R. E. Pollock

Dependence of {rvec {ital p}}{rvec {ital p}} {r_arrow} {ital pp{pi}}thinsp{sup 0} near Threshold on the Spin of the Colliding Nucleons

A polarized internal atomic hydrogen target and a stored, polarized beam are used to measure the spin-dependent total cross section Delta_sigma_T/sigma_tot, as well as the polar integrals of the spin correlation coefficient combination A_xx-A_yy, and the analyzing power A_y for pp->pp pi0 at four bombarding energies between 325 and 400 MeV. This experiment is made possible by the use of a cooled beam in a storage ring. The polarization observables are used to study the contribution from individual partial waves.

Measurement of Partial-Wave Contributions in pp{yields}pp{pi}{sup 0}

We report a measurement of the spin-dependent total cross section ratios {delta}{sigma}{sub T}/{sigma}{sub tot} and {delta}{sigma}{sub L}/{sigma}{sub tot} of the pp{yields}pp{pi}{sup 0} reaction between 325 and 400 MeV. The experiment was carried out with a polarized internal target in a storage ring. Nonvertical beam polarization was obtained by the use of solenoidal spin rotators. Near threshold, the knowledge of both spin-dependent total cross sections is sufficient to deduce the strength of certain participating partial waves, free of any model. (c) 1999 The American Physical Society.

Polarization reversal of stored proton beams in the Indiana Cooler

A spin flipper of reliable and robust long‐term operation was developed and has been used successfully at the Indiana University Cooler Storage Ring. To reverse the polarization of the stored beam, the frequency of a rf solenoid is swept adiabatically across a depolarizing resonance frequency. Depolarizing sidebands to the resonance are eliminated by shorting out the ring’s bunching rf cavity prior to the frequency sweep. With the spin flipper it is no longer necessary to dump the stored beam and to refill the ring with protons of opposite spin state. Rather, beam accumulation continues without reversing the spin at injection, and instead the polarization of the stored beam is flipped periodically. Thus the luminosity is significantly increased when the flipper is used.

Measurement of spin correlation coefficients in p→p→→d π+

The spin correlation coefficent combinations

Spin correlation coefficients in from 325 to 400 MeV

{A}_{\mathrm{xx}}{+A}_{\mathrm{yy}}

Polarization lifetime near an induced depolarizing resonance

and

Nuclear polarization of H2 molecules formed from polarized atoms

{A}_{\mathrm{xx}}\ensuremath{-}{A}_{\mathrm{yy}},

Measurement of spin correlation coefficients in [Formula Presented]

the spin correlation coefficients

Angular distribution of the longitudinal p(vector sign)p(vector sign) spin correlation parameter A{sub zz} at 197.4 MeV

{A}_{\mathrm{xz}}

Angular distribution of the longitudinal [Formula Presented] spin correlation parameter [Formula Presented] at 197.4 MeV

and