+++ /dev/null
-<chapter name="Program Files">
-
-<h2>Program Files</h2>
-
-The code is subdivided into a set of files, mainly by physics
-task. Each file typically contains one main class, but often
-with a few related helper classes that are not used elsewhere in
-the program. Normally the files come in pairs.
-<ul>
-<li>A header file, <code>.h</code> in the <code>include</code>
-subdirectory, where the public interface of the class is declared,
-and inline methods are defined.</li>
-<li>A source code file, <code>.cc</code> in the <code>src</code>
-subdirectory, where most of the methods are implemented.</li>
-</ul>
-During compilation, related dependency files, <code>.d</code>, and
-compiled code, <code>.o</code> are created in the <code>tmp</code>
-subdirectory.
-
-<p/>
-In part the <code>.xml</code> documentation files in the
-<code>xmldoc</code> subdirectory have matching names, but the match
-is broken by the desire to group topics more by user interaction than
-internal operation. On these pages the function of the different code
-files is summarized. Currently, each <code>.xml</code> file is also
-translated into an <code>.html</code> one in the
-<code>htmldoc</code> subdirectory, to allow easy viewing of the
-contents in a web browser, and an <code>.php</code> one in
-<code>phpdoc</code>, for more sophisticated interactivity
-if that subdirectory is installed on a web server.
-
-<p/>
-Here is the current list of files, ordered alphabetically, with a brief
-description of contents.
-
-<file name="Analysis">
-contains routines to analyze events. Currently it can do sphericity,
-thrust, Lund/Jade/Durham jet clustering, cone-jet finding, and the
-<ei>kT</ei>, anti-<ei>kT</ei> and Cambridge/Aachen algorithms for
-hadron colliders.
-</file>
-
-<file name="Basics">
-contains some basic facilities of general use: a random number
-generator <code>Rndm</code>, a four-vector class <code>Vec4</code>, and a
-histogram class <code>Hist</code>.
-</file>
-
-<file name="BeamParticle">
-contains information on all partons extracted from one of the two
-beams. Defines modified parton distributions accordingly during the
-showering and multiparton interactions processing, thereby extending on
-the one-particle-inclusive distributions defined by the previous class.
-Finds the internal structure for a beam remnant.
-</file>
-
-<file name="BeamRemnants">
-adds primordial <ei>kT</ei> to the set of hard subsystems,
-and combines these subsystems with the two beam remnants to provide
-the overall energy-momentum picture. Also ties together all the
-colour lines into consistent singlets.
-</file>
-
-<file name="BeamShape">
-generates momentum spread of beams, and spread of collision vertex
-position.
-</file>
-
-<file name="BoseEinstein">
-provides a simple method to impose Bose-Einstein correlations on
-pairs of identical mesons.
-</file>
-
-<file name="Event">
-contains the event record, which basically is a vector of particles.
-This file also contains the <code>Particle</code> class, used by
-<code>Event</code>. <code>Pythia</code> uses two <code>Event</code>
-objects, one for the process-level record (<code>process</code>) and
-one for the complete event (<code>event</code>).
-</file>
-
-<file name="FragmentationFlavZpT">
-contains the classes for describing the fragmentation steps in
-flavour and in longitudinal and transverse momentum.
-</file>
-
-<file name="FragmentationSystems">
-defines some containers of parton systems, for use in
-the fragmentation routines.
-</file>
-
-<file name="HadronLevel">
-turns the parton-level event above into a set of outgoing particles,
-by applying string fragmentation (with special treatment for low-mass
-systems) and secondary decays, and optionally Bose-Einstein corrections.
-</file>
-
-<file name="HelicityBasics">
-basic classes for the handling of helicities in tau lepton decays.
-</file>
-
-<file name="HelicityMatrixElements">
-helicity-dependent decay matrix elements for the tau lepton.
-</file>
-
-<file name="HepMCInterface">
-contains an interface to convert the PYTHIA 8 event record into the
-HepMC format. The <code>HepMCInterface.cc</code> file is located in
-the subdirectory <code>hepmcinterface</code> and is used to build a
-separate <code>libhepmcinterface</code> library.
-</file>
-
-<file name="HiddenValleyFragmentation">
-hadronization in models with a hidden sector that contains an unbroken
-<ei>SU(N)</ei>, which gives confinement. The model and code is largely
-derived from the normal fragmentation classes.
-</file>
-
-<file name="History">
-methods to reconstruct the imagined shower history of a
-matrix-element-generated multiparton configuration, as part of
-the CKKW-L matrix element merging.
