Image: A graphic I used in my interview for my job as junior professor at Université Clermont Auvergne. It’s an adaptation of “Wanderer above the Sea of Fog” by Caspar David Friedrich, but I photoshopped out the fog in favour of the beautiful Chaîne des Puys which Clermont-Ferrand is nestled in.
About a month ago, I got some excellent news: a bid that my post-doc Marion and I put in to host the next ATLAS Exotics/HMBS Workshop in Clermont-Ferrand was successful. We saw off competition from Cambridge, Shanghai and CERN. That mean, for a week in late October, that the capital of Auvergne will become the beating heart of the search for new particles at the ATLAS experiment.
Practically speaking, the search for new fundamental particles in ATLAS is divided into two large groups*:
- The Exotics group (which I am coordinating at the moment), which specialises in heavy resonances (such as Z’ and W’, dark photons, gravitons, etc…), additional quarks or lepton partners (“vector-like fermions”, which arise in models where the Higgs boson is a composite particle), weird quark-lepton hybrids (appropriately named “lepton-quarks”), exotic particles with long lifetimes, and searches for dark matter particles.
- The HMBS (Higgs, Multi-Boson and SUSY) group, which is focused on searches for exotic Higgs bosons, light resonances (such as as axions or dark photons), new particles which decay to W or Z, as well as the vast programme of searches for supersymmetry.
Each of those two groups involves around 500 people. You can already see from the descriptions above that there is significant overlap between the activities of the groups. For example, supersymmetry can lead to long-lived particles. Conversely, leptoquarks can also give SUSY-like final states. Many models searched for in Exotics also involve additional Higgs bosons. Clearly these two groups need to speak to each other and have a common big-picture plan.
The ATLAS Exotics/HMBS Workshop will be a time to define and refine the big picture plan, while taking stock of the progress made over the last year. We will discuss operational aspects on how we can be more efficient and how we can make best use of new techniques in our search for new physics. It’s an important occasion, where we will have representatives from across the whole ATLAS new physics programme in a room, teasing out the details. Obviously we can’t have the whole community (1000 people is a lot even for large conference centres), but usually these events attract around 120 people from across the spectrum of our activities, including the leadership (group conveners and subgroup conveners), experienced professors with the wide-angle view, and post-doctoral researchers and PhD students who actually do the hands-on work.
Perhaps the word “Workshop” is a bit of a surprising tag for such an event. Usually, a conference is an open affair where results are presented publicly across the community. A workshop, by contrast, is usually a collaboration-internal event where work in progress can be discussed, and we can discuss strategy and operational elements which we might not want our competitors to know about (don’t air your dirty laundry in public and all that). I think the term “Workshop” makes reference to the fact that it should be an event where things actually get done, and decisions are actually made, rather than a conference which is more of a performative event to show off polished results.
The workshop will come right at the end of my tenure as Exotics group convener, and it will be a capstone of an intense couple fo years for me: a great sendoff, setting the direction of the programme for the next few years of searches for new particles before handing over the keys to my successors. This is a critical time for the LHC experiments, with planned upgrades being installed in 2027, before the final phase of the LHC begins. It’s so important for us to plan adequately for how we approach the “endgame” of the LHC, and the decisions we make at the next workshop will help shape our strategy for years to come. Some of the questions we need to discuss are:
- How to prepare and set up a search programme for LHC Run 4 ?
- How can we ensure our results are re-useable in the long term ?
- Even as datasets increase tenfold in size, how can we ensure analyses are completed in a timely manner ?
- What can we learn from our colleagues in CMS, or in astrophysics ?
- How can we ensure we make best use of new machine learning techniques (like anomaly detection or agentic AI) for physics ?
I am proud that some of those decisions will be made in Clermont-Ferrand. It’s not every day that an event of this type comes to this charming but out-of-the-way student town in France (“La Capitale de la Diagonale”, ie the only large town in the so called “Empty Diagonal” in France). It’s my plan to make sure that the local students and residents can also benefit from this meeting of minds. We can achieve this by involving our PhD students in the local organising committee, organising sessions which our masters students can attend, and a public engagement event for the wider audience. It’s already my opinion that Clermont-Ferrand punches way above its weight in terms of its visibility in Particle Physics, and this is a chance to double down on that reputation.
No LLMs were used in the making of this article, all typos and grammar issues are my own 🙂
*A small part of the new particle search program also lives in the Higgs physics group.
Louie D. Corpe 