diff --git a/draft.tex b/draft.tex index 7bc39ea..58eb033 100644 --- a/draft.tex +++ b/draft.tex @@ -433,21 +433,23 @@ Moreover, the differential decay width can receive additional complex amplitudes from signal-like backgrounds, \textit{e.g.} $K\pi$ S-wave from a non-resonant decay and/or a scalar resonance (see detailed discussion in Ref.~\cite{Hurth:2017hxg}). These contributions are in general expected to be small~\cite{Aaij:2015oid,Aaij:2016flj}, -and in the proposed formalism these are introduced in an identical manner for muons and electrons. -Therefore, in this constrained framework these effects are even further suppressed and can then be neglected. +and in the proposed formalism they benefit from the same description between the muon and electron mode. +%these are introduced in an identical manner for muons and electrons. +Therefore, in this constrained framework these effects are even further suppressed and can then be neglected +for the scope of this work. Another important test to probe the stability of the model consists in changing the description of the non-local hadronic effects in the generation of the pseudo-experiments. In this way we analyse potential issues that can rise if the truncation $\mathcal{H}_\lambda[z^n]$ is not a good description of nature. -We proceed as follows: we generate toys with non-zero coefficients for +We proceed as follows: we generate ensembles with non-zero coefficients for $\mathcal{H}_\lambda[z^3]$ and $\mathcal{H}_\lambda[z^4]$, and we perform the fit with $\mathcal{H}_\lambda[z^2]$. We vary the choice of the $\mathcal{H}_\lambda[z^{(3,4)}]$ generated parameters, including a \textit{provocative} set of values that minimises the tension with the $P_5'$ anomaly~\cite{Aaij:2015oid}, while keeping $\WC_9^{(\mu)}$ and $\WC_{10}^{(\mu)}$ at their SM values. -Despite the mis-modelling of the non-local hadronic effects in the fit results, we observe +Despite the mis-modelling of the non-local hadronic effects in the fit, we observe that the determination of $\Delta\WC_9$ and $\Delta\WC_{10}$ is always unbiased, thanks to the relative cancellation of all the shared parameters between the two channels. It is worth emphasizing that a hypothetical determination of the individual @@ -460,13 +462,13 @@ all the available information from $\bar{B}\to \bar{K}^*\ell^+\ell^-$ decays for a precise determination of LFU-breaking differences of WCs, \textit{i.e.} $\Delta\WC_9$ and $\Delta\WC_{10}$. -This relies on a shared parametrisation of the local (form-factors) and non-local ($\mathcal{H}_\lambda[q^2]$) +This relies on a shared parametrisation of the local (form-factors) and non-local ($\mathcal{H}_\lambda(q^2)$) hadronic matrix elements between the muonic and electronic channels, that in turn enables the determination of the observables of interest free from any theoretical uncertainty. Figure~\ref{fig:allComponents} illustrates the usefulness of the newly-proposed observables by combining -the different information from angular analysis to branching ratio measurements. +the different information from angular analysis and branching ratio measurements. Due to the inclusiveness of the approach, the expected sensitivity surpasses any -of projection for the current anomalous measurements alone given the benchmark points. +of projection for the current $R_{K^{*}}$ and $P^{\prime}_{5}$ anomalies alone, given the benchmark points. Therefore, this novel formalism can be the \textit{holy grail} to observe NP in $\bar{B}\to \bar{K}^*\ell^+\ell^-$ decays in near future. @@ -511,20 +513,20 @@ An extension of the physics case of the proposed method is to investigate the sensitivity to the chirality-flipped counterparts of the usual Wilson coefficients, -\textit{i.e.} $\WC^{\prime (\mu)}_9$ and $\WC^{\prime(\mu)}_{10}$. +\textit{i.e.