-based event-generator framework for high energy hadron-collision
interactions.
, to add initial- and final-state parton showers and the simulation of
hadronization and decays.
References
The reference to GR@PPA 2.9 is
S. Odaka, Y. Kurihara, GR@PPA 2.9: radiation matching for simulating photon production processes in hadron collisions, Comput. Phys. Commun. 232 (2018) 214; arXiv:1712.02132 [hep-ph].
The reference to GR@PPA 2.8 is
S. Odaka, Y. Kurihara, GR@PPA 2.8: initial-state jet matching for weak boson production processes at hadron collisions, Comput. Phys. Commun. 183 (2012) 1014; arXiv:1107.4467 [hep-ph],
and S. Odaka, GR@PPA 2.8.3 update, arXiv:1201.5702 [hep-ph]for the updates.
For GR@PPA 2.7, please refer to
S. Tsuno et al., GR@PPA
2.7 event generator for
pp/ppbar collisions, Comput. Phys. Commun. 175 (2006) 665;
hep-ph/0602213.
What's
New
- May 9, 2017: minor update of GR@PPA
2.9.
- May 9, 2017: GR@PPA
2.8.6.2 update uploaded.
- Feb. 10, 2017: GR@PPA
2.9 uploaded.
- Jan. 20, 2017: GR@PPA
2.8.6.1 update uploaded.
- Jan. 24, 2013: GR@PPA
2.8.4 update uploaded.
- Dec. 27, 2011: GR@PPA
2.8.3 update released.
- Jul. 19, 2011: GR@PPA
2.8.2 update released.
- Apr. 27, 2011: GR@PPA
2.8.1 update released.
- Nov. 17, 2010: GR@PPA
2.8 release.
- Jun. 9, 2010: GR@PPA-2.8-rc3 was uploaded.
- Jan. 18, 2010: a release-candidate of version 2.8
(GR@PPA-2.8-rc2) was uploaded.
- Feb. 24, 2006: GR@PPA 2.76 release
Contents
- GR@PPA 2.9: ME-PS matching for photon production processes
- GR@PPA 2.8.6: the latest
release of the GR@PPA 2.8 series (the jet matching has been extended to two jets for single weak-boson production)
- GR@PPA 2.8: ME-PS matching of hadron-jet production in single and double weak-boson production processes
- GR@PPA
2.7: the previous
distribution including many multi-particle production processes
- LhaExt: an interface to PYTHIA, HERWIG etc.
using data files
- GR@PPA_All: a package of GR@PPA event generators for various
multi-body
processes.
- GR@PPA_4b:
an event generator for the four-bottom quark production processes
(the 1st product).
GR@PPA 2.9
The ME-PS matching method is applied to direct photon and diphoton production. The associated hadron-jet production is supported up to two jets as in GR@PPA 2.8.6. The collinear photon divergences are also regularized using the QED-LLL subtraction,
and the PS simulation which restores the subtracted collinear
components includes collinear photon radiation. The PS simulation
is capable of enforcing the radiation of given number of energetic photons for efficient event generation.
The
distribution package can be downloaded
here. We provide
sample programs for
direct photon and
diphoton
production in 7-TeV proton-proton collisions. In these samples, the
events of different subprocesses to be combined are separately
generated. The
generated events can be mixed when the PYTHIA simulation is applied.
Such a
separate generation is convenient because the generation condition
and required CPU time are much different between the subprocesses.
This distribution also includes
LhaExt 2.0.
References:
S. Odaka and Y. Kurihara, Consistent simulation of non-resonant diphoton production at hadron collisions with a custom-made parton shower, Phys. Rev. D 85, 114022 (2012); arXiv:1203.4038 [hep-ph]S. Odaka and Y. Kurihara, Consistent simulation of direct-photon production in hadron collisions including associated two-jet production, Mod. Phys. Lett. A 31, 1650099 (2016); arXiv:1509.04813 [hep-ph]
S. Odaka and Y. Kurihara, Consistent simulation of nonresonant diphoton production in hadron collisions including associated jet production up to two jets, Phys. Rev. D 94, 114015 (2016); arXiv:1607.00204 [hep-ph]
GR@PPA 2.8.6
The matched jet production has been extended to
two jets for single W and Z production. In addition to the collinear divergences,
soft-gluon divergences
have to be subtracted in order to make the two-jet production MEs
finite. We have introduced a combined subtraction method to
acomplish the subtraction of the two kinds of divergences simultaneously.
The
distribution package can be downloaded
here. We provide
sample programs for
W boson and
Z boson production in 7-TeV proton-proton collisions. In these samples,
W/Z
+ 0-jet, 1-jet, and 2-jet events are separately generated, and the
generated events are mixed when the PYTHIA simulation is applied. Such a
separate generation is convenient because the generation condition
and required CPU time are much different for the three subprocesses.
