First observation of forward Z→bb¯ production in pp collisions at s√=8 TeV

Journal article

The decay Z→bb¯ is reconstructed in pp collision data, corresponding to 2 fb −1 of integrated luminosity, collected by the LHCb experiment at a centre-of-mass energy of s=8 TeV. The product of the Z production cross-section and the Z→bb¯ branching fraction is measured for candidates in the fiducial region defined by two particle-level b-quark jets with pseudorapidities in the range 2.2 < η < 4.2, with transverse momenta p T > 20 GeV and dijet invariant mass in the range 45 < m jj < 165 GeV. From a signal yield of 5462±763 Z→bb¯ events, where the uncertainty is statistical, a production cross-section times branching fraction of 332±46±59 pb is obtained, where the first uncertainty is statistical and the second systematic. The measured significance of the signal yield is 6.0 standard deviations. This measurement represents the first observation of the Z→bb¯ production in the forward region of pp collisions.

Authors: LHCb Collaboration; Bjørn, M; Cheung, S; Evans, T; Gandini, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Physics Letters B
• Volume: 776
• Pages: 430-439
• Publication date: 2017-12-05
• Acceptance date: 2017-11-28
• DOI: 10.1016/j.physletb.2017.11.066
• EISSN: 1873-2445
• ISSN: 0370-2693
• Keywords: Journal Article