Propagator

struct Propagator

An internal line of a Diagram.

Holds the propagator mass, width and PDG id, and the energy window [e_min, e_max] its invariant is restricted to. The integer integration_order hint orders the s-channel invariants, a lower value being sampled first. See Topology.

Public Members

double mass

Propagator mass.

double width

Propagator width (0 for a stable / off-shell propagator).

int integration_order

Sampling-order hint; lower values are generated first.

double e_min

Lower bound on the propagator energy.

double e_max

Upper bound on the propagator energy.

int pdg_id

PDG id of the propagating particle.

double flat_window

Half-width, in units of width, of the window where the Breit-Wigner sampling is flattened ($-excluded propagator); 0 for none.