How important are next-to-leading order models for predicting strange particle spectra in p+p collisions at sqrt(s)=200 GeV ?

Mark Heinz

Particle production in elementary p+p collisions is well described by perturbative QCD (pQCD) calculations applying the factorization theorem. Monte Carlo models incorporating a leading order (LO) pQCD formalism based on string fragmentation, such as PYTHIA, have been widely used in the past to make basic predictions of hadron production in jets. More sophisticated next-to-leading order (NLO) calculations use parametrized flavor dependent fragmentation functions obtained from e^{+}+e^{-} collider data.

We present the STAR measurement of various strange and multi-strange particles in 200 GeV p+p collisions and compare the pT-spectra to results from LO and NLO calculations. We show that species dependent tuning of K-factors in LO-models allows us to achieve good agreement with our data. This leads us to discuss recent NLO comparisons for strange particle production and the importance of including higher order parton processes.