Engineering topics

Pascolini, A.

Publications and source records attributed to Pascolini, A..

3 records

DOE OSTI2014

Overview and highlights of the Spin Asymmetries of the Nucleon Experiment – SANE

The Spin Asymmetries of the Nucleon Experiment – SANE took data on inelastic and elastic inclusive and coincidence beam-target asymmetries in the Hall C facility at Jefferson Lab, detecting the scattered electrons with the large non-magnetic Big Electron Telescope Array – BETA and the High Momentum Spectrometer. The Continuous Electron Beam Accelerator Facility – CEBAF delivered polarized electrons that were incident on the U. of Virginia polarized proton target. An overview and selected examples of the wealth of collected data, extending from the elastic to the deep inelastic scattering regions, and spanning the four-momentum range from 0.8 to 6GeV{sup 2}, will be presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2014

Test of fundamental symmetries via the Primakoff effect

The three neutral pseudoscalar mesons, pi^0, eta and eta', represent one of the most interesting systems in strong interaction physics. A study of the electromagnetic properties of these mesons provides a sensitive probe of the symmetry structure of QCD at low energy. A comprehensive experimental program at Jefferson Laboratory (Jlab) is aimed at gathering high precision measurements on the two-photon decay widths and transition form factors at low Q^2 of pi^0, eta and eta' via the Primakoff effect. The completed experiments on the pi^0 radiative decay width at Jlab 6 GeV, and other planned measurements at Jlab 12GeV will provide a rich laboratory to test the chiral anomaly and to study the origin and dynamics of chiral symmetry breaking at the confinement scale of QCD.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2014

First result from Q weak

Initial results are presented from the recently-completed Q{sub weak} experiment at Jefferson Lab. The goal is a precise measurement of the proton's weak charge Q{sub w}{sup p}, to yield a test of the standard model and to search for evidence of new physics. The weak charge is extracted from the parity-violating asymmetry in elastic {rvec e}p scattering at low momentum transfer, Q{sup 2} = 0.025GeV{sup 2}. A 180 {micro} A longitudinally-polarized 1.16 GeV electron beam was scattered from a 35 cm long liquid hydrogen at small angles, 6 {degrees} < {theta} < 12 {degrees} Scattered electrons were analyzed in a toroidal magnetic field and detected using an array of eight Cerenkov detectors arranged symmetrically about the beam axis. The initial result, from 4% of the complete data set, is Q{sub W}{sup p} = 0.064 ± 0.012, in excellent agreement with the standard model expectation. Full analysis of the data is expected to yield a value for the weak charge to about 5% precision.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