Bottom Production in Hadronic Collisions A

I review the status of the comparison between theoretical predictions and experimental results for bottom production in hadronic collisions, and discuss the possible sources of the discrepancies found. The study of jets containing bottom quarks is proposed as a promising tool to investigate the b production mechanism. I present next-to-leading order QCD predictions for this process, and compare them with data. 1 Open bottom at fixed-target and collider experiments Bottom production constitutes a challenging testing ground for perturbative QCD. The quark mass, which sets the scale of the hard process, is such that α s ≃ 0.2. Therefore, the bottom rates cannot be predicted with full reliability at NLO in QCD, the radiative corrections being of the same size of the leading-order contribution. On the other hand, non-perturbative phenomena are expected to play a less important rôle than in the case, for example, of charm. Fixed-target experiments have in general too a low energy to perform a statistically significant study of bottom production. Most of the available data have been obtained in πN collisions, and allow for a measurement of the total cross section 1,2. A measurement of the total cross section has also been performed in pN collisions 3. Unfortunately, due to the limited coverage of the detectors, the results are somewhat model-dependent. Taking into account the large theoretical uncertainties, the data and the theory are in reasonable agreement. There is no value of the bottom mass which allows to describe all the experimental results; at variance with the measurements at colliders, some results favour large values of the bottom mass. The E653 collaboration 2 also presented a measurement for single-inclusive and double differential distributions, which turn out to be consistent with QCD predictions. Bottom quarks are copiously produced at colliders. Although the rejection of the background in the low-p T region, where most of the b's are produced,