QCD analysis of first b cross section data at 1.96 TeV
M. Cacciari, S. Frixione, M. L. Mangano, P. Nason, G. Ridolfi
TL;DR
The paper addresses the longstanding tension between observed hadronic $b$-quark production rates and perturbative QCD predictions. It re-evaluates NLO predictions by incorporating modern inputs and cross-checks with resummed approaches (FONLL) and MC@NLO, extending the theoretical predictions to $p_T$ down to zero. The authors extract a representative integrated cross section for $|y_b|<1$ with explicit uncertainties: $\sigma^{\rm NLO}_b(|y_b|<1)=23.6^{+4.5}_{-3.6}$ (from $m_b$) $^{+10.8}_{-6.3}$ (from $\mu_R,\mu_F$) $\mu$b, using $m_b=4.75$ GeV and CTCEQ6M PDFs, with central predictions from FONLL and MC@NLO at $\sim25.0$ and $25.2$ μb, respectively. The results suggest that the new $\sqrt{S}=1.96$ TeV data from CDF are compatible with NLO QCD, potentially resolving the long-standing discrepancy and clarifying the roles of fragmentation and small-$x$ effects in bottom production.
Abstract
The first data on bottom quark production in p-pbar collisions at 1.96 TeV have recently been obtained by the CDF collaboration. These data probe the region of pt~0, providing a new invaluable input on the issue of the compatibility between next-to-leading-order (NLO) QCD and data. We reconsider the evaluation of the b cross section, in view of recent theoretical developments, and of the latest inputs on structure function fits. We show that the new CDF measurements are in good agreement with NLO QCD. If CDF preliminary data are confirmed, a long-standing discrepancy between NLO QCD predictions and hadron-collider data can be settled.