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Transmissão via YouTube e Zoom.

Abstract: There has been a long-standing discrepancy between the measured and predicted value of the anomalous magnetic moment of the muon, g-2.  After two decades of anticipation, an updated measurement is now available.  I'll give an experimentalist's view of the expected value followed by a description of the measurement.  As has been widely reported, the mystery of the discrepancy between the measured and predicted value remains.

Bio:
Brendan received his PhD at the University of Hawaii as one of the first graduate students of the Belle Collaboration.  He did a postdoc at Brown University working on luminosity measurements and heavy flavor physics at the Dzero experiment. He then became a Wilson Fellow at Fermilab and worked on Higgs searches at Dzero while co-leading efforts to get Muon g-2 off the ground.  He received a DOE Early Career Award to design the Muon g-2 straw tracking detectors which have played a key role in extracting the first g-2 result. He is currently the Head of the Muon Department at Fermilab and is working on getting a mu- g-2 run approved as well as R&D for tracker upgrades for the Mu2e-II experiment.

Transmissão via YouTube e/ou Zoom

Resumo: Wilson loops are among the most interesting observables one can consider in any gauge theory. They are non-local operators associated to the phase acquired by a charged particle propagating in a gauge field and capture global information about the theory they probe. Among other things, they serve as order parameters for confinement/deconfinement phase transitions and as a way to compute the Bremsstrahlung energy of accelerated particles, knot invariants, scattering amplitudes, and so on.

In this informal and minimally technical seminar, I will try to illustrate the many uses of Wilson loops, especially in the context of supersymmetric gauge theories (where sometimes they can be computed exactly thanks to the so-called “localization") and holographic dualities (where they are associated to dual objects as minimal surfaces, D-branes and more complicated geometries). I will try to focus on the concepts, rather than on giving precise details, to try to make this accessible to all.

Transmissão via Zoom e  YouTube 

Resumo: We will review the scientific motivation and the early R&D that eventually led the IceCube project to transform a cubic kilometer of natural Antarctic ice into a neutrino detector. The instrument detects more than 100,000 neutrinos per year in the GeV to 10 PeV energy range. Among those, we have isolated a flux of high-energy neutrinos of cosmic origin, with an energy density similar to that of high-energy photons and cosmic rays in the extreme universe. We identified their first source: on September 22, 2017, several astronomical telescopes pinpointed a flaring galaxy, powered by an active supermassive black hole, as the source of a cosmic neutrino with an energy of 290 TeV. Archival IceCube data subsequently revealed a flare in 2014-15 of more than a dozen neutrinos from the same direction. Accumulating evidence suggests that the first cosmic ray accelerator belongs to a special class of active galactic nuclei that is responsible for the origin of the highest energy particles in the Universe.