POLARIZATION CORRELATION-MEASUREMENTS OF ELECTRON-IMPACT EXCITATION OF H(2P) AT 54.4 EV

First direct measurements are reported of the linear reduced Stokes pa rameters (P) over bar(1),(P) over bar(2) for H(2p) excited by electron impact at the benchmark energy of 54.4 eV. The results differ signifi cantly from previous values deduced from angular correlation measureme nts which are in serious conflict with all sophisticated theoretical a pproaches. Our results support the trend of theoretical predictions fo r (P) over bar(2) and confirm that its value is negative at electron s cattering angles above 100 degrees, as predicted by theory.