14,146 research outputs found

    Muon g−2g-2: current status

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    The muon magnetic anomaly, aμ=(gμ−2)/2a_{\mu}=(g_{\mu}-2)/2, plays a special role in the history of the Standard Model (SM). Precise calculations and measurements of this fundamental quantity provide a stringent test of the SM and a window to the physics beyond. In light of the first result published by the Fermilab Muon g−2g-2 experiment, this article reviews the current status of the theoretical prediction and experimental measurement of the muon anomalous magnetic moment. It also provides an overview on resulting constraints of associated physics beyond the SM (BSM), future muon g−2g-2 experiments and on the progress of experiments that are closely connected to the physics of the muon g−2g-2, such as measurements that could provide complementary information about BSM physics in the muon sector.Comment: Submitted to Nuclear Physics B for revie

    Other Atmospheric Neutrino Experiments

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    The history and recent progress of atmospheric neutrinos are reviewed. An emphasis is placed on results from experiments other than Super-Kamiokande.Comment: 8 pages, 10 figures, Contribution to Neutrino 200

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

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    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-

    Detection of Near Horizontal Muons with the HAWC Observatory

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    The HAWC (High Altitude Water Cherenkov) gamma ray observatory is able to observe muons with nearly horizontal trajectories. HAWC is located at an altitude of 4100 meters a.s.l. on the Sierra Negra volcano in Mexico. The HAWC detector is composed of 300 water tanks, each 7.3 m in diameter and 4.5 m tall, densely packed over a physical area of 22,000 m2^{2}. Previous and current experiments have observed high zenith angle (near horizontal) muons at or near sea level. HAWC operates as a hodoscope able to observe multi-TeV muons at zenith angles greater than 75 degrees. This is the first experiment to measure near horizontal muons at high altitude and with large (≥\geq 10 m) separations for multiple muons. These muons are distinguishable from extensive air showers by observing near horizontal particles propagating with the speed of light. The proximity of Sierra Negra and Pico de Orizaba volcanoes provides an additional measurement of muons with rock overburdens of several km water equivalent. We will present the angular distribution and rate at which HAWC observes these muon eventsComment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution
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