This distribution includes
LhaExt version 2.0, which supports the LHEF file format (*) for the event output.
(*) J. Alwall et al., A Standard format for Les Houches event files, Comput. Phys. Commun. 176, 300 (2007); arXiv:hep-ph/0609017References:
S. Odaka, N. Watanabe and Y. Kurihara, ME–PS matching in the simulation of multi-jet production in hadron collisions using a subtraction
method, Prog. Theor. Exp. Phys. 2015, 53B04 (2015); arXiv:1409.3334 [hep-ph]
GR@PPA 2.8
A
0-jet/1-jet matching mechanism is implemented for the
W and
Z production
processes and diboson (
W+W-,
ZW,
ZZ) production
processes. A
gzipped tar file
of the released package (GR@PPA-2.8.x) can be downloaded. Expand the downloaded file and move into the created directory.
> tar zxf GR@PPA-2.8.x.tgz
> cd GR@PPA-2.8.x
Instructions for the installation and the execution of sample programs
can be found in the
README file in the top directory.
Feedbacks are greatly appreciated.
References:
S. Odaka and Y. Kurihara,
Initial-state parton shower
kinematics for NLO event generators, Eur. Phys. J. C 51, 867 (2007);
arXiv:hep-ph/0702138
S. Odaka, Simulation
of Z boson pT spectrum at Tevatron by leading-order event generators,
Mod. Phys. Lett. A 25,
3047 (2010); arXiv:0907.5056 [hep-ph]
S. Odaka, Y. Kurihara, GR@PPA 2.8: initial-state jet matching for weak boson production processes at hadron collisions, Comput. Phys. Commun. 183 (2012) 1014; arXiv:1107.4467 [hep-ph]S. Odaka, GR@PPA 2.8.3 update, arXiv:1201.5702 [hep-ph]S. Odaka, Simulation of Z-boson pT spectrum at LHC and Tevatron using GR@PPA, arXiv:1206.3398 [hep-ph]S. Odaka, Precise simulation of the initial-state QCD activity associated with Z-boson production in hadron collisions, Mod. Phys. Lett. A 28, 1350098 (2013); arXiv:1301.5082 [hep-ph]
Updates:
2.8: official release (Nov. 17, 2010)
2.8.1:
bug fix in parton shower routines (QCDPSb.f and pskini.f). In addition,
the Q0 cutoff of parton showers was increased from 4.6 GeV to 5.0 GeV
for safety. (Apr. 27, 2011)
2.8.2: the energy scale setting in the LLL subtraction was improved.(1) The usage of the random number generator was improved, and the random
number generators themselves were replaced with more reliable ones.(2) (July 19, 2011)
2.8.3:
the final-state PS kinematics was modified so that the memonta of
spectator particles (e.g., weak bosons) should not be altered by the
application of PS. The routine to set the QCD lambda value for PS was
modified so that the derived alpha_s value should reproduce the value
in PDF as precisely as possible even when there is a mismatch in the
approximation order. (Dec. 27, 2011)
2.8.4: improvements established in the study of diphoton production(3), which are mainly concerned with the final-state PS, have been backported. The subroutines, scale_fsr and scale_fsub, have been added to grcpar.F of sample programs in order to define the energy scales
for the final-state PS and the final-state LLL subtraction,
respectively. From this update, the sample programs utilizing RBOOK can
be produced from those utilizing HBOOK by executing the ./Config script in the relevant directory. (Jan. 24, 2013)
(1)
It is better to take the factorization scale of the non-radiative
subsystem as the energy scale in the LLL subtraction in order to
achieve good matching between the ME and PS for hard radiations.
Since the update 2.8.2, we provide the subroutine setscale in grcpar.F of sample programs for defining the renormalization and factorization scales,
so that an identical definition can be refered to from both PDF/PS
routines in non-radiative processes and LLL subtraction routines
in radiative processes. In order to have this scheme work properly, we
have to set the parameters ICOUP and IFACT in the subroutine GRCPAR in grcpar.F to be equal to 6 in all processes.
(2) The performance of the random number generators, DRN in BASES/SPRING and QPRAND
in QCDPS, was found to be unsatisfactory for the present use in GR@PPA.
These routines have been modified so that they call routines in mt19937.f and randgen.f, respectively.
(3) S. Odaka and Y. Kurihara, Consistent simulation of non-resonant diphoton production at hadron collisions with a custom-made parton shower, Phys. Rev. D 85, 114022 (2012); arXiv:1203.4038.
GR@PPA 2.7
Several
multi-jet processes have been added to the
previous
GR@PPA_All
distribution. New
processes are
- W + 4 jets,
- Z + 3 jets
and 4 jets,
- di-boson (WW, WZ
and ZZ) + 1
jet,
- top-quark pair (6 body) + 1
jet,
- QCD 2 jets, 3 jets and 4 jets.
