Xi0 and anti-Xi0 Polarization Measurements at 800-GeV/c

The KTeV collaboration Abouzaid, E. ; Alavi-Harati, A. ; Alexopoulos, T. ; et al.
Phys.Rev.D 75 (2007) 012005, 2007.
Inspire Record 722906 DOI 10.17182/hepdata.41797

The polarization of neutral Cascade and anti-Cascade hyperons produced by 800 GeV/c protons on a BeO target at a fixed targeting angle of 4.8 mrad is measured by the KTeV experiment at Fermilab. Our result of 9.7% for the neutral Cascade polarization shows no significant energy dependence when compared to a result obtained at 400 GeV/c production energy and at twice our targeting angle. The polarization of the neutral anti-Cascade is measured for the first time and found to be consistent with zero. We also examine the dependence of polarization on transverse production momentum.

1 data table

Measured polarizations as a function of transverse momentum.


First Measurement of Form Factors of the Decay Xi0->Sigma+ e- anti-nu/e

The KTeV collaboration Alavi-Harati, A. ; Alexopoulos, T. ; Arenton, M. ; et al.
Phys.Rev.Lett. 87 (2001) 132001, 2001.
Inspire Record 556399 DOI 10.17182/hepdata.43756

We present the first measurement of the form factor ratios g1/f1 (direct axial-vector to vector), g2/f1 (second class current) and f2/f1 (weak magnetism) for the decay Xi0 -> Sigma+ e- anti-nu/e using the KTeV (E799) beam line and detector at Fermilab. From the Sigma+ polarization measured with the decay Sigma+ -> p pi0 and the e- - anti-nu/e correlation, we measure g1/f1 to be 1.32 +0.21-0.17(stat.) +/- 0.05(syst.), assuming the SU(3)f (flavor) values for g2/f1 and f2/f1. Our results are all consistent with exact SU(3)f symmetry.

1 data table

Vector(F1) to axial(G1) formfactor ratio. Total systematic error is 0.054.