A symmetry-guided phenomenological model organizes leading current-current operators for charged-current decays of heavy-light mesons and reproduces heavy-quark scaling relations for decay constants and form factors.
$R_K$ and future $b \to s \ell \ell$ BSM opportunities
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
Flavor changing neutral current $|\Delta B|=|\Delta S|=1$ processes are sensitive to possible new physics at the electroweak scale and beyond, providing detailed information about flavor, chirality and Lorentz structure. Recently the LHCb collaboration announced a $2.6 \sigma$ deviation in the measurement of $R_K={\cal{B}}(\bar B \to \bar K \mu \mu)/{\cal{B}}(\bar B \to \bar K ee)$ from the standard model's prediction of lepton universality. We identify dimension six operators which could explain this deviation and study constraints from other measurements. Vector and axial-vector four-fermion operators with flavor structure $\bar s b \bar \ell \ell$ can provide a good description of the data. Tensor operators cannot describe the data. Pseudo-scalar and scalar operators only fit the data with some fine-tuning; they can be further probed with the $\bar B \to \bar K ee$ angular distribution. The data appears to point towards $C_9^{\rm NP \mu} = -C_{10}^{\rm NP \mu }<0$, an $SU(2)_{L}$ invariant direction in parameter space supported by $R_K$, the $\bar B \to \bar K^* \mu \mu$ forward-backward asymmetry and the $\bar B_s \to \mu \mu$ branching ratio, which is currently allowed to be smaller than the standard model prediction. We present two leptoquark models which can explain the FCNC data and give predictions for the LHC and rare decays.
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Predictions for Br(Λ_b → Λ^{(*)} ν ν̄) are 2.07 times the SM value with new physics scale constrained to 2.04–11.76 TeV at 1σ, plus a sum rule linking baryonic and mesonic modes.
A tauphilic leptoquark model with S1 explaining R(D(*)), ~R2 fitting B to K nu nu via right-handed coefficients, and S3 satisfying Delta m_Bs via mixing predicts subdominant negative C_VL, dominant positive C_SL, C9^LQ approx +1, and masses below 3 TeV.
citing papers explorer
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A Phenomenological Model of Mesons for Charged Current Weak Decays
A symmetry-guided phenomenological model organizes leading current-current operators for charged-current decays of heavy-light mesons and reproduces heavy-quark scaling relations for decay constants and form factors.
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$\Lambda_b\to\Lambda^{(*)}\nu{\bar\nu}$ and $b\to s$ $B$ decays
Predictions for Br(Λ_b → Λ^{(*)} ν ν̄) are 2.07 times the SM value with new physics scale constrained to 2.04–11.76 TeV at 1σ, plus a sum rule linking baryonic and mesonic modes.
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$B$ anomalies and the tauphilic leptoquark model
A tauphilic leptoquark model with S1 explaining R(D(*)), ~R2 fitting B to K nu nu via right-handed coefficients, and S3 satisfying Delta m_Bs via mixing predicts subdominant negative C_VL, dominant positive C_SL, C9^LQ approx +1, and masses below 3 TeV.