Morris Swartz


Contact Information

Research Interests: Experimental high-energy physics; precision tests of and searches for physics beyond the Standard Model

Education: PhD, University of Chicago

Morris L. Swartz received a BS in physics from Worcester Polytechnic Institute in 1976 and a PhD in physics from the University of Chicago in 1983. He spent three years as a scientific associate and staff physicist at CERN and 12 years as an assistant professor and staff physicist at SLAC before joining the Johns Hopkins faculty in 1998 as a full professor. He is also a fellow of the APS.

Swartz's research has involved many aspects of experimental particle physics. From 1977 until 1983, he worked on several fixed target experiments at the Fermi National Accelerator Laboratory. These included a proposal to measure the cross sections for neutrino- and antineutrino-electron elastic scattering, a measurement of the transverse momentum spectra of final state hadrons produced in pion-nucleon interactions, and a study of large mass muon pairs produced in pion-nucleon collisions. His thesis on the atomic mass dependence of the muon pair cross section was supervised by Melvin Shochet.

From 1983 through 1986, Swartz was a member of the UA2 Collaboration at the CERN SPS Collider where he studied various properties of the recently discovered W and Z bosons. He also searched for several exotic particle states in the decays W and Z bosons.

In late 1986, he moved to SLAC, where he joined the Mark II Collaboration working at the SLAC Linear Collider (SLC) and an informal collaboration of Mark II and SLD physicists working to polarize the electron beam of the SLC (SLCPOL Collaboration). As a member of the Mark II Collaboration, he became interested in lepton flavor violation and searched for doubly-charged Higgs scalars in Z data and elsewhere. As a member of the SLCPOL Collaboration, he worked on the production, transport, and monitoring of a polarized electron beam for the SLC. When the Mark II experiment ended in 1991, he joined the SLD Collaboration which was preparing a new experiment for the SLC. He became the co-leader of the SLD Electroweak Working Group which has performed several measurements of the left-right Z cross section asymmetry ALR. This series of progressively more precise measurements constitutes the most precise test of the electroweak Standard Model yet performed.

In 1998, Swartz joined the CMS Collaboration at the CERN LHC to search for physical processes that are beyond the Standard Model. His recent work in CMS has focused on the development of radiation-hard silicon pixel sensors. He has produced a detailed double junction model of irradiated silicon that agrees well with beam test data and also rules-out the commonly held picture of uniformly type-inverted material. This model is now used to drive a new algorithm for the reconstruction of pixel hits. Although the algorithm was designed to provide optimal resolution after irradiation it also provides superior performance with unirradiated sensors. It reduces resolution tails and significantly improves b-tagging in CMS. The algorithm also provides cluster shape information that is proving useful in track reconstruction.