- Seminars-iihe - listserv.vub.be

IIHE invited seminar: Ultrahigh energy cosmic rays: an origin story,by Dr James Matthews, 31st of March
by MARIS Ioana Codrina 27 Mar '23

27 Mar '23

Invited Seminars <https://indico.iihe.ac.be/category/6/> IIHE invited seminar: Ultrahigh energy cosmic rays: an origin story //// byDrJames Matthews(University of Oxford) //Friday 31 Mar 2023, 15:00→16:30Europe/Brussels Description Understanding how ultrahigh energy cosmic rays (UHECRs) reach energies in excess of 1e20 eV stretches particle acceleration physics to its very limits. In this talk, I will discuss how such energies can be reached, using general arguments that can often be derived on the back of an envelope. I will review possible particle acceleration mechanisms, with special attention paid to shock acceleration. Informed by the arguments derived in the talk, and with insights from Galactic CR acceleration in supernova remnants, I will then discuss which classes of astrophysical sources might be UHECR sources, including my own (biased) perspective; generally, I favour radio galaxies, GRB afterglows and other sources which are not too compact and dissipate prodigious amounts of energy on large scales. Aided by hydrodynamic simulations, I will show that shocks in the backflows in radio galaxies are good accelerators of UHECRs, then present simulations in which the jet flickers and explore the impact on particle acceleration. I will explore a scenario in which a significant fraction of UHECRs originate from local radio galaxies like Centaurus A and Fornax A, arguing that they can explain the observed UHECR anisotropies. Finally, I will highlight the importance of variability in these potential UHECR sources, and explore the intiguing possibility that the UHECR arrival directions are partly a result of "UHECR echoes" or "reverberation" from magnetic structures in the local Universe. *About the speaker:*Dr. Matthews got his PhD in 2016 from the University of Southampton supervised by Christian Knigge, where he worked on radiative transfer modelling of accretion disc winds. He then moved to Oxford in 2016 for a postdoctoral position working on ultrahigh energy cosmic ray origins before taking up a Herchel Smith Fellowship in Cambridge from 2019-2022. He has recently returned to the Oxford astrophysics department as a Royal Society University Research Fellow, and his research lies at the intersection of theoretical and observational astrophysics, focusing mostly on outflows from accretion discs, astrophysical jets, particle acceleration and axion-like particles. Organised by Ioana Maris and Steven Lowette

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after-seminar beer, 17:00 in CoHop
by MARIS Ioana Codrina 24 Mar '23

24 Mar '23

Dear all, If you would like to join the seminar speaker for discussion and a beer after the seminar, you can do that at 17:00 in CoHop. https://cohop.be/en/ All the best, Ioana and Steven

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IIHE invited seminar: Relativistic Jets from Stellar Mass Black Holes in our galaxy by Prof. Rob Fender, 24th March
by MARIS Ioana Codrina 23 Mar '23

23 Mar '23

Invited Seminars<https://indico.iihe.ac.be/category/6/> IIHE invited seminar: Relativistic Jets from Stellar Mass Black Holes in our galaxy by Prof. Rob Fender (University of Oxford) Friday 24 Mar 2023, 15:00 → 16:30 Europe/Brussels G/0-G.0.20 - Neutrino Room (Building G) Description Astrophysical black holes are the purest manifestations of general relativity, and mark the frontier of our understanding of physics. When accreting gas into their gravitational potential, they can become the most luminous objects in the universe. The most poorly understood aspect of this accretion process is the formation of extremely powerful, highly collimated 'jets' which carry away a large fraction of the liberated gravitational potential energy at relativistic speeds. The most spectacular examples of this process are the supermassive black holes in the centres of giant elliptical galaxies, including M87, the site of the first direct image of a black hole event horizon. However, these supermassive black hole jets are almost frozen in time, and studying how they propagate from the event horizon to their ultimate termination in cluster gas many millions of years later, and how the liberated energy is deposited in the ambient medium, is simply impossible on humanly-accessible timescales. However, stellar mass black holes, the remnants of the most massive stars which lived fast and died young, pervade space, with an estimated 100 million in our galaxy alone. Some of these stellar mass black holes accrete at a high rate from orbiting binary companion stars, and mimic the relativistic accretion and jet formation observed in supermassive systems like M87. In this talk I will explore how rich new sets of observational data have allowed us to measure the state of the accretion flow at the moment of jet launch, and track the relativistically ejected material all the way to its termination in the interstellar medium on a timescale of one or two years. For the first time we are able to edge towards precise calorimetry of these ejections and connect this to the energy balance at the event horizon at the moment of launch. About the speaker: https://www.physics.ox.ac.uk/our-people/fender Organised by Ioana Maris and Steven Lowette

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IHE invited seminar: Friday 17th February, Prof. Freya Bleckman "The CMS physics communication as a lab for science communication"
by MARIS Ioana Codrina 12 Feb '23

