Dire Splitting Enhancements
 
  - QCD splittings
- QED splittings
- Electroweak splittings
- Dark U(1) splittings
The Dire parton shower allows to weight individual splittings to allow 
efficient isolation and study of their impact. This can e.g. be used 
to increase the rate of a single splitting, and/or decrease the rate 
of others, thus e.g. allowing to study rare splittings. It should be 
noted that this can make some splittings much more frequent, at the 
expense of a new event weight, whose fluctuations might require larger 
event samples. 
 
 
 
Nevertheless, sometimes enhancements can be useful. Dire offers the 
option to enhance each available splitting kernel separately. For 
brevity, we here only describe auxiliary parameters, then one 
enhancement factor, and then just list all other corresponding 
keywords.parm   Enhance:pTmin   
 (default = -1.0)
The minimal pT value t (in GeV) of 
emissions below which no enhancement of emission probabilities is 
applied. Negative values mean that enhancements may be applied to 
emissions at any pT. Default value is -1.0 GeV. 
   
 
parm   Enhance:Dire_fsr_qcd_1->1&21   
 (default = 1.0)
The (double) value with 
which the final-state q->qg splitting is enhanced. Note that 
the enhancement is compensated by an additional weight factor included 
in the parton shower weight, to guarantee the correct real-emission and 
no-emission probabilities are generated. 
   
 
 
QCD splittings
 
 
parm   Enhance:Dire_fsr_qcd_1->21&1   
 (default = 1.0)
(FSR, q -> g q) 
   
parm   Enhance:Dire_fsr_qcd_21->21&21a   
 (default = 1.0)
(FSR, g -> g g, 1st color structure) 
   
parm   Enhance:Dire_fsr_qcd_21->21&21b   
 (default = 1.0)
(FSR, g -> g g, 2nd color structure) 
   
parm   Enhance:Dire_fsr_qcd_21->1&1a   
 (default = 1.0)
(FSR, g -> q qbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_21->1&1b   
 (default = 1.0)
(FSR, g -> q qbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_1->2&1&2   
 (default = 1.0)
(FSR, q -> q' q qbar') 
   
parm   Enhance:Dire_fsr_qcd_1->1&1&1   
 (default = 1.0)
(FSR, q -> qbar q qbar) 
   
parm   Enhance:Dire_fsr_qcd_1->1&21_notPartial   
 (default = 1.0)
(FSR q -> q g, with full soft logarithms, as e.g. needed in radiation off 
top decay products) 
   
parm   Enhance:Dire_fsr_qcd_21->21&21_notPartial   
 (default = 1.0)
(FSR g -> g g, with full soft logarithms, as e.g. needed in radiation off 
top decay products) 
   
parm   Enhance:Dire_fsr_qcd_21->1&1_notPartial   
 (default = 1.0)
(FSR g -> q qbar, with full soft logarithms, as e.g. needed in radiation 
off top decay products) 
   
parm   Enhance:Dire_fsr_qcd_1->1&21&21   
 (default = 1.0)
(FSR q -> q g g) 
   
parm   Enhance:Dire_fsr_qcd_1->1&d&dbar   
 (default = 1.0)
(FSR q -> q d dbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&dbar&d   
 (default = 1.0)
(FSR q -> q d dbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&u&ubar   
 (default = 1.0)
(FSR q -> q u ubar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&ubar&u   
 (default = 1.0)
(FSR q -> q u ubar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&s&sbar   
 (default = 1.0)
(FSR q -> q s sbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&sbar&s   
 (default = 1.0)
(FSR q -> q s sbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&c&cbar   
 (default = 1.0)
(FSR q -> q c cbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&cbar&c   
 (default = 1.0)
(FSR q -> q c cbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&b&bbar   
 (default = 1.0)
(FSR q -> q b bbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_1->1&bbar&b   
 (default = 1.0)
(FSR q -> q b bbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&21&21   
 (default = 1.0)
(FSR g -> g g g) 
   
parm   Enhance:Dire_fsr_qcd_21->21&d&dbar   
 (default = 1.0)
(FSR g -> q d dbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&dbar&d   
 (default = 1.0)
(FSR g -> g d dbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&u&ubar   
 (default = 1.0)
(FSR g -> g u ubar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&ubar&u   
 (default = 1.0)
(FSR g -> g u ubar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&s&sbar   
 (default = 1.0)
(FSR g -> g s sbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&sbar&s   
 (default = 1.0)
(FSR g -> g s sbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&c&cbar   
 (default = 1.0)
(FSR g -> g c cbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&cbar&c   
 (default = 1.0)
(FSR g -> g c cbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&b&bbar   
 (default = 1.0)
(FSR g -> g b bbar, soft quark) 
   
parm   Enhance:Dire_fsr_qcd_21->21&bbar&b   
 (default = 1.0)
(FSR g -> g b bbar, soft antiquark) 
   
parm   Enhance:Dire_isr_qcd_1->1&21   
 (default = 1.0)
(ISR q -> q g) 
   
