Thursday, June 12, 2014

Quick Physics Notes

* The seven standard deviation difference between ordinary the proton charge radius, and the muonic hydrogen charge radius is greatly exaggerated because the margin of error of the proton charge radius measurement was greatly underestimated.  An accurate MOE for the proton charge radius reduces the discrepancy to four standard deviations.

* Another study finds that dark photons cannot explain the muon anomalous magnetic moment (whose measured value shows a 3.6 sigma discrepancy from the Standard Model prediction).  The same data set from 1980-1982 whose implications were not appreciated at the time, also significantly constrains the parameter space of sub-GeV dark matter generally.

* A review of the parameter space of a large class of singlet fermion dark matter models (with CDM particle masses up to 1 TeV) which are mediated by an extra Higgs boson are ruled out experimentally.

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