Flavio

This release increments the version number to 1.0 :tada: This does not mean that flavio is "complete", it is just an expression of the relative maturity of the code, as well as a convenient point in time as a short write-up describing the program will appear on the arXiv preprint server soon. Moreover, this release includes loads of new features, most of which have been developed for the new [smelli](https://github.com/smelli/smelli) package that provides a global likelihood in the space of BSM Wilson coefficients and relies heavily on flavio. Special thanks to my collaborators Jason Aebischer, Jacky Kumar, and Peter Stangl.

New observables: electroweak precision tests!

- *Z* production and decays: electroweak precision observables on the *Z* pole, see the [list](https://flav-io.github.io/docs/obs/zdecays-flavourconservingdecays.html)
- LFV *Z* decays: [list](https://flav-io.github.io/docs/obs/zdecays-fcncdecays.html)
- *W* decays and mass: [list](https://flav-io.github.io/docs/obs/wpmdecays-leptonicdecays.html)

These electroweak precision tests were added by David Straub and Peter Stangl. Other observables:

- τ→φl and τ→ρl added by Peter Stangl (cross-checks by Jacky Kumar)
- F_L in B→D*lν
- Anomalous magnetic dipole moments of the electron, muon, and tau

New likelihood module

The new module `statistics.likelihood` allows to construct likelihoods in terms of parameters and Wilson coefficients given theoretical constraints on parameters and experimental measurements of observables. It was developed for the [smelli](https://github.com/smelli/smelli) package that depends on it and is meant to serve as a basis for `statistics.fits` in the future. Right now, the two modules coexist, but the interface of `fits` might be subject to change in the near future.

Other improvements

- A large number of measurements was added
- Various speed optimizations, some of them drastic

Bug fixes

- Matrix element of the ΔF=2 tensor operator corrected (thanks to Matthew Kirk)
- Bounds on B⁰→Kνν corrected (thanks to James Kahn)


Removed features

As announced in [v.30](https://github.com/flav-io/flavio/releases/tag/v0.30), the `io.flha` module has been removed. If you rely on it (even though it is no longer maintained), you can use it as a standalone script downloading it [here](https://github.com/flav-io/flavio/blob/f0242232f652ae2f7b28806a4c1acc9d0022ecf6/flavio/io/flha.py).

New observables

- Neutrino trident production cross section `R_trident`, cf. [arXiv:1406.2332](http://arxiv.org/pdf/1406.2332.pdf)
- Anomalous magnetic moment of the muon `a_mu` (thanks to Jason Aebischer and Andreas Crivellin for enlightening discussions on sign conventions!)

Other improvements

- Various improvements to the `statistics.fits` module contributed by Peter Stangl (peterstangl)
- Many experimental measurements added, e.g.
- bounds on tau and muon LFV decays by Jacky Kumar (jackypheno)
- bounds on LFV B decays
- Differential measurements of B→D^(*)τν by Jason Aebischer (jasonaebischerGIT), cf. [arXiv:1612.07757](https://arxiv.org/abs/1612.07757)
- Various speed optimizations
- B→Vll decay binned observables should be a factor of a few faster now!
- `sm_uncertainty` is up to factor 20 faster for some observables

Upcoming changes

- the `io.flha` module for importing FLHA files from FlavorKit has been deprecated and will be removed in the future. Please use te [WCxf](https://wcxf.github.io/) format instead.

This is a bug fix release due to a problem with the interpolation of NNLO corrections in b->sll at very low q² (see issue 61). Note that this release does not yet contain the modifications in the master branch since v0.29.1.

Due to a mistake, the release notes for v0.29.1, the previous bugfix release, had not been published on Github. Instead they are given below.

Bugs fixed

- Overall sign error in the new physics contribution to ε'/ε
- Sign error in one of the K→ππ matrix elements
- Normalization of K→ππ lattice matrix elements changed (numerical impact small)

This was used in v2 of [arXiv:1807.02520](https://arxiv.org/abs/1807.02520).

Other changes

The default values for the kaon bag parameters of BSM operators have been changed from ETM 2015 to [RBC/UKQCD 2016](https://arxiv.org/abs/1609.03334).

New physics in ε'/ε

The highlight of this release is the addition of the observable ε'/ε, measuring the ratio of direct over indirect CP violation in K→ππ decays. This implementation is based on the results presented in [arXiv:1807.02520](https://arxiv.org/abs/1807.02520) by J. Aebischer, C. Bobeth, A. Buras, J.-M. Gérard, and D. Straub. This is the first open source implementation of new physics contributions to this important observable taking into account all 114 ΔS=1 operators below the electroweak scale (or arbitrary SMEFT operators through [wilson](https://wilson-eft.github.io/)).

Bugs fixed

- Sign error in new physics contributions to τ→Vl decays fixed
- Font issue when plotting on certain systems fixed (thanks to peterstangl)
- Regression introduced in v0.28 affecting new physics contributions to meson mixing fixed

Other improvements

- Various speed optimizations

This release brings a large number of new observables as well as changes under the hood.

Treatment of new physics

The treatment of new physics Wilson coefficients was completely overhauled and is now entirely based on the brand new [wilson package](https://wilson-eft.github.io). Since wilson is capable of RG running and matching the *complete set* of dimension-6 operators not only in the weak effective theory but also in SMEFT, this opens up many new possibilities for flavio. As a start, it is now possible to use instances of wilson's `Wilson` class as an argument to functions like `np_prediction`. The fit classes in `flavio.statistics.fits` support the new optional arguments `fit_wc_eft` and `fit_wc_basis` that allow to directly make fits in a different EFT (e.g. SMEFT) or basis.

New observables

- Various observables in the neutral *D* meson system have been added. Note that the SM predictions are not really predictions, as the long distance contributions are poorly known, but merely parametrizations accounting for the ballpark of the experimental measurements. For testing CP violating new physics in D mixing, the observable `x12Im_D` can be used, that is negligibly small in the SM.
- The neutron EDM `d_n`
- Lepton flavour violating muon and tau decays
- `BR(mu->egamma)`
- `BR(mu->eee)`
- `BR(tau->egamma)`
- `BR(tau->mugamma)`
- `BR(tau->eee)`
- `BR(tau->mumumu)`
- `BR(tau->muee)`
- `BR(tau->rhoe)`
- `BR(tau->rhomu)`
- Hadronic tau decays
- `BR(tau->pinu)`
- `BR(tau->Knu)`
- Leptonic tau decays
- `BR(tau->mununu)`
- `BR(tau->enunu)`