12 Feb '23

Invited Seminars <https://indico.iihe.ac.be/category/6/> IIHE invited seminar: The CMS physics communication as a lab for science communication. //// byProf.Freya Blekman(DESY and University of Hamburg) //Friday 17 Feb 2023, 15:00→16:30Europe/Brussels //G/0-G.0.20 - Neutrino Room (Building G) Description Abstract: This colloquium is about (why and) how to communicate your work as a scientist, something that is important for all physicists independent of their career stage. Some examples on strategies and data-driven interpretation of successful science communication by the CMS communication through the physics briefings will be used to highlight the different aspects. Finally, some tips & tricks on how to get started with science communication will be discussed. While the speaker obviously comes from an LHC physics background, the talk is intended for a general physics audience. Brief Bio Freya Blekman works on breaking the standard model at the LHC and with future colliders and was until recently coordinating the physics communication activities for the over 4000 physicists in one of the large LHC collaborations, the Compact Muon Solenoid. Freya Blekman has been communicating science since she was a bachelor student. She started in 2010 as a professor at the Vrije Universiteit Brussel, and since October 2021 is a lead researcher at DESY (the German national particle physics laboratory) with a professorship at the University of Hamburg. Blekman is also a visiting professor at the Vrije Universiteit Brussel and the University of Oxford. Organised by Ioana Maris and Steven Lowette

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IIHE invited seminar by Prof. Marcello Messina: The PTOLEMY project: from an idea to a real experiment to detect the Cosmological Relic Neutrinos
by MARIS Ioana Codrina 03 Feb '23

03 Feb '23

IIHE invited seminar: The PTOLEMY project: from an idea to a real experiment to detect the Cosmological Relic Neutrinos //// byProf.Marcello Messina(LNGS) //Friday 3 Feb 2023, 15:00→16:30Europe/Brussels //G/0-G.0.20 - Neutrino Room (Building G) Description In the first partthe seminara novelideaonthe detectionofCosmological Relic Neutrinos(CRN)andmore in general, onthe detection of neutrinos of vanishing energywill be presented.This ideais described in detail in the paper[1].The method is based on the factthatneutrino interactions on beta-instable nuclei havethe key feature of requiring no energy threshold for the neutrino interaction.Some phenomenological aspects will be presented. The second part of the seminar will be dedicated to the PTOLEMY project, in a starting phase at the Laboratori Nazionali del Gran Sasso, Italy.In this project we aim at demonstrating the detection principle of the CRN and finalize the design of the future full scale experiment. The technologies on which the detector concept is based will be presented and the key features explained. A new-concept of electrostatic filter discussedin a paper [2] recently published by the PTOLEMY collaboration will also be explained in details. [1] A. Cocco, G. Manganoand M. Messina, “Probing Low Energy Neutrino Backgrounds with Neutrino Capture on Beta Decaying Nuclei,” Journal of Cosmological and Astroparticle Physics0706(2007),15. [2]M.G. Betti et al, “A Design for an electromagnetic filter for precision energymeasurements at tritium endpoint”, Progress in particle and Nuclear Physics, 1206 (2019),120. *Short bio: *Dr, MessinagottheMaster degree and then the Ph.D. on the CHORUS experiment on the numu tonutau oscillation searches.After Ph.D.hemovedto the ETH-Zurich on a researchposition and then to theUniversity ofBern as Ober Assistant.In theseyearsheparticipated to several importantexperimentslikeOPERA, ICARUS, T2Kwith relevantcoordination roles of R&Ds activities and working groups.In 2011hemovedto the Columbia University in New Yorkon aposition of Research Scientist and lead the R&D effort that brought to designofthe XENON1T detector.In thesame experiment he hasbeenfirst theCommissioningand then the Operationmanager of the Experiment until 2017whenhemovedon the roleof Technical Coordinatorof the XENONnTexperiment, which is the upgrade of theXENON1T.After the seminal paper[1]on therelic neutrino detection his interests switched towards relic neutrino detection up totheparticipatation to the conceptual design ofa novel electromagnetic filter concept. Dr. Messina ispresently theCo-Spokespersonsof the PTOLEMY project. Organised by Ioana Maris and Steven Lowette

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IIHE seminar: Friday 13/01 at 15:00 by Prof. Roberto Tenchini "The running of the electromagnetic coupling constant and the MUonE experiment"
by MARIS Ioana Codrina 13 Jan '23

13 Jan '23

Invited Seminars <https://indico.iihe.ac.be/category/6/> IIHE invited seminar: The running of the electromagnetic coupling constant and the MUonE experiment //// byProf.Roberto Tenchini //Friday 13 Jan 2023, 15:00→16:30Europe/Brussels //G/1-G.1.03 - J. Sacton (Building G) Description *Abstract:*Precision measurements in the electroweak sector require the knowledge of the fine structure constant, a(q^2 ), for their interpretation. In electroweak global fits, or in the interpretation of the results of the g-2 experiment, this “running constant” is computed from theory. In this seminar I will discuss the perspectives for direct measurements of a(q^2 ). In particular, I will describe in some detail the MUonE experiment, aimed at measuring the leading hadronic contribution to g-2 via high energy me scattering. *About the speaker:*prof. Roberto Tenchini played an important role in the fixed target NA7 experiment in the eighties. He then moved to LEP where he was involved in several measurements in the electroweak sector and became spokesperson for the ALEPH experiment. At LHC he has been convener of electroweak and top-quark physics groups within the CMS experiment. A few years ago, he proposed the MUonE experiment. He is currently president of the Italian national committee for particle physics at accelerators (INFN CSN1). Organised by Ioana Maris and Steven Lowette

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