!====================================================================== ! Consider the following possibility: want special types for ! set of LO splitting functions ! set of coefficient functions !---------------------------------------------------------------------- ! NB: compared to all normal splitting functions we have multiplied ! by x, to allow for integration measure. NB: this applies also ! to the plus functions, which do not care about integration measures? ! ! \int dx f(x)_+ g(x) = \int dy [exp(-y)f(exp(-y))]_+ g(exp(-y)) ! ! module splitting_functions use types; use consts_dp; use convolution_communicator use coefficient_functions; use qcd; use warnings_and_errors !! early estimate of splitting function based on fit to moments !!use splitting_functions_nnlo_n !! parametrization of exact splitting functions !!use splitting_functions_nnlo_p ! this one gives a set that depends on imod. use splitting_functions_nnlo implicit none private public :: sf_Pgg, sf_Pqq, sf_Pgq, sf_Pqg public :: sf_P1qqV, sf_P1gg, sf_P1qqbarV, sf_P1qqS, sf_P1qg, sf_P1gq public :: sf_P1qqBryan, sf_P1qgBryan, sf_P1minus public :: sf_P1fromg, sf_P1fromq public :: sf_P1qqV_DIS, sf_P1qg_DIS public :: sf_A2PShq, sf_A2PShg, sf_A2PShg_vogt public :: sf_A2NSqq_H, sf_A2Sgg_H, sf_A2Sgq_H public :: sf_P2gg, sf_P2qg2nf, sf_P2PS, sf_P2gq public :: sf_P2NSPlus, sf_P2NSMinus, sf_P2NSS public :: sf_DPqq, sf_DPqg, sf_DPgq, sf_DPgg public :: sf_DP1qqV, sf_DP1qqbarV, sf_DP1qqS public :: sf_DP1qg, sf_DP1gq, sf_DP1gg public :: sf_S2 ! for outside things that might need it !!$ ! these are of help elsewhere in identifying (run-time) the sets of !!$ ! splitting functions that have been used? !!$ public :: name_xpij2, name_xpns2 real(dp), parameter :: four_thirds = four/three contains !---------------------------------------------------------------------- function sf_Pgg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = two*ca*(x/(one-x) + (one-x)/x + x*(1-x)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - two*ca*one/(one-x) case(cc_DELTA) res = (11.0_dp*ca - four*nf*tr)/6.0_dp end select if (cc_piece /= cc_DELTA) res = res * x end function sf_Pgg !---------------------------------------------------------------------- function sf_Pqq(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = cf*(one+x**2)/(one-x) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - cf*two/(one-x) case(cc_DELTA) res = cf*three*half end select if (cc_piece /= cc_DELTA) res = res * x end function sf_Pqq !---------------------------------------------------------------------- function sf_Pgq(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = cf*(one + (one-x)**2)/x end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_Pgq !---------------------------------------------------------------------- function sf_Pqg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = tr*(x**2 + (one-x)**2) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_Pqg !====================================================================== ! From here onwards, the NLO splitting functions function sf_P1qqV(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, pqq x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = log(x); ln1mx = log(one - x) pqq = two/(one-x) - one - x !!