Spring Commencement Program, May 7, 2022

Program of Commencement Exercises at Coastal Carolina University.https://digitalcommons.coastal.edu/commencement-programs/1094/thumbnail.jp

First Results from The GlueX Experiment

The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic and liquid hydrogen targets, and much of the detector has been commissioned. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed, including exclusive production of pi(0), eta and omega mesons. Linearly-polarized photons were successfully produced through coherent bremsstrahlung and polarization transfer to the rho has been observed

Hadronic form factors in lattice QCD at small and vanishing momentum transfer

The introduction of partially twisted boundary conditions allows weak and electromagnetic form factors to be evaluated at specified values of the hadronic momenta (and hence momentum transfers) in lattice simulations. We present and demonstrate this technique for the computation of the K ? ? semileptonic form factor at zero momentum transfer and for the electromagnetic form factor of the pion at arbitrarily small momentum transfers. These exploratory computations are carried out in full QCD with 3 flavours of sea quarks, but with only two values of mu = md which limits our ability to perform the chiral extrapolations. The results should therefore be viewed primarily as a demonstration of the feasibility of the method. For the K ? ? form factor we compare the new technique to the conventional approach and for the pion form factor we assess our results for very small momentum transfer with the help of chiral perturbation theory

Cross Sections for the γp→K∗0Σ+\gamma p \to K^{*0}\Sigma^+ Reaction at Eγ=1.7−3.0E_\gamma = 1.7 - 3.0 GeV

7 pages, 5 figuresDifferential cross sections for the reaction $\gamma p \to K^{*0} \Sigma^+$ are presented at nine bins in photon energy in the range from 1.7 to 3.0 GeV. The \kstar was detected by its decay products, $K^+\pi^-$, in the CLAS detector at Jefferson Lab. These data are the first \kstar photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor $K^*$-quark couplings shows good agreement with the data in general, after adjusting the model's two parameters in a fit to our data. Disagreement between the data at forward angles and the global angle-energy fit to the model suggests that the role of scalar $\kappa$ meson exchange in $t$-channel diagrams should be investigated