SERC, Room 430
1925 N. 12th Street
Philadelphia, PA 19122

Zein-Eddine Meziani

Professor of Physics

Ph.D., Université de Paris XI, Orsay

Research Goals

The overarching goal of our research is to understand the structure of nucleons, the building blocks of nuclei, in terms of their constituents called quarks and gluons. The fundamental properties of the nucleon such as its mass, charge and spin are investigated within the theory of "strong" interactions known as Quantum Chromodynamics (QCD). QCD describes, from basic principles, the complex nature of the interactions (known as color interactions) among the nucleon's constituents. The Temple University Nuclear Physics Group is engaged in a series of experiments that aim at addressing the following science questions of nucleon/hadron structure:

  • Is the nucleon modified in the nuclear medium and if so how? 

  • What is the size of the average "strong" (color) force a valence quark feels when it starts its journey leaving the nucleon to become a hadron? 

  • How much of the valence quarks orbital motion contribute to the total "spin" half of the nucleon and how is this contribution distributed for each longitudinal momentum of these quarks? 

  • How much of the proton mass is carried by the mass, kinetic and potential energy of the quarks, the kinetic and potential energy of the gluons and a fundamental piece known as the "trace anomaly"? 

  • How are the quark and gluon density distributions of a free nucleon different from that of a nucleon embedded in a nucleus?

The research to answer these questions includes analysis of Jefferson Lab 6 GeV era experiments as well as simulations, design, R&D of detector components for the new CLAS‐12, Super High Momentum Spectrometer (SHMS) experiments and the longer‐term SoLID experiment. We are also invested in providing for technology that will enhance higher luminosity capabilities for threshold Cherenkov counters used in both CLAS‐12 and SoLID.