$ res = cf**2*( -(two*lnx*ln1mx + 1.5_dp*lnx)*pqq& !!$ & -(1.5_dp + 3.5_dp*x)*lnx - half*(one+x)*lnx**2 - 5*(1-x))& !!$ & + cf*ca*( (half*lnx**2 + 11/6.0_dp * lnx& !!$ & + 67/18.0_dp - pi**2/6.0_dp) * pqq + (1+x)*lnx& !!$ & + 20/three*(1-x))& !!$ & + cf*tf*(-(two/three*lnx + 10/9.0_dp)*pqq - four/three*(1-x)) res= CF*Tf*((-1.1111111111111112_dp - (2*lnx)/3._dp)*pqq - & & (4*(1 - x))/3._dp) + & & CA*CF*((3.7222222222222223_dp + (11*lnx)/6._dp + lnx**2/2._dp -& & Pi**2/6._dp)*pqq + (20*(1 - x))/3._dp + lnx*(1 + x)) + & & CF**2*(((-3*lnx)/2._dp - 2*ln1mx*lnx)*pqq - 5*(1 - x) - & & (lnx**2*(1 + x))/2._dp - lnx*(1.5_dp + (7*x)/2._dp)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) pqq = -two/(1-x) res = res + CA*CF*(3.7222222222222223_dp - Pi**2/6._dp)*pqq - (10*CF& & *pqq*Tf)/9._dp case(cc_DELTA) res = -(CF*(0.16666666666666666_dp + (2*Pi**2)/9._dp)*Tf) + CA& & *CF*(0.7083333333333334_dp + (11*Pi**2)/18._dp - 3*zeta3) +& & CF**2*(0.375_dp - Pi**2/2._dp + 6*zeta3) end select if (cc_piece /= cc_DELTA) res = res * x end function sf_P1qqV !====================================================================== ! DIS version of the above. ! Currently the formulae are wrong. Use the complete formulae from ! module dglap_holders (where double convolutions are used to work them out). function sf_P1qqV_DIS(y) result(res) real(dp), intent(in) :: y real(dp) :: res write(0,*) 'sf_P1qqV_DIS: DIS scheme splitting functions & ¤tly not supported' stop res = sf_P1qqV(y) - cf_CqF2MSbar(y)*(11*CA - 2*nf)/6.0_dp end function sf_P1qqV_DIS !---------------------------------------------------------------------- function sf_P1gg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, pgg, S2x, pggmx x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = log(x); ln1mx = log(one - x) pgg = (one/(one-x) + one/x -two + x*(one-x)) pggmx = (one/(one+x) - one/x -two - x*(one+x)) S2x = sf_S2(x) res = CF*Tf*(-16 + 4/(3._dp*x) + 8*x + (20*x**2)/3._dp - lnx**2*(2& & + 2*x)- lnx*(6 + 10*x)) + CA*Tf*(2 - (20*pgg)/9._dp - 2*x -& & (4*lnx*(1 + x))/3._dp + (26*(-(1/x) + x**2))/9._dp) + CA**2& & *(pgg*(7.444444444444445_dp - 4*ln1mx*lnx + lnx**2 - Pi**2& & /3._dp) + 2*pggmx*S2x + (27*(1 - x))/2._dp + 4*lnx**2*(1 + x)& & + (67*(-(1/x) + x**2))/9._dp - lnx*(8.333333333333334_dp -& & (11*x)/3._dp + (44*x**2)/3._dp)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) pgg = -one/(1-x) res = res + CA**2*pgg*(7.444444444444445_dp - Pi**2/3._dp) - (20*CA& & *pgg*Tf)/9._dp case(cc_DELTA) res = (-4*CA*Tf)/3._dp - CF*Tf + CA**2*(2.6666666666666665_dp& & + 3*zeta3) end select if (cc_piece /= cc_DELTA) res = res * x end function sf_P1gg !---------------------------------------------------------------------- function sf_P1qqbarV(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, pqqmx, S2x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = log(x) pqqmx = two/(one+x) - one + x S2x = sf_S2(x) res = CF*(-CA/2._dp + CF)*(2*pqqmx*S2x + 4*(1 - x) + 2*lnx*(1 + x)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res + zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_P1qqbarV !