Neutrino asymmetry evolution + BBN | Public grids

<h3>Datasets associated to &ldquo;Constraints on primordial lepton asymmetries with full neutrino transport&rdquo;, J. Froustey and C. Pitrou [2405.06509].</h3> <p>We solve the neutrino Quantum Kinetic Equations with the full collision term in the range of temperatures [25 MeV, 0.006 MeV], in order to get the evolution of neutrino distributions. We explore a range of primordial neutrino asymmetries, whose evolution results from a complicated interplay between the Hamiltonian terms (in particular, the self-interaction mean-field) and collisions. The output of this neutrino calculation is used in the Big Bang nucleosynthesis code <em>PRIMAT</em> to determine the primordial abundances obtained in this cosmological scenario.</p> <p>&nbsp;</p> <p>The datasets are respectively:</p> <ul> <li><code>NEVO_PRIMAT_grid_equalxi.csv</code>, used in Section IV.A ;</li> <li><code>NEVO_PRIMAT_grid_xiav_xie.csv</code>, used in Section IV.B ;</li> <li><code>NEVO_PRIMAT_grid_ximu_xitau.csv</code>, used in Section IV.C ;</li> <li><code>NEVO_PRIMAT_grid_xiav_xie_zoom.csv</code>, used in Section V ;</li> <li><code>NEVO_PRIMAT_grid_3D.csv</code>, an additional grid exploring the full 3D parameter space (xi_e,xi_mu,xi_tau).</li> </ul> <p>Each dataset has the same format, with 21 columns identified in the header of each file:</p> <ol> <li>xit_av, average of the initial xitilde (= xi + xi^3/pi^2)</li> <li>xit_e - xit_av, initial difference between the e flavor xitilde and the average</li> <li>(xit_mu - xit_tau)/2, also called \tilde{Delta}, difference between the mu and tau flavor initial asymmetries</li> <li>xi_e, reduced initial chemical potential of nu_e (opposite one for nu_ebar)</li> <li>xi_mu</li> <li>xi_tau</li> <li>N_eff, effective number of neutrino species after decoupling (i.e., for T = 0.006 MeV)</li> <li>Y_He4, primordial helium-4 abundance obtained from PRIMAT (with omega_baryon = 0.02242)</li> <li>D/H, primordial deuterium abundance obtained from PRIMAT (with omega_baryon = 0.02242)</li> <li>d[ln(Y_He4)]/d[ln(omega_b)] = dY, relative derivative such that Y_He4(omega) = Y_He4^ref * (1+dY*(omega-omega^ref)/omega^ref)</li> <li>d[ln(D/H)]/d[ln(omega_b)], same for D/H</li> <li>eta^f_e, final electron flavor asymmetry, defined as eta_e = (n_nue - n_nuebar)/Tcm^3</li> <li>eta^f_mu, final muon flavor asymmetry</li> <li>eta^f_tau, final tau flavor asymmetry</li> <li>eta^f_1, final asymmetry of the nu_1 mass eigenstate</li> <li>eta^f_2, final asymmetry of the nu_2 mass eigenstate</li> <li>eta^f_3, final asymmetry of the nu_3 mass eigenstate. <em>These "mass asymmetries" are determined using the fact that the final density matrix is diagonal in the mass basis, which allows to relate {eta_alpha}_(flavor) to {eta_i}_(mass). Note that we take the mean values of each mixing parameter from the <a href="https://pdg.lbl.gov/2023/tables/rpp2023-sum-leptons.pdf" target="_blank" rel="noopener">Particle Data Group (2023)</a>, neglecting the CP-phase.</em></li> <li>rho^f_e, final comoving energy density of nu_e + nu_ebar</li> <li>rho^f_mu, final comoving energy density of nu_mu + nu_mubar</li> <li>rho^f_tau, final comoving energy density of nu_tau + nu_taubar</li> <li>z^f, final dimensionless photon temperature (z = T_gamma/T_cm)</li> </ol>