- #1
karlzr
- 131
- 2
When temperature of the universe falls below nucleon mass ##T<<1## GeV, the number densities of nucleons (proton and neutron) which are in kinetic equilibrium can be obtained as
##n_i=g_i (\frac{m_i T}{2\pi})^{3/2} e^{\frac{\mu_i-m_i}{T}}##. Since baryon number should be conserved, then I expect ##n_p+n_n \propto a^{-3} \propto T^{3}##, which is not obvious from the above formula. I have taken for granted that there are no anti-particles for nucleons and all baryon number is in proton and neutron. So what 's going wrong? Does chemical potential have anything to do with it?
What do we know about antiproton/antineutron? Do they annihilate with proton/neutron around ##T\approx m_i## or what? I am trying to relate this process with that in Tevatron.
##n_i=g_i (\frac{m_i T}{2\pi})^{3/2} e^{\frac{\mu_i-m_i}{T}}##. Since baryon number should be conserved, then I expect ##n_p+n_n \propto a^{-3} \propto T^{3}##, which is not obvious from the above formula. I have taken for granted that there are no anti-particles for nucleons and all baryon number is in proton and neutron. So what 's going wrong? Does chemical potential have anything to do with it?
What do we know about antiproton/antineutron? Do they annihilate with proton/neutron around ##T\approx m_i## or what? I am trying to relate this process with that in Tevatron.