About

Julian Heeck, Ph.D., completed his doctoral studies at Heidelberg University in 2014 and is currently serving as an Assistant Professor in Theoretical High Energy Physics at the University of Virginia. His research focuses on the Standard Model of particle physics, which is a highly successful description of nature at the most fundamental level, completed with the discovery of the Higgs boson in 2012. Heeck's work addresses empirical issues that demonstrate the incompleteness of the Standard Model, such as neutrino oscillations and dark matter, exploring models that extend the Standard Model to include neutrino masses and dark matter candidates. His research involves dedicated phenomenological studies of well-motivated theoretical models to identify promising search channels and distinctive signatures, facilitating experimental efforts to determine which models might succeed the Standard Model. Heeck has contributed to the field through various publications and has been recognized with awards such as the Adolphe Wetrems Prize in 2023 and the Otto Hahn Medal in 2014. He is actively involved in departmental committees and is an affiliated faculty member at the University of Virginia.

Research topics

• Physics
• Particle physics
• Geometry
• Mathematics
• Statistics
• Geography
• Nuclear physics

Selected publications

• Gauged Q-balls in flat potentials

  arXiv (Cornell University) · 2026-04-08

  preprintOpen access1st authorCorresponding

  Q-balls are large bound-state systems of scalar particles, described classically through localized solutions of the equations of motion. Promoting the required stabilizing $U(1)$ symmetry to a gauge symmetry leads to gauged Q-balls, which cannot grow beyond some maximal size and charge on account of the repulsive gauge interactions. These gauged Q-balls have been studied extensively for scalar potentials that satisfy Coleman's thin-wall criterion; here, we explore gauged Q-balls in flat potentials, which often occur in supersymmetric models. Even though global Q-balls in flat potentials are qualitatively different from Coleman's Q-balls, we find that the gauged versions are remarkably similar. We provide analytic approximations for these solitons and compare to numerical solutions. In addition, we study Proca Q-balls, i.e. make the gauge bosons massive, which interpolates between the global and gauged cases.

  PublisherDOI

• Basis for non-derivative baryon-number-violating operators

  ArXiv.org · 2026-04-28

  articleOpen access1st authorCorresponding

  We present a minimal basis for non-derivative baryon-number-violating operators in the Standard Model Effective Field Theory up to mass dimension 11, as well as for the $(ΔB,ΔL) = (2,2)$ and $(2,-2)$ operators at dimension 12. Compared to existing results, our bases generally contain fewer terms and simpler contractions, although we also highlight select cases where a minimal basis is incompatible with simple structures.

  PublisherOA PDF

• New avenues for tau flavor violation

  Zenodo (CERN European Organization for Nuclear Research) · 2026-04-01

  articleOpen access1st authorCorresponding
  PublisherDOI

• Gauged Q-balls in flat potentials

  arXiv (Cornell University) · 2026-04-08

  articleOpen access1st authorCorresponding

  Q-balls are large bound-state systems of scalar particles, described classically through localized solutions of the equations of motion. Promoting the required stabilizing $U(1)$ symmetry to a gauge symmetry leads to gauged Q-balls, which cannot grow beyond some maximal size and charge on account of the repulsive gauge interactions. These gauged Q-balls have been studied extensively for scalar potentials that satisfy Coleman's thin-wall criterion; here, we explore gauged Q-balls in flat potentials, which often occur in supersymmetric models. Even though global Q-balls in flat potentials are qualitatively different from Coleman's Q-balls, we find that the gauged versions are remarkably similar. We provide analytic approximations for these solitons and compare to numerical solutions. In addition, we study Proca Q-balls, i.e. make the gauge bosons massive, which interpolates between the global and gauged cases.

  PublisherOA PDF

• Opening up baryon-number-violating operators

  arXiv (Cornell University) · 2026-03-17

  preprintOpen access1st authorCorresponding

  Baryon number violation is our most sensitive probe of physics beyond the Standard Model. Its realization through heavy new particles can be conveniently encoded in higher-dimensional operators that allow for model-agnostic analyses. The unparalleled sensitivity of nuclear decays to baryon number violation makes it possible to probe effective operators of very high mass dimension, far beyond the commonly discussed dimension-six operators. To facilitate studies of this ginormous and scarcely explored testable operator landscape we provide the exhaustive set of tree-level UV completions consisting of scalars, fermions, and vectors for non-derivative baryon-number-violating operators in this Standard Model effective field theory up to mass dimension 15, which corresponds roughly to the border of sensitivity. In addition to the known Standard Model fields we also include right-handed neutrinos in our operators. Our public code can be used to UV-complete any non-derivative operator and match it onto an operator basis.