parm   Enhance:Dire_isr_qcd_21->1&1   
 (default = 1.0)
(ISR g -> q qbar) 
   
parm   Enhance:Dire_isr_qcd_21->21&21a   
 (default = 1.0)
(ISR g -> g g, soft quark) 
   
parm   Enhance:Dire_isr_qcd_21->21&21b   
 (default = 1.0)
(ISR g -> g g, soft antiquark) 
   
parm   Enhance:Dire_isr_qcd_1->21&1   
 (default = 1.0)
(ISR q -> g q) 
   
parm   Enhance:Dire_isr_qcd_1->2&1&2   
 (default = 1.0)
(ISR q -> q' q qbar') 
   
parm   Enhance:Dire_isr_qcd_1->1&1&1   
 (default = 1.0)
(ISR q -> qbar q qbar) 
   
 
 
QED splittings
 
 
parm   Enhance:Dire_fsr_qed_1->1&22   
 (default = 1.0)
(FSR q -> q a) 
   
parm   Enhance:Dire_fsr_qed_1->22&1   
 (default = 1.0)
(FSR q -> a q) 
   
parm   Enhance:Dire_fsr_qed_11->11&22   
 (default = 1.0)
(FSR l -> l a) 
   
parm   Enhance:Dire_fsr_qed_11->22&11   
 (default = 1.0)
(FSR l -> a l) 
   
parm   Enhance:Dire_fsr_qed_22->1&1a   
 (default = 1.0)
(FSR a -> d dbar, soft quark) 
   
parm   Enhance:Dire_fsr_qed_22->1&1b   
 (default = 1.0)
(FSR a -> d dbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qed_22->2&2a   
 (default = 1.0)
(FSR a -> u ubar, soft quark) 
   
parm   Enhance:Dire_fsr_qed_22->2&2b   
 (default = 1.0)
(FSR a -> u ubar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qed_22->3&3a   
 (default = 1.0)
(FSR a -> s sbar, soft quark) 
   
parm   Enhance:Dire_fsr_qed_22->3&3b   
 (default = 1.0)
(FSR a -> s sbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qed_22->4&4a   
 (default = 1.0)
(FSR a -> c cbar, soft quark) 
   
parm   Enhance:Dire_fsr_qed_22->4&4b   
 (default = 1.0)
(FSR a -> c cbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qed_22->5&5a   
 (default = 1.0)
(FSR a -> b bbar, soft quark) 
   
parm   Enhance:Dire_fsr_qed_22->5&5b   
 (default = 1.0)
(FSR a -> b bbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_qed_22->11&11a   
 (default = 1.0)
(FSR a -> e+ e-, soft e-) 
   
parm   Enhance:Dire_fsr_qed_22->11&11b   
 (default = 1.0)
(FSR a -> e+ e-, soft e+) 
   
parm   Enhance:Dire_fsr_qed_22->13&13a   
 (default = 1.0)
(FSR a -> mu+ mu-, soft mu-) 
   
parm   Enhance:Dire_fsr_qed_22->13&13b   
 (default = 1.0)
(FSR a -> mu+ mu-, soft mu+) 
   
parm   Enhance:Dire_fsr_qed_22->15&15a   
 (default = 1.0)
(FSR a -> tau+ tau-, soft tau-) 
   
parm   Enhance:Dire_fsr_qed_22->15&15b   
 (default = 1.0)
(FSR a -> tau+ tau-, soft tau+) 
   
parm   Enhance:Dire_fsr_qed_1->1&22_notPartial   
 (default = 1.0)
(FSR q -> q a, with full soft logarithms, as e.g. needed in radiation off 
top decay products) 
   
parm   Enhance:Dire_fsr_qed_11->11&22_notPartial   
 (default = 1.0)
(FSR l -> l a, with full soft logarithms, as e.g. needed in radiation off 
top decay products) 
   
parm   Enhance:Dire_isr_qed_1->1&22   
 (default = 1.0)
(ISR q -> q a) 
   
parm   Enhance:Dire_isr_qed_1->22&1   
 (default = 1.0)
(ISR q -> a q) 
   
parm   Enhance:Dire_isr_qed_22->1&1   
 (default = 1.0)
(ISR a -> q qbar) 
   
parm   Enhance:Dire_isr_qed_11->11&22   
 (default = 1.0)
(ISR l -> l a) 
   
parm   Enhance:Dire_isr_qed_11->22&11   
 (default = 1.0)
(FSR l -> a l) 
   
parm   Enhance:Dire_isr_qed_22->11&11   
 (default = 1.0)
(FSR a -> l+ l-). 
   
