POLARIZATION IN PION-PROTON SCATTERING FROM 670-3750 MeV/c

Using a polarized proton target, we have measured the polarization parameter P({theta}) in pion-proton scattering for both positive and negative pions. Because there seems to be a great deal of current interest in the analysis of pion-proton scattering we wish to present these experimental results at this time even though we have not yet completed their analysis. The measurement consisted of scattering pions from polarized target protons and observing the asymmetry in scattered intensity, I({theta}), as the target protons spin directions were reversed. The intensity for scattering from a target of polarization P{sub T} is I({theta}){sub pol.} = I({theta}){sub unpol.} (1 + P({theta})P{sub T}), where the parameter P({theta}) is the same as the recoil proton polarization in scattering pions from unpolarized protons under the assumption that parity is conserved in the process

Real-time imaging using a 2.8 THz quantum cascade laser and uncooled infrared microbolometer camera

Optics Letters, Volume 33, No. 5, pp. 440-442 (March 1, 2008)Real-time imaging in the terahertz (THz) spectral range was achieved using a milliwatt-scale, 2.8 THz quantum cascade laser and an uncooled, 160 120 pixel microbolometer camera modified with Picarin optics...This work is supported by the Air Force Office of Scientific Research (AFOSR)

BACKWARD np SCATTERING WITH A POLARIZED TARGET

The authors have measured the polarization parameter P in neutron-proton elastic scattering near the backward direction, using a polarized proton target. Measurements covered the range of incident neutron moment from 1.0 to 5.5 GeV/c and of four-momentum transfer squared u from -0.005 to -0.5 (GeV/c){sup 2}. Forward going protons were detected by means of a wire-spark-chamber spectrometer. Slow neutrons near 90 deg lab angle were detected in coincidence by means of an array of plastic scintillation counters. P was determined from the change in counting rate I of scattered particles upon reversal of the target polarization P{sub T} according to I = I{sub 0}[l + P(P{sub T} {center_dot} k incident neutron x k final neutron/sin {theta} final neutron)]. They find that P is consistently negative and shows no marked structure as a function of u and of incident momentum. The data roughly follow the simple form P = -0.5 {radical}-u/m{sub p}