Proton-proton Polarization Research Articles

Impact-picture description of high-energy elastic proton-proton polarization

A model of rotating matter inside the proton was recently proposed to explain low- and high-energy proton-proton elastic scattering. Predictions made for the polarization at high energy and recent experiments at CERN and Fermilab support this concept of matter current inside a hadron.

Large-angle elastic proton-proton polarization at 5.15GeVc

We present herein the initial results of a large-angle elastic $p\ensuremath{-}p$ polarization experiment which is now in progress at the Argonne ZGS (Zero-Gradient Synchrotron) accelerator. Data for the incident proton momentum of 5.15 $\frac{\mathrm{GeV}}{c}$ are presented for ${30}^{\ensuremath{\circ}}\ensuremath{\lesssim}{\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\lesssim}{90}^{\ensuremath{\circ}}$. These results, which extend to $t\ensuremath{\approx}\ensuremath{-}4.0{(\frac{\mathrm{GeV}}{c})}^{2}$, represent the first high-statistics $p\ensuremath{-}p$ polarization measurements for $|t|$ values greater than \ensuremath{\sim}2.5 ${(\frac{\mathrm{GeV}}{c})}^{2}$. We observe a minimum in the polarization near $t=\ensuremath{-}0.8{(\frac{\mathrm{GeV}}{c})}^{2}$, a smooth increase in the polarization until a maximum is attained near $t=\ensuremath{-}1.8{(\frac{\mathrm{GeV}}{c})}^{2}$, and then a monotonic decline in the polarization until the value of zero is reached at ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}={90}^{\ensuremath{\circ}}$. The data are analyzed in terms of an optical model.

Measurement of Proton-Proton Polarization at 20 MeV

Measurement of Proton-Proton Polarization at 20 MeV

High-Precision Measurement of Proton-Proton Polarization Between 10 and 20 MeV

The $p\ensuremath{-}p$ polarization asymmetry has been measured at 9.6-, 15.6-, and 19.7-MeV laboratory energy with accuracy down to \ifmmode\pm\else\textpm\fi{}0.003. The interpretation of our results requires a significant spin-orbit term in the interaction.

Small-Angle Proton-Proton Polarization and Cross Section at 213 MeV

This experiment was a simultaneous measurement of the proton-proton cross section and polarization for the angular range 8.9\ifmmode^\circ\else\textdegree\fi{}-38.7\ifmmode^\circ\else\textdegree\fi{} c.m. at 213\ifmmode\pm\else\textpm\fi{}6 MeV. An experimental normalization of the cross section of \ifmmode\pm\else\textpm\fi{}1.3% accuracy was obtained. The results agree with the predictions of the latest phase-shift analyses except for ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\lesssim}15$\ifmmode^\circ\else\textdegree\fi{}.

Absolute polarization measurements in proton scattering in the 140 MeV energy range

The polarization of the proton beam extracted from the Harwell 279 cm synchrocyclotron has been determined to an accurac of ±1% using two independent techniques. Measurements with this beam have shown that the absolute calibrations of all the published proton-nucleus polarization data in the energy range between 50 and 150 MeV are considerably in error. This fact means that the published proton-proton polarization data are also in error. The appropriate correction factors to be applied to the published experimental results are given.

Proton-proton polarization between 27 MeV and 100 MeV

The polarization in p-p scattering has been measured at various energies between 27 MeV and 100 MeV in a counter experiment using the 150 MeV, 48% polarized proton beam of the Harwell synchrocyclotron incident on a liquid hydrogen target. The beam energy was reduced by suitable absorbers, and the mean energy resolution of each measurement were defined by absorbers in an anti-coincidence range counter telescope. A solenoid was used to rotate the polarization of the beam through ± 180° in order to eliminate geometrical false asymmetries. It was found possible to represent the energy dependence of the polarization by a simple power law P = aE b up to about 70 MeV.

Significance of Neutron-Proton Polarization Measurements in the 20-Mev Energy Range

Neutron-proton polarizations were calculated theoretically and observed experimentally at 16 and 24 Mev. It was found that combinations of parameters determining proton-proton polarization enter the calculations. The validity of charge independence is assumed by the employment of T = 1 phase parameters determined from p-p scattering in the analysis of n-p scattering data. Effects of magnetic scattering are negligible. (L.N.N.)

Proton-Proton Polarization at 16 Mev

The proton-proton polarization has been measured at 16.2\ifmmode\pm\else\textpm\fi{}0.2 Mev and 25 degrees in the laboratory system, using the familiar double-scattering method, with hydrogen gas as second scatterer. Instrumental asymmetries were practically eliminated by using carbon and copper alternately as first targets. The polarization was found to be +(0.6\ifmmode\pm\else\textpm\fi{}0.5)%. Theoretical implications of the work are discussed.

Polarization Experiments in Proton-Proton Scattering

Possible proton-proton polarization experiments and the information that can be gained from them are reported here. In this paper we write down the formalism and list formulae from which a quantity which can be measured in such experiments can easily be obtained in terms of the theoretical quantities. We employ the formalism of the statistical matrix for spin ½ particles and the representation of the scattering matrix in spin space. The chief aim of this paper is to present a complete set of formulae covering all experiments which appear to be possible in the near future. In a second paper we shall discuss in more detail a group of experiments which are now of great interest, namely, those involving analysis in coincidence. In § 1 we introduce the formalism to be employed and give an elementary discussion of polarization phenomena. In § 2 results of the algebra needed to carry out the analysis of experiments are given, and in § 3, these are used to show what quantities the experiments determine.

Proton-Proton Polarization at 170 Mev

The proton-proton polarization has been measured at 170 Mev. The data have been fit to a curve of the form $P=sin\ensuremath{\theta}cos\ensuremath{\theta}(\ensuremath{\alpha}+\ensuremath{\beta}{cos}^{2}\ensuremath{\theta})$, yielding $\ensuremath{\alpha}=0.31\ifmmode\pm\else\textpm\fi{}0.09$ and $\ensuremath{\beta}=0.30\ifmmode\pm\else\textpm\fi{}0.14$. A comparison is made with results obtained at other energies.