Using 3 fb-1 of pp collision data collected at √s = 7 and 8 TeV by the LHCb experiment in the 2011 and 2012 data taking periods, the decays B⁰s → ϕπ+π- and B⁰d → ϕπ+π- have been studied in the π+π- invariant mass range below 1600 MeV/c². The B⁰s,d → ϕπ+π- branching fractions are determined to be: B(B⁰s → ϕπ+π-;mππ < 1600) = [3:72 ± 0:18 ± 0:38 ± 0:38] x 10-6 B(B⁰d → ϕπ+π-,mππ < 1600) = [1:75 ± 0:25 ± 0:42 ± 0:14] x 10-7 where the first uncertainty is statistical, the second is systematic, and the third comes from the normalisation mode B⁰s → ϕϕ. From the π+π- mass distribution and fits to angular distributions, the resonant decay mode B⁰s → ϕf₀(980) is observed and the branching fraction is measured to be: B(B⁰s → ϕf₀(980); f₀(980) → π+π-) = [1:23 ± 0:15 ± 0:12 ± 0:12] x 10-6 The fit also requires contributions from B⁰s → ϕf2(1270). A search for a P-wave contribution from B⁰s → ϕρ⁰(770) finds evidence at ~ 4σ but confirmation will require more data. An upper limit of the B⁰s → ϕρ⁰(770) decay branching fraction at 90% C.L. is measured to be: B(B⁰s → ϕρ⁰(770)) < 4 x 10-7.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:726566 |
| Date | January 2016 |
| Creators | Luo, Haofei |
| Contributors | Playfer, Stephen ; Muheim, Franz |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/25426 |
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