AMS-02: no cutoff in positron fraction up to \(400^+\GeV\)

Fer137 has pointed out that the AMS-02 collaboration has published some new data a few days ago.



In contradiction with my previous sociological speculations 14 months ago, they still don't show any cutoff after 11 million electron-positron events have been taken into account.




See AMS-02's Twitter account or this NASA page for some more images and links to documents about their incomplete 2014 release (it's really this PDF file that is new) that hasn't taken the form of a paper yet.

Discovery News published a short article, too.




There's of course still some room for cutoff but AMS-02 disappointingly continues to prolong the status quo in this particular approach to detect dark matter. Recall that certain popular theories of WIMP dark matter predict that the positron fraction should be a function of energy that gradually increases but suddenly drops dramatically if the energy is increased.

With these new graphs – accurate but disappointing graphs – Sam Ting's hype about his experiment last year looks more bizarre than ever before.