[PAST EVENT] Timothy B. Hayward, Physics - Final Oral Dissertation Defense [Zoom]

March 29, 2021
8am - 11am
Timothy Hayward

Timothy B. Hayward , Physics - Final Oral Dissertation Defense

Zoom link is available upon request. Please email [[w|evwilk,Ellie]]

Title: Dihadron Beam Spin Asymmetries on an Unpolarized Hydrogen Target with CLAS12

Abstract: Azimuthal correlations in the production of hadron pairs in semi-inclusive deep-inelastic scattering provide rich information on nucleon structure. A high precision study of data taken with the newly upgraded CLAS12 detector has been used to extract beam-spin asymmetries for the channel corresponding to a final state positive and negative pion. These data represent the first experimental results obtained with the new CLAS12 system. Beam spin asymmetry amplitudes are presented with respect to the fraction of longitudinal momentum carried by the struck quark and the invariant mass of the hadron pair. One extracted asymmetry provides the first opportunity to extract the parton distribution function e(x), which provides information about the interaction between gluons and quarks, in a colinear framework. This measurement provides cleaner access to e(x) than alternative methods that also depend on the transverse momentum of the struck quark. A second modulation corresponds to the first ever signal sensitive to a helicity-dependent two-pion fragmentation function. A nonzero signal is reported which describes the dependence of the produced pions on the helicity of the fragmenting quark. A clear sign change is observed around the mass of the rho-meson that appears in model calculations and results from the interference of s and p wave dihadrons. Numerous other asymmetry amplitudes, each sensitive to its own combination of parton distribution functions and fragmentation functions, are also extracted.

Bio: Timothy Hayward was raised in Camden, SC. He developed an early interest in science and physics in particular and already intended on a physics major before he enrolled at the College of Charleston in 2010. Timothy graduated in 2014 and enrolled in William and Mary for his graduate studies. During his time at W&M Timothy has been actively involved with Jefferson Laboratory and the initial run period of the CLAS collaboration following the long-awaited update to the 12 GeV era. His studies involve probing the 3D structure of the nucleon and will continue with a post-doctoral position following graduation.