Dr. James L. Drachenberg

Dr. James Drachenberg


General Information


  • Ph.D. in Physics, Texas A&M University
  • B.S.  in Physics, Abilene Christian University

Research Interests

  • “Spin Physics”: Every proton has an intrinsic angular momentum called “spin.” This spin is measured, well known, and exactly the same value for every proton. It is known that the proton (the nucleus of the hydrogen atom) is not a fundamental particle but rather a composite of objects called quarks and anti-quarks held together by different objects called gluons. Furthermore, quarks and gluons, themselves, are known to have intrinsic angular momentum and, potentially, an angular momentum associated with their motion inside the proton. What is not known is how these constituents conspire to produce the known angular momentum associated with each proton. Understanding this mystery has implications for fundamental understanding of all elementary particles and the potential to be exploited in ways not yet fully understood.
  • “Fragmentation Functions”: One of the many fascinating features of the strong (nuclear) force is that quarks and gluons, the fundamental particles that make up protons and neutrons, cannot exist in isolation. Therefore, we cannot observe them directly. What we can observe, however, is the spray or “jet” of particles emitted as these quarks and gluons interact and bond to form “hadrons.” Many aspects of this “hadronization” and “fragmentation” process are not understood. Illuminating this mystery has implications for fundamental understanding of the strong (nuclear) force and the nature of elementary particle interactions.

Areas of Teaching

  • College Physics II
  • Data Reduction and Error Analysis

Recent Research

  • The STAR Collaboration: Brookhaven National Laboratory’s Relativistic Heavy-ion Collider (RHIC) is a unique facility in the world. RHIC is the only machine that can collide beams of protons where the directions of the proton “spins” are largely controlled. These “spin-polarized” proton-proton collisions are exploited by RHIC experiments, such as the Solenoidal Tracker at RHIC (STAR), to unlock some of the mysteries of the nature of spin and how the spins of quarks and gluons contribute to the known value of the intrinsic angular momentum of the proton.

Selected STAR Publications

  • L. Adamczyk et al. (STAR Collaboration), “Precision Measurement of the Longitudinal Double-Spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at √s = 200 GeV,” Phys. Rev. Lett. 115, 092002 (2015).
  • L. Adamczyk et al. (STAR Collaboration), “Measurement of Longitudinal Spin Asymmetries for Weak Boson Production in Polarized Proton-Proton Collisions at RHIC,” Phys. Rev. Lett. 113, 072301 (2014).
  • L. Adamczyk et al. (STAR Collaboration), “Neutral pion cross section and spin asymmetries at intermediate pseudorapidity in polarized proton collisions at √s = 200 GeV,” Phys. Rev. D 89, 012001 (2014).
  • L. Adamczyk et al. (STAR Collaboration), “Transverse single-spin asymmetry and cross section for π0 and η mesons at large Feynman x in p↑+p collisions at √s = 200 GeV,” Phys. Rev. D 86, 051101(R) (2012).

Selected Presentations

  • May 2015: "Recent Transverse Spin Results from STAR." BNL Nuclear Physics Seminar, Brookhaven National Laboratory, Upton, NY.
  • April 2015: “Constraining Transversity and Nucleon Transverse-polarization Structure Through Polarized-proton Collisions at STAR.” XXIII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2015), Dallas, TX.
  • August 2014: “Constraining Transversity and Nucleon Transverse-polarization Structure Through Polarized Proton Collisions at STAR.” 20th Particles and Nuclei International Conference (PANIC 2014), Hamburg, Germany.
  • February 2014: "Recent Spin Results from STAR.” Lake Louise Winter Institute, Lake Louise, Alberta, Canada.
  • December 2013: "Overview of STAR Spin Measurements." Indiana-Illinois Workshop on Fragmentation Functions, Indiana University, Bloomington, IN.
  • October 2013: “Transverse Single-spin Asymmetries from p↑ + p → jet + X and p↑ + p → jet + π± + X at √s = 500 GeV at RHIC.” 13th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2013), Rome, Italy.