Namely, processes up to
seven-body productions
(top-quark pair
+ 1 jet) can be simulated, based on ordinary Feynman diagram
calculations at the tree level.
In this version,
the GR@PPA framework and the process
dependent
matrix-element routines are separately provided. This makes
it
easier to add further new processes, and allows users to make a choice
of processes to implement.
This version has several
new features to handle
complicated
multi-body production processes. A systematic way to combine many
subprocesses to a single base-subprocess has been introduced, and a new
method has been adopted to calculate the color factors of complicated
QCD processes. They speed up the calculation significantly.
Manual:
S. Tsuno et
al.,
GR@PPA 2.7 event generator for pp/ppbar collisions, Comput.
Phys. Commun. 175, 665 (2006); hep-ph/0602213
Download:
- Framework (GR@PPA
2.76)
- Matrix Elements (process
list)
- W + jets: W
+ 0 jet, W
+ 1 jet, W
+ 2 jets, W
+ 3 jets, W
+ 4 jets
- Z + jets: Z
+ 0 jet, Z
+ 1 jet, Z
+ 2 jets, Z
+ 3 jets, Z
+ 4 jets
- WW + jets:
WW
+ 0 jet, WW
+ 1 jet, WW
+ 2 jets
- ZZ + jets: ZZ
+ 0 jet, ZZ
+ 1 jet, ZZ
+ 2 jets
- ZW + jets:
ZW
+ 0 jet, ZW
+ 1 jet, ZW
+ 2 jets
- top-quark pair + jets: top-quark pair + 0
jet, top-quark
pair + 1 jet
- QCD jets: 2
jets, 3
jets, 4
jets
- bbbb: Hbb,
HZ,
pure QCD,
Zbb,
ZZ
- List all files
Installation:
The following shows the instruction to setup the GR@PPA framework
version 2.76 with the
W + 1 jet and
W
+ 2 jets matrix
elements, and execute one of the example programs. The example programs
generate 100
W + 1 jet events using the built-in
CTEQ6L
PDF. Edit the file
inc/define.h beforehand in
order to use an
external PDF library (PDFLIB or LHAPDF). See the manual for more
details.
- Place the downloaded tar files in a certain directory, and cd
to it.
- tar zxvf GR@PPA-2.76.tgz
- cd GR@PPA-2.76
- tar zxvf ../matrix_w1j_v1.03.tgz
- tar zxvf ../matrix_w2j_v1.03.tgz
- ./Config.perl
- Edit the Makefile to setup the
compiler and paths to
the libraries. Example programs require some external libraries,
depending on the choice of the user. Users can give their paths later
by editting the Makefile to build the example
program (before
the step 15).
- make w1j
- make w2j
- make integ
- make kinem
- make install
- make example
- cd example/pythia
- make
- ./pysample
How to add matrix elements:
Assuming the downloaded file (
matrix_w0j_v1.03.tgz
for
instance) is at the same place as the above, and the current directory
is
GR@PPA-2.76, do as
- tar zxvf ../matrix_w0j_v1.03.tgz
- ./Config.perl
- Edit the Makefile again.
- make w0j
- make integ
- make kinem
- make install
- make example
Edit the subroutine
upinit.F in a sample-program
directory as
IPRUP(1) = 100, and do
make
there. Then, you will
have an example program to generate
W + 0 jet
events.
See also
another
GR@PPA page by S. Tsuno.
LhaExt
an interface using external event data files from GR@PPA to
PYTHIA,
HERWIG and any other general-purpose event generators supporting the
Les Houches
Accord (LHA) event interface [1].
Since the event generators besed on the GR@PPA framework (
e.g.,
GR@PPA_All) directly
generate unweighted
events, they can be easily enbedded in general-purpose event generators
such as PYTHIA and HERWIG. The embedding uses are convenient in quick
analyses where input physical parameters and/or kinematical cuts are
frequently changed. However, in some environments (
e.g.,
a mass
production of events), it is more favourable to separate the jobs for
the event generation by GR@PPA and those for parton showers,
hadronisation, decays
etc. by general-purpose
generators.
Generated parton-level event data are to be passed by
using
external data
files in such uses. The
LhaExt package
has been made as a
simple
example for such uses.
Program download: questions, comments and bug
reports should be
sent to
S. Odaka
The routines in LhaExt
simply write/read the whole contents
of the
LHA interface commons, HEPRUP and HEPEUP, to/from a data
file. They
do not dedicate to GR@PPA generators, but are
universal for
any
event generators supporting the LHA event interface in which
the
two interface commons are properly filled. It is very easy to implement
these routines since they do not depend on any specific generator. The
package is composed of "write" routines and "read" routines. Of course,
"write" routines are to be used in
pre-generators such as GR@PPA_All, and "read" routines in
post-generators such as PYTHIA. There are two kinds of
"write"
routines. One is to write the
run information
in HEPRUP,
and the other to write the
event data in HEPEUP.
