Thursday 24 July 2025, 13:00: Simon Jolly, Sonia Escribano Rodriguez & Joe Bateman (UCL) — PBT Seminar Room, UCLH Grafton Way Building

Latest Developments with the QuADProBe: the Quality Assurance Detector for Proton Beam Therapy

Comprehensive Quality Assurance (QA) continues to underpin safe treatment with proton beam therapy. With increasing patient numbers and treatment complexity, there is greater pressure on effective QA to minimise the time and staff resources needed for carrying out such measurements whilst increasing the accuracy and resolution of the measurements. This is particularly true for Patient Specific Quality Assurance (PSQA): although significant time savings may be possible with a fully log file-based workflow, this places tighter constraints on the beam QA measurements — specifically proton pencil beam position, size, dose and range in water — to ensure the subsequent accuracy of the log files.

A pair of quality assurance detectors for proton beam therapy are under development within the UCL High Energy Physics group. These detectors are intended to improve both the speed and accuracy of the QA process, allowing QA to be carried out more quickly and comprehensively. The first detector, the Quality Assurance Range Calorimeter (QuARC), is designed to make realtime measurements of the proton beam range in water. This also forms part of the larger Quality Assurance Detector for Proton Beam Therapy (QuADProBe) that will integrate beam spot size and position measurements alongside range and absolute dose.

This talk will present the current status of the QuADProBe development, including recent measurements with the QuARC at the Prague PTC and UCLH. The QuARC itself will be available during and after the talk for those attending in person to see.

Thursday 17 July 2025, 15:30: Tommaso Treu — E28 Harrie Massey LT

New measurements of H0 and dark matter properties based on JWST observations of lensed quasars

I will present new cosmological measurements based on JWST observations of strong gravitationally lensed quasars. In the first part of the talk, I will show the results of a multi-year effort by the TDCOSMO collaboration to use gravitational time delays to infer the expansion history of the universe and thus the Hubble constant. This method is completely independent of the local distance ladder and the cosmic microwave background and thus provides a new opportunity to understand whether the tension between the two arises from systematic uncertainties or may be indicative of new physics. In the second part of the talk, I will use new JWST-MIRI observations of strongly lensed quasars to detect dark subhalos independent of their stellar content. This measurement tests a fundamental prediction of the cold dark matter model, i.e. that galaxies should be surrounded by large numbers of dark satellite subhalos. I will discuss the implications of this measurement in terms of fundamental properties of dark matter, such as free streaming length and self-interaction cross section.

Friday 16 May 2025, 16:00: Ioannis Xiotidis and Noah Clarke Hall (UCL) — Maths 505, 25 Gordon Street

ML development for the Level-0 Global Trigger of ATLAS

With the High-Luminosity upgrade of the LHC ATLAS will enter an exciting new phase of data collection. The new datasets will have an unprecedented complexity pushing traditional algorithms and the existing hardware for data selection to their limits. For this reason ATLAS has an extensive upgrade plan which will provide new capabilities in the realm of triggering and data acquisition. One of the most challenging upgrades concerns the Level-0 Global Trigger. This sub-system will receive the full granularity of the calorimenter detector at the level of the hardware trigger and with the use of high end FPGAs perform elaborate selections. Having access to all those data allows for Machine Learning deployment at scale in such edge conditions. This seminar will present some of the cutting edge R&D activities in ML development for the Level-0 Global Trigger of ATLAS and a natural interface towards the Next Generation Trigger project of ATLAS. The latter is a new initiative within CERN focusing on R&D of novel machine learning techniques and development of cutting edge tools that assist with the task of wide application of ML in the CERN experiments.

Friday 11 April 2025, 16:00 (Physics A1/3): Max Knobbe

Fast, Portable, and Stable Event Generation with PEPPER

I introduce PEPPER, an innovative portable parton-level event generator designed to operate across various modern CPU and GPU architectures in the modern high-performance computing (HPC) environment. PEPPER significantly speeds up tree-level calculations with high jet multiplicities, increasing throughput by 1-2 orders of magnitude. I will also cover key ongoing developments ranging from machine learning for phase-space generation to physics-driven enhancements to improve numerical stability in the infrared limits.

Friday 04 April 2025, 15:00 (Bentham House, Room 124 (Gideon Schreier LT): Multiple Speakers

IoP Practice Talks

Friday 21 March 2025, 15:00 (Anatomy LT G04)

Sinead Farrington

Director of Particle Physics, STFC : Visit and Q&A

Prof. Sinead Farrington, the Director of Particle Physics at STFC, will visit UCL to hear about the UCL High Energy Physics group and some of our existing collaborations with national labs. Prof. Farrington will then discuss the strategy for the Particle Physics Division, give an update on the European Strategy for Particle Physics Update process, and finally take questions. Everyone in the group is invited to attend.

Friday 28 February 2025, 16:00 (North-West Wing Lecture Theatre G22)

Alessio Spurio Mancini (Royal Holloway)

Cosmology with Euclid: an Overview

The Euclid mission, launched in July 2023 by the European Space Agency, is set to revolutionise our understanding of the Universe by probing the nature of dark energy, dark matter, and fundamental physics with unprecedented precision. By surveying approximately one third of the sky, Euclid will create a 3D map of the Universe observing around 1.5 billion galaxies across 10 billion years of cosmic history. In this talk, I will provide an overview of Euclid’s scientific goals and its unique observational strategy. I will focus on the “3x2pt analysis”—combining weak lensing and galaxy clustering measurements—as a powerful tool to constrain modifications to General Relativity, neutrino masses, and the nature of dark energy. Additionally, I will discuss the computational challenges posed by Euclid’s unprecedented dataset, and highlight the role of advanced statistical methods and machine learning in tackling them.

Tuesday 18 February 2025, 16:00 (B05 LT Chadwick Building)

Michael Ramsey-Musolf

SPECIAL SEMINAR:: Was There an Electroweak Phase Transition?

The possible existence of beyond Standard Model physics at the TeV scale or below has important implications for the thermal history of electroweak symmetry-breaking. A first order phase transition -- not possible in the minimal Standard Model with a 125 GeV Higgs boson -- would provide the preconditions for generating the cosmic matter-antimatter asymmetry through electroweak baryogenesis and provide a source of primordial gravitational radiation. I discuss recent theoretical developments in assessing this possibility and the implications for high energy collider phenomenology and next generation gravitational wave searches.

Friday 24 January 2025, 16:00 (LG11 Lecture Room, Bentham House)

Ivan Martinez-Soler

Status and Prospects of the Three-Neutrino Mixing Scenario

Over the past decade, significant experimental efforts have been dedicated to measuring the parameters governing neutrino evolution. These efforts span a diverse range of sources, including solar, atmospheric, accelerator, and reactor neutrinos. The integration of these results into global analyses has been pivotal in examining the consistency among datasets and providing a comprehensive description of neutrino evolution. In this talk, I will present the latest findings from our global analysis, highlighting the major uncertainties and tensions observed across various datasets. Additionally, I will explore the potential of a combined analysis of atmospheric neutrino experiments, encompassing Super-Kamiokande, Hyper-Kamiokande, IceCube-Upgrade, and ORCA. By addressing shared systematic uncertainties—such as those arising from flux and neutrino-water interactions—alongside the unique uncertainties of each experiment, our study predicts transformative advances by 2030. These include determining the octant of θ23 with 99% confidence, establishing the neutrino mass ordering with a significance greater than 5σ, and providing critical insights into the CP-violating phase (δCP) in the leptonic sector.