---------------------------------------------------------------------- function sf_P1qqS(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = log(x); ln1mx = log(one - x) res = (CF*TR*(20 - 9*(2 - lnx + lnx**2)*x - 9*(-6 - 5*lnx + lnx& & **2)*x**2 + 8*(-7 + 3*lnx)*x**3))/(9._dp*x) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res + zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_P1qqS !---------------------------------------------------------------------- function sf_P1qg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, pqg, pqgmx, S2x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = log(x); ln1mx = log(one - x) pqg = x**2 + (one-x)**2 pqgmx = x**2 + (one+x)**2 S2x = sf_S2(x) res = CF*(half*TR)*(4 + 4*ln1mx + (10 - 4*(ln1mx - lnx) + 2*(-ln1mx& & + lnx)& & **2 - (2*Pi**2)/3._dp)* pqg - lnx*(1 - 4*x) - lnx**2*(1 - 2& & *x) - 9*x) + CA*(half*TR)*(20.22222222222222_dp - 4*ln1mx + (& & -24.22222222222222_dp + 4*ln1mx - 2*ln1mx**2 + (44*lnx)/3._dp& & - lnx**2 + Pi**2/3._dp)*pqg + 2*pqgmx*S2x + 40/(9._dp*x) +& & (14*x)/9._dp - lnx**2*(2 + 8*x) + lnx*(-12.666666666666666_dp& & + (136*x)/3._dp)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res + zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_P1qg !====================================================================== ! DIS version of the above function sf_P1qg_DIS(y) result(res) real(dp), intent(in) :: y real(dp) :: res write(0,*) 'sf_P1qg_DIS: DIS scheme splitting functions currently not supported' stop res = sf_P1qg(y) - cf_CgF2MSbar(y)*(11*CA - 2*nf)/6.0_dp end function sf_P1qg_DIS !---------------------------------------------------------------------- function sf_P1gq(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, pgq, pgqmx,S2x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = log(x); ln1mx = log(one - x) pgq = (one + (one-x)**2)/x pgqmx = -(one + (one+x)**2)/x S2x = sf_S2(x) res = CF*Tf*(-((2.2222222222222223_dp + (4*ln1mx)/3._dp)*pgq) - (4& & *x)/3._dp) + CF**2*(-2.5_dp - (3*ln1mx + ln1mx**2)*pgq - lnx& & **2*(1 - x/2._dp) - (7*x)/2._dp - 2*ln1mx*x + lnx*(2 + (7*x)& & /2._dp)) + CA*CF*(3.111111111111111_dp + pgq*(0.5_dp + (11& & *ln1mx)/3._dp + ln1mx**2 - 2*ln1mx*lnx + lnx**2/2._dp - Pi**2& & /6._dp) + pgqmx*S2x + (65*x)/18._dp + 2*ln1mx*x + (44*x**2)& & /9._dp + lnx**2*(4 + x) - lnx*(12 + 5*x + (8*x**2)/3._dp)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res + zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_P1gq !====================================================================== ! Alternative versions of the splitting functions, more similar ! to what is in the ESW book ! and some things for checking sum rules more easily function sf_P1qqBryan(y) result(res) real(dp), intent(in) :: y real(dp) :: res res = sf_P1qqV(y) + sf_P1qqbarV(y) + two*nf * sf_P1qqS(y) !res = sf_P1qqBryanTyped(y) end function sf_P1qqBryan function sf_P1qgBryan(y) result(res) real(dp), intent(in) :: y real(dp) :: res res = two*nf * sf_P1qg(y) end function sf_P1qgBryan function sf_P1minus(y) result(res) real(dp), intent(in) :: y real(dp) :: res res = sf_P1qqV(y) - sf_P1qqbarV(y) end function sf_P1minus function sf_P1fromq(y) result(res) real(dp), intent(in) :: y real(dp) :: res res = sf_P1qqBryan(y) + sf_P1gq(y) end function sf_P1fromq function sf_P1fromg(y) result(res) real(dp), intent(in) :: y real(dp) :: res res = sf_P1gg(y) + sf_P1qgBryan(y) end function sf_P1fromg !