First observation of forward $Z\to b\bar{b}$ production in $pp$ collisions at $\sqrt{s}=8$ TeV

Abstract

The decay $Z\to b\bar{b}$ 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 $\sqrt{s}=8$ TeV. The product of the $Z$ production cross-section and the $Z\to b\bar{b}$ branching fraction is measured for candidates in the fiducial region defined by two particle-level $b$-quark jets with pseudorapidities in the range $2.2<\eta <4.2$, with transverse momenta $p_T>20$ GeV and dijet invariant mass in the range $45<m_{jj}<165$ GeV. From a signal yield of $5462\pm 763$ $Z\to b\bar{b}$ events, where the uncertainty is statistical, a production cross-section times branching fraction of $332\pm 46\pm 59$ 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 $Z\to b\bar{b}$ production in the forward region of $pp$ collisions.

arXiv commentAll figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-024.html

References in corpus (23)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• The anti-k_t jet clustering algorithm
• A Brief Introduction to PYTHIA 8.1
• Parton distributions for the LHC Run II
• LHCb Detector Performance
• PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays
• Hard Interactions of Quarks and Gluons: a Primer for LHC Physics
• Precision luminosity measurements at LHCb
• Correlation functions in conformal Toda field theory II
• LHCb Topological Trigger Reoptimization
• Identification of beauty and charm quark jets at LHCb
• Study of forward Z+jet production in pp collisions at $\sqrt{s}=7$ TeV
• First observation of top quark production in the forward region
• Search for low mass vector resonances decaying to quark-antiquark pairs in proton-proton collisions at sqrt(s) = 13 TeV
• Study of $W$ boson production in association with beauty and charm
• Measurement of forward $W$ and $Z$ boson production in association with jets in proton-proton collisions at $\sqrt{s}=8$ TeV
• First measurement of the charge asymmetry in beauty-quark pair production at a hadron collider
• Measurement of the cross section of high transverse momentum $Z\to b\bar{b}$ production in proton--proton collisions at $\sqrt{s}=8TeV$ with the ATLAS Detector
• Bottom-Quark Forward-Backward Asymmetry in the Standard Model and Beyond
• Energy Calibration of b-Quark Jets with Z->b-bbar Decays at the Tevatron Collider
• New approaches for boosting to uniformity

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