6,031 research outputs found
Perturbative and non-perturbative QCD corrections to wide-angle Compton scattering
We investigate corrections to the handbag approach for wide-angle Compton
scattering off protons at moderately large momentum transfer: the photon-parton
subprocess is calculated to next-to-leading order QCD and contributions from
the generalized parton distribution E} are taken into account. Photon and
proton helicity flip amplitudes are non-zero due to these corrections which
leads to a wealth of polarization phenomena in Compton scattering. Thus, for
instance, the incoming photon asymmetry or the transverse polarization of the
proton are non-zero although small.Comment: 19 pages, 9 figures (using LATEX with epsfig
Revisiting W gamma production at RHIC
We discuss W gamma production in polarized p p collisions at RHIC energy. We
point out that the RHIC collider has two advantages over other hadron colliders
to measure the characteristic feature of W gamma production: (1) the RHIC
energy is not so high and (2) the polarized beams are available. We calculate
the tree level cross section for W gamma production using a generic spin basis
for W and discuss both the angular dependence and spin correlation.Comment: 14 pages, 15 Postscript figure
High stability design for new centrifugal compressor
It is essential that high-performance centrifugal compressors be free of subsynchronous vibrations. A new high-performance centrifugal compressor has been developed by applying the latest rotordynamics knowledge and design techniques: (1) To improve the system damping, a specially designed oil film seal was developed. This seal attained a damping ratio three times that of the conventional design. The oil film seal contains a special damper ring in the seal cartridge. (2) To reduce the destabilizing effect of the labyrinth seal, a special swirl canceler (anti-swirl nozzle) was applied to the balance piston seal. (3) To confirm the system damping margin, the dynamic simulation rotor model test and the full load test applied the vibration exciting test in actual load conditions
<Advanced Energy Utilization Division> Biofunctional Chemistry Research Section
3-1. Research Activities in 202
An aerogel Cherenkov detector for multi-GeV photon detection with low sensitivity to neutrons
We describe a novel photon detector which operates under an intense flux of
neutrons. It is composed of lead-aerogel sandwich counter modules. Its salient
features are high photon detection efficiency and blindness to neutrons. As a
result of Monte Carlo (MC) simulations, the efficiency for photons with the
energy larger than 1 GeV is expected to be higher than 99.5% and that for 2
GeV/ neutrons less than 1%. The performance on the photon detection under
such a large flux of neutrons was measured for a part of the detector. It was
confirmed that the efficiency to photons with the energy 1 GeV was
consistent with the MC expectation within 8.2% uncertainty.Comment: 16 pages, 16 figures, submitted to Prog. Theor. Exp. Phy
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