Identification of Pions from the \gamma p -> \pi^+ n Reaction

Description

One of the important questions in nuclear science today is to describe the properties of the nucleon in terms of Quantum Chromodynamics (QCD) theory. An understanding of quark behavior can be gained through studying pion photoproduction because it involves a direct rearrangement of quarks. Neutral pion photoproduction reactions have been extensively studied, where as the charged reactions lack available data from the ranges of 150 MeV to 180 MeV. The newly upgraded tagging facility at MAX-lab in Lund, Sweden is capable of tagging photons at energies up to 200 MeV and is ideally suited for investigating pion photoproduction reactions. In the summer of 2009 MAX-lab ran NP014, an experiment that collected data for the gamma+p -> pi++n reaction. Although standard dE vs. E particle identification methods are insufficient to separate pions from a very large proton and electron background, by searching for the 4.12 MeV muon from pion decay in the E counter, candidate pion events were identified. A final cross-check of the pion identification was made by examining the decay curve for the candidate pion events and comparing this with the 26 ns lifetime for the pion to muon decay.

Period	2010
Examinee/Supervised person	Colleen Allen
Examination/Supervision held at
Degree of Recognition	National