Conveners
(DNP) M2-4 Hadronic physics, nucleon structure, QCD | Physique hadronique, structure des nucléons, QCD (DPN)
- Thomas Brunner (McGill University)
A key question of modern physics concerns how the bulk of the universe's visible mass emerges from the Standard Model (SM). Some of this mass is generated by Higgs boson couplings to matter fields in the SM, but of the constituents of atomic matter, this suffices to explain only the mass of electrons in its entirety. The overwhelming majority of atomic mass resides in the nucleus, which is...
There are many open questions in the field of hadronic structure, as the properties of constituent quarks and gluons (e.g. spin and mass) do not explicitly add up to the properties of hadrons. The pion is a simple hadron, consisting of only two valence quarks (up and down), which makes it an ideal candidate for studies of hadronic structure. The exclusive pion electroproduction reaction, with...
Photoproduction mechanisms studied in the GlueX experiment allows the mapping of light mesons in unprecedented detail with particular interest in exotic meson candidates. This is achieved by impinging an 8.2-8.8 GeV linearly polarized photon beam on a liquid hydrogen target. The measurement of beam asymmetry $\Sigma$ will help constrain quasi-particle t-channel exchange processes using Regge...
The KaonLT/PionLT Collaboration probes hadron structure by measuring deep exclusive meson production reactions at Jefferson Lab. A set of high momentum, high resolution spectrometers in Hall C allow for precision measurements from which form factors and other observables can be extracted. One possible measurement is the beam spin asymmetry, which describes the fractional difference in...
Hadrons are typically described using "quenched" constituent quark models, which posit a Hamiltonian acting on the state space of the valence quarks, neglecting mixing of higher Fock states. In recent years, experimentalists have observed states which are not well characterized by these models, motivating quark modellers to examine the effects of unquenching. The resultant mass shifts throw...
