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Register a new userFlavour Les Houches Accord: Interfacing Flavour related Codes
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We present the Flavour Les Houches Accord (FLHA) which specifies a unique set of conventions for flavour-related parameters and observables. The FLHA uses the generic SUSY Les Houches Accord (SLHA) file structure. It defines the relevant Standard Model masses, Wilson coefficients, decay constants, bag parameters, flavour observables, etc. The accord provides a universal and model-independent interface between codes evaluating and/or using flavour-related observables.
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The Supersymmetry Les Houches Accord (SLHA) provides a universal set of conventions for conveying spectral and decay information for supersymmetry analysis problems in high energy physics. Here, we propose extensions of the conventions of the first SLHA to include various generalisations: the minimal supersymmetric standard model with violation of CP, R-parity, and flavour, as well as the simplest next-to-minimal model.
In this short presentation I emphasize the increased importance of kaon flavour physics in the search for new physics (NP) that we should witness in the rest of this decade and in the next decade. The main actors will be the branching ratios for the rare decays $K^+rightarrowpi^+ ubar u$ and $K_{L}rightarrowpi^0 ubar u$, to be measured by NA62 and KOTO, and their correlations with the ratio $varepsilon/varepsilon$ on which recently progress by lattice QCD and large $N$ dual QCD approach has been made implying a new flavour anomaly. Further correlations of $K^+rightarrowpi^+ ubar u$, $K_{L}rightarrowpi^0 ubar u$ and $varepsilon/varepsilon$ with $varepsilon_K$, $Delta M_K$, $K_Ltomu^+mu^-$ and $K_Ltopi^0ell^+ell^-$ will help us to identify indirectly possible NP at short distance scales. This talk summarizes the present highlights of this fascinating field including some results from concrete NP scenarios.
Kaon flavour physics has played in the 1960s and 1970s a very important role in the construction of the Standard Model (SM) and in the 1980s and 1990s in SM tests with the help of CP violation in $K_Ltopipi$ decays represented by $varepsilon_K$ and the ratio $varepsilon/varepsilon$. In this millennium this role has been taken over by $B_{s,d}$ and $D$ mesons. However there is no doubt that in the coming years we will witness the return of kaon flavour physics with the highlights being the measurements of the theoretically clean branching ratios for the rare decays $K^+rightarrow pi^+ ubar u$ and $K_{L}rightarrowpi^0 ubar u$ and the improved SM predictions for the ratio $varepsilon/varepsilon$, for $varepsilon_K$ and the $K^0-bar K^0$ mixing mass difference $Delta M_K$. Theoretical progress on the decays $K_{L,S}tomu^+mu^-$ and $K_Ltopi^0ell^+ell^-$ is also expected. They all are very sensitive to new physics (NP) contributions and the correlations between them should help us to identify new dynamics at very short distance scales. These studies will be enriched when theory on the $Ktopipi$ isospin amplitudes ${rm Re} A_0$ and ${rm Re} A_2$ improves. This talk summarizes several aspects of this exciting field. In particular we emphasize the role of the Dual QCD approach in getting the insight into the numerical Lattice QCD results on $K^0-bar K^0$ mixing and $Ktopipi$ decays.
We study the phenomenology of simplified $Z^prime$ models with a global $U(2)^3$ flavour symmetry in the quark sector, broken solely by the Standard Model Yukawa couplings. This flavour symmetry, known as less-minimal flavour violation, protects $Delta F=2$ processes from dangerously large new physics (NP) effects, and at the same time provides a free complex phase in $bto s$ transitions, allowing for an explanation of the hints for additional direct CP violation in kaon decays ($epsilon^prime/epsilon$) and in hadronic $B$-decays ($Bto Kpi$ puzzle). Furthermore, once the couplings of the $Z^prime$ boson to the leptons are included, it is possible to address the intriguing hints for NP (above the 5$,sigma$ level) in $bto s ell^+ell^-$ transitions. Taking into account all flavour observables in a global fit, we find that $epsilon^prime/epsilon$, the $Bto Kpi$ puzzle and $bto s ell^+ell^-$ data can be explained simultaneously. Sizeable CP violation in $bto s ell^+ell^-$ observables, in particular $A_8$, is predicted, which can be tested in the near future, and an explanation of the $Bto Kpi$ and $epsilon^prime/epsilon$ puzzles leads to effects in di-jet tails at the LHC, that are not far below the current limits. Once $bto s ell^+ell^-$ is included, cancellations in di-muon tails, possibly by a second $Z^prime$, are required by LHC data.
Several experiments observed deviations from the Standard Model (SM) in the flavour sector: LHCb found a $4-5,sigma$ discrepancy compared to the SM in $bto smu^+mu^-$ transitions (recently supported by an Belle analysis) and CMS reported a non-zero measurement of $htomutau$ with a significance of $2.4,sigma$. Furthermore, BELLE, BABAR and LHCb founds hints for the violation of flavour universality in $Bto D^{(*)}tau u$. In addition, there is the long-standing discrepancy in the anomalous magnetic moment of the muon. Interestingly, all these anomalies are related to muons and taus, while the corresponding electron channels seem to be SM like. This suggests that these deviations from the SM might be correlated and we briefly review some selected models providing simultaneous explanations.
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