in the search index on
search.maven.org. The search index and the browsing view are, in fact, completely decoupled from the actual storage backend, and http://search.maven.org is regularly updated about 1 to 2 hours AFTER an artifact has been pushed to Maven Central.
If an artifact does not show up in the browse view on http://search.maven.org, browse the Maven Central repository directly at http://repo1.maven.org/maven2/. Artifacts should show up there within 10-15 minutes after doing a release. If they are not visible after 20 minutes, the deployment most likely failed.