DIS: IC FONLL-A q Matching for NC FL

[felixhekhorn]

• we believe the NLO IC contributions to FL for FONLL (massive-zero coefficient) is not correctly normalized
  

  apfel/src/DIS/IncludeIntrinsicCharm.f

  Lines 143 to 146 in fdfd068

  	CLRS = CLRS - 4d0 * ( 1d0 - eta ) / ( 2d0 - eta )
  	1 * nsDIC
  	CLL = CLL - 4d0 * ( 1d0 - eta ) / ( 2d0 - eta )
  	1 * DICc(xi,c)

• these lines should contain an additional division by factL as is present for the gluon:
  

  apfel/src/DIS/IncludeIntrinsicCharm.f

  Lines 132 to 134 in fdfd068

  	SCLmNC(igrid,ixi,1,0,beta,alpha) =
  	1 - 4d0 * ( 1d0 - eta ) / ( 2d0 - eta ) / factL
  	2 * lnF * gDIC

• this is just the LO as prefactor
  

  apfel/src/DIS/IncludeIntrinsicCharm.f

  Lines 93 to 94 in fdfd068

  	SCLmNC(igrid,ixi,3,0,beta,alpha) = 4d0 * ( 1d0 - eta )
  	1 / ( 2d0 - eta ) / factL * fL

Benchmarking to yadism with the error fixed gives:

