Are protons still dominant at the knee of the cosmic-ray energy spectrum?
Are protons still dominant at the knee of the cosmic-ray energy spectrum?
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DOI：
10.1016/j.physletb.2005.10.048
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发表时间：
2005-11
影响因子：
4.4
通讯作者：
M. Amenomori;S. Ayabe;D. Chen;S. Cui;Danzengluobu;L. Ding;X. Ding;C. Feng;Z. Feng;X. Gao;Q. Geng;H. Guo;Hao-Ning He;M. He;K. Hibino;N. Hotta;Haibing Hu;Haiming Hu;J. Huang;Q. Huang;H. Jia;F. Kajino;K. Kasahara;Y. Katayose;C. Kato;K. Kawata;Labaciren;G. Le;J. Li;H. Lu;Shan Lu;X. Meng;K. Mizutani;J. Mu;K. Munakata;A. Nagai;H. Nanjo;M. Nishizawa;M. Ohnishi;I. Ohta;H. Onuma;T. Ouchi;S. Ozawa;J. Ren;T. Saito;M. Sakata;T. Sasaki;M. Shibata;A. Shiomi;T. Shirai;H. Sugimoto;M. Takita;Y. Tan;N. Tateyama;S. Torii;H. Tsuchiya;S. Udo;H. Wang;X. Wang;Y. Wang;H. Wu;L. Xue;Y. Yamamoto;C. Yan;X. Yang;S. Yasue;Z. Ye;G. Yu;A. Yuan;T. Yuda;H. Zhang;J. Zhang;N. Zhang;Xueyao Zhang;Yanjuan Zhang;Yi. Zhang;Zhaxisangzhu;X. Zhou
中科院分区：
文献类型：
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作者：
M. Amenomori;S. Ayabe;D. Chen;S. Cui;Danzengluobu;L. Ding;X. Ding;C. Feng;Z. Feng;X. Gao;Q. Geng;H. Guo;Hao-Ning He;M. He;K. Hibino;N. Hotta;Haibing Hu;Haiming Hu;J. Huang;Q. Huang;H. Jia;F. Kajino;K. Kasahara;Y. Katayose;C. Kato;K. Kawata;Labaciren;G. Le;J. Li;H. Lu;Shan Lu;X. Meng;K. Mizutani;J. Mu;K. Munakata;A. Nagai;H. Nanjo;M. Nishizawa;M. Ohnishi;I. Ohta;H. Onuma;T. Ouchi;S. Ozawa;J. Ren;T. Saito;M. Sakata;T. Sasaki;M. Shibata;A. Shiomi;T. Shirai;H. Sugimoto;M. Takita;Y. Tan;N. Tateyama;S. Torii;H. Tsuchiya;S. Udo;H. Wang;X. Wang;Y. Wang;H. Wu;L. Xue;Y. Yamamoto;C. Yan;X. Yang;S. Yasue;Z. Ye;G. Yu;A. Yuan;T. Yuda;H. Zhang;J. Zhang;N. Zhang;Xueyao Zhang;Yanjuan Zhang;Yi. Zhang;Zhaxisangzhu;X. Zhou
在三年的运行中，通过触发与高能核心相关的空气阵雨，并在初级质量分离中使用神经网络方法，推导出了这些能谱在1015 ~ 1016eV之间。基于QGSJET+HD和SIBYLL+HD模型的质子谱可以用单个幂律函数表示，其微分指数分别为- 3.01±0.11和- 3.05±0.12，比直接观测所得的1014eV以下能量范围内的- 2.74±0.01更为陡峭。根据蒙特卡罗模拟中使用的强子相互作用模型，质子和氦的绝对通量在30%的系统误差范围内得到。我们的实验结果表明，造成3×1015eV周围全粒子光谱功率指数变化的主要成分，即所谓的“膝盖”，是由比氦重的原子核组成的。这是第一次通过在膝能区逐个选择质子和氦的事件来测量初级质子和氦的微分能谱。
A hybrid experiment consisting of emulsion chambers, burst detectors and the Tibet-II air-shower array was carried out at Yangbajing (4300 m a.s.l., 606 g/cm2) in Tibet to obtain the energy spectra of primary protons and heliums. From three-year operation, these energy spectra are deduced between 1015and 1016eV by triggering the air showers associated with a high energy core and using a neural network method in the primary mass separation. The proton spectrum can be expressed by a single power-law function with a differential index of −3.01±0.11 and −3.05±0.12 based on the QGSJET+HD and SIBYLL+HD models, respectively, which are steeper than that extrapolated from the direct observations of −2.74±0.01 in the energy range below 1014eV. The absolute fluxes of protons and heliums are derived within 30% systematic errors depending on the hadronic interaction models used in Monte Carlo simulation. The result of our experiment suggests that the main component responsible for the change of the power index of the all-particle spectrum around 3×1015eV, so-called “knee”, is composed of nuclei heavier than helium. This is the first measurement of the differential energy spectra of primary protons and heliums by selecting them event by event at the knee energy region.