1 Happy New Year! 2 3 Notes from User's Meeting 29.01.2014 4 ==================================== 5 6 Report on QCDNUM (Michiel Botje): 7 === 8 -> a beta release qcdnum-17-01-0c available on 9 www.nikhef.nl/user/h24/download 10 11 All the standard functionality is put back, except for the routine SETCUT (set kinematic cuts) 12 which is still disabled, you get an error message if you try to call it. The ZMSTF and 13 HQSTF packages work fine again. So it must be possible to use this version in the standard 14 HeraFitter package (except for cuts). 15 16 As for the nxn coupled DGLAP evolution, still missing is: 17 - backward evolution; 18 - the routine EVPDFXQ for fast interpolation of the pdfs on a x-Q2 table; 19 - the routine EVPCOPY for fast copying of pdfs into internal memory. 20 You will get an error message if you try any of these things. 21 22 A new release is expected by next User's meeting. 23 24 === 25 Report on HERAFitter Status (conveners) 26 === 27 -> stable release out (10.12.2013) 28 -> new results based on HERAFitter from LHC(ATLAS, CMS), independent users 29 -> New developments for next release: 30 o) Successful transition to LHAPDF v6 (covered also in V. Kolesnikov's talk) 31 o) More options for Drawing Tools available 32 o) Possibility to fit deuteron data 33 34 -> Perspectives: 35 o) implementations of QED+DGLAP (covered also in R. Sadykov's talk) 36 o) implementation of DifTOP for approximate NNLO differential cross sections 37 o) Heavy Flavour Schemes: FONLL, BMSN, ACOT 38 o) Other developments: 39 - independent Evolutions 40 - intrinsic charm 41 - EW codes 42 - minimisation codes 43 44 45 Discussions on CMS results for the alphas+gluon vs alphas only fit 46 -> is there a visible gain in precision to determine alphas from 47 a simultaneous fit? The answer is not clear, as gluon is 48 constrained by the HERA data, something worth investigating. 49 50 51 === 52 Report from QED piece implementation in HERAFitter (R. Sadykov) 53 === 54 55 -> Renat already has tested the stand-alone new version of QCDNUM 56 vs a previous version and the new code works. 57 -> Renat has defined a strategy and steps in implementing the 58 QED modified DGLAP evolution in HERAFitter. 59 60 o) Possible limitation with the minuit number of free parameters 61 (occupied currently by standard PDFs: 100 hardwired slots), however 62 a round about this could be the use of ExternalMinuitParameters option 63 (50 available, some already occupied) 64 o) Also needs to wait for readiness of QCDNUM in providing 65 copying of the PDFs to internal memory. 66 67 -> Perspective is to extend to NLO QED pieces 68 in DGLAP formalism. 69 70 71 === 72 Report on transition to LHAPDFv6 (V. Kolesnikov) 73 === 74 75 -> LHAPDFv6 was successfully interfaced into HERAFitter 76 o) validation performed on testing the INPUT files comparing 77 v5 vs v6 formats of LHAPDF and checking the outputs. 78 The transformation from v5 to v6 of PDF grid was performed 79 using LHAPDF script for that. Cteq nlo set has been used 80 for this validation. 81 -----> no coding was necessary for this part, LHAPDF 82 scripts are enough. 83 84 o) validation performed on testing the new OUTPUT format 85 86 -----> coding was required to produce outputs in the 87 YAML format needed for v6 of LHAPDF. 88 89 Also, it was noticed that there in in fact no need of using 90 external interpolation routine, one could just use 91 QCDNUM internal grids for that, now made it also 92 possible to control the number of grid points via steering card. 93 This procedure avoids double interpolation which could lead 94 to artificial behaviour. 95 96 Validation plots based on fits to HERA I data show good agreement 97 for the central fits. 98 99 100 101 Discussions on need for 6 flavour PDFs vs 5 flavour PDFs 102 -> there was a sort of inclination towards the use of 6 flavour 103 as default (including mt, which now could be possible with the new LHAPDF 104 interface for the grids..). 105 106 === 107 108 Next meeting will be settled via doodle (likely end of February).
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