feynlag.pheno.integrate

Numerical Dalitz-plot integration for 1→3 decay widths.

The two-body width is a closed form; a three-body width through a resonance is a 2-D integral over the Dalitz region with a Breit–Wigner in the integrand, and has no closed form in general. This module is the library’s numerical integration layer.

Two backends: SciPy (scipy.integrate) when installed — robust adaptive quadrature — and a dependency-free numpy Gauss–Legendre fallback. SciPy is the optional [numeric] extra; it is imported lazily here (the one place it is used) so the rest of the library stays pure-SymPy/numpy.

Functions

dalitz_integral(integrand, s23_lo, s23_hi, ...)	Integrate integrand(s12, s23) over the physical Dalitz region.
have_scipy()	Whether SciPy is importable (the [numeric] extra is installed).