UCL HEP Seminars
Seminars are generally held at 4pm on Fridays in room A1 on the top floor of the physics department
A calendar of all seminars in the Physics Department
is available on the Physics Events Calendar page.
If you use Google Calendar or similar, such as Apple iCal, it is possible to subscribe to this calendar via: XML, ICAL or HTML.
Please send suggestions for topics and/or speakers to Andreas Korn and Lucian Harland-Lang.
26/05/2017 : Leigh Whitehead (CERN)
Sterile Neutrino searches with MINOS and MINOS+
Three-flavour neutrino oscillations have proved very successful in describing the observed neutrino oscillation data. However, there are also some anomalies, including the excesses of appeared electron neutrino interactions in LSND and MiniBooNE, and a sterile neutrino state at a larger mass-splitting scale can provide an explanation for these results. The MINOS/MINOS+ experiment was a long-baseline neutrino experiment in the US, collecting beam and atmospheric neutrino interactions from 2003 until 2016. MINOS was optimised for the study of muon neutrino disappearance in the NuMI beam at Fermilab. The continuation of the experiment with a medium energy beam configuration is called MINOS+. A sterile neutrino in MINOS/MINOS+ would appear as a modulation on the three-flavour oscillations. A search for sterile neutrinos has been performed using charged-current and neutral-current interactions in two detectors separated by a distance of 734km. The inclusion of two years of MINOS+ data and an improved fit method provides a much increased sensitivity over the previous MINOS result that was combined with Daya Bay.
02/06/2017 : Edward Daw (Sheffield)
Axions and Axion-Like Particles
In recent years, searches for new physics beyond the standard model have focussed on the electroweak scale, using channels that are reachable in high energy accelerators and through induced interactions of hypothesised electroweak-scale relic particles (WIMPs) in tonne-scale direct search experiments. A second possibility which is scientifically just as well-motivated is that the dark matter consists of much lighter pseudoscalars, called axions, whose origin is in low energy quantum chromodynamics, whose coupling to ordinary matter is feeble because their low mass, and consequently their feeble couplings to other particles, renders them 'invisible' to ordinary accelerator searches. The same feeble couplings mean that axions have very long decay times, so that relic axions generated in the very early Universe may be the dark matter evidenced through its gravitational effects today. I shall survey the field of axion-sector experimental searches. Experiments that look directly for the axion itself attempt to induce dark matter axions to convert into microwave photons in closed electromagnetic resonators. Other experiments identify other by-products of the symmetry breaking mechanism that may have yielded axions; these other by-products are sometimes called ALPs (axion-like particles), and experiments to search for ALPs typically use a 'light shining through a wall' technique. Overall this is an exciting and growing field. I will also discuss some of my own work on axion searches with the ADMX experiment, aimed towards improvements in the sensitivity and search rate of such experiments by means of novel modifications to the resonant detector design.
16/06/2017 Sarah Bridle (Manchester)
Gastrophysics: Food security for astro/physicists
In this seminar I will describe my motivations for being interested in food research, and my belief that STFC researchers bring a lot of relevant skills to the challenges of providing food that consumers want. The STFC Food Network+ aims to bring STFC researchers and facilities together with food researchers and industry, through network meetings and funding for new projects. Some background about food: There is an impending perfect storm of pressure on our food production system, with increasing population and changing consumer tastes, in the face of rising temperatures and extreme weather events. Tim Gore, head of food policy and climate change for Oxfam, said “The main way that most people will experience climate change is through the impact on food: the food they eat, the price they pay for it, and the availability and choice that they have.”. Yet, at the same time, food production is a bigger contributor to climate change than transport. A 2014 Chatham House report states “Dietary change is essential if global warming is not to exceed 2C.”.