  PublisherDOI

• Basis for non-derivative baryon-number-violating operators

  arXiv (Cornell University) · 2026-04-28

  preprintOpen access1st authorCorresponding

  We present a minimal basis for non-derivative baryon-number-violating operators in the Standard Model Effective Field Theory up to mass dimension 11, as well as for the $(ΔB,ΔL) = (2,2)$ and $(2,-2)$ operators at dimension 12. Compared to existing results, our bases generally contain fewer terms and simpler contractions, although we also highlight select cases where a minimal basis is incompatible with simple structures.

  PublisherDOI

• Opening up baryon-number-violating operators

  ArXiv.org · 2026-03-17

  articleOpen access1st authorCorresponding

  Baryon number violation is our most sensitive probe of physics beyond the Standard Model. Its realization through heavy new particles can be conveniently encoded in higher-dimensional operators that allow for model-agnostic analyses. The unparalleled sensitivity of nuclear decays to baryon number violation makes it possible to probe effective operators of very high mass dimension, far beyond the commonly discussed dimension-six operators. To facilitate studies of this ginormous and scarcely explored testable operator landscape we provide the exhaustive set of tree-level UV completions consisting of scalars, fermions, and vectors for non-derivative baryon-number-violating operators in this Standard Model effective field theory up to mass dimension 15, which corresponds roughly to the border of sensitivity. In addition to the known Standard Model fields we also include right-handed neutrinos in our operators. Our public code can be used to UV-complete any non-derivative operator and match it onto an operator basis.

  PublisherOA PDF

• Q-balls across dimensions

  arXiv (Cornell University) · 2026-04-01

  preprintOpen accessSenior author

  Scalars carrying a conserved global charge $Q$ can form stable localized field configurations composed of a large number of particles. These non-topological solitons are spherically symmetric and are called Q-balls. While usually analyzed in three spatial dimensions, these solitons can be straightforwardly generalized to $d$ spatial dimensions. For $d=1$, we can analytically solve the non-linear differential equation for an important class of single-field potentials; for $d>1$, we can analytically approximate the solutions in the thin-wall or large Q-ball regime, including the first sub-leading correction consistently. Since the underlying differential equations have the same form as vacuum-decay bounce solutions, our results find applications there, too.

  PublisherDOI

• Q-balls across dimensions

  ArXiv.org · 2026-04-01

  articleOpen accessSenior author

  Scalars carrying a conserved global charge $Q$ can form stable localized field configurations composed of a large number of particles. These non-topological solitons are spherically symmetric and are called Q-balls. While usually analyzed in three spatial dimensions, these solitons can be straightforwardly generalized to $d$ spatial dimensions. For $d=1$, we can analytically solve the non-linear differential equation for an important class of single-field potentials; for $d>1$, we can analytically approximate the solutions in the thin-wall or large Q-ball regime, including the first sub-leading correction consistently. Since the underlying differential equations have the same form as vacuum-decay bounce solutions, our results find applications there, too.

  PublisherOA PDF

• New avenues for tau flavor violation

  Zenodo (CERN European Organization for Nuclear Research) · 2026-04-01

  articleOpen access1st authorCorresponding
  PublisherDOI

Recent grants

• Light Particles in the Lab and in the Sky

  NSF · $150k · 2022–2024

Frequent coauthors

• Werner Rodejohann

  Max Planck Institute for Nuclear Physics

  34 shared

• Anil Thapa

  University of Virginia

  17 shared

• Arvind Rajaraman

  University of California, Irvine

  11 shared

• Andreas Crivellin

  University of Zurich

  10 shared

• Jan Heisig

  University of Virginia

  10 shared

• Christopher B. Verhaaren

  Brigham Young University

  9 shared

• Mikheil Sokhashvili

  University of Virginia

  8 shared

• T. Lasserre

  Commissariat à l'Énergie Atomique et aux Énergies Alternatives

  7 shared

Education

• Ph.D.

  Heidelberg University

  2014

Awards & honors

• Adolphe Wetrems Prize [2023]
• Otto Hahn Medal [2014]