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HEP Seminars

22 Sep 2020

UCL HEP Seminars 2020

05-06-2020 : Anna Sfyrla (Geneva)

FASER

TBC

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29-05-2020 : Stefan Schoernert (TUM)

LEGEND

TBC

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22-05-2020 : Robert Thorne (UCL)

Inferring the effective fraction of the population already infected with Covid-19 by comparing rates in different regions of the same country

I use a very simple deterministic model for the spread of Covid-19 in a large population. Using this to compare the relative decay of the number of deaths per day between different regions in Italy, Spain and England, each applying in principle the same social distancing procedures across the whole country, I obtain an estimate of the total fraction of the population which has already become infected. In the most heavily affected regions, Lombardy, Madrid and London, this fraction is higher than expected, i.e. ~ 0.3. This result can then be converted to a determination of the infection fatality rate ifr, which appears to be ifr ~ 0.0025-0.005, and even smaller in London, somewhat lower than usually assumed. Alternatively, this can also be interpreted as a effectively larger fraction of the population than simple counting would suggest if there is a variation in susceptibility to infection with a variance of up to a value of about 2. The implications are very similar for either interpretation or for a combination of effects.

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15-05-2020 : Matthias Becker (Dortmund)

The Neutrino Portal To Dark Matter

If Dark Matter is an electroweak gauge singlet, it cannot interact with the standard model via these interactions, thereby requiring the existence of so-called portal couplings. The three renormalizable portal couplings are the Higgs portal, the vector portal, and the neutrino portal. In this talk, we investigate the neutrino portal to Dark Matter and inspect the viable production mechanisms and different constraints on the resulting parameter space.

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10-04-2020 : EASTER!

No seminar

TBC

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03-04-2020 : IOP Practice TALKS

IoP Practice talks

TBC

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27-03-2020 : Kirsty Duffy (FNAL)

Latest neutrino cross-section results from MicroBooNE

MicroBooNE, the Micro Booster Neutrino Experiment at Fermilab, is an 85-ton active mass liquid argon time projection chamber (LArTPC) located in the Booster Neutrino Beam at Fermilab. The LArTPC technology with 3mm wire spacing enables high-precision imaging of neutrino interactions, which leads to high-efficiency, low-threshold measurements with full angular coverage. As the largest liquid argon detector worldwide taking neutrino beam data, MicroBooNE provides a unique opportunity to investigate neutrino interactions in neutrino-argon scattering at O(1 GeV) energies. These measurements are of broad interest to neutrino physicists because of their application to Fermilab's Short Baseline Neutrino program and the Deep Underground Neutrino Experiment (which will both rely on LArTPC technology), as well as the possibility for new insights into A-dependent effects in neutrino scattering on heavier targets such as argon. In this seminar I will present the most recent cross-section results from MicroBooNE, including measurements of inclusive charged-current neutrino scattering, neutral pion production, and low-energy protons. Many of the results I will show represent the first measurements of these interactions on argon nuclei, as well as an exciting demonstration of the potential of LArTPC detector technology to improve our current understanding of neutrino scattering physics.

[slides]

20-03-2020 : Theresa Fruth (UCL)

Searching for Dark Matter with the LZ experiment

The nature of dark matter remains one of the biggest mysteries of the universe. Extensions to the Standard Model of particle physics provide potential candidates for it. Such dark matter particles can be searched for using direct detection experiments. The LUX-ZEPLIN (LZ) experiment is a next-generation direct detection experiment, which employs a two-phase, liquid xenon time projection chamber. It is currently under construction 4850 feet underground in an old gold mine in South Dakota. In this talk I will give an overview of the experiment and its projected sensitivity reach, as well as the current status of construction and integration.

[slides]

13-03-2020 : Susanne WestHoff (Heidelberg) POSTPONED

Dark matter searches with long-lived particles POSTPONED

In cosmological scenarios beyond thermal freeze-out dark matter interactions with standard-model particles can be tiny. This leads to mediators with a lifetime that is long compared with the scales of particle colliders. In this talk I will discuss two new ideas for collider searches with long-lived mediators: soft displaced objects as signs of compressed dark sectors at the LHC; and displaced vertices from long-lived light scalars at flavor and long-distance experiments. I will show that novel search strategies allow us to explore dark matter interactions ranging over several orders of magnitude.

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06-03-2020 : Alex Martyniuk (UCL)

Recent results from the LHC

Between 2015 to 2018 (a.k.a. Run 2) the LHC delivered around 160fb^-1 to both of its general purpose detectors: ATLAS and CMS. In this talk I will try to roughly outline what the experiments have done so far with this bounty of data, and where they are headed in the future. (This talk was previously given as the opening talk of the Lake Louise Winter Institute).

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14-02-2020 : Ilektra Christidi (UCL)

Research Software Development at UCL and the software landscape in HEP

With computing and large amounts of data becoming more and more an everyday reality in all research domains, the world is waking up to what High Energy Physicists knew all along: software is an integral part of research, and as such, it is a necessity to have the infrastructure and people to support its sustainable development. The UCL Research Software Development Group, a centralised service for the whole university research community, and the first group of its kind in the UK, has been here since 2012 to serve exactly this purpose. In the first part of this talk, I'll introduce the scope and work of our group, and will try to identify (with your help!) ways that we can be of service to the UCL HEP researchers. In the second part, I'll present a review of the latest PyHEP workshop, a forum where developments in the use of Python in Particle Physics are presented.

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07-02-2020 : Katharina Behr (DESY)

The puzzle of dark matter: missing pieces at the LHC?

Unravelling the particle nature of dark matter is one of the key goals of the LHC physics programme. Dark matter cannot be detected directly by the LHC experiments but would manifest itself as missing energy in the detector signature of collision events. Complementary resonance searches targeting new mediator particles between dark and known matter provide an additional approach to explore the interactions of dark matter. To date, no evidence for dark matter or related mediators has been found. Could dark matter interactions be more complex or have otherwise have evaded detection? I will review the diverse programme of dark matter searches on LHC Run 2 data and address strategies to extend our coverage of possible dark matter signatures at the LHC.

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31-01-2020 : Tevong You (Cambridge)

Where art thou, new physics?

Searching for new fundamental physics beyond the Standard Model, by experimenting, observing and theorising, is a tremendously exciting journey. One of our most reliable guides in this voyage of exploration is the framework of effective field theory. Through this lens, I will survey the landscape of where new physics may be hiding, from electroweak precision observables, diboson, Higgs, and flavour physics to light dark sectors. I conclude with the question of what, if anything, could we ultimately discover at future colliders?

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24-01-2020 : POSTPONED till 14.02.

Enjoy cake and puppies instead

TBC

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