标题： 银河系伽马晕由重中微子湮灭产生吗？ 显示英文标题

标题： Galactic Gamma Halo by Heavy Neutrino annihilations?

摘要： 我们银河系周围由EGRET最近发现的弥散伽马晕可能由第四代重子中微子N的湮灭产生，其质量处于一个狭窄范围内（Mz /2 < M < Mz）。晕中的中微子湮灭可能导致超相对论电子对，这些电子对在红外或光学银河光子上的逆康普顿散射可能是观测到的GeV伽马射线的来源，或者导致100 MeV-1 GeV光子（由于中性π介子次级粒子）由N - anti N --> Z-->夸克对反应产生。随后的伽马通量（10 ^(-7)- 10^(-6) cm ^(-2) s^(-1) sr^(-1)）与EGRET观测到的相当，并且也符合中微子质量的狭窄窗口：45 GeV < M < 50 GeV，这最近被要求用来解释地下DAMA信号。第四代重中微子的存在并不能显著解决宇宙的暗物质问题，但它可能很容易通过LEP II数据进行检测。 显示英文摘要

摘要： The diffused gamma halo around our Galaxy recently discovered by EGRET could be produced by annihilations of relic neutrinos N (of fourth generation), whose mass is within a narrow range (Mz /2 < M < Mz). Neutrino annihilations in the halo may lead to either ultrarelativistic electron pairs whose inverse Compton Scattering on infrared or optical galactic photons could be the source of the observed GeV gamma rays, or to prompt 100 MeV- 1 GeV photons (due to neutral pion secondaries) born by N - anti N --> Z--> quark pairs reactions. The consequent gamma flux (10 ^(-7)- 10^(-6) cm ^(-2) s^(-1) sr^(-1)) is well comparable to the EGRET observed one and it is also compatible with the narrow window of neutrino mass : 45 GeV < M < 50 GeV recently required to explain the underground DAMA signals. The presence of heavy neutrinos of fourth generation do not contribute much to solve the dark matter problem of the Universe, but it may be easily detectable by outcoming LEP II data.