Resolving the ϕ2 (α) ambiguity in $$ {\mathrm{B}}^0\to {\mathrm{a}}_1^{\pm }{\uppi}^{\mp } $$

Dalseno, J.

doi:10.1007/jhep10(2019)191

Cited by 3 publications

(3 citation statements)

References 53 publications

(62 reference statements)

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“…2 is its effective weak phase. As these quantities are now related to the isospin triangles at amplitude level, the solution degeneracy in φ 2 for the range [0, 180] • is resolved [32] and as an added incentive, the eightfold solution degeneracy in B 0 → a ± 1 π ∓ can also be lifted for the same range in the SU(3) approach with the added possibility to directly constrain non-factorisable symmetry-breaking effects [33].…”

Section: Next-generation Approachmentioning

confidence: 99%

Rescaling the isospin triangle argument for constraining $$\phi _2$$ ($$\alpha$$): Consolidating Belle II and a potential path forward for LHCb

Dalseno

2022

Eur. Phys. J. Plus

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A rescaling of the SU(2) isospin triangles constraining $$\phi _2$$ ϕ 2 ($$\alpha$$ α ) that relies on measurements of the experimentally cleaner relative branching fractions, as opposed to those absolute, is proposed. Paving the way towards more systematically sustainable analysis, this method promises to eliminate a dominant systematic at Belle II amongst others, namely the uncertainty on the number of $$B {\bar{B}}$$ B B ¯ pairs in data. Furthermore, a $$\phi _2$$ ϕ 2 constraint in the $$B \rightarrow \rho \rho$$ B → ρ ρ system at LHCb that is more independent of Belle II input is shown to become viable even without a measurement of $$C\!P$$ C P violation in $$B^0 \rightarrow \rho ^+\rho ^-$$ B 0 → ρ + ρ - .

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Section: Next-generation Approachmentioning

confidence: 99%

Rescaling the isospin triangle argument for constraining $$\phi _2$$ ($$\alpha$$): Consolidating Belle II and a potential path forward for LHCb

Dalseno

2022

Eur. Phys. J. Plus

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“…where λ ij CP is a CP -violation parameter and φ ij 2 is its effective weak phase. As these quantities are now related to the isospin triangles at amplitude level, the solution degeneracy in φ 2 for the range [0, 180] • is resolved [45] and as an added incentive, the 8-fold solution degeneracy in B 0 → a ± 1 π ∓ can also be lifted for the same range in the SU(3) approach [46]. Naturally, this method raises concerns regarding the potential impact on φ 2 coming from correlated amplitude model systematics which will be studied here.…”

Section: Next-generation Approachmentioning

confidence: 99%

“…Then to generate these samples, amplitude models are first required for which information is sparse, meaning that assumptions will have to be made on the magnitudes and relative phases between the B → ρρ polarisations. In previous works [45,46], unknown physics parameters were uniformly distributed in an ensemble test to give a sense of what to expect on average in their respective φ 2 studies. However in this case, applying systematic variations on top of all three amplitude analyses in an ensemble is not a practical endeavour and would be of unclear benefit, besides.…”

Section: Amplitude Model Correlations Within Systemsmentioning

confidence: 99%

Impact of systematic and amplitude model correlations within and between systems of combined input: a case study with ϕ2 (α)

Dalseno

2021

J. High Energ. Phys.

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The pursuit of experimental precision in the CP-violating weak phase ϕ2 (α) is not without its challenges, in part due to the need to combine multiple physical observables from various related decay channels, and therein lies a fundamental issue. Similarities in analysis procedures give rise to systematic correlations between the measured inputs constraining ϕ2 that must be taken into account to avoid bias. Specifically, in the case of the irreducible model uncertainty accompanying analyses involving the ρ meson, it is demonstrated that ignoring correlations derived from its pole parameters, or indeed even treating correlations individually contained within each decay channel, can ultimately lead to a bias in ϕ2 of (1°). Correct treatment on the other hand, markedly reduces wandering of its central value as a function of the model uncertainty strength with the added dividend of a further improved overall uncertainty. Bias in the combination of B0 → (ρπ)0 and B → ρρ is also seen to depend on the statistical strength of the former in relation to that of the model uncertainty in the latter. This work can inspire other studies into the points at which systematic correlations beyond those determined in single measurements matter in combinations leading to other CP-violating weak phases such as ϕ1 (β), ϕ3 (γ) and ϕs.

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The hadronic $$\tau $$ decay $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau $$ and the axial vector mixing angle

2021

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We propose to measure the $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau \ $$ τ - → K 1 - ν τ → ( K - ω ) ν τ → ( K - π + π - π 0 ) ν τ decay in order to determine the $$K_1$$ K 1 axial vector mixing angle $$\theta _{K_1}$$ θ K 1 . We derive, for the first time, the differential decay rate formula for this decay mode. Using the obtained result, we perform a sensitivity study for the Belle (II) experiment. We will show that the $$K^-\pi ^+\pi ^-\pi ^0$$ K - π + π - π 0 spectrum of the $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau \ $$ τ - → K 1 - ν τ → ( K - ω ) ν τ → ( K - π + π - π 0 ) ν τ decay can discriminate the two solutions $$\theta _{K_1}=\sim 30^{\circ }$$ θ K 1 = ∼ 30 ∘ or $$\sim 60^{\circ }$$ ∼ 60 ∘ observed in the other measurements.

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Resolving the ϕ2 (α) ambiguity in $$ {\mathrm{B}}^0\to {\mathrm{a}}_1^{\pm }{\uppi}^{\mp } $$

Cited by 3 publications

References 53 publications

Rescaling the isospin triangle argument for constraining $$\phi _2$$ ($$\alpha$$): Consolidating Belle II and a potential path forward for LHCb

Rescaling the isospin triangle argument for constraining $$\phi _2$$ ($$\alpha$$): Consolidating Belle II and a potential path forward for LHCb

Impact of systematic and amplitude model correlations within and between systems of combined input: a case study with ϕ2 (α)

The hadronic $$\tau $$ decay $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau $$ and the axial vector mixing angle

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