A study of the decays B0s -> mu+mu- and B0 -> mu+mu- has been performed using 26-3 fb-1 of 13TeV LHC proton-proton collision data collected with the ATLAS detector in 2015 and 2016. Since the detector resolution in mu+mu- invariant mass is comparable to the B0s -B0 mass difference, a single fit determines the signal yields for both decay modes. This results in a measurement of the branching fraction B(B0s -> mu+mu-) = 3.2+1.1-1.0 x10-9 and an upper limit B(B0 -> mu+mu-) < 4.3 x 10-10 at 95% confidence level. The result is combined with the Run 1 ATLAS result, yielding B(B0s -> mu+mu-) = 2.8+0.8-0.7 x 10-9 and B(B0 -> mu+mu-) < 2.1 x 10-10 at 95% confidence level. The combined result is consistent with the Standard Model prediction within 2.4 standard deviations in the B(B0s -> mu+mu)- plane.
Study of the rare decays of Bs0 and B0 mesons into muon pairs using data collected during 2015 and 2016 with the ATLAS detector
G Chiodini;E Gorini;F Gravili;L Longo;A Mirto;M Reale;E Schioppa;S Spagnolo;A Ventura;
2019-01-01
Abstract
A study of the decays B0s -> mu+mu- and B0 -> mu+mu- has been performed using 26-3 fb-1 of 13TeV LHC proton-proton collision data collected with the ATLAS detector in 2015 and 2016. Since the detector resolution in mu+mu- invariant mass is comparable to the B0s -B0 mass difference, a single fit determines the signal yields for both decay modes. This results in a measurement of the branching fraction B(B0s -> mu+mu-) = 3.2+1.1-1.0 x10-9 and an upper limit B(B0 -> mu+mu-) < 4.3 x 10-10 at 95% confidence level. The result is combined with the Run 1 ATLAS result, yielding B(B0s -> mu+mu-) = 2.8+0.8-0.7 x 10-9 and B(B0 -> mu+mu-) < 2.1 x 10-10 at 95% confidence level. The combined result is consistent with the Standard Model prediction within 2.4 standard deviations in the B(B0s -> mu+mu)- plane.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
