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CATEGORIES:Institute of Astronomy Seminars
SUMMARY:Neutrinos and Other Dark Lights:  Cosmological Con
 straints - Lloyd Knox (UC Davis)
DTSTART;TZID=Europe/London:20120425T134500
DTEND;TZID=Europe/London:20120425T141500
UID:TALK37643AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/37643
DESCRIPTION:A number of lines of evidence\, both laboratory an
 d astrophysical\,  \nsuggest that there are extra 
 (sterile) neutrino species\, or otherwise  \nextra
  light and dark degrees of freedom ('dark lights')
  than exist in  \nthe standard model of particle p
 hysics.  I will review the physical  \norigin of c
 osmological constraints on $N_{\\rm eff}$ which is
  the  \nenergy density in dark lights expressed in
  units of the contribution  \nfrom one active and 
 massless neutrino species.  I will also review the
   \ncurrent constraints from light element abundan
 ces\, high-resolution  \ncosmic microwave backgrou
 nd data\, distance vs. redshift measurements\,  \n
 and galaxy cluster abundances.\n\n
LOCATION:Sackler Lecture Theatre\, IoA
CONTACT:Ben Davies
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