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HEP: Beyond the classical paradigm of Galactic high energy particles

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Nahee Park, University of Chicago
24 February 2016 from 2:30 PM to 3:30 PM
339 Davey Laboratory
Contact Name
Stephane Coutu
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Cosmic rays, high energy particles originating from outside of the solar system, are believed to be dominated by particles from our Galaxy at least up to the energy of 10^15 eV. In the last few years, we have seen the most precise measurements of cosmic rays from space-borne experiments. These new results from direct measurements, including the rise of the positron flux, the hardening of the light nuclei, and the different spectral indexes of the proton and helium spectra, challenge the classical paradigm of the Galactic high energy particles. Meanwhile, the development of gamma-ray experiments has opened a new window to study the acceleration and propagation of high energy particles in the vicinity of the source sites. More than a hundred new gamma-ray sources have been discovered in the TeV energy range. These new measurements have provided a test bench for acceleration theories and data sets for source population studies.

I will present the Galactic gamma-ray measurements from the VERITAS experiment, an imaging atmospheric Cherenkov telescope measuring gamma rays with energy higher than 85 GeV and up to ~ 30 TeV. I will discuss what we have learned about the dynamics of high energy particles with gamma-ray observations and what we expect to learn with a future experiment, CTA. I will also introduce the near-future balloon-borne experiment, HELIX (high energy light isotope experiment), which is designed to measure the clock isotope 10^Be up to 10 GeV/n to study the propagation of Galactic cosmic rays. Finally, I will highlight how measurements from different disciplines, such as cosmic-ray and gamma-ray, will broaden our perspectives on high energy particles and advance us towards a new paradigm of Galactic cosmic rays.