Naslov
Observation of Upsilon(1S) pair production in proton-proton collisions at sqrt(s) = 8 TeV

Autori
Khachatryan, Vardan ; ... ; Godinović, Nikola ; Lelas, Damir ; Puljak, Ivica ; ... ; Šćulac, Toni ; Antunović, Željko ; Kovač, Marko ; Brigljević, Vuko ; Kadija, Krešo ; Luetić, Jelena ; Mićanović, Saša ; Sudić, Lucija ; ... ; Morović, Srećko ; ... ; Ferenček, Dinko ; ... ; Đurić, Senka ; Šuša, Tatjana ; ... ; Woods, Nate

Kolaboracija
CMS Collaboration

Izvornik
The Journal of high energy physics (1126-6708) 5 (2017); 13, 34

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
High energy physics ; Experimental particle physics ; LHC ; CMS ; Standard Model

Sažetak
Pair production of Upsilon(1S) mesons is observed at the LHC in proton-proton collisions at sqrt(s) = 8 TeV by the CMS experiment in a data sample corresponding to an integrated luminosity of 20.7 inverse-femtobarns. Both Upsilon(1S) candidates are fully reconstructed via their decays to mu+ mu-. The fiducial acceptance region is defined by an absolute Upsilon(1S) rapidity smaller than 2.0. The fiducial cross section for the production of Upsilon(1S) pairs, assuming that both mesons decay isotropically, is measured to be 68.8 +/- 12.7 (stat) +/- 7.4 (syst) +/- 2.8 (B) pb, where the third uncertainty comes from the uncertainty in the branching fraction of Upsilon(1S) decays to mu+ mu-. Assuming instead that the Upsilon(1S) mesons are produced with different polarizations leads to variations in the measured cross section in the range from -38% to +36%.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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