The theoretical particle physics group pursues a broad and balanced spectrum of research directions and spearheaded a number of major developments in theoretical particle physics. These stretch from hadronic physics at the MeV scale to string theory at the Planck scale, and from phenomenological studies of collider physics and high-energy astrophysical processes to formal studies of extra spacetime dimensions, unification, surprising features of the scattering amplitudes that arise in quantum field theory, and alternative cosmological timelines. Our work is relevant for all of the major experimental frontiers of particle physics, including not only the Energy Frontier (Higgs physics, electroweak symmetry-breaking, beyond the Standard Model physics) but also the Intensity Frontier (neutrinos, rare processes, low-energy tests of fundamental physics) as well as the Cosmic Frontier. Our research stretches across many different styles and techniques, from the data-driven to the speculative and from the computational to the more abstract. We have done important work relevant to current and future particle accelerators.
Members of the group are also expanding the connections between particle physics, astrophysics, and cosmology by probing the properties of dark matter using cosmic neutrinos, by exploring new methods of dark-matter detection, and by developing new dark-matter scenarios beyond the Weakly Interacting Massive Particle (WIMP) paradigm. The group also has intense interactions with our Nuclear Theory group, with our General Relativity/Cosmology group, and with members of the Astronomy Department and applied mathematics faculty. Indeed, Dienes, Sarcevic and Su are active members of our interdepartmental Theoretical Astrophysics Program.
Theoretical Particle Physics Faculty
The Dienes group conducts theoretical research in particle physics and cosmology, with a focus on physics beyond the Standard Model and its cosmological implications. One major research direction develops the framework of Dynamical Dark Matter, which opens the possibility that the dark sector consists of a large ensemble of states. More recently, the group identified a new cosmological epoch—termed “stasis”—in which the relative abundances of matter, radiation, and vacuum energy remain constant despite cosmic expansion, leading to far-reaching implications across the cosmological timeline. A third line of research investigates non-supersymmetric string theories, demonstrating that nonperturbative UV/IR mixing can reproduce effects traditionally attributed to supersymmetry. This work has involved close collaboration with former UA graduate students and postdocs and has received broad visibility within both the scientific community and the popular science press. Dienes is an APS Fellow and serves as the Program Director for Theoretical High-Energy Physics, Particle Astrophysics, and Cosmology at the NSF. In this capacity, he oversees all NSF funding for these disciplines across the entire US.
The Jones group applies modern on-shell scattering amplitudes techniques to problems in perturbative quantum field theory, gravity, and cosmology. Current research includes the use of amplitudes-based methods to compute gravitational-wave observables in the post-Minkowskian expansion of the early inspirals of binary black hole and neutron star systems, as well as applications to the “cosmological bootstrap” of signals of primordial non-Gaussianity during inflation. Recent highlights include the development of an open effective field theory for horizon absorption effects and rigorous no-go theorems for gravitationally interacting “partially-massless” fields in de Sitter space. Jones joined the University of Arizona as an Assistant Professor in Fall 2025, strengthening the department’s profile in modern theoretical methods at the interface of particle physics, gravity, and cosmology.
The Meinel group performs large-scale lattice QCD calculations aimed at precision tests of the Standard Model and searches for small beyond Standard Model effects. The group has produced world-first lattice-QCD predictions for several heavy-baryon semileptonic decays, subsequently confirmed by experimental measurements at LHCb and BESIII. Recent work includes the first lattice calculation of a semileptonic meson decay producing two final-state mesons, a major technical advance published in Physical Review Letters as an Editor’s Suggestion. Meinel’s contributions have been recognized with the Kenneth G. Wilson Award for Excellence in Lattice Field Theory, and he plays a leading service role in the field through USQCD, the Particle Data Group, and national community-planning efforts.
The Sarcevic group investigates a broad range of topics at the interface of particle physics and astrophysics, with particular emphasis on neutrinos and dark matter. Research highlights include studies of dark-matter capture in neutron stars, revealing correlations between dark-matter properties and neutron-star ages, and proposals for novel searches for hadrophilic dark matter using neutrinos from the Sun at experiments such as DUNE. Her work maintains strong connections to major experimental efforts, including IceCube and DUNE, and has attracted substantial international attention. Sarcevic represents the University of Arizona on the DUNE Institutional Board, serves on the DUNE Authorization and Publication Board and is an APS Fellow.
The Su group conducts research in particle physics phenomenology, providing critical connections between theoretical models and experimental searches for new physics. Her work spans Higgs physics, dark matter, and collider signatures of physics beyond the Standard Model, with recent contributions to Higgs precision measurements, exotic Higgs decays, quantum correlations at the LHC, and searches for light scalars at forward experiments. Su’s research has played an important role in shaping experimental strategies at current and future facilities. Her contributions have been recognized as an APS Fellow, as a UA College of Science Galileo Circle Fellow in 2023 and the UA Women of Impact Award in 2023, and she provides national leadership through service on advisory committees and community.
