By: Dylan Rankin
February 21, 2024

The Reach of High Energy Physics

The A3D3 institute innovates in AI to enable discovery across science, with high energy physics (HEP) being one of the three research thrusts. Within the field of HEP there are a dizzying array of research topics and the tools physicists must use to study them are equally so. There are experiments in HEP that collide particles traveling near the speed of light and study the aftermath of the collisions to search for hints of new phenomena. Other experiments observe the vast reaches of space to try to understand the forces that shaped our universe. And still others seek to detect and measure incredibly rare interactions of elusive particles with our world that might shed light on the most mysterious known particle, the neutrino. These experiments study our universe from the quantum realm of subatomic particles to the astronomical realm of galaxies and black holes.

The Particle Physics Prioritization Panel Report

Once every decade a group of high energy physicists is charged by the Department of Energy (DOE) with evaluating the projects on the horizon across HEP and charting a fiscally responsible path for the next ten years. This involves a multi-year process and hundreds of studies by the community but allows every group within HEP to make the case for the projects and actions they believe to be the most exciting. This report, called the Particle Physics Project Prioritization Panel (P5) report, was released on December 8th, 2023, and sets out the goals across the field for the next decade. While members of A3D3 participate in many projects outside of HEP, the P5 report is very important in that it helps guide a lot of focus inside HEP for the next 10 years.

A3D3 Members Collaborate on Projects Recognized in Report

One major outcome of the P5 report is the suggestions regarding how best to utilize the funding we expect over the next ten years. While it would be wonderful if there were enough funding for all the great ideas in HEP, in practice some tough decisions must be made. Some projects are deemed more critical or cost-effective than others. Some projects must be prioritized now and others must be delayed for the future. A3D3 members contributed heavily to the planning process and many projects that count A3D3 members as leaders were strongly endorsed in the report, demonstrating major support for our work. These projects include the High-Luminosity Large Hadron Collider upgrade, multiple phases of the Deep Underground Neutrino Experiment, the IceCube experiment, and, implicitly, the Laser interferometer for Gravitational-wave Observation experiment. 

The P5 report is more than just a priority list of HEP projects. It also attempts to take a wide-angle look at the field as a whole and provide guidelines for areas of growth. One of the most overarching callouts in the P5 report is the use of Artificial Intelligence and Machine Learning (AI/ML). AI/ML is obviously a main component of the work in A3D3. Even more so, the ways in which A3D3 is pioneering AI/ML usage were called out as future directions for investment. These include the major A3D3 work on real-time systems like the ATLAS and CMS trigger systems, as well as significant computational work being spearheaded by A3D3 members related to the effective use of emerging hardware. 

The High-Luminosity Large Hadron Collider Upgrade

As the most powerful particle collider ever built the LHC is capable of producing conditions unlike any other machine on earth. It made the discovery of the Higgs boson possible and continues to allow many searches for new particles. But in order to continue to push the boundaries of the so-called energy frontier of HEP, the collider and the detectors need to be upgraded to allow us to collect even more data, or luminosity. This upgrade is called the High-Luminosity Large Hadron Collider, and its successful execution is one of the utmost importance according to the P5 report. The contributions of A3D3 members who work within the ATLAS and CMS experiments will be critical to the success of the HL-LHC upgrade.

The Deep Underground Neutrino Experiment

The Deep Underground Neutrino Experiment (DUNE) at Fermi National Accelerator Laboratory will allow incredibly precise measurements of elusive neutrinos. The detector is comprised of multiple stages, each with its own role to play in helping enable these measurements. Multiple future phases of the Deep Underground Neutrino Experiment (DUNE) were a focus of the report. The endorsement is a testament to the importance of neutrinos for a long time to come in US HEP research.

The IceCube Experiment

The IceCube experiment at the South Pole also seeks to study the properties of neutrinos. However, while the neutrinos at the DUNE detector are produced by the accelerator complex at Fermi National Accelerator Laboratory, those detected by IceCube are produced in space and can have energies higher even than particles produced at the LHC. The current IceCube detector instruments a volume of roughly 1 cubic kilometer, but a proposed IceCube Gen-2 would increase this volume ten-fold to further study of these astrophysical neutrinos. This upgrade is recommended by the P5 report to unlock the wide set of physics it can enable.

Multi-Messenger Astronomy and the Laser Interferometer for Gravitational-wave Observation

Although the Laser Interferometer for Gravitational-wave Observation (LIGO) is not funded by the DOE, the physics that it and other similar gravitational-wave experiments enable was strongly supported in the P5 report. Specifically, the report calls out the emerging field of Multi-Messenger Astronomy (MMA) that seeks to observe astronomical sources through both gravitational waves and electromagnetic signals. This field has largely been born out of the success of the LIGO experiment, and the strong endorsement of MMA from the P5 report represents a strong endorsement of the future of LIGO.

A3D3 Shows Promise of Bridging the Gap Between Hardware and Fundamental Science

It is clear that the work represented in A3D3 is strongly aligned not only with the endorsed experiments but also with the modes of discovery. The report comments that “upgraded detectors and advances in software and computing, including artificial intelligence/machine learning (AI/ML), will enable the experiments to detect rare events with higher efficiency and greater purity.” The connections in A3D3 between the hardware and the fundamental science are intended to facilitate the advances that the P5 report notes.

Much of the importance of this work was demonstrated in studies performed by A3D3 members during the planning process. In addition to work on the experiments above, A3D3 members led a review of the community needs, tools, and resources for AI/ML across HEP [], which was a primary resource of its kind. The alignment of the P5 recommendations with the work done by A3D3 members is a strong demonstration of the support in the HEP community for this sort of work.

Finally, one major component of the work in A3D3 is its cross-disciplinary nature. Solutions to problems in HEP are likely to come not only from within the field but through collaboration with other domains. The sharing of tools, problems, and expertise has the potential to unlock solutions across traditional research boundaries. The study of neural computations involved in sensory and motor behavior is seemingly far removed from the trigger systems in CMS and ATLAS. However, both areas of research require solutions for data processing that are capable of extremely high throughput. This connection has been strengthened through A3D3 work to enable ultrafast recurrent neural networks []. The P5 report makes explicit mention of collaborations to take advantage of these sorts of connections and suggests increasing their prevalence. This signals strong support for the sorts of trans-disciplinary connections A3D3 has fostered, both now and in the future.