论文标题
具有六年的IceCube高能量级联数据的弥漫性天体物理电子和Tau中微子通量的特征
Characteristics of the diffuse astrophysical electron and tau neutrino flux with six years of IceCube high energy cascade data
论文作者
论文摘要
我们在2010年至2015年的Icecube数据中使用粒子淋浴(级联反弹)报告了天体中微子通量的首次测量。假设标准振荡,该专用级联样品中的天体中微子在Electron and tau flavors中以$ \ \ sim 90 \ sim 90 \ sim 90 \%)为主导。在敏感能量中观察到的通量范围从$ 16 \,\ mathrm {tev} $到$ 2.6 \,\ mathrm {pev} $,与单一的幂律模型一致,如Fermi-type从天体物理学源高能量颗粒的Fermi-Type加速所预期的。 We find the flux spectral index to be $γ=2.53\pm0.07$ and a flux normalization for each neutrino flavor of $ϕ_{astro} = 1.66^{+0.25}_{-0.27}$ at $E_{0} = 100\, \mathrm{TeV}$, in agreement with IceCube's complementary muon neutrino results and具有全中性风味的效果。在测得的能量范围内,我们拒绝频谱指数$γ\ leq2.28 $ in $ \ge3σ$显着性水平。由于中微子的高能分辨率和低大气中微子的背景,该分析提供了低于$ \ sim100 \,{\ rm {tev}} $的中微子通量最详细的表征。假设更复杂的中微子通量模型的拟合结果表明,在高能量下的通量软化,而在低能(p值$ \ ge 0.06 $)下加强度变化。 $ \ sim 100 \,{\ rm {tev}} $在$ \ sim 100 \以下测量的巨大而光滑的通量仍然是一个难题。为了不违反Fermi-Lat测量的各向同性弥漫性伽马射射线背景,它表明存在以密集的环境为特征的天体中微子来源,这些环境是密集的环境,对伽马射线不透明。
We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010 -- 2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated ($\sim 90 \%$) by electron and tau flavors. The flux, observed in the sensitive energy range from $16\,\mathrm{TeV}$ to $2.6\,\mathrm{PeV}$, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be $γ=2.53\pm0.07$ and a flux normalization for each neutrino flavor of $ϕ_{astro} = 1.66^{+0.25}_{-0.27}$ at $E_{0} = 100\, \mathrm{TeV}$, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices $γ\leq2.28$ at $\ge3σ$ significance level. Due to high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below $\sim100\,{\rm{TeV}}$ compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p-value $\ge 0.06$). The sizable and smooth flux measured below $\sim 100\,{\rm{TeV}}$ remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi-LAT, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma-rays.