Understanding forward B hadron production

  • Rhorry GauldEmail author
Open Access
Regular Article - Theoretical Physics


The LHCb collaboration has recently performed a measurement of the production rate of inclusive B hadron production (ppBX) at both 7 and 13 TeV centre-of-mass (CoM) energies. As part of this measurement, the ratio of these two cross section measurements has been presented differentially in B hadron pseudorapidity within the range of η B ∈ [2.0, 5.0]. A large tension (4σ) is observed for the ratio measurement in the lower pseudorapidity range of η B ∈ [2.0, 3.0], where the data is observed to exceed theoretical predictions, while consistency is found at larger η B values. This behaviour is not expected within perturbative QCD, and can only be achieved by introducing ad-hoc features into the structure of the non-perturbative gluon PDF within the region of x ∈ [10−3 , 10−4]. Specifically, the gluon PDF must grow extremely quickly with decreasing x within this kinematic range, closely followed by a period of decelerated growth. However, such behaviour is highly disfavoured by global fits of proton structure. Further studies of the available LHCb B and D hadron cross section data, available for a range of CoM energies, indicate systematic tension in the (pseudo)rapidity region of [2.0, 2.5].


QCD Phenomenology 


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© The Author(s) 2017

Authors and Affiliations

  1. 1.ETH Zurich, Institut fur theoretische PhysikZurichSwitzerland

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