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61 lines
1.8 KiB
61 lines
1.8 KiB
!
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! SPDX-License-Identifier: GPL-3.0-or-later
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! Copyright (C) 2019-2022, respective authors of MCFM.
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!
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subroutine gg_hWWg_v(p,msq)
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implicit none
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include 'types.f'
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c----Author: R.K. Ellis May 2007
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c----Virtual corrections matrix element for H production
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c----in the heavy quark (mt=Infinity) limit.
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c----averaged over initial colours and spins
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c----f(p1)+f(p2) --> H(W^+(-->nu(p3)+e^+(p4)) +W^-(-->e^-(p5)+nu~(p6)))+g(p7)
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include 'constants.f'
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include 'nf.f'
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include 'mxpart.f'
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include 'masses.f'
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include 'ewcouple.f'
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include 'qcdcouple.f'
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include 'sprods_com.f'
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include 'scheme.f'
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c (Taken from Ravindran, Smith, van Neerven hep-ph/0201114)
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c Modified by overall factors
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integer:: iglue,j,k
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real(dp):: p(mxpart,4),msq(fn:nf,fn:nf),s3456
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real(dp):: ss,tt,uu,
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& virtgg,virtqa,virtaq,virtqg,virtgq,hdecay,Asq,fac
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parameter(iglue=7)
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scheme='tH-V'
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call dotem(iglue,p,s)
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ss=s(1,2)
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tt=s(1,iglue)
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uu=s(2,iglue)
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Asq=(as/(3._dp*pi))**2/vevsq
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c Deal with Higgs decay
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s3456=s(3,4)+s(3,5)+s(3,6)+s(4,5)+s(4,6)+s(5,6)
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hdecay=gwsq**3*wmass**2*s(3,5)*s(6,4)
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hdecay=hdecay/(((s3456-hmass**2)**2+(hmass*hwidth)**2)
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& *((s(3,4)-wmass**2)**2+(wmass*wwidth)**2)
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& *((s(5,6)-wmass**2)**2+(wmass*wwidth)**2))
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fac=ason2pi*Asq*gsq*hdecay
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call hjetfill(ss,tt,uu,virtgg,virtqa,virtaq,virtqg,virtgq)
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do j=-nf,nf
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do k=-nf,nf
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msq(j,k)=0._dp
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if ((j==0).and.(k==0)) msq(j,k)=avegg*fac*virtgg
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if ((j>0).and.(k==-j)) msq(j,k)=aveqq*fac*virtqa
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if ((j<0).and.(k==-j)) msq(j,k)=aveqq*fac*virtaq
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if ((j==0).and.(k /= 0)) msq(j,k)=aveqg*fac*virtgq
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if ((j /= 0).and.(k==0)) msq(j,k)=aveqg*fac*virtqg
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enddo
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enddo
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return
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end
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