feynlag.pheno.vertices.DecayVertex

class feynlag.pheno.vertices.DecayVertex(particles, vertex_type, coupling=0, g_left=0, g_right=0, meta=<factory>)

One three-leg vertex, usable by amplitudes.

Parameters:

• particles (tuple)

• vertex_type (str)

• coupling (Expr)

• g_left (Expr)

• g_right (Expr)

• meta (dict)

particles

the leg symbols. Bosonic vertices carry the field symbols; fermionic ones carry (bar_leg, field_leg, boson).

Type:

tuple

vertex_type

closed-catalog key ('FFV', 'VVS', …).

Type:

str

coupling

full Feynman rule for a bosonic vertex (carries the i).

Type:

sympy.core.expr.Expr

g_left / g_right

coefficients of P_L / P_R (or γ^μP_L / γ^μP_R) for a fermionic vertex, each carrying the Feynman-rule i and the boson multiplicity factor.

meta

extra bookkeeping ('bar', 'field', 'boson', …).

Type:

dict

__init__(particles, vertex_type, coupling=0, g_left=0, g_right=0, meta=<factory>)

Parameters:

• particles (tuple)

• vertex_type (str)

• coupling (Expr)

• g_left (Expr)

• g_right (Expr)

• meta (dict)

Return type:

None

Methods

__init__(particles, vertex_type[, coupling, ...])

Attributes

coupling
g_left
g_right
particles
vertex_type
meta