Computation of resummed diphoton production cross sections in pp collisions
at the LHC at the collider c.m. energy 14 TeV

References:
1. C. Balazs, E. Berger, P. Nadolsky, and C.-P. Yuan, Phys. Lett. B637:235 (2006)
2. P. Nadolsky, C. Balazs, E. Berger, and C.-P. Yuan, Phys.Rev.D76:013008  (2007)
3. C. Balazs, E. Berger, P. Nadolsky, and C.-P. Yuan, Phys.Rev.D76:013009  (2007)

Computation of resummed diphoton production cross sections for the LHC

References:
1. C. Balazs, E. Berger, P. Nadolsky, and C.-P. Yuan, 
   Phys. Lett. B637:235 (2006);
2. P. Nadolsky, C. Balazs, E. Berger, and C.-P. Yuan, hep-ph/0702003.

Contents
diphoton_grids_lhc.tar.gz    -- subdirectory with input grids for the LHC
diphoton_ins_lhc.tar.gz          -- subdirectory with resbos.in template files
book_ntuple_lhc_public.bat   -- a UNIX shell script for automated computation
                       and matching of resummed cross sections
h0_lhc_ct6m_m110_140_grids.tar.gz -- input grids for SM Higgs production with 
                                 masses 110, 120, 130, 140 GeV
lo_lhc_ct6m.tar.gz   -- leading-order diphoton cross sections, obtained using
                        CTEQ6M

To compute the matched resummed cross sections in the form of PAW ntuples,
compile the ResBos executable using make and execute the above shell script.
The values of the relevant parameters are specified in the header of the 
script. The script automatically updates the resbos.in file and runs 
ResBos several times to produce ntuples for qqbar+qg, gg+gq 
and combined channels. You will need to create subdirectories 
grids/ and ins/ with input grids and resbos.in 
templates beforehand. The returned files are called

res321_aa_lhc_ct6m.hbook  -- the NNLL/NLO resummed cross section for the 
                             qqbar+qg channel
res321_ag_lhc_ct6m.hbook  -- the NNLL/NLO resummed cross section for the 
                             gg+gq channel
res321_all_lhc_ct6m.hbook -- the resummed cross section for all 
                             (qqbar+qg+gg+gq) channels, i.e., the final output
                             that can be compared to the data

The cross section grids are computed along the lines 
described in Refs. [1] and [2]. The CTEQ6M PDF's [J. Pumplin et al., 
JHEP 0207, 012 (2002)] and nonperturbative Sudakov function obtained in
A. Konychev, P. Nadolsky, Phys. Lett. B633, 710 (2006) were used.
The final-state fragmentation singularity arising in qg direct channel is
regularized using a combination of quasi-experimental isolation and Catani-
Seymour subtraction described in Ref. [2] and corresponding to the parameter
isub=12 in book_ntuple_lhc_public.bat. An alternative regularization by
quasi-experimental isolation and smooth-cone subtraction (introduced in 
Ref. [1]) may be turned on by choosing isub=-2.

Subdirectories
sqrt_s_10TeV/ contains analogous grids for the LHC c.m. energy 10 TeV
tools/ : standalone utilities for adding the distributions in the format of
         GBOOKs, PAW HBOOKs/Ntuples, or ROOT Ntuples