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

Resolving the ϕ2 (α) ambiguity in B → ρρ

“…Reference negligible levels. Expanding to the entire phase space doubles that yield as mentioned in the LHCb analysis of the B 0 → (π + π − )(π + π − ) system [17]. Assuming uniform detection efficiency, the total yield also including the axial vectors should then be roughly 1200 events in Run 1.…”

“…Decays that proceed predominantly through theb →ūud tree transition (figure 1a) in the presence of B 0 -B 0 mixing are sensitive to the interior angle of the Unitarity Triangle φ 2 = α ≡ arg(−V td V * tb )/(V ud V * ub ), which can be accessed through mixing-induced CP violation observables measured from time-dependent, flavour-tagged analyses. This quark process manifests itself in multiple systems, including B → ππ [3][4][5][6][7][8], ρπ [9,10], ρρ [11][12][13][14][15][16][17] and a ± 1 π ∓ [18][19][20], where the angle φ 2 has so far been constrained with an overall uncertainty of around 4 • [21][22][23]. However, one of the salient features of the overall φ 2 combination is the persistence of degenerate solutions within the range [0, π]: up to the 2σ level, two solutions currently remain, while beyond this further solutions emerge.…”

Isospin analysis of charmless B-meson decays

“…The following two-side sums are consistent with flat triangles for both B → ρρ andB → ρρ systems: t = 1.00 ± 0.10 andt = 0.97 ± 0.11 . [43,44] [43,44] [47,48,49] (2). The zoom in the vicinity of α = 0 (right) displays the punctual discontinuity, whose width, due to the scan binning, has no physical meaning.…”

Nonleptonic decays of B→(f1(1285),f1Liu1, Xiao2 2016Phys. Rev. D15190View full textAdd to dashboardCite

“…−0.22 ± 0.13 [47] provided by the Belle Collaboration cannot match with that given by the BABAR [48] and LHCb [49] collaborations, respectively. Therefore, it is important to make a refined measurement at the forthcoming Belle-II experiment to give a definitive conclusion.…”