The decay Z -> b (b) over bar 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 root s = 8 TeV. The product of the Z production cross-section and the Z -> b (b) over bar 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 +/- 763 Z -> b (b) over bar 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 (b) over bar production in the forward region of pp collisions. (c) 2017 The Author(s). Published by Elsevier B.V.
Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., et al. (2018). First observation of forward Z -> b(b)over-bar production in pp collisions at root s=8 TeV. PHYSICS LETTERS. SECTION B, 776, 430-439 [10.1016/j.physletb.2017.11.066].
First observation of forward Z -> b(b)over-bar production in pp collisions at root s=8 TeV
Archilli, F.;Santovetti, E.Membro del Collaboration Group
;
2018-01-01
Abstract
The decay Z -> b (b) over bar 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 root s = 8 TeV. The product of the Z production cross-section and the Z -> b (b) over bar 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 +/- 763 Z -> b (b) over bar 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 (b) over bar production in the forward region of pp collisions. (c) 2017 The Author(s). Published by Elsevier B.V.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
