Martin Schmaltz

Research Interests: Laws of Physics.

I am interested in understanding the fundamental laws of physics. Particle physics and Cosmology have recently celebrated the experimental confirmation of their respective “standard models”. However, in both areas there are also intriguing isolated discrepancies between predictions of the model and experimental observations. These suggest that there may be physics beyond the Standard Models lurking, ready for us to discover, describe and conform. My work involves constructing new models which could explain these discrepant observations, studies of the viability of such alternate scenarios and suggestions for new experiments which could help confirm or refute them.

In the area of Cosmology, I am interested in the physics of “dark sectors”, particles which are not directly observable in laboratory experiments but which contribute to the energy budget of the universe and thereby affect its expansion history. Our universe’s dark sectors must contain cold dark matter but it it could also contain additional relativistic and non-relativistic particles with interactions. Recently, my research group has shown that the observational “H0 crisis” could be pointing towards dark sectors with “stepped radiation”. Currently we are investigating if “stepped radiation” could also be responsible for the lower than expected clustering of galaxies observed at scales of ~10 Mpc.

In the area of particle phenomenology, I have recently published several works on the theory and phenomenology of Leptoquarks. These are a hypothetical new particle with quantum numbers allowing them to couple to quarks and leptons simultaneously. Leptoquarks might be behind the recently observed violations of lepton flavor universality in experiments at LHCb and Belle and could be discovered either directly or indirectly through their signatures at the LHC.

Currently, my group members include postdoc Daniel Aloni and graduate student Melissa Joseph and I am recruiting a new student.

Selected Publications:

“A Step in Understanding the Hubble Tension”, Daniel Aloni, Asher Berlin, Melissa Joseph, Martin Schmaltz, Neal Weiner, arXiv:2111.00014 (2021) [astro-ph.CO]].

“The Leptoquark Hunter’s Guide: Pair Production”, Bastian Diaz, Martin Schmaltz, Yi-Ming Zhong, JHEP 10 (2017) 097.

“Evidence for dark matter interactions in cosmological precision data?” Julien Lesgourgues, Gustavo Marques-Tavares, Martin Schmaltz, JCAP 1602 (2016) no.02, 097.

“Diagnosing lepton-nonuniversality in b→sℓℓ”, Gudrun Hiller, Martin Schmaltz, JHEP 1502 (2015) 055.

“The Little Higgs from a simple group”, David E. Kaplan, Martin Schmaltz, JHEP 0310 (2003) 039.

For a full list of publications, please see the attached CV.

Honors/Awards:

• Sloan Foundation Research Fellowship
• DOE Outstanding Junior Investigator Award