flavio: a Python package for flavour and precision phenomenology in the Standard Model and beyond (1810.08132v1)

Abstract: flavio is an open source tool for phenomenological analyses in flavour physics and other precision observables in the Standard Model and beyond. It consists of a library to compute predictions for a plethora of observables in quark and lepton flavour physics and electroweak precision tests, a database of experimental measurements of these observables, a statistics package that allows to construct Bayesian and frequentist likelihoods, and of convenient plotting and visualization routines. New physics effects are parameterised as Wilson coefficients of dimension-six operators in the weak effective theory below the electroweak scale or the Standard Model EFT above it. At present, observables implemented include numerous rare $B$ decays (including angular observables of exclusive decays, lepton flavour and lepton universality violating $B$ decays), meson-antimeson mixing observables in the $B_{d,s}$, $K$, and $D$ systems, tree-level semi-leptonic $B$, $K$, and $D$ decays (including possible lepton universality violation), rare $K$ decays, lepton flavour violating $\tau$ and $\mu$ decays, $Z$ pole electroweak precision observables, the neutron electric dipole moment, and anomalous magnetic moments of leptons. Not only central values but also theory uncertainties of all observables can be computed. Input parameters and their uncertainties can be easily modified by the user. Written in Python, the code does not require compilation and can be run in an interactive session. This document gives an overview of the features as of version 1.0 but does not represent a manual. The full documentation of the code can be found in its web site.

Overview of the flavio Package for Flavour Physics

The paper introduces "flavio," an open-source Python package designed for phenomenological analyses within the field of flavour physics, as well as other precision observables related to the Standard Model (SM) and beyond. The package serves as a comprehensive tool that encompasses a wide range of observables in quark and lepton flavour physics and electroweak precision tests. Central to its utility is the capacity to facilitate analysis of new physics (NP) effects parameterized as Wilson coefficients within both the weak effective field theory (WEFT) below the electroweak scale and the Standard Model effective field theory (SMEFT) above it.

Functionalities of flavio

1. Prediction of Observables: flavio provides users with the ability to compute predictions for a diverse set of observables in both the SM and NP scenarios. This capability includes not only the central values but also the associated theoretical uncertainties, thereby allowing for a more nuanced understanding of the prediction landscape.
2. Database of Experimental Measurements: The package contains a comprehensive database of experimental results. This database is crucial for comparing theoretical predictions with observed data and facilitates the construction of likelihoods needed for statistical analyses.
3. Statistical Analysis Tools: Users can leverage flavio to construct Bayesian and frequentist likelihoods. This feature is pivotal for conducting statistical inference, enabling the integration of both theory predictions and experimental measurements.
4. Interactive and Flexible Use: Written entirely in Python, flavio offers ease of installation and modification. It supports interactive sessions, making it accessible for users to run analyses in real-time environments like Jupyter notebooks.
5. Visualization Utilities: The package includes routines for visualizing data and results, aiding in the interpretation and presentation of research findings.

Coverage and Applications

flavio supports numerous processes in flavour physics. These include, but are not limited to, rare $B$ decays, meson-antimeson mixing, rare $K$ decays, and lepton flavour violating decays. By considering NP effects in the form of dimension-six operators, flavio allows researchers to test for deviations from the SM and explore potential NP scenarios.

The package is designed not only as a computational tool but also as an integrative platform that facilitates cross-validation with other frameworks such as EOS, HEPfit, and SuperIso. Each of these packages shares some scope with flavio, but flavio's emphasis on easy extensibility, accessibility, and broad observability makes it a distinct choice for researchers focusing on NP within an EFT framework.

Implications and Future Directions

The implications of flavio's development are multifaceted. Practically, it serves as an essential tool for researchers probing beyond the SM physics, potentially leading to the identification of new particles or interactions. Theoretically, it aids in refining models and enhancing the precision of SM predictions. Given the active development status of the package, there is potential for further expansion to include additional observables and extend its applicability within the field.

As flavio continues to evolve, contributing to its future development and integrating it with other platforms will ensure that it remains a versatile and powerful resource for the high-energy physics community. The collaborative nature of its development encourages contributions from researchers, fostering an open environment for scientific advancement.