Search for a diffuse flux of astrophysical muon neutrinos with the IceCube 59-string configuration
Search for a diffuse flux of astrophysical muon neutrinos with the IceCube 59-string configuration
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DOI：
10.1103/physrevd.89.062007
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发表时间：
2014-03-25
影响因子：
5
通讯作者：
Zoll, M.
中科院分区：
文献类型：
--
作者：
Aartsen, M. G.;Abbasi, R.;Zoll, M.
研究人员使用冰立方中微子天文台在2009年5月至2010年5月期间收集的数据进行了高能中微子的搜索，当时该阵列以59弦配置运行。数据样本进行了优化，以包含μ子中微子诱导的事件与小于1%的大气μ子的背景污染。这些数据，这是占主导地位的大气中微子，分析与全球的可能性适合搜索提示大气和天体物理中微子，这两个尚未确定的可能的贡献。这样的信号预计将遵循比传统大气中微子更硬的能谱。此外，天顶角分布对于天体物理信号和大气信号是不同的。的重建的能量和观测事件的方向进行了全球拟合，包括可能的中微子通量的贡献的天体物理信号和大气背景，以及系统的实验和理论预测的不确定性。最佳拟合产生了nu（mu）+（nu）在E-2的bar（mu）上的天体物理信号通量。Phi（E）= 0.25 × 10（-8）GeV cm（-2）s（-1）sr（-1），零瞬发分量。虽然这种分析的灵敏度超过了Waxman和Bahcall的上限，但在90%置信水平下的实验极限是E-2通量的1.5倍以上。Phi（E）= 1.44 x 10（-8）GeV cm（-2）s（-1）Sr（-1）。
A search for high-energy neutrinos was performed using data collected by the IceCube Neutrino Observatory from May 2009 to May 2010, when the array was running in its 59-string configuration. The data sample was optimized to contain muon neutrino induced events with a background contamination of atmospheric muons of less than 1%. These data, which are dominated by atmospheric neutrinos, are analyzed with a global likelihood fit to search for possible contributions of prompt atmospheric and astrophysical neutrinos, neither of which have yet been identified. Such signals are expected to follow a harder energy spectrum than conventional atmospheric neutrinos. In addition, the zenith angle distribution differs for astrophysical and atmospheric signals. A global fit of the reconstructed energies and directions of observed events is performed, including possible neutrino flux contributions for an astrophysical signal and atmospheric backgrounds as well as systematic uncertainties of the experiment and theoretical predictions. The best fit yields an astrophysical signal flux for nu(mu) + (nu) over bar (mu) of E-2. Phi(E) = 0.25 x 10(-8) GeV cm(-2) s(-1) sr(-1), and a zero prompt component. Although the sensitivity of this analysis for astrophysical neutrinos surpasses the Waxman and Bahcall upper bound, the experimental limit at 90% confidence level is a factor of 1.5 above at a flux of E-2 . Phi(E) = 1.44 x 10(-8) GeV cm(-2) s(-1) sr(-1).