CharmingFit — UTfit-style Bayesian analysis for charmless two-body B decays

This package performs a Bayesian (Monte Carlo importance-sampling) fit of charmless two-body decays of B+, B0, and Bs mesons into ππ, Kπ, and KK final states.

• Amplitudes: SU(2) isospin basis, with SU(3)-breaking factors in polar form.
• CKM inputs: Flat priors on (λ, A, ρ̄, η̄) within UTfit 2022 ranges.
• Observables: Branching ratios, direct A_CP, and S coefficients from CP analyses.
• Output: ROOT ntuple with sampled parameters and likelihood weights.

Main entry point:

python run_fit.py --observables data/observables.yaml --out charmless_fit.root -N 500000