Kisoo Lee

Measurements of the inclusive jet cross section in photon-photon interactions at TRISTAN

Abstract We present cross section measurements for inclusive jet production in almost-real photon-photon interactions at TRISTAN using the AMY detector. The results are compared with leading-order QCD calculations for different parameterizations of the parton density in the photon.

THE HERMES POLARIZED 3HE INTERNAL GAS TARGET

Abstract The HERMES experiment is investigating the spin structure of the proton and neutron via deep-inelastic scattering of polarized positrons from polarized nuclear targets. The polarized positrons are provided by the HERA positron storage ring at DESY, Hamburg, Germany. The targets are pure internal gas targets. Data acquisition began in 1995, utilizing a polarized 3 He internal gas target to study the spin structure of the neutron. The target gas was polarized using the metastability-exchange optical-pumping technique and then injected into a cryogenically cooled target cell. The target was designed to operate with either longitudinal or transverse directions of polarization. Operating conditions included polarizations of up to 54% and target thicknesses of 1×10 15 nucleons/cm 2 . In this paper the HERMES polarized 3 He internal gas target is described in detail.

A laser optically pumped polarized 3He target for storage rings

Abstract A polarized 3 He target for use in a storage ring has been constructed and tested. The target employs an infrared laser to polarize 3 He atoms by metastability exchange optical pumping in a Pyrex glass cell which is connected by a glass capillary to a windowless target storage cell. The target polarization direction is determined by a 3 mT magnetic field. With 3 W of incident laser power, equilibrium polarizations of 50% at a flow rate of 1 × 10 17 3 He atoms/s have been routinely achieved. Two techniques have been investigated to rapidly reverse the 3 He target polarization. Further, a scheme to interface the glass pumping cell with the storage ring vacuum has been developed.

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.

Measurement of spin observables in quasielastic scattering of polarized protons from polarized 3He

Measurements of analyzing powers and spin correlation parameters for 3He(p↘,2p) and 3H↘e(p↘,pn) quasielastic scattering have been carried out using a polarized internal 3He target and a stored, polarized proton beam. They were made over a wide kinematic range with a proton energy of 197 MeV and a large acceptance detector system which allowed the simultaneous measurement of both reactions. At momentum transfers sufficiently high to minimize rescattering effects, the (p,pn) results are in agreement with PWIA calculations. The (p,2p) results were found to be less sensitive to kinematic conditions and are also in agreement with calculations.