© 2020 by Kim SignoretPaar Photographs

Passing of Physics Professor Emeritus, Hans P. Paar

      It is with great sadness that we announce the passing of Hans P. Paar, professor emeritus of physics, on June 17, 2018, after a short illness. He was 74.

      Born June 2, 1944, in Rotterdam, Professor Paar earned his bachelor’s degree in physics at Delft University of Technology in the Netherlands. Interested in continuing studies in physics, he wrote letters to UC Berkeley and Columbia University expressing his interest in studying particle physics. Columbia responded, and he moved to New York City with his late wife, Nettie, and their late son Rob. Paar planned to spend one year in the United States, but ended up spending his life here.

      Paar completed his Ph.D. at Columbia University in 1974, advised by Leon Lederman, who won the Nobel Prize in Physics in 1988.  At Columbia, Lederman supervised Paar’s work on one of the first Fermilab experiments (E70). After completing his Ph.D. thesis on the project, Paar relocated to France to work as a CERN fellow with another Nobel Laureate, Jack Steinberger, on WA1, the first experiment with the high-energy neutrino beam of the newly commissioned Super Proton Synchrotron.

      In 1978, Paar was appointed a research scientist with the Dutch NIKHEF institute. After a brief stint in Amsterdam, he became a member of the Dutch team that worked on a gamma-gamma scattering experiment at the Stanford Linear Accelerator Center (SLAC) and quickly became one of the leaders of the collaboration that carried out this experiment. His visibility at SLAC led to an offer from the Department of Physics at UC San Diego, which he joined as a faculty member in 1986.

      Paar was an internationally recognized physicist. He researched the properties of the bottom quark (an elementary particle) since the early 1990s, first as a member of the CLEO Collaboration at the Cornell Electron-positron Storage Ring (CESR) and from 2001-2008 at the BaBar experiment at SLAC. He was integral in the design, construction and testing of the upgrade to the muon detector there. The signature achievement of the BaBar experiment was the measurement of time reversal asymmetry in neutral bottom meson decay. These were some of several measurements that lead to the 2008 Nobel Prize in Physics being awarded to Nambu, Kobayashi, and Maskawa. Paar contributed to novel techniques for designing and building 

prototype calorimeters, a critical element used in particle physics experiments.

      Later in Paar’s career, his research interests changed from experimental particle physics to

observational cosmology, a branch of astrophysics. He had been interested in the origin of the universe and its evolution as a function of time, so much so that he began to teach parts of this in his particle physics courses. Paar and his colleagues set out to detect B-mode polarization of the Cosmic Microwave Background (CMB) to address one of the most important and fundamental problems in astrophysics— the inflation of the universe during and after the Big Bang event. The project, named POLARBEAR, required that he make several expeditions to the demanding site at 17,000 feet above sea level in the Atacama Desert of Northern Chile. During this time, Paar supervised two Ph.D. theses in cosmology in under eight years. Brian Keating, UC San Diego professor of physics states, “Without Hans, POLARBEAR would not have been possible. Not only did he provide expert leadership, design and analysis skills, he also secured a private donation for $600,000 which helped enable the fabrication of the first 3.5 meter diameter POLARBEAR telescope.”

      Paar cared deeply about education and creating a nurturing and motivating environment for students, undergraduate and graduate alike. As such, he served multiple terms as the Vice Chair for Education in the Department of Physics, from 1993-1998 and again 2008-2013. He was instrumental in modernizing the quantum curriculum at all levels and authored the textbook, “An Introduction to Advanced Quantum Physics.” Paar served as co-principal investigator of the NSF Grant for Research Experience for Undergraduates (REU). This program gave undergraduate students from institutions with little research opportunities the opportunity for hands-on research experience in physics labs. As part of the REU program, he gave a “Physics of Sailing” course consisting of lectures on the actual physics of the sport (Bernouilli’s Law and the forces and torques involved in sailing), followed by a full day of sailing on San Diego Bay.


    Paar had many interests outside of physics, including music. He played the piano since he was nine years old and was a founding member of the UC San Diego Oceanids Piano Soiree group. He was one of the early faculty supporters of the university’s performing arts program, now known as ArtPower, which brings internationally acclaimed string quartets to campus. He was an N-Scale model train modeler and a long-time member of the San Diego Railroad Museum in Balboa Park.

      Paar is survived by his wife Kim Signoret-Paar, daughter Suzanne Paar, stepsons Eric and Alain Signoret, and brothers Paul and Wim Paar.

      Those wishing to honor Hans Paar’s memory can make a donation to the “Physics Chair Challenge” (https://espi.ucsd.edu/) fund which supports educational excellence and training for current physics students (fund number 4079), or to ArtPower’s Robert & Sonia Hamburger Family Chamber Music Series Endowment (fund number 1519). Checks should be made out to the “UC San Diego Foundation,” with the appropriate fund numbers placed in the memo line and mailed to:

UC San Diego Gift Processing

9500 Gilman Drive #0940

La Jolla, CA 92093-0940

Steven Boggs


Division of Physical Sciences


Benjamin Grinstein

Professor and Chair

Department of Physics

University of California, San Diego

July 5, 2018