CMS collaboration (2207 authors)Hollar, JonathanNayak, ArunaCalpas, BettyAlmeida, NunoBargassa, PedrameBeirão Da Cruz E Silva, CristóvãoFaccioli, PietroFerreira Parracho, Pedro GuilhermeGallinaro, MicheleRodrigues Antunes, JoaoSeixas, JoaoVarela, JoaoVischia, PietroLloret Iglesias, LaraDavid Tinoco Mendes, AndreMusella, PasqualeSilva, PedroPela, JoaoLeonardo, Nuno2019-02-032019-02-032013-12-06http://dx.doi.org/10.1007/JHEP12(2013)039http://hdl.handle.net/10400.26/26480A study of proton-proton collisions in which two b hadrons are produced in association with a Z boson is reported. The collisions were recorded at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC, for an integrated luminosity of 5.2 inverse femtobarns. The b hadrons are identified by means of displaced secondary vertices, without the use of reconstructed jets, permitting the study of b-hadron pair production at small angular separation. Differential cross sections are presented as a function of the angular separation of the b hadrons and the Z boson. In addition, inclusive measurements are presented. For both the inclusive and differential studies, different ranges of Z boson momentum are considered, and each measurement is compared to the predictions from different event generators at leading-order and next-to-leading-order accuracy.engjournal article2019-02-03