tag:blogger.com,1999:blog-7315236707728759521.post3352438226099790243..comments2024-03-27T22:28:06.861-06:00Comments on Dispatches From Turtle Island: More Neutrino Data From Daya BayAndrew Oh-Willekehttp://www.blogger.com/profile/02537151821869153861noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-7315236707728759521.post-17288785877817646792013-08-22T18:48:57.345-06:002013-08-22T18:48:57.345-06:00In a "normal" neutrino mass hierarchy, a...In a "normal" neutrino mass hierarchy, an example of a set of masses that would fit the current data would be roughly:<br /><br />Mass State 1: 1 meV/c^2<br />Mass State 2: 9 meV/c^2<br />Mass State 3: 50 meV/c^2<br />Total number of mass states: 3<br />Combined mass of three states: 60 meV/c^2<br /><br />In a normal hierarchy, there is more room (on a percentage basis) for downward uncertainty in mass state 1 than there is for mass state 1 on the upside or in the estimates of mass states 2 and 3. Mass state three is 20,000 to 40,000 times lighter than the preferred 2 keV mass estimate for warm dark matter particles.<br /><br />andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-21644529423822337082013-08-22T13:20:01.585-06:002013-08-22T13:20:01.585-06:00"The result I read in paper sixteen was Neff=..."The result I read in paper sixteen was Neff=3.30 +/- 0.27 v. Neff 3.046 for the three Standard Model neutrinos. So, their result is a little less than one sigma from the Standard Model value. A four neutrino model would have an Neff of a bit more than 4.05, which is about three sigma from the measured value which is roughly a 99% exclusion and is a confirmation of the Standard Model. <br /><br /><b>Planck also combines data from multiple sources puts a cap on the sum of three neutrino masses in a three Standard Model neutrino scenario of 0.24 eV (at 95% CI) with a best fit value of 0.06 eV. The floor from non-astronomy experiments is 0.06 eV in a normal neutrino mass hierachy (based on the difference between mass one and mass two, and between mass two and mass three which are both known to about two significant digits) and 0.1 eV in an inverted neutrino mass hierachy. In a normal neutrino mass hierarchy, this puts the mass of the electron neutrino at between 0 and 0.06 eV, with the low end preferred (I personally expect that an electron neutrino is significantly less than the mass difference between the first and second neutrino type of about 0.006 eV).</b><br /><br />Note that a particle that is in the hundreds or thousands of eVs would not count towards Neff because it is not light enough to be relativistic at 380,000 years after the Big Bang. So, it really only rules out a light sterile neutrino, rather than a heavy one. The LSND and MiniBooNE reactor anomalies have hinted at a possible fourth generation sterile-ish neutrino of about 1.3 eV +/- about 30%, so the Planck people did a study on the sum of mass limits if there were a disfavored four and not just three relativistic species and came up with a cap on sterile neutrino mass in that scenario of about 0.5 eV +/- 0.1 eV, which is about 2.5 sigma away from the value of the LSND/MiniBooNE anomaly estimates considering the combined uncertainties.<br /><br />LEP ruled out a fourth species of fertile neutrino of under 45 GeV, and I wouldn’t be going out on a limb to say without actually doing the calculations that a fertile neutrino of 45 GeV to 63 GeV, if it existed, would have wildly thrown off all of the Higgs boson decay cross-sections observed (since a decay to a 45 GeV to 63 GeV neutrino-antineutrino pair from a 125.7 GeV Higgs boson would have been a strongly favored decay path if it existed) and is in fact therefore excluded by the lastest round of LHC data."<br /><br />From <a href="http://dispatchesfromturtleisland.blogspot.com/2013/03/precision-cosmic-background-radiation.html" rel="nofollow">here</a>.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-7082775141958463702013-08-22T13:11:40.244-06:002013-08-22T13:11:40.244-06:00A post from April 2013 summary with PDG data.A <a href="http://dispatchesfromturtleisland.blogspot.com/2013/04/neutrino-cp-violating-phase-numerology.html" rel="nofollow">post from April 2013</a> summary with PDG data.andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.comtag:blogger.com,1999:blog-7315236707728759521.post-55314142886216413792013-08-22T12:34:56.845-06:002013-08-22T12:34:56.845-06:00A September 26, 2013 summary is also here and is s...A September 26, 2013 summary is also <a href="http://dispatchesfromturtleisland.blogspot.com/2012/11/consensus-value-for-theta-13-emerging.html" rel="nofollow">here</a> and is similarly consistent. andrewhttps://www.blogger.com/profile/08172964121659914379noreply@blogger.com