First Observation of Forward Z → b[¯ over b] Production in Pp Collisions at √s = 8 TeV
Author(s)Boettcher, Thomas Julian; Craik, Daniel C; Ilten, Philip J; Williams, Michael
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The decay Z→b[¯ over b] is reconstructed in pp collision data, corresponding to 2 fb[superscript −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→b[¯ over b] 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[subscript T]>20 GeV and dijet invariant mass in the range 45<m[subscript jj]<165 GeV. From a signal yield of 5462 ± 763 Z→b[¯ over b] 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→b[¯ over b] production in the forward region of pp collisions.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear Science
Physics Letters B
Aaij, R., et al. “First Observation of Forward Z → b[¯ over b] Production in Pp Collisions at √s = 8 TeV.” Physics Letters B, vol. 776, Jan. 2018, pp. 430–39. © 2017 The Authors
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