Related papers: The Q_weak Experimental Apparatus
To probe CP violation in the leptonic sector using GeV energy neutrino beams in current and future experiments using argon detectors, precise models of the complex underlying neutrino and antineutrino interactions are needed. The E12-14-012…
The parameters of the electroweak theory are determined in a combined electroweak and QCD analysis using all deep-inelastic $e^+p$ and $e^-p$ neutral current and charged current scattering cross sections published by the H1 Collaboration,…
The Continuous Electron Beam Accelerator Facility (CEBAF) was built with a thermionic electron source and the three original experimental hall lines reflected this. A few years after beam delivery began a parity violation experiment was…
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from ^4He at an average scattering angle <theta_lab> = 5.7 degrees and a four-momentum transfer Q^2 = 0.091 GeV^2. From these data,…
The double-polarization observable $E$ was studied for the reaction $\gamma p\to p\omega$ using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally-polarized…
Due to the inconsistency in the results of the GEp/Gmp ratio of the proton, as extracted from the Rosenbluth and recoil polarization techniques, high precision measurements of the e-p elastic scattering cross sections were made at Q^2 =…
The HJET Polarized Atomic Hydrogen Gas Jet Target polarimeter (HJET) polarimeter was designed to measure the absolute polarization of the proton beams at the Relativistic Heavy Ion Collider. In these measurements, the small scattering angle…
The first observation of electroweak production of a photon in association with two forward jets in proton-proton collisions is presented. The measurement uses data recorded by the CMS experiment at the LHC during 2016$-$2018 at a…
We study the possibility to measure sin^2 theta_W by neutrino-electron scattering at a value of the momentum transfer Q ~ 30 MeV with a precision of 0.24% which is only a factor three below the one obtained by LEP-I at the Z-pole. The…
The forward-backward charge asymmetry for the process $q\bar{q} \rightarrow Z/\gamma^{\ast} \rightarrow \mu^{+}\mu^{-}$ is measured as a function of the invariant mass of the dimuon system. Measurements are performed using proton proton…
Several important and unique measurements, within the standard model and of possible physics beyond it, could be made with {\em polarized HERA} in which both the proton and the electron beams are polarized. With a $\sim$820 GeV proton beam…
Polarization transfer in quasi-elastic nucleon knockout is sensitive to the properties of the nucleon in the nuclear medium, including possible modification of the nucleon form factor and/or spinor. In our recently completed experiment…
Precise measurements of the proton form factor ratio mu*GE/GM from Rosenbluth separation measurements can be combined with Polarization based extractions to provide significant constraints on two-photon exchange contributions to the elastic…
Differential cross sections for Compton scattering from the proton have been measured at scattering angles of $55^\circ$, $90^\circ$, and $125^\circ$ in the laboratory frame using quasimonoenergetic linearly (circularly) polarized photon…
The E12-14-012 experiment performed at Jefferson Lab Hall A has collected inclusive electron-scattering data for different targets at the kinematics corresponding to beam energy 2.222 GeV and scattering angle 15.54 deg. Here we present a…
In this paper, we describe an experiment measuring low-$Q^2$ elastic electron-proton scattering using a newly developed cryogenic supersonic gas jet target in the A1 three-spectrometer facility at the Mainz Microtron. We measured the proton…
I calculate the parity violating asymmetry A_{pv} for elastic electron scattering from 27Al in order to compare with the Qweak experiment "background" 27Al measurement. I find that Coulomb distortions, and the quadrupole form factor, reduce…
Charge radii of hadrons are back in the focus since precision spectroscopic measurements in muonic hydrogen revealed a proton charge radius considerably smaller than generally accepted ever since R.~Hofstaedter's pioneering experiments.…
Results are presented for the first measurement of the double-polarization helicity asymmetry E for the $\eta$ photoproduction reaction $\gamma p \rightarrow \eta p$. Data were obtained using the FROzen Spin Target (FROST) with the CLAS…
The recently published final results of experiment E04-108 in Jefferson Lab Hall C extend the recoil polarization measurements of the ratio of the proton electric and magnetic form factors to $Q^2 = 8.5$ GeV$^2$, an increase in $Q^2$…