There’s a new paper from the PAMELA dark matter search out that’s written up in Physics, including a link to a free version of the PDF. This paper is considerably less dramatic than one that appeared last year, leading Physics World to suggest that they’re backing off the earlier claim.
What’s the deal? Sean Carroll has you covered, with a detailed explanation of what’s in both papers, and why the findings have been published and reported the way they have:
What happened is that the PAMELA collaboration submitted their second paper (anomalous positrons) to Nature, and their first paper (well-behaved antiprotons) to Physical Review Letters. The latter paper has just now appeared in print, which is why Simon Swordy’s commentary in Physics appeared, etc. Although the idea behind Physics (expert-level commentary on recently published articles) is a good one, it’s sponsored by the American Physical Society, and therefore pretends that the only interesting articles are those that appear in journals published by the American Physical Society. Which Nature is most surely not.
So one might get the impression that the antiproton result is a blow against the idea that we are seeing dark-matter annihilations. Which it is; if you didn’t know any better, you would certainly expect to see an excess of antiprotons in dark-matter annihilations just as surely as you would expect to see an excess of positrons. But it’s not a new blow; the papers appeared on arxiv (which is what really matters) at the same time!
It’s a good post, both on the science and the messy process of publicizing the science. There’s some interesting discussion in the comments of the problems with treating the arxiv as “what really matters” as well, which ties back to all those tedious posts about filthy journalists vs. noble bloggers and so on.