############################################################################### # This is VUB.DEC by Sven Menke for the X_u l nu mixture: # # Up(4S) -> B0 B0bar +CC # # | | # # | -> X_u l- nu_bar (l = e or mu) # # | # # -> X # # # # # # Up(4S) -> B+ B- +CC # # | | # # | -> X_u l- nu_bar (l = e or mu) # # | # # -> X # # # # it uses the model VUB which is an O(alpha_s) triple differential decay rate # # for the B Meson to an inclusive X_u state and a lepton and neutrino. # # The model has the following parameters: # # 1) mb : the b-Quark mass. The authors of hep-ph/9905351 claim that # # a range of 4.65 GeV to 4.95 GeV is reasonable. # # 2) a : the Fermi Motion parameter. its default is 1.29 # # smaller values give broader distributions; larger values # # more narrow distributions for the fermi momentum. # # 3) alpha_s : the strong coupling constant at the b-Quark Mass. This is # # direct proportional to the amount of the built in radiative # # QCD corrections # # 4) N : the number of mass thresholds. This parameter should be at # # least 1 # # This mechanism allows to modify the Xu mass spectra in order# # to mix this inclusive model with exclusive models. # # For the purpose of a dedicated standalone inclusive run this# # parameter should be 1 # # Extra Feature: If the parameter is set to -N (minus N) # # the internal parameter q+/10000 is stored as the ctau # # value of the produced Xu. It can be reconstructed by # # multiplying the difference of the vertex times of any # # daughter of the Xu and the Xu by 10000 and reversing the # # boost which can be done by multiplying this number by # # m_Xu/E_Xu (the ratio of Xu mass over Xu energy in the lab). # # This cludge allows for easy reweighting of the Fermi-motion.# # 5) m0 : the lowest mass threshold (must be larger than 2*m_pi) # # 6) w0 : the relative weight for the bin ]m0,m1] if N > 1 or for the # # entire range ]m0,Infinity] if this is the last threshold # # 7 - 2N+3) odd : next mass threshold in ascending order. # # 8 - 2N+4) even: next relative weight # ############################################################################### # Create our own versions of B-, B+, B0, anti-B0 which will decay to Xu l nu # and specify that they should be treated as antiparticles # Alias myB- B- Alias myB+ B+ ChargeConj myB+ myB- # # the same for B0, B0bar # Alias myB0 B0 Alias myantiB0 anti-B0 ChargeConj myB0 myantiB0 # # Decay Upsilon(4S) 0.25000 B+ myB- VSS; 0.25000 B- myB+ VSS; 0.21000 B0 myantiB0 VSS_MIX dm; 0.21000 myB0 anti-B0 VSS_MIX dm; 0.04000 anti-B0 myantiB0 VSS_MIX dm; 0.04000 B0 myB0 VSS_MIX dm; Enddecay # # force all myB particles to always decay to Xu l nu # # Decay myantiB0 # b -> u l nu # .5 Xu+ e- anti-nu_e PHOTOS VUB 4.80 1.29 0.22 1 0.28 1; .5 Xu+ mu- anti-nu_mu VUB 4.80 1.29 0.22 1 0.28 1; # # use the following lines instead if you need access to the hidden # parameter q+ # # .5 Xu+ e- anti-nu_e PHOTOS VUB 4.80 1.29 0.22 -1 0.28 1; # .5 Xu+ mu- anti-nu_mu VUB 4.80 1.29 0.22 -1 0.28 1; Enddecay CDecay myB0 Decay myB+ # b -> u l nu # .5 Xu0 e+ nu_e PHOTOS VUB 4.80 1.29 0.22 1 0.28 1; .5 Xu0 mu+ nu_mu VUB 4.80 1.29 0.22 1 0.28 1; # # use the following lines instead if you need access to the hidden # parameter q+ # # .5 Xu0 e+ nu_e PHOTOS VUB 4.80 1.29 0.22 -1 0.28 1; # .5 Xu0 mu+ nu_mu VUB 4.80 1.29 0.22 -1 0.28 1; Enddecay CDecay myB- End