***********************************************************************

             FONLL            version 1.3.3 (April 2014)

 Program to calculate heavy quark transverse momentum and
 rapidity distributions in hadron-hadron and photon-hadron
 collisions, matching Fixed Order next-to-leading order terms
 and Next-to-Leading-Log large-p_T resummation.

 by Matteo Cacciari, Stefano Frixione, Paolo Nason

 Citation for this work:
		 
1)  M. Cacciari, M. Greco and P. Nason,
       "The p_T Spectrum in Heavy Flavor Hadroproduction",
       JHEP 9805 (1998) 007 [hep-ph/9803400]
2)  M. Cacciari, S. Frixione and P. Nason,
       "The p_T Spectrum in Heavy Flavor Photoproduction",
       JHEP 0103 (2001) 006 [hep-ph/0102134]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%\cite{Cacciari:1998it}
\bibitem{Cacciari:1998it}
M.~Cacciari, M.~Greco and P.~Nason,
%``The p(T) spectrum in heavy-flavour hadroproduction,''
JHEP {\bf 9805} (1998) 007
[arXiv:hep-ph/9803400].
%%CITATION = HEP-PH 9803400;%%
%\cite{Cacciari:2001td}
\bibitem{Cacciari:2001td}
M.~Cacciari, S.~Frixione and P.~Nason,
%``The p(T) spectrum in heavy-flavor photoproduction,''
JHEP {\bf 0103} (2001) 006
[arXiv:hep-ph/0102134].
%%CITATION = HEP-PH 0102134;%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				 

  Built upon the following papers/codes:
			 
  S. Frixione and P. Nason,
       "Phenomenological study of charm photoproduction at HERA",
       JHEP 0203 (2002) 053 [hep-ph/0201281]
  M. Cacciari, S. Frixione and P. Nason,
       "The p_T Spectrum in Heavy Flavor Photoproduction",
       JHEP 0103 (2001) 006 [hep-ph/0102134]
  M. Cacciari, M. Greco and P. Nason,
       "The p_T Spectrum in Heavy Flavor Hadroproduction",
       JHEP 9805 (1998) 007 [hep-ph/9803400]
  M. Cacciari and M. Greco,
       "Charm Photoproduction via Fragmentation",
       Z.Phys. C69 (1996) 459 [hep-ph/9505419] 
  M. Cacciari and M. Greco,			 
       "Large p_T Hadroproduction of Heavy Quarks",
       Nucl.Phys. B421 (1994) 530 [hep-ph/9311260]
  B. Mele and P. Nason, 
       "The Fragmentation Function for Heavy Quarks in QCD",
       Nucl.Phys. B361 (1991) 626
  P. Nason, S. Dawson and R.K. Ellis,
       "The One-Particle Inclusive Differential Cross-Section
	for Heavy Quark Production in Hadronic Collisions",
       Nucl.Phys. B327 (1989) 49
  F. Aversa, P. Chiappetta, M. Greco and J.-Ph. Guillet,
       "QCD Corrections to Parton-Parton Scattering Processes",
       Nucl.Phys. B327 (1989) 105
  R.K. Ellis and P. Nason,
       "QCD Radiative Corrections to the Photoproduction
	of Heavy Quarks",
       Nucl.Phys. B312 (1989) 551
  P. Aurenche, R. Baier, A. Douiri, M. Fontannaz and D. Schiff,
       "Scheme Invariant Higher Order QCD Predictions for
	Large p_T Photoproduction Reactions",
       Nucl.Phys. B286 (1987) 553

**********************************************************************

The installation instructions are given in the file INSTALL. See that
file also for instructions about running a test of the installed code.

The FONLL code produces a SINGLE point of the double-differential cross
section dsigma/dpT^2/dy, and outputs it (in picobarn) in a file .out
with format pt,y,dsigma

A file .outlog is created  containing all the relevant inputs of a run,
and the various components of the final result. All the results of runs
made with the same name tag are appended to this file.

If integrated cross sections are needed, it is up to the user to collect
these differential results and to integrate them.

A grid can be produced either by running the whole code several times,
or by building a Fortran code which loops over the subroutine fonll0
(see the file FONLL/main/fonll0.f, and how it is called from
FONLL/main/fonll.f, which is the main program of the FONLL code).

