MRIConsortium: Development of a Neutral Particle Spectrometer to Investigate the Quark Structure of the Proton at JLab 12 GeV

Catholic University Of America, Washington DC

Investigators

Abstract

Gaining a quantitative description of the nature of strongly bound systems is of great importance for our understanding of the fundamental structure and origin of matter. Revealing the inner structure of the core of the atom that contains the protons and neutrons and understanding the dynamics that bind these most basic elements of nuclear physics is an essential part to advance this knowledge. This project is aimed at conducting leading-edge research to construct a neutral particle spectrometer (NPS) critical to confirm the understanding of the structure of the proton. The NPS enables a multifaceted experimental physics program at the Jefferson National Accelerator Facility, in which the PIs play a leading role. The participation of postdoctoral researchers, graduate students, and undergraduate students is an integral part of this project and contributes to the development of the technological work force in the USA. The all-female project leadership will provide role models that could encourage under-represented groups to pursue advanced studies in physics or technical fields. The two-arm combination of neutral-particle detection as provided by the NPS and a high-resolution magnetic spectrometer offers unique scientific capabilities to push the energy scale for studies of the transverse spatial and momentum structure of the nucleon through reactions with neutral particles requiring precision and high luminosity. The NPS allows accurate access to measurements of so-called hard exclusive (the recoiling proton stays intact in the energetic electron-quark scattering process) and semi-inclusive (the energy loss of the electron-quark scattering process gets predominantly absorbed by a single pion or kaon) scattering processes. To extract the rich information on proton structure through spatial and momentum imaging, it is of prime importance to show in accurate measurements, pushing the energy scales, that the scattering process is understood. Precision measurements of real photons or neutral-pions with the NPS offer unique advantages here. The instrument will be built by a collaboration of researchers forming a consortium led by the Catholic Univ. of America and Ohio Univ. It will also include the Old Dominion Univ. and as non-lead partners, the Jefferson Lab, North Carolina A&T University, the Yerevan Physics Institute, U. of Glasgow, and the Institute of Nuclear Physics at Orsay.