v1.2

New observables

• Leptonic kaon decays BR(KL->mumu), BR(KS->mumu) (as well as the electronic modes)
• Lepton flavour violating kaon decays BR(KL->emu,mue), BR(KS->emu,mue)
• π→μν total rate, Gamma(pi+->munu)
• Some additional Z and W pole observables, e.g. the LFU ratio Rmue(W->lnu)

Other improvements

• The B→D and B→D* form factor parameters have been improved: while still using the parametrization from arXiv:1801.01112, the parameters have been updated from a fit where the LCSR input is taken from arXiv:1811.00983 rather than arXiv:0809.0222. This leads in particular to a more reliable prediction for R_D and R_D*.
• Various parametric updates, e.g. quark masses are now taken from lattice QCD.
• Correlation among B meson bag parameters from FLAG now properly taken into account.
• Two-dimensional likelihoods of the CMS and ATLAS measurements of B_s,d→μμ added (thanks Peter Stangl!)

Breaking change

• The CKM parameter gamma has been renamed to delta to more accuretely reflect the fact that this is treated internally precisely as the Dirac phase δ. Although this is numerically almost identical with the unitarity triangle angle γ, it is not equivalent.

Fixes

• Factor of 2 in tau->emue and tau->muemu fixed (thanks to Andrzej Buras!)

... and a couple of smaller fixes.

v1.1

The first minor release in the v1.x series brings a couple of new observables and some other improvements. Many of these improvements where motivated by smelli and special thanks go to Jason Aebischer, Jacky Kumar, and Peter Stangl.

New observables

• More leptonic LFV τ decays: τ→3e, τ^-→e^-μ⁺μ^-, τ^-→e^-μ⁺e^-, τ^-→μ^-e⁺μ^-
• τ→πl and τ→Kl (implemented by @jackypheno)
• K_S→πlν

Other improvements

• Improved treatment of likelihoods of τ LFV limits
• Implemented the B form factors from a combined fit to an improved LCSR calculation and LQCD results in arXiv:1811.00983. These form factors have been made the default for B→π and B→K.
• Updated all particle masses and widths to PDG 2018 values
• Other parameter updates: f_K and f_π from FLAG; B bag parameters now use the FLAG average for the SM operator
• Consistent treatment of scale dependence of longitudinal meson decay constants (implemented by @peterstangl)

Fixes

• A missing factor of 2 in the dipole contribution to τ→3l was fixed (thanks to Andrzej Buras [yes!] for noticing this)

v1.0.1

This minor release was necessary due to changes in the wilson and wcxf libraries that flavio depends on.

v1.0

This release increments the version number to 1.0 🎉 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 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
• LFV Z decays: list
• W decays and mass: list

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 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, 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.

v0.30

New observables

• Neutrino trident production cross section R_trident, cf. arXiv:1406.2332
• 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
• 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 format instead.

v0.29.2

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.

v0.29.1

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.

Other changes

The default values for the kaon bag parameters of BSM operators have been changed from ETM 2015 to RBC/UKQCD 2016.

v0.29

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 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).

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

v0.28

0.28: SMEFT, lepton flavour violation, D mixing, EDMs

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. 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)

v0.27.3

This minor release fixes a bug and brings a few minor improvements.

• A bug in the new physics contributions to B→lν decays was fixed.
• The methods get_central_all and get_random_all of ParameterConstraints have been accelerated.
• The mpmath package was dropped as a dependency since the complex dilogarithm, for which it was needed in the past, has been implemented in scipy and is 20 times faster. The minimum scipy version required is now 0.18.
• A new probability distribution LogNormalDistribution has been added. This is particularly useful for poorly known multiplicative factors in theory calculations. In YAML files, it can be specified with the notation 1 */ 3, corresponding to the exponential of a random variable normally distributed around ln(1) with mean and standard deviation ln(3) (the notation reminds of the fact that 68% probability is contained within 1*3 and 1/3).