-</file>
-
-<file name="Info">
-is a simple container that gives access to some information on the
-nature of the current process, such as Mandelstam variables.
-Also contains a small database for errors and warnings encountered
-during program execution.
-</file>
-
-<file name="LesHouches">
-gives the possibility to feed in parton configurations for the
-subsequent event generation. One base class is defined, with containers
-for initialization and event information, that can be read from
-<code>Pythia</code>. Derived classes allow for a few different cases.
-</file>
-
-<file name="LHAFortran">
-is a header file only, for a class derived from the above LesHouches
-one, to be used for runtime interfacing to Fortran programs, such as
-PYTHIA 6.
-</file>
-
-<file name="LHAPDFInterface">
-is a header file only, with interfaces to the key LHAPDF routines,
-as needed for a runtime interface. There is a file
-<code>lhapdfdummy/LHAPDFdummy.cc</code> with matching dummy
-implementations, however. This file is used to build a separate
-<code>liblhapdfdummy</code> library, to be linked when the LHAPDF
-library is not used, so as to avoid problems with undefined references.
-</file>
-
-<file name="MergingHooks">
-intercede in the normal shower evolution to construct the relevant
-Sudakov form factor suppressions as part of the CKKW-L matrix element
-merging.
-</file>
-
-<file name="MiniStringFragmentation">
-performs string fragmentation in cases where the colour singlet
-subsystem mass is so small that one or at most two primary hadrons
-should be produced from it.
-</file>
-
-<file name="MultipartonInteractions">
-performs multiparton interactions.
-</file>
-
-<file name="ParticleData">
-contains a database of all necessary particle data (masses, names, ..)
-and decay channels.
-</file>
-
-<file name="ParticleDecays">
-performs the decays of all normal unstable hadrons and leptons, i.e.
-in mass up to and including <ei>b bbar</ei> systems. It is not
-intended for decays of electroweak resonances, like <ei>Z^0</ei>.
-</file>
-
-<file name="PartonDistributions">
-contains parton distribution functions for the proton and electron.
-Currently very simple, with only two <ei>p</ei> parametrizations
-and one <ei>e</ei> ditto available, but it is possible to link in
-external sets.
-</file>
-
-<file name="PartonLevel">
-turns the (hard) process above into a complete set of partons, by
-adding initial- and final-state radiation, multiparton
-interactions, and beam remnants.
-</file>
-
-<file name="PartonSystems">
-keeps track of which partons belong to which partonic subsystem,
-i.e. one of the multiparton (semi)hard interactions with associated
-showers.
-</file>
-
-<file name="PhaseSpace">
-selects a point in phase space for the hard-process generation,
-optimized separately for each process to give improved Monte Carlo
-efficiency.
-</file>
-
-<file name="ProcessContainer">
-packages the information on a given subprocess, combining the
-phase-space selection and cross-section evaluation machineries
-with some statistics information. Also sets up the list of processes
-to be studied in a run.
-</file>
-
-<file name="ProcessLevel">
-handles the generation of the (hard) process that sets the character
-of the event. This involves either using internally implemented
-processes or linking to Les Houches information. The latter can
-be by runtime interfaces or by reading in a file. This step also
-includes resonance decays.
-</file>
-
-<file name="Pythia">
-is the main class, that administrates the whole event generation
-process by making use of all the others classes. Objects of most
-other classes reside (directly or indirectly) inside <code>Pythia</code>,
-so only a <code>Pythia</code> object needs to be explicitly instantiated
-and addressed by the user.
-</file>
-
-<file name="PythiaComplex">
-is only a <code>.h</code> file, containing a <code>typedef</code> for
-double precision complex numbers.
-</file>
-
-<file name="PythiaStdlib">
-contains most of the <code>Stdlib</code> headers used in PYTHIA 8,
-with <code>using</code> directives. It defines <code>M_PI</code> if
-this is not already done. Also a few simple inline methods:
-<code>pow2(x)</code>, <code>pow3(x)</code>, <code>pow4(x)</code>,
-<code>pow5(x)</code> and <code>pow6(x)</code> for small integer
-powers, and <code>sqrtpos(x)</code> where a <code>max(0., x)</code>
-ensures that one does not take the square root of a negative number.
-Also non-inlined <code>GammaReal(x)</code> for the <ei>Gamma</ei>
-function value of a real argument.
-</file>
-
-<file name="ResonanceDecays">
-decays resonances as part of the hard-process stage, in many cases
-(but not all) including angular correlations between the decay products.