 
 
 
Electroweak splittings
 
 
At present, electroweak evolution is under development, so that these 
settings should not be touched for production for now. 
 
parm   Enhance:Dire_fsr_ew_1->1&23   
 (default = 1.0)
(FSR q -> q z) 
   
parm   Enhance:Dire_fsr_ew_1->23&1   
 (default = 1.0)
(FSR q -> z q) 
   
parm   Enhance:Dire_fsr_ew_23->1&1a   
 (default = 1.0)
(FSR z -> q qbar, soft quark) 
   
parm   Enhance:Dire_fsr_ew_23->1&1b   
 (default = 1.0)
(FSR z -> q qbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_ew_24->1&1a   
 (default = 1.0)
FSR w -> q qbar', soft quark) 
   
parm   Enhance:Dire_fsr_ew_24->1&1b   
 (default = 1.0)
(FSR w -> q qbar', soft antiquark). 
   
parm   Enhance:Dire_fsr_ew_24->24&22   
 (default = 1.0)
(FSR w -> w a). 
   
parm   Enhance:Dire_fsr_ew_25->21&21   
 (default = 1.0)
(FSR h -> g g, as e.g. needed for Higgs hypothesis testing). 
   
parm   Enhance:Dire_fsr_ew_25->22&22   
 (default = 1.0)
(FSR h -> a a, as e.g. needed for Higgs hypothesis testing). 
   
 
 
Dark U(1) splittings
 
 
At present, dark photon evolution is under development, so that these 
settings should not be touched for production for now. 
 
parm   Enhance:Dire_fsr_u1new_1->1&22   
 (default = 1.0)
(FSR q -> q aDark) 
   
parm   Enhance:Dire_fsr_u1new_1->22&1   
 (default = 1.0)
(FSR q -> aDark q) 
   
parm   Enhance:Dire_fsr_u1new_11->11&22   
 (default = 1.0)
(FSR l -> l aDark) 
   
parm   Enhance:Dire_fsr_u1new_11->22&11   
 (default = 1.0)
(FSR l -> aDark l) 
   
parm   Enhance:Dire_fsr_u1new_22->1&1a   
 (default = 1.0)
(FSR aDark -> d dbar, soft quark) 
   
parm   Enhance:Dire_fsr_u1new_22->1&1b   
 (default = 1.0)
(FSR aDark -> d dbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_u1new_22->2&2a   
 (default = 1.0)
(FSR aDark -> u ubar, soft quark) 
   
parm   Enhance:Dire_fsr_u1new_22->2&2b   
 (default = 1.0)
(FSR aDark -> u ubar, soft antiquark) 
   
parm   Enhance:Dire_fsr_u1new_22->3&3a   
 (default = 1.0)
(FSR aDark -> s sbar, soft quark) 
   
parm   Enhance:Dire_fsr_u1new_22->3&3b   
 (default = 1.0)
(FSR aDark -> s sbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_u1new_22->4&4a   
 (default = 1.0)
(FSR aDark -> c cbar, soft quark) 
   
parm   Enhance:Dire_fsr_u1new_22->4&4b   
 (default = 1.0)
(FSR aDark -> c cbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_u1new_22->5&5a   
 (default = 1.0)
(FSR aDark -> b bbar, soft quark) 
   
parm   Enhance:Dire_fsr_u1new_22->5&5b   
 (default = 1.0)
(FSR aDark -> b bbar, soft antiquark) 
   
parm   Enhance:Dire_fsr_u1new_22->11&11a   
 (default = 1.0)
(FSR aDark -> e+ e-, soft e-) 
   
parm   Enhance:Dire_fsr_u1new_22->11&11b   
 (default = 1.0)
(FSR aDark -> e+ e-, soft e+) 
   
parm   Enhance:Dire_fsr_u1new_22->13&13a   
 (default = 1.0)
(FSR aDark -> mu+ mu-, soft mu-) 
   
parm   Enhance:Dire_fsr_u1new_22->13&13b   
 (default = 1.0)
(FSR aDark -> mu+ mu-, soft mu+) 
   
parm   Enhance:Dire_fsr_u1new_22->15&15a   
 (default = 1.0)
(FSR aDark -> tau+ tau-, soft tau-) 
   
parm   Enhance:Dire_fsr_u1new_22->15&15b   
 (default = 1.0)
(FSR aDark -> tau+ tau-, soft tau+) 
   
parm   Enhance:Dire_fsr_u1new_22->211&211a   
 (default = 1.0)
(FSR aDark -> pi+ pi-, soft pi-) 
   
parm   Enhance:Dire_fsr_u1new_22->211&211b   
 (default = 1.0)
(FSR aDark -> pi+ pi-, soft pi+) 
   
parm   Enhance:Dire_isr_u1new_1->1&22   
 (default = 1.0)
(ISR q -> q aDark) 
   
parm   Enhance:Dire_isr_u1new_1->22&1   
 (default = 1.0)
(ISR q -> aDark a) 
   
parm   Enhance:Dire_isr_u1new_22->1&1   
 (default = 1.0)
(ISR aDark -> q qbar) 
   
parm   Enhance:Dire_isr_u1new_11->11&22   
 (default = 1.0)
(ISR l -> l aDark) 
   
parm   Enhance:Dire_isr_u1new_11->22&11   
 (default = 1.0)
(ISR l -> aDark l) 
   
parm   Enhance:Dire_isr_u1new_22->11&11   
 (default = 1.0)
(ISR aDark -> l+ l-).