Detector Depth Dependence of the High Energy Atmospheric Neutrino Flux

We note that detector depth can influence the decay path length available for the primary and secondary particles that are the source of atmospheric neutrinos. As a consequence there is a location dependent modulation to the neutrino flux, which could be as large as 5-10% in some directions

History of "Anomalous" Atmospheric Neutrino Events: A First Person Account

The modern picture of the neutrino as a multiple mass highly mixed neutral particle has emerged over 40 years of study. Best known of the issues leading to this picture was the apparent loss of neutrinos coming from the sun. This article describes another piece of evidence that supports the picture; the substantial reduction of high energy muon type neutrinos observed in nature. For much of the 40 year period, before the modern picture emerged this observation was known as the "atmospheric neutrino anomaly", since as will be seen, these neutrinos originate in the Earth's atmosphere. This paper describes the discovery of the atmospheric neutrino anomaly. We explore the scientific context and motivations in the late 1970's from which this work emerged. The gradual awareness that the observations of atmospheric neutrinos were not as expected took place in the 1983-1986 period.Comment: 46 pages, 24 figures. To be published in Physics in Perspective Version 2 has a table of contents, a table of figures and the DOI added The final publication is available at Springer via http://dx.doi.org/10.1007/s00016-016-0185-