Universal neutrino degeneracy
Universal neutrino degeneracy
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DOI：
10.1103/physrev.128.1457
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发表时间：
1962-11
期刊：
影响因子：
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通讯作者：
S. Weinberg
中科院分区：
文献类型：
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作者：
S. Weinberg
现代宇宙学理论意味着宇宙充满了浅简并的费米中微子海。在稳态和振荡模型（也许还有”大爆炸”理论）中，可以严格地证明，充满中微子能级的比例（加上充满反中微子能级的比例）正好是有限费米能量E F的一个。这个证明考虑了吸收和已经充满的能级对中微子发射的抑制作用。实验表明，反中微子的EF ≤ 200 eV，中微子的EF ≤ 1000 eV.如果E F> 10 eV，则可以通过寻找β−衰变中能量守恒的明显违反来观察简并中微子。在稳定态和演化宇宙学中，EF太低而无法观测到，但在振荡宇宙学中，EF = 5 Rc MeV，其中Rc是宇宙的最小半径，以当前半径为单位;因此实验已经表明，宇宙将收缩超过10 3倍，如果有的话。天文学证据加上爱因斯坦的场方程（没有宇宙常数）要求振荡宇宙学中的E F< 2× 10− 3 eV（因此Rc < 10− 9），并建议更高能量的中微子可能代表宇宙能量的大部分。一个模型宇宙结合这一想法的构建。
Modern cosmological theories imply that the universe is filled with a shallow degenerate Fermi sea of neutrinos. In the steady state and oscillating models (and perhaps also the" big bang" theories) it can be shown rigorously that the proportion of filled neutrino levels (plus the proportion of filled antineutrino levels) is precisely one up to a finite Fermi energy E F. The proof takes into account both absorption and the repressive effects of already filled levels on neutrino emission. Experiment shows that E F≤ 200 eV for antineutrinos and E F≤ 1000 eV for neutrinos. The degenerate neutrinos could be observed (if E F> 10 eV) by looking for apparent violations of energy conservation in β− decay. In the steady state and evolutionary cosmologies E F is much too low to ever be observed, but in the oscillating cosmologies E F≃ 5 R c MeV, where R c is the minimum radius of the universe in units of its present radius; thus experiment already shows that the universe will contract by a factor over 10 3, if at all. Astronomical evidence plus Einstein's field equation (without cosmological constant) require in an oscillating cosmology that E F< 2× 10− 3 eV (so R c< 10− 9) and suggest that higher energy neutrinos may represent the bulk of the energy of the universe. A model universe incorporating this idea is constructed.