---------------------------------------------------------------------- ! Following was useful for debugging purposes... function sf_P1qqBryanTyped(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, pqq, pqqmx, S2x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = log(x); ln1mx = log(one - x) pqq = two/(one-x) - one - x pqqmx = two/(one+x) - one + x S2x = sf_S2(x) res = CA*CF*((3.7222222222222223_dp + (11*lnx)/6._dp + lnx**2/2._dp& & - Pi**2/6._dp)*pqq - pqqmx*S2x + (14*(1 - x))/3._dp) +& & CF**2*(-1 - ((3*lnx)/2._dp + 2*ln1mx*lnx)*pqq + 2*pqqmx*S2x + & & lnx*(0.5_dp - (3*x)/2._dp) + x - (lnx**2*(1 + x))/2._dp) +& & CF*Tf*(-5.333333333333333_dp - & & (1.1111111111111112_dp + (2*lnx)/3._dp)*pqq + 40/(9._dp*x) +& & (40*x)/3._dp - (112*x**2)/9._dp - 2*lnx**2*(1 + x) +& & lnx*(2 + 10*x + (16*x**2)/3._dp)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) pqq = -two/(1-x) res = res + CA*CF*(3.7222222222222223_dp - Pi**2/6._dp)*pqq - (10*CF& & *pqq*Tf)/9._dp case(cc_DELTA) res = -(CF*(0.16666666666666666_dp + (2*Pi**2)/9._dp)*Tf) + CA& & *CF*(0.7083333333333334_dp + (11*Pi**2)/18._dp - 3*zeta3) +& & CF**2*(0.375_dp - Pi**2/2._dp + 6*zeta3) end select if (cc_piece /= cc_DELTA) res = res * x end function sf_P1qqBryanTyped !====================================================================== ! helper... function sf_S2(x) result(S2) use special_functions real(dp), intent(in) :: x real(dp) :: S2, lnx lnx = log(x) S2 = -two*ddilog(-x) + half * lnx**2 - two*lnx*log(one+x) - pi**2& & /6.0_dp end function sf_S2 !====================================================================== ! What follows is stuff for VFNS. ! It has been hacked in one way or another from the code provided ! by W.L. van Neerven (~/src/HEP/vannerven-vfns.f), and appropriate ! citations are ! ! M. Buza, Y. Matiounine, J. Smith, R. Migneron, W.L. van Neerven, ! Nucl. Phys. B472 (1996) 611, hep-ph/9601302. ! M. Buza, Y. Matiounine, J. Smith, W.L. van Neerven, ! Eur. Phys. J. C1 (1998) 301. ! ! Pieces that are going to be needed for my purposes are those from that ! code which are free of logs of mu^2/m^2, since we will for the time being ! keep these two scales equal (and later on, if we do not then pieces ! with logs will be reconstructed appropriately?) ! ! Thus the pieces needed, in the notation of the second of the above ! papers, are: ! ! For Delta (f_k + f_kbar): ! A^{2,NS}_{qq,H} CODED ! A^{2,PS}_{qq,H} <-- this is zero at O(as^2) ! A^{2,S}_{qg,H} <-- this is zero at O(as^2) ! ! For Delta (f_H + f_Hbar) ! A^{2,PS}_{Hq} CODED ! A^{2,S}_{Hg} CODED ! ! For Delta (G) ! A^{2,S}_{gq,H} CODED ! A^{2,S}_{gg,H} CODED ! ! NB: currently using cernlib version of WGPLG. This should be hacked ! out of CERNLIB and inserted explicitly into special functions. !---------------------------------------------------------------------- !