Freiburg 1999 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 7: Elektromagnetische und hadronische Proben I

HK 7.5: Vortrag

Montag, 22. März 1999, 15:15–15:30, E

p p → pp π⁰ with longitudinal beam and target polarization — •F. Rathmann¹, J. Balewski², W. Daehnick³, J. Doskow², R. Flammang³, W. Haeberli⁴, B. Lorentz⁴, H.O. Meyer², P.V. Pancella⁵, R.E. Pollock², B.v. Przewoski², T. Rinckel², S.K. Saha³, B. Schwartz⁴, P. Thörngren Engblom², and T. Wise⁴ — ¹Physikalisches Institut II, Universit"at Erlangen-N"urnberg, Erwin-Rommel-Str. 1, 91058 Erlangen, Germany — ²Indiana University Cyclotron Facility, Bloomington, IN 47408, USA — ³Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA — ⁴Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA — ⁵Physics Department, Western Michigan University, Kalamazoo, MI 49007, USA

Recently, the spin-dependent cross section Δ σ _T, the spin correlation parameters A_xx and A_yy, and the analyzing power A_y of the reaction p p → pp π⁰ was measured at beam energies of 325, 350, 375 and 400 MeV [1]. The experiment was carried out at the IUCF Cooler ring using a cooled polarized proton beam and an internal polarized gas target. The subject of this talk will be the measurements carried out in order to obtain the rema ining observables Δ σ_L, A_xz and A_zz. During these new measurements (at the same beam energies as given above) the beam polarization was aligned along the proton momentum vector (± z) and the target polarization was switched betw een horizontal (±x), vertical (±y) and longitudinal (±z) direction. Energy and angular information of the outgoing protons was measured and the mass and the emission angle of the neutral pion were deduced. A preliminary analysis of the data indicates a sizeable contribution of Ps final states.

[1] Phys. Rev. Lett, 81, 3096 (1998).