Occasional momentum violation warnings from METS scale setter in W+3jets

[Frank Siegert]

During the integration of a W+3jets process with Comix, the METS scale setter occasionally outputs warnings about momentum violation (~1 in 10000 points):

METS_Scale_Setter::CalculateScale(): Momentum not conserved.
\sum p = (0.0176599,-4.60007e-09,-2.43899e-09,0.0176599) in
(0xb058c30)[0]: 2 -> 2 {
  \mu_r = 0, \mu_f = 0
  x_1 = 0.000380436, x_2 = 4.87896e-07
  k_{T,QCD} = 5.13693, (R/B)_{max} = 1
  oew = 0, oqcd = 0, kin = 0
  swap = 0, new = (<no entry>)
       (0,4,5)           u (-0.157356,-1.84872e-14,-2.03303e-14,-0.157355) (1,0) [0|0,0]
         (1,6)          db (0.00320843,-9.63653e-10,-1.05972e-09,0.0321047) (0,1) [0|0,0]
           (2)          e- (0.0772658,0.047331,-0.000374175,0.0610708) (0,0) [0|0,0]
           (3)       nu_eb (0.0945418,-0.047331,0.000374174,0.08184) (0,0) [0|0,0]
}

[Frank Siegert]

The number of errors reduces significantly if I impose a cut on m_W_>2 GeV (actually only one error left during the integration). So this definitely is minor priority and could even be closed if we don't think we can fix this.

[Stefan Hoeche]

This bug is fixed in r14888. In case of further problems, please list them under report #60.

[Stefan Hoeche]

Milestone old deleted