---------------------------------------------------------------------- ! This one hacked out of vanneerven-vfns.f90 function sf_A2Sgq_H(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: z real(dp) :: ln1mz z = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) ln1mz = log(one - z) res = (four*(two/z-two+z)*ln1mz**2/3.0_dp+8.0_dp*(10.0_dp/z & &-10.0_dp+8.0_dp*z)*ln1mz/9.0_dp+(448.0_dp/z-448.0_dp+344.0_dp*z)& &/27.0_dp)*cf*tr end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res + zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * z !-- recall that above results are for (as/4pi)^2, whereas ! we actually use (as/2pi)^2 res = res * 0.25_dp end function sf_A2Sgq_H !----------------------------------------------------------------- ! This one typed in by hand from article function sf_A2Sgg_H(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: z real(dp) :: lnz, lnz2, lnz3,ln1mz z = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnz = log(z); lnz2 = lnz*lnz; lnz3 = lnz2*lnz ln1mz = log(one - z) res = CF*TR*(four_thirds*(1+z)*lnz3+(6+10*z)*lnz2+(32+48*z)*lnz& &-8/z+80-48*z-24*z**2) + & &CA*TR*((four_thirds*(1+z)*lnz2+(52+88*z)*lnz/9.0_dp& & -four_thirds*z*ln1mz)& & + (224/(1-z)+556/z-628+548*z-700*z**2)/27.0_dp ) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - CA*TR*224.0_dp/(27.0_dp*(1-z)) case(cc_DELTA) res = -15*CF*TR + CA*TR*10.0_dp/9.0_dp end select if (cc_piece /= cc_DELTA) res = res * z !-- recall that above results are for (as/4pi)^2, whereas ! we actually use (as/2pi)^2 res = res * 0.25_dp end function sf_A2Sgg_H !----------------------------------------------------------------- ! This one partially hacked out of vanneerven-vfns.f90 function sf_A2NSqq_H(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: z real(dp) :: lnz, lnz2, ln1mz z = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnz = log(z); lnz2 = lnz*lnz ln1mz = log(one - z) res = ((one+Z*Z)*(2.0D0*lnz2/3.0D0+20.0D0*lnz/9.0D0)& &/(one-Z)+8.0D0*(one-Z)*lnz/3.0D0+44.0D0/27.0D0 & &-268.0D0*Z/27.0D0 + 224.0_dp/(27.0_dp*(1-z)) )*CF*TR end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - (224.0_dp/(27.0_dp*(1-z)) )*CF*TR case(cc_DELTA) res = CF*TR*(-8*zeta3/3.0_dp + 40.0_dp*zeta2/9.0_dp+73.0_dp/18.0_dp) end select if (cc_piece /= cc_DELTA) res = res * z !-- recall that above results are for (as/4pi)^2, whereas ! we actually use (as/2pi)^2 res = res * 0.25_dp end function sf_A2NSqq_H !----------------------------------------------------------------- ! This one largely hacked out of vanneerven-vfns.f90 function sf_A2PShg(y) result(res) use special_functions real(dp), intent(in) :: y real(dp) :: res real(dp) :: z real(dp) :: lnz, lnz2, lnz3, ln1mz, ln1mz2, ln1mz3 real(dp) :: ln1pz, ln1pz2 real(dp) :: S121MZ, S12MZ,S211MZ,S21MZ,S111MZ,S11MZ real(dp) :: A01, A02, B01, B02 !complex(dp) :: WGPLG z = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) ! these will need to be sorted out properly S121MZ=WGPLG(1,2,1.0D0-Z) S12MZ=WGPLG(1,2,-Z) S211MZ=WGPLG(2,1,1.0D0-Z) S21MZ=WGPLG(2,1,-Z) S111MZ=WGPLG(1,1,1.0D0-Z) S11MZ=WGPLG(1,1,-Z) lnz = log(z); lnz2 = lnz*lnz; lnz3 = lnz2*lnz ln1mz = log(one - z) ln1mz2=ln1mz*ln1mz ln1mz3=ln1mz2*ln1mz ln1pz=log(1.0d0+z) ln1pz2=ln1pz*ln1pz ! C_F.T_r PART A01=(1-2._dp*z+2._dp*z*z)*(8._dp*zeta3+4._dp*ln1mz3/3._dp & &-8._dp*ln1mz*s111mz+8._dp*zeta2*lnz-4._dp*lnz*ln1mz2+2._dp*lnz3 & &/3._dp-8._dp*lnz*s111mz+8._dp*s211mz-24._dp*s121mz) A02=-(4._dp+96._dp*z-64._dp*z*z)*s111mz-(4._dp-48._dp*z & &+40._dp*z*z)*zeta2-(8._dp+48._dp*z-24._dp*z*z)*lnz*ln1mz & &+(4._dp+8._dp*z-12._dp*z*z)*ln1mz2-(1._dp+12._dp*z-20._dp*z*z) & &*lnz2-(52._dp*z-48._dp*z*z)*ln1mz-(16._dp+18._dp*z+48._dp*z*z) & &*lnz+26._dp-82._dp*z+80._dp*z*z+z*z*(-16._dp*zeta2*lnz & &+4._dp*lnz3/3._dp+ 16._dp*lnz*s111mz+ 32._dp*s121mz) ! c_a.t_r part B01=(1._dp-2._dp*z+2._dp*z*z)*(-4._dp*ln1mz3/3._dp+8._dp*ln1mz & &*s111mz-8._dp*s211mz)+(1._dp+2._dp*z+2._dp*z*z)*(-8._dp*zeta2 & &*ln1pz-16._dp*ln1pz*s11mz-8._dp*lnz*ln1pz2+& &4._dp*lnz2*ln1pz+8._dp*lnz & &*s11mz-8._dp*s21mz-16._dp*s12mz)+(16._dp+64._dp*z)*(2._dp*s121mz & &+lnz*s111mz)-(4._dp+8._dp*z)*lnz3/3._dp+(8._dp-32._dp*z & &+16._dp*z*z)*zeta3-(16._dp+64._dp*z)*zeta2*lnz B02=(16._dp*z+16._dp*z*z)*(s11mz+lnz*ln1pz)+(32._dp/z/3._dp+12._dp & &+64._dp*z-272._dp*z*z/3._dp)*s111mz-(12._dp+48._dp*z & &-260._dp*z*z/3._dp+32._dp/z/3._dp)*zeta2-4._dp*z*z*lnz*ln1mz & &-(2._dp+8._dp*z-10._dp*z*z)*ln1mz2+& &(2._dp+8._dp*z+46._dp*z*z/3._dp)& &*lnz2+(4._dp+16._dp*z-16._dp*z*z)*ln1mz-(56._dp/3._dp+172._dp*z & &/3._dp+1600._dp*z*z/9._dp)*lnz-448._dp/z/27._dp-4._dp/3._dp & &-628._dp*z/3._dp+6352._dp*z*z/27._dp res = TR*(CF*(A01+A02) + CA*(B01+B02)) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * z !-- recall that above results are for (as/4pi)^2, whereas ! we actually use (as/2pi)^2 res = res * 0.25_dp end function sf_A2PShg !----------------------------------------------------------------- ! This one will use Vogts parameterisation function sf_A2PShg_vogt(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: z real(dp) :: A2HGA, A2HGC z = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = A2HGA(z) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res case(cc_DELTA) res = A2HGC(zero) end select if (cc_piece /= cc_DELTA) res = res * z !-- recall that above results are for (as/4pi)^2, whereas ! we actually use (as/2pi)^2 res = res * 0.25_dp end function sf_A2PShg_vogt !----------------------------------------------------------------- ! This one largely hacked out of vanneerven-vfns.f90 function sf_A2PShq(y) result(res) use special_functions real(dp), intent(in) :: y real(dp) :: res real(dp) :: z real(dp) :: lnz, lnz2, lnz3 real(dp) :: S121MZ, S111MZ real(dp) :: A0 !complex(dp) :: WGPLG z = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) ! these will need to be sorted out properly S121MZ=WGPLG(1,2,1.0D0-Z) S111MZ=WGPLG(1,1,1.0D0-Z) lnz = log(z); lnz2 = lnz*lnz; lnz3 = lnz2*lnz ! C_F.T_r PART A0=(1._dp+Z)*(32._dp*S121MZ+16._dp*lnz*S111MZ-16._dp*ZETA2 & &*lnz-4._dp*lnz3/3._dp)+(32._dp/Z/3._dp+8._dp-8._dp*Z-32._dp & &*Z*Z/3._dp)*S111MZ+(-32._dp/Z/3._dp-8._dp+8._dp*Z & &+32._dp*Z*Z/3._dp)*ZETA2+(2._dp+10._dp*Z+16._dp*Z*Z/3._dp) & &*lnz2-(56._dp/3._dp+88._dp*Z/3._dp+448._dp*Z*Z/9._dp)*lnz & &-448._dp/Z/27._dp-4._dp/3._dp-124._dp*Z/3._dp+1600._dp*Z*Z & &/27._dp res = TR*CF*A0 end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * z !