The former is
to be called once in each run after the initialisation is completed,
while the latter must be called every after an
event is generated. The created data file is composed of a header where
the
run information is recorded, and event data following it. Both
ASCII-formatted
and unformatted
binary data can be created
according to the
users' choice. An example for the usage in GR@PPA_All is provided in
the package.
In addition to simple
"read" routines for the
header (run
information) and the event data, we provide some utility routines in
order to realize the
following features:
- Multiple input data files are supported.
The present
LhaExt supports a sequential read only, though some parallel read
(event mixing) schemes are specified in the Les Houches Accord.
- The read process can skip a certain
number of events at
the beginning.
- Users can choose any unweighting scheme
specified in the
Les Houches Accord. It can be different from the scheme determined in
the "write" procedure.
- Users can choose LUNs (Logical Unit
Numbers) for the
control file and the data file. They can choose an automatic
assignment, as well.
An example of the usage is provided as the subroutines UPINIT and
UPEVNT in the package. The above fratures become available if one
replaces the dummy routines of the same names in PYTHIA or HERWIG with
these examples. See the README file in the package for more details.
[1] E. Boos
et al., hep-ph/0109068; see also p. 226
in the
PYTHIA 6.2 manual, hep-ph/0010017.
GR@PPA_All
an event generator program package for proton-proton and
proton-antiproton collider experiments, such as those at
Tevatron
and LHC. Calculations are all at the
tree level (leading
order)
within the framework of the minimal Standard Model. The most recent
version of GR@PPA_All supports processes to produce following final
states:
- W + jets (up to 3
jets) with the subsequent W
decay to a fermion pair,
- Z + jets (up to 2
jets) with the subsequent Z
decay to a fermion pair,
- four bottom quarks via Z
and Higgs-boson mediated
processes as well as those from pure QCD interactions (same as GR@PPA_4b),
- top-quark pair with the subsequent decay
to W and b,
and the W decay to a fermion pair,
- di-boson (WW, WZ
and ZZ) with the
subsequent W/Z decay to a fermion pair.
Note that matrix elements are evaluated for Feynman diagrams
including
heavy particle (W, Z and top
quark) decays down to
light partons (bottom quarks or lighter). Thus, we can expect that
phase-space effects and decay correlations due to quantum effects are
exactly reproduced. For instance, the former alter the resonance shape
of
W,
Z and top quarks, and the
latter generate a decay
plane correlation in di-boson events.
The program is coded within the framework of GR@PPA, an extention of
the
GRACE
system to hadron
collisions. Events are generated by BASES/SPRING included in the GRACE
system. Thus,
generated events are already unweighted
(
i.e.,
event weight = 1).
GR@PPA_All generates events at the
parton level.
Users have
to feed the generated events to a suitable general-purpose event
generator, if they want to have hadron-level realistic events.The
present version of GR@PPA_All supports the
LHA event interface
[1]. Therefore, the program can be easily interfaced to widely-used
general-purpose event genetators,
PYTHIA
6.2
and
HERWIG
6.5, which support the LHA event interface, too. Since unweighted
events are directly generated,
GR@PPA_All can be embedded
in
these general-purpose event generators. Of course, a stand-alone use is
also possible. The distribution package includes aample programs for
these uses.
As for the PDF library, the most popular ones,
PDFLIB
in
CERNLIB
and
LHAPDF,
are supported.
PYTHIA built-in
PDFs can be used as well when the PYTHIA-embedding mode is chosen.
Manual: An
online
manual
is available. The concept and the basic structure of the program are
same as those of
GR@PPA_4b.
See the GR@PPA_4b
manual for the details of GR@PPA.
Program download: questions, comments and bug
reports should be
sent to
S.
Tsuno or
S. Odaka .
- version
2.65 (gzipped tar file, 1.3 MB): the first release;
13
February, 2004
Caution: The support to the LHAPDF PDF library is
still
preliminary in the version 2.65. The calculations are unstable on Linux
PCs with the GNU g77 compiler in the combination with LHAPDF. The
integrated cross sections show differences at the 4th or 5th digit from
those evaluated in other environments in many processes, and the "W + 3
jets" generator gives an anomalously large cross section and error. No
such problem has been found in other environments: on the same platfoem
with Intel and Fujitsu compilers, and on an AIX server with an IBM
compiler (xlf). This problem will be solved in the next version, which
we are now preparing for the release.
[1] E. Boos
et al., hep-ph/0109068; see also p. 226
in the
PYTHIA 6.2 manual, hep-ph/0010017.