Hadroproduction of D* going to (kaon,pion)pion

Abstract

A study of the decay D*$\sp+$ $\to$ (K$\sp-$ $\pi\sp+$) $\pi\sp+$ (and charge conjugate) has been performed based on data taken from n-nucleus collisions by the experiment E400 at the Proton East area of FNAL. A signal was observed at the 3.3$\sigma$ level that behaves properly under lifetime cuts. A method for determining the acceptance due to spectrometer geometry and analysis cuts was developed with the intention of making the acceptance as independent as possible of biases resulting from the production model chosen for the Monte Carlo studies that determined the acceptance. The acceptance was parameterized in two different ways chosen so that inconsistencies would expose any remaining model dependence. The cross-sections resulting from these two parameterizations were consistent and the average of the two is $\Delta\sigma$ $\cdot$ Br = 2.36 $\pm$.72 (statistical) $\pm$ 1.18 (systematic) over the range $-$.02 $<$ x$\sb{F}$ $<$.3. A comparison is made between this cross-section and the cross-section found for the decay D* $\to$ (K$\sp+$ K$\sp-$) $\pi$, also measured by E400, over the more limited range 0. $<$ x$\sb{F}$ $<$.14 and the two values are found to be statistically consistent. The cross-section from D* $\to$ (K $\pi$) $\pi$ is compared to cross-sections determined by LEBC, an experiment also using a hadron beam of energy similar to E400, with considerable disagreement although no explicit explanation is readily available. Both experiments, as well as many others, measure cross-sections that are considerably larger than lowest order QCD calculations.