-- recall that above results are for (as/4pi)^2, whereas ! we actually use (as/2pi)^2 res = res * 0.25_dp end function sf_A2PShq !====================================================================== ! polarized splitting functions... !====================================================================== ! LO: from ESW. ! Original reference: Altarelli & Parisi NPB126 (1977) 298 !---------------------------------------------------------------------- function sf_DPgg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = ca*(two/(one-x) - four*x + two) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - two*ca/(one-x) case(cc_DELTA) res = (11.0_dp*ca - four*nf*tr)/6.0_dp end select if (cc_piece /= cc_DELTA) res = res * x end function sf_DPgg !---------------------------------------------------------------------- function sf_DPqq(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = cf*(two/(1-x) - 1 - x) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - cf*two/(one-x) case(cc_DELTA) res = cf*three*half end select if (cc_piece /= cc_DELTA) res = res * x end function sf_DPqq !---------------------------------------------------------------------- function sf_DPgq(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = cf*(two-x) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_DPgq !---------------------------------------------------------------------- function sf_DPqg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) res = tr*(two*x - one) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res - zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_DPqg !====================================================================== ! NLO spin-dependent splitting functions ! THE CALCULATION OF THE TWO LOOP SPIN SPLITTING FUNCTIONS P(IJ)(1)(X). ! By R. Mertig (NIKHEF, Amsterdam), W.L. van Neerven (Leiden U.),. ! INLO-PUB-6-95, NIKHEF-H-95-031, Jun 1995. 33pp. ! Published in Z.Phys.C70:637-654,1996 ! e-Print Archive: hep-ph/9506451 ! The spin dependent two loop splitting functions ! W. Vogelsang (Rutherford),. RAL-TR-96-020, Mar 1996. 25pp. ! Published in Nucl.Phys.B475:47-72,1996 ! e-Print Archive: hep-ph/9603366 ! Will use the Vogelsang paper for input. His convention coincides ! with the one used above with regards to alphas/two and derivative ! wrt ln Q^2. However it differs in use of nf factors. Will stay ! consistent with the unpolarized case (i.e. not include 2nf factors). ! ! Tests carried out (NLL): comparison to omega=0 (N=1) momenta, eqs.54. ! All work out (after fixing a line in wrong place), though since Pqg->0 ! one cannot check normalisation of this one... ! ! He also provides coefficient functions, should one ! wish to implement them... !-------------------------------------------------- ! identical to P1qqV function sf_DP1qqV(y) result(res) real(dp), intent(in) :: y real(dp) :: res res = sf_P1qqV(y) end function sf_DP1qqV !-------------------------------------------------- ! identical to -P1qqbarV function sf_DP1qqbarV(y) result(res) real(dp), intent(in) :: y real(dp) :: res res = -sf_P1qqbarV(y) end function sf_DP1qqbarV !