The world of cosmology is abuzz with rumours that an orbiting observatory called PAMELA has discovered dark matter. Last month, the PAMELA team gave a few selected physicists a sneak preview of their results at a conference in Stockholm.
Here’s the deal. The PAMELA people say their experiment has seen more positrons than can be explained by known physics and that this excess exactly matches what dark matter particles would produce if they were annihilating each other at the center of the galaxy.
What makes this particularly exciting is that other orbiting observatories have also seen similar, but less clear cut, evidence of dark matter annihilations.
Since then, the shutters have come down. With the prospect of a major discovery on their hands and with publication in a major journal at stake, the team has closed ranks to re-analyse their data and prepare it for exclusive publication. Not a word has leaked from the PAMELA team since their preliminary announcement.
That hasn’t stopped physicists speculating for themselves. Today Marco Cirelli from the CEA near Paris in France and Alessandro Strumia from the Università di Pisa in Italy present their own analysis of the PAMELA data.
Cosmologists have long speculated on the nature of dark matter and dreamt up all manner of models and particles to explain it. The big question is which type of particle does the PAMELA data point towards.
Today, Cirelli and Strumia stake their own claim. They say the data agrees with their own model called Minimal Dark Matter in which the particle responsible is called the “Wino” (no, it really is called the wino).
But given the PAMELA team’s reluctance to publish just yet, where did Cirelli and Strumia get the data? The answer is buried in a footnote in their paper.
“The preliminary data points for positron and antiproton fluxes plotted in our figures have been extracted from a photo of the slides taken during the talk, and can thereby slightly differ from the data that the PAMELA collaboration will officially publish.”
Can’t fault them for initiative.
Ref: arxiv.org/abs/0808.3867: Minimal Dark Matter Predictions and the PAMELA Positron Excess