Log added, hash=3594cca65cabea4b2cec85345986c0fb978b9fedaf5b2dd69ff53368680a9301
 ────────── 
  F2_charm  
 ────────── 
           x         Q2    yadism  yadism_error     APFEL  percent_error
0   0.000100  20.000000  0.000132 -1.629179e-13  0.000132       0.183309
1   0.000278  20.000000  0.000316  1.282237e-12  0.000315       0.112155
2   0.000774  20.000000  0.000749 -5.303289e-12  0.000749       0.020648
3   0.002154  20.000000  0.001766 -5.497683e-12  0.001766       0.008649
4   0.005995  20.000000  0.004159 -2.203334e-11  0.004160      -0.028787
5   0.016681  20.000000  0.009780 -4.266334e-11  0.009806      -0.257337
6   0.046416  20.000000  0.022883 -1.142255e-10  0.023073      -0.824161
7   0.129155  20.000000  0.051691 -6.739887e-11  0.052715      -1.942159
8   0.359381  20.000000  0.095410 -1.148124e-09  0.105458      -9.527575
9   1.000000  20.000000  0.000000  0.000000e+00  0.000000            NaN
10  0.000100   2.280100  0.000190 -5.409928e-13  0.000190      -0.070432
11  0.000278   2.280100  0.000454 -1.627653e-12  0.000454      -0.045346
12  0.000774   2.280100  0.001075 -8.679910e-13  0.001076      -0.130771
13  0.002154   2.280100  0.002523 -8.150368e-12  0.002525      -0.107948
14  0.005995   2.280100  0.005879 -4.668564e-11  0.005880      -0.017036
15  0.016681   2.280100  0.013619 -3.032851e-11  0.013582       0.272896
16  0.046416   2.280100  0.031256 -9.510437e-11  0.030975       0.906939
17  0.129155   2.280100  0.069233 -2.617881e-10  0.067295       2.880376
18  0.359381   2.280100  0.115947 -1.927640e-09  0.116128      -0.155885
19  1.000000   2.280100  0.000000  0.000000e+00  0.000000            NaN
20  0.100000   4.000000  0.059420  1.094726e-10  0.059094       0.550973
21  0.100000   4.783253  0.056225 -3.421848e-10  0.056151       0.131524
22  0.100000   5.719877  0.053445 -3.893411e-10  0.053563      -0.220346
23  0.100000   6.839904  0.051039 -4.499993e-10  0.051319      -0.544447
24  0.100000   8.179247  0.048972 -2.546579e-10  0.049383      -0.831340
25  0.100000   9.780851  0.047206 -2.433610e-10  0.047706      -1.048973
26  0.100000  11.696071  0.045706 -2.289117e-10  0.046287      -1.255947
27  0.100000  13.986316  0.044438 -2.061357e-10  0.045081      -1.425556
28  0.100000  16.725021  0.043373 -1.307333e-10  0.044064      -1.569260
29  0.100000  20.000000  0.042481 -4.404693e-10  0.043211      -1.688722
30  0.001000   4.000000  0.001330 -1.039740e-11  0.001330       0.022644
31  0.001000   4.783253  0.001251  2.227644e-12  0.001250       0.083949
32  0.001000   5.719877  0.001184 -1.421386e-12  0.001183       0.087022
33  0.001000   6.839904  0.001128 -1.325243e-12  0.001126       0.134046
34  0.001000   8.179247  0.001080 -2.238019e-12  0.001078       0.133931
35  0.001000   9.780851  0.001039 -3.464261e-12  0.001036       0.270599
36  0.001000  11.696071  0.001005 -2.260645e-12  0.001005      -0.024660
37  0.001000  13.986316  0.000975 -3.595089e-12  0.000977      -0.168079
38  0.001000  16.725021  0.000950 -3.651491e-12  0.000949       0.080485
39  0.001000  20.000000  0.000928 -2.905575e-12  0.000927       0.078009
 ────────── 
  FL_charm  
 ────────── 
           x         Q2    yadism  yadism_error     APFEL  percent_error
0   0.000100  20.000000  0.000005 -5.098901e-14  0.000005      -0.230613
1   0.000278  20.000000  0.000017  2.898225e-13  0.000017      -0.450185
2   0.000774  20.000000  0.000055 -1.642976e-12  0.000056      -0.444158
3   0.002154  20.000000  0.000174 -1.713579e-12  0.000174      -0.395645
4   0.005995  20.000000  0.000534 -6.902627e-12  0.000537      -0.479797
5   0.016681  20.000000  0.001609 -1.336231e-11  0.001620      -0.701185
6   0.046416  20.000000  0.004668 -3.577503e-11  0.004740      -1.517500
7   0.129155  20.000000  0.012471 -2.107481e-11  0.012829      -2.787246
8   0.359381  20.000000  0.025555 -3.595873e-10  0.028757     -11.135603
9   1.000000  20.000000  0.000000  0.000000e+00  0.000000            NaN
10  0.000100   2.280100  0.000075 -4.328476e-13  0.000075      -0.302434
11  0.000278   2.280100  0.000196 -1.302162e-12  0.000197      -0.229494
12  0.000774   2.280100  0.000510 -6.883614e-13  0.000511      -0.278590
13  0.002154   2.280100  0.001318 -6.521384e-12  0.001321      -0.231433
14  0.005995   2.280100  0.003384 -3.734854e-11  0.003385      -0.035319
15  0.016681   2.280100  0.008610 -2.426286e-11  0.008579       0.364472
16  0.046416   2.280100  0.021500 -7.608356e-11  0.021281       1.028513
17  0.129155   2.280100  0.050964 -2.094306e-10  0.049420       3.124914
18  0.359381   2.280100  0.089296 -1.542112e-09  0.089411      -0.128247
19  1.000000   2.280100  0.000000  0.000000e+00  0.000000            NaN
20  0.100000   4.000000  0.035471  6.754984e-11  0.035258       0.602447
21  0.100000   4.783253  0.031047 -2.244614e-10  0.031010       0.119739
22  0.100000   5.719877  0.027081 -2.392777e-10  0.027160      -0.289815
23  0.100000   6.839904  0.023550 -2.571488e-10  0.023704      -0.653177
24  0.100000   8.179247  0.020424 -1.342561e-10  0.020645      -1.068999
25  0.100000   9.780851  0.017678 -1.174287e-10  0.017936      -1.437156
26  0.100000  11.696071  0.015280 -1.002940e-10  0.015556      -1.770667
27  0.100000  13.986316  0.013202 -8.136334e-11  0.013479      -2.053995
28  0.100000  16.725021  0.011412 -4.613363e-11  0.011680      -2.291399
29  0.100000  20.000000  0.009881 -1.379583e-10  0.010132      -2.475503
30  0.001000   4.000000  0.000453 -7.227605e-12  0.000453      -0.018019
31  0.001000   4.783253  0.000373  8.304087e-13  0.000373       0.035504
32  0.001000   5.719877  0.000305 -8.726530e-13  0.000305       0.196615
33  0.001000   6.839904  0.000249 -7.211695e-13  0.000249       0.301937
34  0.001000   8.179247  0.000203 -1.179184e-12  0.000203       0.169805
35  0.001000   9.780851  0.000165 -1.671592e-12  0.000165       0.028966
36  0.001000  11.696071  0.000134 -9.904684e-13  0.000134      -0.084462
37  0.001000  13.986316  0.000109 -1.419030e-12  0.000110      -0.148850
38  0.001000  16.725021  0.000090 -1.288593e-12  0.000090      -0.254437
39  0.001000  20.000000  0.000074 -9.100151e-13  0.000074      -0.271499