Workshop Home

March 28-29, 2016
Walk Auditorium in Ritter Hall (42B on the map),
Temple University, Philadelphia
See Travel for more info

For almost 3 decades the study of the spin of the proton and its decomposition in terms of the spin and motion of its basic constituents, quarks and gluons, has taken center stage and generated many fruitful past and present experimental programs of nucleon spin structure worldwide. Along the way a paradigm shift in the way nucleon structure is viewed has emerged in attempting to access all the pieces of the proton spin decomposition, namely through the window of Wigner distributions that encapsulate the information of nucleon structure.

In contrast, the "mass decomposition of the proton" in terms of its constituents and their dynamics has not received as much attention from the hadron/nuclear physics community. Although one of the outstanding successes of lattice QCD is to reproduce the baryon mass spectrum, it doesn’t lend itself to communicating to a general audience a deeper understanding of how the different parts contribute to the whole.

In an effort to explore the fundamental importance and meaning of the "proton mass decomposition" in terms of the confined motion of the constituents we would like to organize an intensive 2-day workshop with enough time for discussions. The expected outcome of this workshop is a path forward to organize a week long workshop at the Institute of Nuclear Theory where a wider group of theorists and experimentalists will define a platform where experimental proposals to laboratories like Jefferson Lab and the future Electron Ion Collider will be put forward.

In this workshop we would like to discuss and address the following questions:

  • What do we know and don't know about the mass of hadrons and its origin?
  • What do we know about the hadron mass spectrum from Lattice QCD?
  • What do we know about the hadron mass from model calculations? What is in common from seemly different models?
  • Can we get any insight on the hadron’s mass structure by decomposing it into the mass and motion of quarks and gluons? Is such decomposition unique and can it be tested? Can we relate the individual terms of such decomposition to independent physical observables or lattice QCD calculations?