1. High-energy Astroparticle DetectionLili Yang, predavanje na tuji univerzi Opis: Astroparticle Physics has evolved as a new interdisciplinary field at the intersection of particle physics, astronomy and cosmology, addressing some of the most fundamental questions of contemporary physics. As the cosmic messengers, neutrinos, cosmic rays, gamma rays and also gravitational waves, take the information from the universe to tell us more about the story. Physicists have been developing experiments to detect and study these messengers. I would like to talk about the basic ideas and searching results from the dedicate cosmic ray detector Pierre Auger Observatory and also the future performance of Cherenkov Telescope Array (CTA), the next-generation ground based telescope array. CTA will play an very important role in detecting GeV-TeV gamma rays and represents the era of precision gamma ray astronomy. The multi-messenger and multi-wavelength study with various messengers are the main field in astrophysics.
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Povzetek najdenega: ...High-energy astroparticles, CTA, Pierre Auger Observatory...
Ključne besede: High-energy astroparticles, CTA, Pierre Auger Observatory
Objavljeno: 06.12.2016; Ogledov: 3176; Prenosov: 0
 Polno besedilo (32,92 MB)
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2. High Energy AstrophysicsLili Yang, prispevek na konferenci brez natisa Opis: I was invited as a lecturer at the Sumer School on Astrophysics and Astroparticles in Petnica Serbia. I gave talks on "High Energy Astrophysics", where I mainly focused on the production, propagation and detection of high energy astroparticles. Especially, I introduced the current experiments and technique and facilities.
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Povzetek najdenega: ...at the Sumer School on Astrophysics and Astroparticles in Petnica Serbia. I gave talks on...
Ključne besede: High-energy astroparticles, experiments, detection, production
Objavljeno: 06.12.2016; Ogledov: 3379; Prenosov: 0
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3. SEARCH FOR NEUTRINOS AT EXTREME ENERGIES WITH THE PIERRE AUGER OBSERVATORYMarta Trini, 2019, doktorska disertacija Opis: The detection of Ultra-High-Energy (UHE) neutrinos around and above 10 18 eV (1 EeV) can be the key to
answering the long-standing question of the origin of the UHE cosmic rays. The Pierre Auger Observatory
is the largest experiment that can detect the extensive air showers produced when the cosmic rays and
neutrinos interact in the earth’s atmosphere. In particular, with the Infilled array of the Surface Detector
of the Pierre Auger Observatory we can detect sub-EeV neutrino-induced particle showers. In this thesis
we demonstrate that it is possible to discriminate neutrino-induced showers from the background showers
produced by the more numerous nucleonic cosmic rays. The sensitivity to neutrinos is enhanced in the
inclined directions with respect to the vertical to the ground, where cosmic ray-induced showers starting in
the upper layers of the atmosphere are dominated by the muonic component of the shower, while deeply-
penetrating neutrino showers in contrast exhibit a large electromagnetic component. Based on this idea in
this thesis we have developed a search procedure for UHE neutrinos that consists on selecting inclined
events in the Infilled array of the Pierre Auger Observatory in which the signals in the water-Cherenkov
stations are spread in time, characteristic of the presence of electromagnetic component in the shower. We
have established a complete chain of criteria to first select the inclined events among the sample of all
events triggering the Infilled array, and then identifying those that have a large electromagnetic component
at ground, and hence can be considered as neutrino candidates. We have identified a single variable, the
so-called area-over-peak averaged over all of the stations in each event, as a suitable observable for neutrino
identification purposes. The neutrino selection was established using extensive Monte Carlo simulations of
the neutrino-induced showers in the Infilled array of Auger as well as a fraction of the data assumed to
be totally constituted of background nucleonic cosmic rays. Using these neutrino simulations we have also
computed the exposure of the Infilled array to UHE neutrinos in the period 1 January 04 - 31 December 2017.
Associated systematic uncertainties on the exposure are also described. Expecting no candidate neutrinos in
the period up to 31 December 2017, and adopting a differential neutrino diffuse flux dN ν /dE ν = k E ν −2 in
the energy range from 0.05 to 1 EeV, we have obtained a 90% C.L. upper limit on the all neutrino flavor,
k 90 < 7.97 × 10 −8 GeV cm −2 s −1 sr −1 .
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Povzetek najdenega: ... astroparticles, astrophysical neutrinos, cosmic rays showers, Pierre Auger...
Ključne besede: astroparticles, astrophysical neutrinos, cosmic rays showers, Pierre Auger Observatory, Infilled
array
Objavljeno: 03.10.2019; Ogledov: 2957; Prenosov: 90
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4. Measurement of the proton-air cross section with Telescope Array's Black Rock Mesa and Long Ridge fluorescence detectors, and surface array in hybrid modeMitsuhiro Abe, R. U. Abbasi, T. Abu-Zayyad, M. Allen, R. Azuma, E. Barcikowski, J. W. Belz, Jon Paul Lundquist, S. A. Blake, D. R. Bergman, 2020, izvirni znanstveni članek Opis: Ultra high energy cosmic rays provide the highest known energy source in the universe to measure proton cross sections. Though conditions for collecting such data are less controlled than an
accelerator environment, current generation cosmic ray observatories have large enough exposures to collect significant statistics for a reliable measurement for energies above what can be attained in the lab. Cosmic ray measurements of cross section use atmospheric calorimetry to measure depth of air shower maximum (Xmax), which is related to the primary particle’s energy and mass. The tail of the Xmax distribution is assumed to be dominated by showers generated by protons, allowing measurement of the inelastic proton-air cross section. In this work the proton-air inelastic
cross section measurement, σ_inel_p−air, using data observed by Telescope Array’s Black Rock Mesa and Long Ridge fluorescence detectors and surface detector array in hybrid mode is presented. σ_inel_p−air is observed to be 520.1 ± 35.8 [Stat.] +25.0 −40 [Sys.] mb at √s = 73 TeV. The total proton-proton cross section is subsequently inferred from Glauber formalism and is found to be σ_tot_pp = 139.4 +23.4−21.3[Stat.] +15.0−24.0[Sys.] mb.
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Povzetek najdenega: ...cosmic rays, astroparticles, proton-air cross section...
Ključne besede: cosmic rays, astroparticles, proton-air cross section
Objavljeno: 04.02.2021; Ogledov: 1079; Prenosov: 0
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