17742099
Cosmic-ray tests for quality control of the CDF plug upgrade EM calorimeter and the CDF plug preshower detector
The CDF Plug Upgrade electromagnetic (EM) calorimeter and the preshower detector consist of tile-"ber elements forming a projective tower geometry. Each of the 23 longitudinal layers is separated into 24 units in the azimuthal direction. Cosmic-ray tests as a quality control of these mechanically basic units, called the 153 units, were carried out since January 1995 and completed in June 1996. All the units amounting to a total 1200 units were processed. By using HAMAMASU R4125 for the photon readout, the average light yields were measured to be 5.8 and 21 photoelectrons for the EM and the preshower units, respectively. The light yield variation along the longitudinal layers of EM tower was measured to be 10%. A GEANT-simulation study using the results of the cosmic-ray tests was performed for a realistic calorimeter con"guration. It was found that the simulated energy resolution was consistent with the requirement of *E/E"J(16%)2/E#(1%)2 (E in GeV). Adding preshower response to EM response improved in particular the linearity of the calorimeter. It was possible to achieve the non-linearity of 1% level for energies in the range of 10}200 GeV. ( 2000 Elsevier Science B.V. All rights reserved.
121310929
A gas sampling calorimeter using conductive plastic tubes (II)
Abstract Conductive plastic tubes are extruded, and used to construct planar proportional chambers as a sampling medium of electromagnetic showers. Pick-up electrodes of an arbitrary shape can be placed on both sides of the proportional chamber to read out induced signals from the wires. A prototype shower calorimeter, consisting of 32 layers of such chambers interleaved with lead plates of varying thickness is tested with high energy electron beams. Energy resolution, position resolution, linearity and π/e discrimination are all found to be quite satisfactory.
119946613
Mass production of tile/fiber units for the CDF plug upgrade EM calorimeter
Abstract We have fabricated scintillating tile/fiber units for the CDF plug upgrade electromagnetic calorimeter. The total number of tile/fiber systems amounts to ∼23 000. We describe the quality control tests of scintillator plates, optical fibers, and tile/fiber units which we placed at various stages in the fabrication procedures. We have completed the production retaining the tile/fiber units which satisfy our requirements.
123095140
PRESENT AND FUTURE OF HIGH ENERGY PHYSICS WITH HADRON COLLIDERS
121508472
New method for measurement of γ-ray polarization by detection of angular correlation in pair production
Abstract A method of measuring γ-ray polarization by observing the angular correlation in pair production is proposed. The method consists in taking a correlation between one dimensionally projected angles of the emitted electron and positron. A large analyzing power can be obtained for those pairs whose projected emission angles are large with the same sign, although it generally accompanies a small intensity. If the projected emission angles are limited to within 1.5 reduced angles, the maximum analyzing power is about 0.71.
120794161
ANALYSIS OF PION PHOTOPRODUCTION ON NUCLEONS BELOW 500 MeV.
The differential cross sections, asymmetry ratios and recoil-nucleon polarizations of pion photoproduction on protons and neutrons below 500 MeV have been studied. It is shown that the dispersion theory of Berends, Donnachie and Weaver is unfavorable because of their inadequate treatments of the P 11 (1470) and D 13 (1518) resonances. The phenomenological analysis shows that the effect of the Roper P 11 (1470) resonance is negligible and the isovector amplitude is dominant in the multipole amplitudes leading to the final D 13 state. The experimental data are also favorably explained by the crude dispersion-theoretical model of Schmidt et al.
123383131
Multipole Amplitudes for Pion Weak-Production near Threshold by Charged Current
We investigated pion production by charged weak current, which comprises vector and axial vector current. In particular, the contribution by the axial vector current is detailed at the pion threshold in terms of multipole amplitudes, which could be useful tools for understanding the pion weak-production by combining the multipole amplitudes deduced from other probes. By exploiting the chiral Ward identities based on the QCD Lagrangian, we derived relevant multipole amplitudes in closed forms and showed their numerical results. In the amplitudes, scalar and pseudo scalar form factor generating sigma terms manifest by themselves. Physical implications and roles of the scalar and the pseudo scalar form factor in pion weak-production are also discussed.
118015801
Strange quark contributions to neutrino and antineutrino nucleus scattering via neutral current in quasi-elastic region
Strange quark contributions to the neutral current reaction in the neutrino scattering are investigated on the nucleon level and extended to the $^{12}$C target nucleus through the neutrino-induced knocked-out nucleon process in the quasi-elastic region within the framework of a relativistic single particle model. The incident energy range between 500 MeV and 1.0 GeV is used for the neutrino(antineutrino) scattering. Effects of the final state interaction for the knocked-out nucleon are included by a relativistic optical potential. We found that the sensitivity of the strange quark contents could be salient on the asymmetry between neutrino and antineutrino scattering cross sections. In specific, $A (\nu ({\bar \nu}), \nu^{'} ({\bar \nu}^{'}) N)$ reaction is shown to be very sensitive test in the searches of the strangeness.