When run, the program describes the inputs it expects. Sample input files
are as follows:

1) bottom production at the Tevatron (run 2) using the hvqpdfpho.f 
   library (cteq6m in this case):
**********************************************************************
b-Tevatron        ! tag for output files
  1  980. 0 0 131 ! beam1: type, ener.,  nptype, ngroup, nset
 -1  980. 0 0 131 ! beam2: type, ener.,  nptype, ngroup, nset
  5               ! heavy quark mass
  -1              ! Lambda_5, <=0 for default
  1   1           ! ren. and fact. scale factors
  30. 0.          ! pt,y_lab
  1               ! icalctype
**********************************************************************
This should return the file b-Tevatron.out containing three numbers
per line: pt, y and dsigma/dpT^2/dy (in picobarn)

In b-Tevatron.outlog a move verbose output is written,
reporting all input parameters and several partial results:
hdmv=hadronic massive O(as^3) result (FO in ref.1, FO_{hdr} in ref. 2)
hdml=as above, without mass terms (FOM0 in ref.1, FOM0_{hdr} in ref. 2)
phmv=in case of photoproduction or electroproduction, O(as^2 aem) cross section
     (FO_{pnt} in ref. 2).
phml=as above, without mass terms (FOM0_{pnt} in ref. 2).
hdrs=hadroproduction resummed result (RS in ref.1, RS_{hdr} in ref. 2)
phrs=pointlike photon resummed result (RS_{pnt} in ref.2)

In the case of hadroproduction, the photonic components of the cross
section are reported to be zero.

2) charm electroproduction at HERA (H1 ETAG33 setup):
**********************************************************************
c-HERA          ! tag for output files
 1  920. 0 0 81 ! beam1: type, ener.,  nptype, ngroup, nset
 5  27.5 0 0 42 ! beam2: type, ener.,  nptype, ngroup, nset
  1.5           ! heavy quark mass
  -1            ! Lambda_5, <=0 for default
  1    1        ! ren. and fact. scale factors
  10. 1.        ! pt,y_lab
 1              ! icalctype
 1              ! WW type  
.1              ! max. sqrt(Q^2) (GeV)
.29  .62        ! zmin and zmax in the WW integration
**********************************************************************
Note the choice of a PHOTON PDF set (AFG in this case) for doing
electroproduction. The FONLL code handles the convolution with the
Weizsaecker-Williams function.
Results will be in c-HERA.out and c-HERA.outlog


The program incorporates three different interfaces to Parton 
Distribution Function libraries, which can be selected by
building the proper executable:

- A proprietary one is given by the file hvqpdfpho.f.
  Data files are collected in FONLL/pdfdata/. The numbering scheme can be 
  found in the file FONLL/common/hvqpdfpho.f

- The interface to the (old and not anymore maintained) PDFLIB library
  is provided by the file common/jetpdflib.f
  When linking the code to the PDFLIB package from the CERN libraries,
  three numbers have to be provided in order to determine the PDF set,
  rather than only one.
  NB: our interface to PDFLIB compensates for a bug which multiplies by
  two the outputs of the AFG photon PDF set. As of version 8.04 of PDFLIB
  this bug is still present. If removed, one should then update the
  interface.

- Finally, the program also provides an interface to the modern PDF
  library LHAPDF via the file common/lhapdfif.f 
  In this case a single number, in the place of the one used by 
  hvqpdfpho.f, has to be provided to indentify the pdf set (for
  instance "0 0 10050" will choose cteq6m)
  The AFG bug is present here too, and has finally been corrected in 
  LHAPDF v5.8.5. 
     - FONLL <= v1.3.2 was always fixing the bug itself, so it is fine
       to use with any version of LHAPDF < 5.8.5. 
     - FONLL >= v1.3.3 checks for the LHAPDF version used before deciding 
       whether to fix the bug or not.
     *** It is therefore WRONG to use FONLL <= v1.3.2 with LHAPDF >= v5.8.5 
         for photoproduction or electroproduction ***

Nuclear PDFs, as implemented either in EKS98 or EPS09, can also be used.
 * For EKS, the beam type should be set to -A, where A is the atomic number
   (for instance, -208 will give a Pb beam)
 * For EPS, where multiple error sets exist, the beam type should to
   -(A*1000+pset), where pset is the number of the error set, running from
   1 (central set) to 31 (e.g. -208002)
In both cases the appropriate files containing the PDF sets should be copied 
or linked to the working directory.


The program produces a number of internal files; they all have the form
*.tmp. They can be safely removed.

The other files produced are
tag.out
tag.outlog
tag-fonll.log
where 'tag' is the prefix string entered for the run.
The first two files contain the output of the run. The .log file
contains the input used for the run. Suitably renamed, it can be used
as input file for the run (using redirection).


The FONLL program does not provide for the convolution with a non-perturbative
fragmentation function. The typical time to produce a point in pt and y
is of the order of a minute; it is thus convenient to generate a grid
of cross section values, to be interpolated later in order to perform
the convolution with a non-perturbative fragmentation function.
It is up to the user to make sure that the grid he is using
is sufficient to yield good interpolation. We do however provide
examples of how to set up a grid and interpolate it.
Two different methods are illustrated in the directories misc1 and misc2.
These are provided as a basic set of tools to be modified according to
the user's needs in order to obtain a cross section which includes
a convolution with a fragmentation function, and eventually also
an integrated cross section with given cuts.