R. McKeown

Physics opportunities with the 12 GeV upgrade at Jefferson Lab

We summarize the scientific opportunities for utilization of the upgraded 12GeV Continuous Electron Beam Accelerator Facility (CEBAF) and associated experimental equipment at Jefferson Lab. This is based primarily on the 52 proposals recommended for approval by the Jefferson Lab Program Advisory Committee to date. The upgraded facility will enable a new experimental program with substantial discovery potential to address important topics in nuclear, hadronic, and electroweak physics.

A combined analysis of SLAC experiments on deep inelastic e-p and e-d scattering

We report recent work on the extraction of R = {sigma}{sub L}/{sigma}{sub T} and the structure function F{sub 2} over a large kinematic range, which is based on a reanalysis of deep inelastic {var epsilon} {minus} p and {var epsilon} {minus} d scattering cross sections measured at SLAC between 1970 and 1985. All these data were corrected for radiative effects using improved versions of external and internal radiative correction procedures. The data from seven individual experiments were normalized to those from the recent high-precision SLAC experiment E140. We find that R{sub p} = R{sub d}, as expected in QCD. The value of R is higher than predicted by QCD even when target-mass effects are included. This difference indicates that additional dynamical higher-twist effects may be present. The structure functions F{sub 2}p and F{sub 2}d were also extracted from the full data sets of normalized cross sections using an empirical fit to R. These structure functions were then compared with data from the CERN muon scattering experiments BCDMS and EMC. We find that our data are consistent with the EMC data, if the latter are multiplied by a normalization factor of 1.07. No single, uniform normalization factor can be applied tomorexa0» the BCDMS data that will bring them into agreement with the SLAC data in the region of overlap.«xa0less

A proposed measurement of the ß asymmetry in neutron decay with the Los Alamos Ultra-Cold Neutron Source

This article reviews the status of an experiment to study the neutron spin-electron angular correlation with the Los Alamos Ultra-Cold Neutron (UCN) source. The experiment will generate UCNs from a novel solid deuterium, spallation source, and polarize them in a solenoid magnetic field. The experiment spectrometer will consist of a neutron decay region in a solenoid magnetic field combined with several different detector possibilities. An electron beam and a magnetic spectrometer will provide a precise, absolute calibration for these detectors. An A-correlation measurement with a relative precision of 0.2% is expected by the end of 2002.

High momentum transfer R(T,L) inclusive response functions for He-3, He-4. SLAC-NE-9 experiment

Inclusive electron scattering cross sections for {sup 3,4}He have been measured in the quasielastic region at electron energies between 0.9 and 4.3 GeV, and scattering angles of 15{degree} and 85{degree}. Longitudinal ({ital R}{sub {ital L}}) and transverse ({ital R}{sub {ital T}}) response functions have been extracted using a Rosenbluth separation at constant {vert bar}{bold q}{vert bar} of 1.050 GeV/{ital c}. The ratio of the longitudinal to the transverse reduced response functions in the negative {ital y} region reaches unity.

Overview of Nuclear Physics at Jefferson Lab

The Continuous Electron Beam Accelerator Facility (CEBAF) and associated experimental equipment at Jefferson Lab comprise a unique facility for experimental nuclear physics. This facility is presently being upgraded, which will enable a new experimental program with substantial discovery potential to address important topics in nuclear, hadronic, and electroweak physics. Further in the future, it is envisioned that the Laboratory will evolve into an electron-ion colliding beam facility.

Two body photodisintegration of the deuteron up to 2.8 GeV

Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 GeV to 2.8 GeV and center‐of‐mass angles from 37° to 90°. The measured cross section at θcm=90° are in agreement with the constituent counting rules.

Inclusive electron scattering from nuclei at {ital x}{approx_equal}1

The inclusive A(e, e{prime}) cross section for x {approx_equal} 1 was measured on {sup 2}H, C, Fe, and Au for momentum transfers Q{sup 2} from 1-7 (GeV/c){sup 2}. The scaling behavior of the data was examined in the region of transition from y-scaling to x-scaling. Throughout this transitional region, the data exhibit {zeta}-scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.

Inclusive electron scattering from nuclei atx≃1

The inclusive A(e, e{prime}) cross section for x {approx_equal} 1 was measured on {sup 2}H, C, Fe, and Au for momentum transfers Q{sup 2} from 1-7 (GeV/c){sup 2}. The scaling behavior of the data was examined in the region of transition from y-scaling to x-scaling. Throughout this transitional region, the data exhibit {zeta}-scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.

High momentum transfer R sub T , L inclusive response functions for sup 3,4 He

Inclusive electron scattering cross sections for {sup 3,4}He have been measured in the quasielastic region at electron energies between 0.9 and 4.3 GeV, and scattering angles of 15{degree} and 85{degree}. Longitudinal ({ital R}{sub {ital L}}) and transverse ({ital R}{sub {ital T}}) response functions have been extracted using a Rosenbluth separation at constant {vert bar}{bold q}{vert bar} of 1.050 GeV/{ital c}. The ratio of the longitudinal to the transverse reduced response functions in the negative {ital y} region reaches unity.

High momentum transferRT,Linclusive response functions forHe3,4

Inclusive electron scattering cross sections for {sup 3,4}He have been measured in the quasielastic region at electron energies between 0.9 and 4.3 GeV, and scattering angles of 15{degree} and 85{degree}. Longitudinal ({ital R}{sub {ital L}}) and transverse ({ital R}{sub {ital T}}) response functions have been extracted using a Rosenbluth separation at constant {vert bar}{bold q}{vert bar} of 1.050 GeV/{ital c}. The ratio of the longitudinal to the transverse reduced response functions in the negative {ital y} region reaches unity.