Measurement of inclusive Lambda / Antilambda hyperon polarisation in proton nucleus collisions at 920 GeV proton beam energy

A minimum bias dataset was analysed for transverse hyperon polarisation in p + A -> Lambda / Antilambda + X events. The data were taken in the commissioning phase of the HERA-B detector at HERA, DESY, using the proton beam of 920 GeV energy to collide with fixed target wires of different materials. A sample of approximately 2900 Lambdas was obtained in a kinematical region of transverse momentum p_t in [0.2,2.2] GeV/c and Feynman variable x_F in [-0.19,0.03] and roughly 1350 Antilambdas were found in the range of p_t in [0.12,1.64] GeV/c and x_F in [-0.13,0.01]. These samples were analysed for transverse polarisation using extensive Monte Carlo studies for acceptance determination, yielding: Pol(Lambda) : 0.073 +/- 0.073 (stat) +/- 0.0095 (syst) Pol(Antilambda): 0.006 +/- 0.129 (stat) +/- 0.0381 (syst). The found result is compatible with the only other inclusive measurement that is available at x_F < 0. Concluding, the possible significant contribution to the field of hyperon polarisation physics of the HERA-B spectrometer due to its unique kinematical range and possibility to study A dependencies is pointed out.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Heidelberg

Year

2002

Author dc:creator

• Pleier, Marc-André

Contributors dc:contributor

• Knöpfle, Karl-Tasso

Repository record source_url

http://www.ub.uni-heidelberg.de/archiv/2292

OAI identifier oai:identifier

oai:archiv.ub.uni-heidelberg.de:2292