Michigan ultra-cold polarized atomic hydrogen jet target

To study spin effects in high energy collisions, we are developing an ultra-cold high-density jet target of proton-spin-polarized hydrogen atoms. The target uses a 12 Tesla magnetic field and a 0.3 K separation cell coated with superfluid helium-4 to produce a slow monochromatic electron-spin-polarized atomic hydrogen beam, which is then focused by a superconducting sextupole into the interaction region. In recent tests, we studied a polarized beam of hydrogen atoms focused by the superconducting sextupole into a compression tube detector, which measured the polarized atoms’ intensity. The Jet produced, at the detector, a spin-polarized atomic hydrogen beam with a measured intensity of about 2.8⋅1015 H s−12.8⋅1015Hs−1 and a FWHM area of less than 0.13 cm2. This intensity corresponds to a free jet density of about 1⋅1012 H cm−31⋅1012Hcm−3 with a proton polarization of about 50%. When the transition RF unit is installed, we expect a proton polarization higher than 90%. © 2001 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87742/2/856_1.pd

The Status of the University of Michigan Polarized Proton Target

The University of Michigan Solid Polarized Proton Target (PPT) was built in the late 1980’s; it uses irradiated NH3 at 5 T and 1 K. It was used in a 1990 experiment in a 24 GeV intense proton beam at the Brookhaven AGS, where its average polarization was about 85%. It was recently upgraded for the 70 GeV SPIN@U‐70 experiment at IHEP‐Protvino in Russia. Improvements were made to its superconducting magnet, its refrigerator, and its NMR and microwave systems. © 2003 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87683/2/916_1.pd

SPIN@U‐70: An Experiment to Measure the Analyzing Power An in Very‐high‐P⟂2P⟂2 p‐p Elastic Scattering at 70 GeV

The SPIN@U‐70 experiment plans to measure the one‐spin analyzing power An for 70 GeV proton‐proton elastic scattering at large P⟂2P⟂2 values of 1 to 12 (GeV/c)2. The Michigan frozen NH3 polarized proton target (Solid PPT) should later be installed in the Channel 8 extracted beam‐line of the 70 GeV U‐70 accelerator in IHEP, Protvino. The forward‐scattered protons are detected by small scintillation counters placed at about 9 m from the PPT, while the recoil‐scattered protons are detected by a 35‐m‐long focusing magnetic spectrometer, with a 12 degree vertical bend, placed at 30 degrees to the beam. A tune‐up run for testing the beam and the spectrometer, using a polyethylene target, was carried out in April 2002 at IHEP. The layout and the results of the test run are presented. © 2003 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87680/2/538_1.pd

Antiproton-proton scattering experiments with polarization.

High Energy Physics Esperiment (hep-ex/0505054). The document describes the physics case of the PAX experiment using polarized antiprotons, which has recently been proposed for the new Facility for Antiprotons and Ions Research (FAIR) at GSI--Darmstadt. Polarized antiprotons provide access to a wealth of single-- and double--spin observables, thereby opening a new window to physics uniquely accessible at the HESR. The polarized antiprotons would be most efficiently produced by spin--filtering in a dedicated Antiproton Polarizer Ring (APR) using an internal polarized hydrogen gas target. In the proposed collider scenario of the PAX experiment, polarized protons stored in a COSY--like Cooler Storage Ring (CSR) up to momenta of 3.5 GeV/c are bombarded head--on with 15 GeV/c polarized antiprotons stored in the HESR. This asymmetric double--polarized antiproton--proton collider is ideally suited to map, e.g., the transversity distribution in the proton. The proposed detector consists of a large--angle apparatus optimized for the detection of Drell--Yan electron pair

"Measurement of the spin-dependence of p-pbar interaction at AD-ring”

Letter of Intent to the CERN SPS Comitee. An internal polarized hydrogen storage cell gas target is proposed for the AD--ring to determine for the first time the two total spin--dependent cross sections $\sigma_1$ and $\sigma_2$ at antiproton beam energies in the range from 50 to 200 MeV. The data will allow the definition of the optimum working parameters of a dedicated Antiproton Polarizer Ring (APR), which has recently been proposed by the PAX collaboration for the new Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt, Germany. The availability of an intense beam of polarized antiprotons will provide access to a wealth of single-- and double--spin observables, thereby opening a new window to QCD transverse spin physics. The physics program proposed by the PAX collaboration includes a first measurement of the transversity distribution of the valence quarks in the proton, a test of the predicted opposite sign of the Sivers--function, related to the quark distribution inside a transversely polarized nucleon, in Drell--Yan (DY) as compared to semi--inclusive Deep Inelastic Scattering, and a first measurement of the moduli and the relative phase of the time--like electric and magnetic form factors $G_{E,M}$ of the proton

Antiproton-proton scattering experiment with polarization (update)

Upgrading to the document High Energy Physics Esperiment (hep-ex/0505054). The document describes the physics case of the PAX experiment using polarized antiprotons, which has recently been proposed for the new Facility for Antiprotons and Ions Research (FAIR) at GSI--Darmstadt. Polarized antiprotons provide access to a wealth of single-- and double--spin observables, thereby opening a new window to physics uniquely accessible at the HESR. The polarized antiprotons would be most efficiently produced by spin--filtering in a dedicated Antiproton Polarizer Ring (APR) using an internal polarized hydrogen gas target. In the proposed collider scenario of the PAX experiment, polarized protons stored in a COSY--like Cooler Storage Ring (CSR) up to momenta of 3.5 GeV/c are bombarded head--on with 15 GeV/c polarized antiprotons stored in the HESR. This asymmetric double--polarized antiproton--proton collider is ideally suited to map, e.g., the transversity distribution in the proton. The proposed detector consists of a large--angle apparatus optimized for the detection of Drell--Yan electron pair