I am a theoretical particle physicist primarily interested in models of dark matter and their experimental signatures. Although dark matter comprises nearly 85% of the matter in the Universe, its fundamental nature remains unknown. My research focuses on elucidating the particle and astrophysical nature of dark matter through its experimental signatures, focusing on data from the Large Hadron Collider, as well as direct and indirect detection experiments.
The Large Hadron Collider (LHC) is a particle accelerator that holds the promise of producing new, heavy particles in its high-energy collisions. I have worked extensively on “Simplified Models” at the LHC, especially with regards to jets plus missing energy searches. Most recently, my collaborators and I have been exploring novel ways to look for hidden dark sectors.
The goal of direct detection experiments is to observe dark matter particles that are streaming through the Earth. These detectors, often located deep underground, are sensitive to dark matter particles that collide with nuclei in their targets. The scattering rate depends on particle and astrophysical uncertainties, a topic that I have studied in-depth, and should also modulate annually due to the Earth’s time-dependent velocity. My collaborators and I recently discovered a novel modulation effect due to gravitational focusing by the Sun that has important implications for the interpretation of a potential signal.
I have considered the implications of data from a variety of indirect detection experiments, including the Fermi satellite and the HESS telescope. These experiments search for the Standard Model products (e.g., photons, quarks) from dark matter annihilation in the Galaxy. Most recently, I have been studying an excess of gamma-rays near the Galactic Center whose energy spectrum and distribution is reminiscent of a dark matter signal. However, using new analysis methods, my collaborators and I showed that these excess photons are most likely coming from a new population of astrophysical sources. I am currently working to understand the nature and origin of these sources, and applying these analysis techniques to search for dark matter in other regions of the Milky Way.
- S. Lee, M. Lisanti, B. Safdi, T. Slatyer, and W. Xue, Evidence for Unresolved Gamma-Ray Point Sources in the Inner Galaxy, Phys. Rev. Lett. 116, 051103 (2016).
- T. Cohen, M. Lisanti, and H. K. Lou, Semivisible Jets: Dark Matter Undercover at the LHC, Phys. Rev. Lett. 115, 171804 (2015).
- S. Lee, M. Lisanti, and B. Safdi, Distinguishing Dark Matter from Unresolved Point Sources in the Inner Galaxy with Photon Statistics, JCAP 1505, 056 (2015).
- B. Safdi, M. Lisanti, J. Spitz, and J. Formaggio, Annual Modulation of Cosmic Relic Neutrinos, Phys. Rev. D 90, 043001 (2014).
S. Lee, M. Lisanti, A. Peter, and B. Safdi, Effect of Gravitational Focusing on Annual Modulation in Dark-Matter Direct-Detection Experiments, Phys. Rev. Lett. 112, 011301 (2014).
S. Lee, M. Lisanti, and B. Safdi, Dark-Matter Harmonics Beyond Annual Modulation, JCAP 1311, 033 (2013).
T. Cohen, M. Lisanti, A. Pierce, and T. Slatyer, Wino Dark Matter Under Siege, JCAP 1310, 061 (2013).
M. Kuhlen, M. Lisanti, and D. Spergel, Direct Detection of Dark Matter Debris Flows, Phys. Rev. D 86, 063505 (2012).
M. Lisanti and D. Spergel, Dark Matter Debris Flows in the Milky Way, Phys. Dark Univ. 1, 155 (2012).
J. Alwall, M-P. Le, M. Lisanti, and J. Wacker, Model-Independent Jets plus Missing Energy Searches, Phys. Rev. D 79, 015005 (2009).
J. Alwall, M-P. Le, M. Lisanti, and J. Wacker, Searching for Directly Decaying Gluinos at the Tevatron, Phys. Lett. B 666, 34 (2008).