Navigating New Horizons: Defining the Next Era of Particle Physics

02 June - 27 June 2025

Andreas Weiler, Prateek Agrawal, Csaba Csaki, Michael Geller, Rachel Houtz

Beyond the Standard Model (BSM) physics has evolved drastically during the last decade due to the ever-tightening experimental constraints on new physics that explains the Fermi scale and the dominant dark matter paradigm of a weakly interacting massive particle (WIMP). The fundamental mysteries of the SM have further deepened. In response to this, physicists have started exploring new avenues for addressing both the hierarchy problem and the dark matter problem, as well as focusing on bottom-up approaches with an improved understanding of the underlying QFT principles. On the experimental side, we are now in the era of high-luminosity data collecting at the LHC, making previously challenging signals accessible. At the same time, many new proposals are being developed for smaller-scale experiments for fundamental physics. We expect the following key topics to be prominently featured: light dark matter, axion-like particles, cosmological solutions to the hierarchy problem, effective field theory methods and positivity bounds, new symmetries, and their potential phenomenological applications. This program will bring together experts in novel theoretical and phenomenological approaches to navigate these new horizons and to help define the next era of particle physics.



Key topics addressed:

Collider Phenomenology in the high-luminosity LHC era and beyondDoes the Higgs boson harbour clues on the origin of the weak scale?

– Can we learn anything new from current and future data by using new collider physics tools such as energy correlators, geometric approaches to collider events?

– Can we employ emerging tools in machine learning for collider physics data?

– What kind of unexplored BSM scenarios are going to be probed by new data? Are there scenarios in natural models such as SUSY or composite Higgs that could avoid detection so far and that are becoming accessible?

– Are there classes of detection strategies that have not yet been explored, beyond the conventional searches?

New solutions to Naturalness problems

– Are there new solutions that were not discovered?

– Could new solutions arise from cosmological mechanisms?

– Could new solution arise from new QFT principles, such as generalized symmetries?

– Are there new classes of predictions both for astrophysical and for high energy experiments?

– Are there new experiments that are needed to discover such ideas?

Dark Matter

– Are there novel production mechanisms for DM that have not yet been discovered?

– Are these scenarios going to be constrained/uncovered in the upcoming generation of dark matter experiments?

– Are there correlated signals, such as phase transitions, or new relativistic degrees of freedom that can show up in next generation cosmological experiments?

– Does dark matter substructure observations necessitate building models beyond the cold dark matter paradigm?

New cosmic phenomenology

– What possible unexplored phenomena in the early universe are our current and future experiments sensitive to?

– What can we learn from potentially discovering gravitational waves from the early universe?

– Are there new sources of gravitational waves that are unexplored? – How can we discover dark sector phase transitions and dynamics with current and future experiments?

Experiments beyond the LHC

- How can flavor-changing neutral current (FCNC) processes in B and D meson decays be used as a probe to uncover new BSM particles and interactions?

– What motivated theoretical predictions haven’t been addressed by current experiments across all energy scales? And what novel experiments might be required to detect them, be it at the energy, intensity, or lifetime frontier?

– Given the recent advancement of experimental proposals for feebly coupled or light dark matter particles, which models can these new detectors potentially uncover? Where are new opportunities for to probe the dark sector.

– What have we learned from the search program for the QCD axion and ALPs, and what are the promising new directions for probing ALP parameter space given the current experimental and theoretical landscape?

Bottom up / Effective field theory approaches to uncovering BSM physics

– How can the geometric formulation of EFT’s be leveraged to improve our understanding of the SMEFT and the HEFT?

– Is electroweak symmetry linearly or non-linearly realized in the effective theory of the Standard Model? In other words, is BSM physics non-decoupling? How can we ensure sensitivity to BSM scenarios of non-decoupling particles, and are they well-motivated?

– How can we identify physically relevant SMEFT parameter space using theoretical arguments like positivity bounds?

New QFT directions, new symmetries

– Generalized symmetries: What are their uses? What can we learn about QFT? How can they inform model building?

– Can we improve our understanding of strong dynamics and of the mechanisms of confinement using QFT tools such as softly broken SUSY?

– Can we use advances in scattering amplitude theory for various BSM directions?