Multijet production in W, Z events at p colliders

Establishing jet scaling patterns with a photon

“…The Poisson scaling pattern, however, has not been observed in inclusive production at hadron colliders since UA1/UA2. Instead, for many processes we find staircase scaling, namely a constant ratio of exclusive n-jet rates σ n+1 /σ n = R [20][21][22]. This feature has been studied by the LHC experiments [23] and also finds application in background-modelling in phenomenological approaches [24,25].…”

“…The constant values R 0 range around 0.14, but with a small spread. In section 4 we will contrast these values with the W/Z+jets cases [14,[20][21][22]. While the definition of the hard process does play a role in determining R 0 , in section 3 we will see that the far dominant factor is p min T,j fixed in eq.(2.4).…”

“…These include pure QCD jets production [14,[44][45][46][47][48][49] and W/Z production with jets [20][21][22][44][45][46][47][48][49]. As we will see, γ+jets production when constrained in certain cut scenarios provides an additional channel, hence contributing to a better understanding of the possibly observed n jets scaling patterns.…”

“…require a widely separated photon we recover staircase scaling σ n+1 /σ n = R 0 for the total cross section [14,[20][21][22].…”

Measurement of the triple gluon vertex from double quark tagged 4-jet events

“…Therefore it is not possible to determine the in uence of higher orders exactly. In order to get an estimate, the 5-parton Born cross section [19] has been implemented in the JETSET event generator [20]. With our cuts, about 37% of the 5-parton events are seen as 4-jet events.…”