The Large Hadron Collider, currently running at CERN, is probing nature at distance scales an order of magnitude smaller than previous machines and has the potential to reveal a new principle of nature. At such small distances, the science of collider phenomenology changes from what was appropriate for previous machines. In particular, collisions at the LHC produce in much greater abundance the collimated beams of particles known as jets.

This award allowed me to develop theoretical tools to understand jets that exploit the improved measurement capabilities of the LHC detectors. For example, I worked on understanding to what extent jets have universal properties, independent of their environment. I was able to establish for the first time a rigorous factorization formula for scattering amplitudes involving jets. I also applied factorization and associated effective-field theory techniques to compute jet properties, such as the mass distribution of jets, to high precision. I developed methods that are able to extract the fundamental origin of a jet, be it from an up quark, a down quark, or a gluon, from the collider data. I also pioneered multivariate and statistical techniques for the analysis of LHC data which have been able to deconstruct jets in greater detail than previously thought possible. My work, and the work of graduate students and postdocs I was able to support with the Office of Science Early Career Award, has been instrumental in establishing the study of jet substructure as an indispensable tool for a great variety of searches and measurements at the LHC.


Matthew D. Schwartz is a professor in the Department of Physics at Harvard University.


The Early Career Award program provides financial support that is foundational to young scientists, freeing them to focus on executing their research goals. The development of outstanding scientists early in their careers is of paramount importance to the Department of Energy Office of Science. By investing in the next generation of researchers, the Office of Science champions lifelong careers in discovery science. 

For more information, please go to the Early Career Research Program page.


Understanding Jets at the Large Hadron Collider

The objective of this project is to develop new theoretical methods to help improve our understanding of the properties of particle jets that are produced in high‐energy collisions. There is also a relatively new area of research on jet substructure that tries to identify characteristics of jets that allows one to distinguish jets produced by known particles from those produced by unknown new particles. Improved knowledge about jets and jet substructure will be very important for correctly interpreting the data from high energy experiments.


David Krohn, Matthew D. Schwartz, Matthew Low, Lian-Tao Wang, “Jet Cleansing: Pileup Removal at High Luminosity,” Phys.Rev. D90 no.6, 065020 (2014). [DOI: 10.1103/PhysRevD.90.065020]

David Krohn, Matthew D. Schwartz, Tongyan Lin, Wouter J. Waalewijn, “Jet Charge at the LHC,” Phys.Rev.Lett. 110 no.21, 212001 (2013). 
[DOI: 10.1103/PhysRevLett.110.212001]

Ilya Feige, Matthew D. Schwartz, “Hard-Soft-Collinear Factorization to All Orders,” Phys.Rev. D90 no.10, 105020 (2014). [DOI: 10.1103/PhysRevD.90.105020]