# Observation of the B0→ρ0ρ0 decay from an amplitude analysis of B0→(π+π−)(π+π−) decays

Abstract : Proton-proton collision data recorded in 2011 and 2012 by the \lhcb experiment, co\-rres\-pon\-ding to an integrated luminosity of 3.0\invfb, are a\-na\-lysed to search for the charmless B0→ρ0ρ0 decay. More than 600 ${\B^0 \to (\pi^+\pi^-)(\pi^+\pi^-)}$ signal decays are selected and used to perform an amplitude analysis from which the B0→ρ0ρ0 decay is observed for the first time with 7.1 standard deviations significance. The fraction of B0→ρ0ρ0 decays yielding a longitudinally polarised final state is measured to be $\fL = 0.745^{+0.048}_{-0.058} ({\rm stat}) \pm 0.034 ({\rm syst})$. The B0→ρ0ρ0 branching fraction, using the ${\B^0 \to \phi K^*(892)^{0}}$ decay as reference, is also reported as ${\BF(B^0 \to \rho^0 \rho^0) = (0.94 \pm 0.17 ({\rm stat}) \pm 0.09 ({\rm syst}) \pm 0.06 ({\rm BF})) \times 10^{-6}}$.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01138334
Contributor : Sabine Starita <>
Submitted on : Wednesday, April 1, 2015 - 5:05:43 PM
Last modification on : Tuesday, April 20, 2021 - 12:00:14 PM

### Citation

R. Aaij, Y. Amhis, S. Barsuk, M. Borsato, O. Kochebina, et al.. Observation of the B0→ρ0ρ0 decay from an amplitude analysis of B0→(π+π−)(π+π−) decays. Physics Letters B, Elsevier, 2015, 747, pp.468-478. ⟨10.1016/j.physletb.2015.06.027⟩. ⟨in2p3-01138334⟩

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