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I How is the value of tT^2 calculated for neucleosynthesis

  1. Feb 10, 2017 #1
    The following quote is from the Wikipedia article
    https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis#Characteristics .
    The temperature/time relation in this era can be given by the equation:​

    tT2 EQ.png
    where
    t is time in seconds,
    T is temperature in MeV, and
    g* is the effective number of particle species.
    (g* includes contributions of 2 from photons, 7/2 from electron-positron pairs and 7/4 from each neutrino flavor. In the standard model g* is 10.75).​
    I would much appreciate seeing a reference citation or an explanation from someone about how the value 0.74 is calculated for the nucleosynthesis era.

    By the way, when I searched the internet for this information, all I could find were articles that quoted the same material from Wikipedia.
     
    Last edited: Feb 10, 2017
  2. jcsd
  3. Feb 17, 2017 #2
    Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.
     
  4. Feb 18, 2017 #3
    Hi @Greg Bernhardt:

    I think it is time to abandon this thread. I have the impression that there are no PF participants who are able to help me with respect to my question here.

    I started a different thread to get help with respect to a different aspect of this thread.
    I was pleased to get one useful response, and I am hoping to continue a discussion about that response.

    Regards,
    Buzz
     
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