A note on the CDF high-p_t charged particle excess

TL;DR

This paper investigates the reported excess of high-p_t charged particles in CDF data, analyzing whether it can be explained by QCD factorisation violations or new physics, and concludes it cannot.

Contribution

The study combines charged particle and jet data to refute the hypothesis that the excess arises from QCD factorisation violations.

Findings

CDF high-p_t charged particle excess is not due to factorisation violation

Charged particle cross sections at high p_t are comparable to jet cross sections

Interpreting the excess as new physics is challenging

Abstract

It has recently been pointed out that CDF data for the cross section of high-p_t charged particles show an excess of up to three orders of magnitude over QCD predictions, a feature tentatively ascribed to possible violations of factorisation. We observe that for p_t > 80 GeV the measured charged-particle cross sections become of the same order as jet cross sections. Combining this information with data on charged particle distributions within jets allows us to rule out the hypothesis that the CDF data could be interpreted in terms of QCD factorisation violation. We also comment on the difficulty of interpreting the excess in terms of new physics scenarios.