-</file>
-
-<file name="ResonanceWidths">
-encodes some properties of resonances, in particular the dynamic
-calculation of widths.
-</file>
-
-<file name="RHadrons">
-handles the production and decay of hadrons formed by long-lived
-gluinos, stops or sbottoms.
-</file>
-
-<file name="Settings">
-contains a database of all flags, modes, parameters and words that
-determine the performance of the generator. Initial values are obtained
-from the contents of the <code>.xml</code> files, but these values can
-then be changed by the user.
-</file>
-
-<file name="SigmaCompositeness">
-contains the cross sections and matrix elements for production of
-some particles in compositeness scenarios, specifically excited
-fermions.
-</file>
-
-<file name="SigmaEW">
-contains the cross sections and matrix elements for electroweak
-processes involving photons, <ei>Z^0</ei>'s and <ei>W^+-</ei>'s.
-</file>
-
-<file name="SigmaExtraDim">
-contains the cross sections and matrix elements for processes in
-scenarios involving extra dimensions.
-</file>
-
-<file name="SigmaGeneric">
-contains the cross sections and matrix elements for some generic
-processes, to be used as building blocks for a few BSM scenarios.
-</file>
-
-<file name="SigmaHiggs">
-contains the cross sections and matrix elements for Higgs production.
-</file>
-
-<file name="SigmaLeftRightSym">
-contains the cross sections and matrix elements for particle production
-in left-right-symmetry scenarios, specifically righthanded <ei>Z</ei>
-and <ei>W</ei> bosons and doubly-charged Higgs bosons.
-</file>
-
-<file name="SigmaLeptoquark">
-contains the cross sections and matrix elements for leptoquark production.
-</file>
-
-<file name="SigmaNewGaugeBosons">
-contains the cross sections and matrix elements for a <ei>Z'^0</ei>,
-a <ei>W^+-</ei> and a horizontal gauge boson <ei>R^0</ei>.
-</file>
-
-<file name="SigmaOnia">
-contains the cross sections and matrix elements for charmonium and
-bottomonium production.
-</file>
-
-<file name="SigmaProcess">
-contains the base class and derived classes for the evaluation of
-different matrix elements. Also keeps track of allowed incoming
-parton configurations and their cross sections, including parton
-densities. In order to keep this file from becoming too big, actual
-cross sections are found in several separate files of derived classes:
-<code>SigmaQCD</code>, <code>SigmaEW</code>, <code>SigmaOnia</code>,
-<code>SigmaHiggs</code>, <code>SigmaSUSY</code>,
-<code>SigmaNewGaugeBosons</code>, <code>SigmaLeftRightSym</code>,
-<code>SigmaLeptoquark</code>, <code>SigmaCompositeness</code>,
-<code>SigmaExtraDim</code> and <code>SigmaGeneric</code>.
-</file>
-
-<file name="SigmaQCD">
-contains the cross sections and matrix elements for soft and hard
-QCD processes.
-</file>
-
-<file name="SigmaSUSY">
-contains the cross sections and matrix elements for Supersymmetric
-processes.
-</file>
-
-<file name="SigmaTotal">
-contains parametrizations of total, elastic and diffractive hadronic
-cross sections.
-</file>
-
-<file name="SpaceShower">
-performs spacelike initial-state transverse-momentum-ordered
-shower evolution.
-</file>
-
-<file name="StandardModel">
-contains the running <ei>alpha_strong</ei>, with <ei>Lambda</ei>
-matching at flavour thresholds, the running <ei>alpha_em</ei>,
-CKM mixing matrices, and a few other parameters such as
-<ei>sin^2(theta_W)</ei>.
-</file>
-
-<file name="StringFragmentation">
-performs string fragmentation of a given set of partons.
-</file>
-
-<file name="SusyCouplings">
-stores the various couplings used for SUSY cross sections and
-decays, as calculated from input e.g. based on the SUSY Les Houches
-Accord.
-</file>
-
-<file name="SusyLesHouches">
-contains information on SUSY parameters and particle data as specified
-by the SUSY Les Houches Accord.
-</file>
-
-<file name="TauDecays">
-the main routines for handling tau lepton decays with helicity
-information.
-</file>
-
-<file name="TimeShower">
-performs timelike final-state transverse-momentum-ordered
-shower evolution.
-</file>
-
-<file name="UserHooks">
-Provides a way for a user to study the event at a few intermediate
-stages of evolution, to reject the event as a whole or to modify
-its cross-section weight.
-</file>
-
-</chapter>
-
-<!-- Copyright (C) 2012 Torbjorn Sjostrand -->
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff