Tuesday, January 6, 2015

Standard Model Particles Don't Couple To Dark Matter

The latest data from the LHC confirms the conclusion that none of the Standard Model particles have meaningful couplings or interactions with relatively light dark matter particles to a high degree of precision.

The cross section of interaction is constrained to be less than 0.22 fb in the most restrictive mono-photon channel, and less than 6.5 fb in the least restrictive Higgs boson channel at the 95% confidence level. The energy scale of which new physics that would allow couplings between dark matter and Standard Model particles to appear is not less than 600 GeV at the 95% confidence level.

The analysis is limited to dark matter particles with masses of 100 GeV or less.

One fb (femtobarn) equals 10-43m2 which is equivalent to 10-39cm2.

These exclusions are less strict than existing direct dark matter detection experiments for dark matter particles with masses of more than 10 GeV, (which are as strict as 10-45cm2), but add considerable rigor to the extent to which interactions between Standard Model particles and light dark matter particles are excluded. The energy threshold also severely constrains the circumstances under which dark matter particles of up to 100 GeV can be created as anything other than thermal relics.

The cross section for a typical interaction involving a neutrino is 5*10^-44 (E/[1 MeV])^2 cm^2." So, the exclusion is on the same order of magnitude as for a 25 MeV energy neutrino.

1 comment:

andrew said...

More dark matter annihilation signals bite the dust.