VINCIA Antenna Functions

2->3 Antennae

qqbar gluon emission antenna

The default coefficients are derived from Z decay and absorb the tree-level matrix element for Z->qgqbar into the shower off Z->qqbar.

flag  Vincia:qQ:emit   (default = on)

parm  Vincia:qQ:emit:chargeFactor   (default = 2.66666667)

parm  Vincia:qQ:emit:LaurentC(-1,-1)   (default = 2.0)

parm  Vincia:qQ:emit:LaurentC(-1,0)   (default = -2.0)

parm  Vincia:qQ:emit:LaurentC(0,-1)   (default = -2.0)

parm  Vincia:qQ:emit:LaurentC(-1,1)   (default = 1.0)

parm  Vincia:qQ:emit:LaurentC(1,-1)   (default = 1.0)

parm  Vincia:qQ:emit:LaurentC(0,0)   (default = 0.0)

parm  Vincia:qQ:emit:LaurentC(1,0)   (default = 0.0)

parm  Vincia:qQ:emit:LaurentC(0,1)   (default = 0.0)

qg gluon emission antenna

The GGG coefficients were derived from neutralino decays and do not absorb any particular physically relevant matrix element into the shower. We have therefore here modified the color factor and the finite terms by comparing to Z->qggqbar. By charge conjugation symmetry, the code also uses this function for qbar-g antennae, with appropriate swapping of invariants.

flag  Vincia:qg:emit   (default = on)

parm  Vincia:qg:emit:chargeFactor   (default = 2.8333333)

parm  Vincia:qg:emit:LaurentC(-1,-1)   (default = 2.0)

parm  Vincia:qg:emit:LaurentC(-1,0)   (default = -2.0)

parm  Vincia:qg:emit:LaurentC(0,-1)   (default = -2.0)

parm  Vincia:qg:emit:LaurentC(1,-1)   (default = 1.0)

parm  Vincia:qg:emit:LaurentC(-1,1)   (default = 1.0)

parm  Vincia:qg:emit:LaurentC(2,-1)   (default = -1.0)

parm  Vincia:qg:emit:LaurentC(0,0)   (default = 1.5)

parm  Vincia:qg:emit:LaurentC(1,0)   (default = -1.0)

parm  Vincia:qg:emit:LaurentC(0,1)   (default = -0.5)

gg gluon emission antenna

The default coefficients are derived from H->gg(g) decay and absorb the tree-level matrix element for H->ggg into the shower off H->gg.

flag  Vincia:gg:emit   (default = on)

parm  Vincia:gg:emit:chargeFactor   (default = 3.0)

parm  Vincia:gg:emit:LaurentC(-1,-1)   (default = 2.0)

parm  Vincia:gg:emit:LaurentC(-1,0)   (default = -2.0)

parm  Vincia:gg:emit:LaurentC(0,-1)   (default = -2.0)

parm  Vincia:gg:emit:LaurentC(-1,1)   (default = 1.0)

parm  Vincia:gg:emit:LaurentC(1,-1)   (default = 1.0)

parm  Vincia:gg:emit:LaurentC(2,-1)   (default = -1.0)

parm  Vincia:gg:emit:LaurentC(-1,2)   (default = -1.0)

parm  Vincia:gg:emit:LaurentC(0,0)   (default = 2.66666667)

parm  Vincia:gg:emit:LaurentC(1,0)   (default = -1.0)

parm  Vincia:gg:emit:LaurentC(0,1)   (default = -1.0)

qg gluon splitting antenna

The default values are derived from neutralino decays and do not absorb any particular physically relevant matrix element into the shower. However, the finite terms have been reduced from GGG, in order to avoid the finite terms being solely responsible for large dead zones. Note: only half a gluon is splitting here.

flag  Vincia:qg:split   (default = on)

parm  Vincia:qg:split:chargeFactor   (default = 1.0)

parm  Vincia:qg:split:LaurentC(-1,-1)   (default = 0.0)

parm  Vincia:qg:split:LaurentC(-1,0)   (default = 0.0)

parm  Vincia:qg:split:LaurentC(-1,1)   (default = 0.0)

parm  Vincia:qg:split:LaurentC(0,-1)   (default = 0.5)

parm  Vincia:qg:split:LaurentC(1,-1)   (default = -1.0)

parm  Vincia:qg:split:LaurentC(2,-1)   (default = 1.0)

parm  Vincia:qg:split:LaurentC(0,0)   (default = -0.4)

parm  Vincia:qg:split:LaurentC(1,0)   (default = 0.8)

parm  Vincia:qg:split:LaurentC(0,1)   (default = 0.0)

gg gluon splitting antenna

The default coefficients are derived from H->gg->gqbarq decays and absorb the tree-level matrix element for H->gqbarq into the shower off H->gg. However, the finite terms have been scaled down a bit here, in order to avoid the finite terms being solely responsible for large dead zones. Note: only half of each gluon is splitting here.

flag  Vincia:gg:split   (default = on)

parm  Vincia:gg:split:chargeFactor   (default = 1.0)
Note: the two permutations g-g -> g-qbar+qbar and g-g -> qbar+q-g are explicitly summed over in the code (with appropriate swapping of invariants in the latter case).

parm  Vincia:gg:split:LaurentC(-1,-1)   (default = 0.0)

parm  Vincia:gg:split:LaurentC(-1,0)   (default = 0.0)

parm  Vincia:gg:split:LaurentC(-1,1)   (default = 0.0)

parm  Vincia:gg:split:LaurentC(0,-1)   (default = 0.5)

parm  Vincia:gg:split:LaurentC(1,-1)   (default = -1.0)

parm  Vincia:gg:split:LaurentC(2,-1)   (default = 1.0)

parm  Vincia:gg:split:LaurentC(0,0)   (default = -0.8)

parm  Vincia:gg:split:LaurentC(1,0)   (default = 0.8)

parm  Vincia:gg:split:LaurentC(0,1)   (default = 0.4)

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