} $\WC^{\prime \,(\mu)}_9$ and $\WC^{\prime \,(\mu)}_{10}$. Following the formalism discussed in this letter, the primed WCs are examined by considering in addition to the -\texttt{BMP}$_{\WC_{9,10}}$ three different modified NP scenarios for the muon only: -$\WC_{9,10}^{\prime(\mu)} = \WC^{\prime \rm{SM}}_{9,10} = 0$; -$\WC^{\prime (\mu)}_9 = \WC^{\prime (\mu)}_{10} = 0.3$; -and $\WC^{\prime (\mu)}_9 = - \WC^{\prime (\mu)}_{10} = 0.3$. -Notice that for the electron mode the $\WC_{9,10}^{\prime(e)}$ is set and fixed to the SM value $\WC^{\prime \rm{SM}}_{9,10} = 0$. +\texttt{BMP}$_{\WC_{9,10}}$ three different modified NP scenarios: +$\WC_{9,10}^{\prime \,(\mu)} = \WC^{\prime \,\rm{SM}}_{9,10} = 0$; +$\WC^{\prime \,(\mu)}_9 = \WC^{\prime \,(\mu)}_{10} = 0.3$; +and $\WC^{\prime \,(\mu)}_9 = - \WC^{\prime \,(\mu)}_{10} = 0.3$. +Notice that for the electron mode the $\WC_{9,10}^{\prime \,(e)}$ is set and fixed to the SM value $\WC^{\prime \,\rm{SM}}_{9,10} = 0$. \begin{figure}[b] \includegraphics[width=.4\textwidth]{plots/ellipses_CpMu_Hz.pdf} \caption{% - Two-dimensional sensitivity scans for the pair of Wilson coefficients $\WC'^{(\mu)}_9$ and - $\WC'^{(\mu)}_{10}$ for different non-local hadronic parametrisation models for a NP scenario - with $\WC'^{(\mu)}_9 = \WC'^{(\mu)}_{10} = 0.3$. + Two-dimensional sensitivity scans for the pair of Wilson coefficients $\WC'^{\,(\mu)}_9$ and + $\WC'^{\,(\mu)}_{10}$ for different non-local hadronic parametrisation models for a NP scenario + with $\WC'^{\,(\mu)}_9 = \WC'^{\,(\mu)}_{10} = 0.3$. The contours correspond to $3\,\sigma$ statistical-only uncertainty bands evaluated with the expected statistics after \lhcb Run II. \label{fig:Cp_Hz} @@ -532,24 +534,25 @@ \end{figure} Figure~\ref{fig:Cp_Hz} shows the fit results for different order of the analytic expansion for -the non-local hadronic contribution for a NP scenario with $\WC'^{(\mu)}_9 = \WC'^{(\mu)}_{10} = 0.3$, -and yields corresponding to the \lhcb Run II expected statistics. -The dependency on the determination of $\WC'^{(\mu)}_9$ and $\WC'^{(\mu)}_{10}$ on the +the non-local hadronic contribution for the NP scenario with $\WC'^{\,(\mu)}_9 = \WC'^{\,(\mu)}_{10} = 0.3$, +and yields corresponding to the expected \lhcb Run II statistics. +The dependency on the determination of $\WC'^{\,(\mu)}_9$ and $\WC'^{\,(\mu)}_{10}$ on the order of the expansion clearly saturates after $\mathcal{H}_\lambda[z^3]$ and allows a measurement of the primed Wilson coefficients for the muon decay channel $B^{0} \to K^{*0} \mumu$ independent on the theoretical hadronic uncertainty. % -Figure~\ref{fig:Cp} shows the prospects for the sensitivity to the $\WC'^{(\mu)}_9$ and -$\WC'^{(\mu)}_{10}$ Wilson coefficients corresponding to the expected statistics at +Figure~\ref{fig:Cp} shows the prospects for the sensitivity to the $\WC'^{\,(\mu)}_9$ and +$\WC'^{\,(\mu)}_{10}$ Wilson coefficients corresponding to the expected statistics at \lhcb +upgrades $50\,$fb$^{-1}$ and $\,300\,$fb$^{-1}$. Note that only with the full capability of the LHCb experiment it is possible to start disentangling the different NP hypotheses. % \begin{figure}[t] \includegraphics[width=.4\textwidth]{plots/ellipses_CpMu.pdf} \caption{% - Two-dimensional sensitivity scans for the pair of Wilson coefficients $\WC'^{(\mu)}_9$ and $\WC'^{(\mu)}_{10}$ - for three NP scenarios: (blue) $\WC'^{(\mu)}_9 = \WC'^{(\mu)}_{10} = 0$, (orange) $\WC'^{(\mu)}_9 = \WC'^{(\mu)}_{10} = 0.3$ - and (magenta) $\WC'^{(\mu)}_9 = - \WC'^{(\mu)}_{10} = 0.3$. + Two-dimensional sensitivity scans for the pair of Wilson coefficients $\WC'^{\,(\mu)}_9$ and $\WC'^{\,(\mu)}_{10}$ + for three NP scenarios: (blue) $\WC'^{\,(\mu)}_9 = \WC'^{\,(\mu)}_{10} = 0$, (orange) $\WC'^{\,(\mu)}_9 = \WC'^{\,(\mu)}_{10} = 0.3$ + and (magenta) $\WC'^{\,(\mu)}_9 = - \WC'^{\,(\mu)}_{10} = 0.3$. The contours correspond to $3\,\sigma$ statistical-only uncertainty bands expected for the LHCb Upgrade (dotted) $50\,$fb$^{-1}$ and (solid) $\,300\,$fb$^{-1}$ statistics. \label{fig:Cp}