Monday, April 15, 2013

Dark Matter and Spacecraft Flyby Anomalies

A number of sources[2][3] today reported on the possible detection of dark matter particles or WIMPs from the CDMS II experiment.  This is pretty slick for a number of reasons.  First, one of the research teams on the CDMS II experiment is located right here at Texas A&M.  Second, the other dark matter experiment that's mentioned in the nature blog, LUX, also has a team of researchers working here at A&M.   I was sitting in a professor's office discussing using liquid helium as a scintillator for the h-ray experiment a few days ago and he mentioned their use of liquid xenon as a scintillator on LUX, and now this!  For those interested, liquid xenon makes a better scintillator than liquid helium for a few reasons.  The most interesting of these to me is that helium is small enough to penetrate into a photomultiplier tube and ruin it's vacuum over time.  Basically, it's very hard to keep helium from penetrating containers.

What about the spacecraft flyby anomalies?
Finally, there's the association between dark matter and the spacecraft flyby anomalies I mentioned in my previous post[4].  I mentioned a paper[1] by Adler that studied whether or not spacecraft flyby anomalies might the result of interactions with dark matter.  The predictions for dark matter mass from Adler's paper do not match the mass measured in the data reported from CDMS II experiment today.  Adler's paper calls for a dark matter particle with a mass below 1 GeV, (look for the white asterisk in picture 1).  The CDMS II data implies a particle mass of roughly 8.6 GeV.  So, for now, no confirmation of any spacecraft interacting with dark matter halos.

References:

1.  Adler on flyby anomalies and dark matter mass
http://dx.doi.org/10.1103%2FPhysRevD.79.023505
Adler S. (2009). Can the flyby anomaly be attributed to earth-bound dark matter?, Physical Review D, 79 (2) DOI: 

2.  Nature blog on the WIMP data
http://blogs.nature.com/news/2013/04/another-dark-matter-sign-from-a-minnesota-mine.html

3.  CMDS II paper
http://cdms.berkeley.edu/CDMSII_Si_DM_Results.pdf

4.  Flyby anomalies and dark matter post
http://copaseticflow.blogspot.com/2013/04/spacecraft-flyby-anomolies.html



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