---------------------------------------------------------------------- ! REMEMBER: 2nf factor NOT included! function sf_DP1qqS(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = -y res = two*CF*TR*((1-x) - (1-3*x)*lnx - (1+x)*lnx**2) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) case(cc_DELTA) res = zero end select res = res * half ! Tf->TR accounts for nf; this accounts for 2 if (cc_piece /= cc_DELTA) res = res * x end function sf_DP1qqS !---------------------------------------------------------------------- ! REMEMBER: 2nf factor NOT included! function sf_DP1qg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, dpqg, dpqgmx, S2x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = -y; ln1mx = log(one - x) dpqg = two*x - one dpqgmx = -two*x - one S2x = sf_S2(x) res = CF*TR*(-22 + 27*x - 9*lnx + 8*(1-x)*ln1mx& & + dpqg*(2*ln1mx**2 - 4*ln1mx*lnx & & + lnx**2 - two/three*pisq))& & + CA*TR*((24-22*x) - 8*(1-x)*ln1mx + (2+16*x)*lnx & & - 2*(ln1mx**2-pisq/6.0_dp)*dpqg & & - (2*S2x - 3*lnx**2) * dpqgmx) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res + zero case(cc_DELTA) res = zero end select res = res * half ! Tf->TR accounts for nf; this accounts for 2 if (cc_piece /= cc_DELTA) res = res * x end function sf_DP1qg !---------------------------------------------------------------------- function sf_DP1gq(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, dpgq, dpgqmx,S2x x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = -y; ln1mx = log(one - x) dpgq = 2 - x dpgqmx = 2 + x S2x = sf_S2(x) res = CF*Tf*(-four/9.0_dp*(x+4) - four/three*dpgq*ln1mx)& &+ CF**2*(-half - half*(4-x)*lnx - dpgqmx*ln1mx& & + (-4 - ln1mx**2 + half*lnx**2)*dpgq)& &+ CF*CA*((4-13*x)*lnx + (10+x)*ln1mx/three + (41+35*x)/9.0_dp& & + half*(-2*S2x + 3*lnx**2)*dpgqmx & & + (ln1mx**2 - 2*ln1mx*lnx - pisq/6.0_dp)*dpgq) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) res = res + zero case(cc_DELTA) res = zero end select if (cc_piece /= cc_DELTA) res = res * x end function sf_DP1gq !---------------------------------------------------------------------- ! Vogelsang says (p.10) that delta-function parts are just those ! of function sf_DP1gg(y) result(res) real(dp), intent(in) :: y real(dp) :: res real(dp) :: x real(dp) :: lnx, ln1mx, S2x, dpgg, dpggmx x = exp(-y) res = zero select case(cc_piece) case(cc_REAL,cc_REALVIRT) lnx = -y; ln1mx = log(one - x) dpgg = one/(1-x) - 2*x + 1 dpggmx = one/(1+x) + 2*x + 1 S2x = sf_S2(x) res = -CA*Tf*(4*(1-x) + four/three*(1+x)*lnx + 20.0_dp/9.0_dp*dpgg)& &-CF*Tf*(10*(1-x) + 2*(5-x)*lnx + 2*(1+x)*lnx**2)& &+CA**2*((29-67*x)*lnx/three - 9.5_dp*(1-x) + 4*(1+x)*lnx**2& & - 2*S2x*dpggmx + (67.0_dp/9.0_dp - 4*ln1mx*lnx & & + lnx**2 - Pi**2/3._dp)*dpgg) end select select case(cc_piece) case(cc_VIRT,cc_REALVIRT) dpgg = -one/(1-x) res = res + CA**2*dpgg*(67.0_dp/9.0_dp - Pi**2/3._dp) - (20*CA& & *dpgg*Tf)/9._dp case(cc_DELTA) res = (-4*CA*Tf)/3._dp - CF*Tf + CA**2*(8.0_dp/three& & + 3*zeta3) end select if (cc_piece /= cc_DELTA) res = res * x end function sf_DP1gg end module splitting_functions