ODU Physicists Lead Project Taking New Look at Old Data

A team of researchers led by ODU physicists Lawrence Weinstein and Sebastian Kuhn has won a $756,000 grant from the Department of Energy to take a fresh look at a decade's worth of data gathered from atom-smashing experiments at the Thomas Jefferson National Accelerator Facility in Newport News.

The goal of the project is to turn up new revelations about the fundamental structures of matter without the help of new experiments, which typically cost millions of dollars and take many months to accomplish at the Jefferson Lab.

"Short Distance Structure of Nuclei - Mining the Wealth of Existing Jefferson Lab Data" is the title of the three-year project. Weinstein, University professor of physics, is the principal investigator for the grant. Kuhn, professor of physics and Eminent Scholar, is co-PI together with Mark Strikman of Penn State and Misak Sargsian of Florida International University. The project team, which brings together physicists from institutions in Israel and Scotland, as well as seven other universities in the United States, includes three additional ODU faculty members: Wallace Van Orden, professor of physics and Eminent Scholar; Moscov Amarian, professor of physics; and Stepan Stepanyan, Jefferson Lab Professor.

Recent findings about the quarks and gluons that make up nucleons (protons and neutrons), and about the nucleon structures within the atomic nucleus have given the researchers new interest in old results from electron scattering experiments at the Jefferson Lab. Just as important, according to Weinstein, stronger computational tools now allow physicists to glean more information than ever before from the data sets.

Data to be mined are from the Jefferson Lab's CLAS detector, which has been "catching" the results of atom-smashing experiments for 10 years. Since its commissioning, CLAS "has accumulated an immense data set of electron (and photon) scattering from nuclear targets," states the team's project proposal. "These data sets have been collected for specific approved experiments, which have published their results. However, due to the use of a wide open, inclusive trigger, the same data sets can be analyzed for additional channels of interest, or for additional kinematic regions not covered by previous analysis."

Furthermore, according to the proposal, "software tools to reconstruct, correct, cut and analyze the data have evolved. Our judgment is that the existing CLAS data will need to be re-analyzed using a consistent set of up-to-date reconstruction software and up-to-date cuts and corrections."

Weinstein said this grant is a first for ODU physicists not only because it will scrutinize existing data, but also because ODU is leading a large experimental collaboration including groups from MIT, the Universities of Glasglow and Edinburgh, Tel Aviv University, Penn State, Ohio State, the College of William and Mary, the University of Richmond, George Washington University, the University of New Hampshire and Florida International.

He said the project is also unusual in the ways it will combine aspects of experimental and theoretical nuclear physics. Most of the ODU team members are experimentalists; Van Orden is one of the project's theorists.

An experimental postdoctoral researcher will be hired with project money to systemize the different methods of data analysis used in the CLAS experiments so that outside collaborators can analyze the information more easily. Another postdoctoral researcher in theoretical nuclear physics will be hired to help interpret the data mining.

The grant also will provide money for travel to facilitate collaboration by the team members.

Eliezer Piasetzky, the professor at Tel Aviv University who is on the team, was a co-author along with Weinstein of an article in Physical Review Letters earlier this year, "Short Range Correlations and the EMC Effect." Their findings about the short-distance structure of nuclei came from the authors' mining of experiment results from Jefferson Lab and the SLAC National Accelerator Laboratory in California.