W. Adam et al., MEASUREMENT OF INCLUSIVE PI(0) PRODUCTION IN HADRONIC Z(0) DECAYS, Zeitschrift fur Physik. C, Particles and fields, 69(4), 1996, pp. 561-573
An analysis is presented of inclusive pi(0) production in Z(0) decays
measured with the DELPHI detector, At low energies, pi(0) decays are r
econstructed by using pairs of converted photons and combinations of c
onverted photons and photons reconstructed in the: barrel electromagne
tic calorimeter (HPC). At high energies (up to x(p) = 2 . p(pi)/root s
= 0.75) the excellent granularity of the HPC is exploited to search f
or two-photon substructures in single showers, The inclusive different
ial cross section is measured as a function of energy for q (q) over b
ar and b (b) over bar events, The number of pi(0)'s per hadronic Z(0)
event is N(pi(0))/Z(had)(0) = 9.2 +/- 0.2(stat) +/- 1.0(syst) and for
b (b) over bar events the number of pi(0),s is N(pi(0))/b (b) over bar
= 10.1 +/- 0.4(stat) +/- 1.1(syst). The ratio of the number of pi(0)'
s in b (b) over bar events to hadronic Z(0) events is less affected by
the systematic errors and is found to be 1.09 +/- 0.05 +/- 0.01. The
measured pi(0) cross sections are compared with the predictions of dif
ferent parton shower models. For hadronic events, the peak position in
the xi(p) = ln(l/X(p)) distribution is xi(p) = 3.90(-0.14)(+0.24). T
he average number of pi(0)'s from the decay of primary B hadrons is fo
und to be N(B --> pi(0) X)/B hadron = 2.78 +/- 0.15(stat) +/- 13.60(sy
st).