The Pythia program can be used to generate high-energy-physics ''events'', i.e. sets of outgoing particles produced in the interactions between two incoming particles. The objective is to provide as accurate as possible a representation of event properties in a wide range of reactions, within and beyond the Standard Model, with emphasis on those where strong interactions play a role, directly or indirectly, and therefore multihadronic final states are produced. The physics is then not understood well enough to give an exact description; instead the program has to be based on a combination of analytical results and various QCD-based models. This physics input is summarized here, for areas such as hard subprocesses, initial- and final-state parton showers, underlying events and beam remnants, fragmentation and decays, and much more. Furthermore, extensive information is provided on all program elements: subroutines and functions, switches and parameters, and particle and process data. This should allow the user to tailor the generation task to the topics of interest.

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PYTHIA 6.4 Physics and Manual

Supersymmetry, Supergravity and Particle Physics

The Search for Supersymmetry: Probing Physics Beyond the Standard Model

Theory and phenomenology of two-Higgs-doublet models

The anatomy of electroweak symmetry breaking: Tome I: The Higgs boson in the Standard Model

Review of particle properties. Particle Data Group

Ultra-heavy particle production from heavy partons at hadron colliders

Discovering supersymmetry with like-sign dileptons

https://slac.stanford.edu/pubs/slacpubs/2250/slac-pub-2325.pdf

The effect of 1Q2 and αs corrections on tests of QCD

In the context of quantum chromodynamics (QCD), an analysis is presented of a compilation of $\mathrm{eN}$ deepinelastic scattering data taken at SLAC. Included are data for ${F}_{2}^{\mathrm{ep}}$, ${F}_{2}^{\mathrm{ed}}$, ${F}_{2}^{\mathrm{ep}}\ensuremath{-}{F}_{2}^{\mathrm{en}}$, and $R$. The interaction between the logarithmic scaling violation from ${\ensuremath{\alpha}}_{s}$ and the power-law scaling violation from higher-twist terms is discussed. This interaction can affect the determination of the parameter $\ensuremath{\Lambda}$ and can alter the predictions for the ratios of anomalous dimensions. Furthermore, we show that, in the context of QCD, higher-twist terms may be able to account for the observed value of $R=\frac{{\ensuremath{\sigma}}_{L}}{{\ensuremath{\sigma}}_{T}}$ which appears to be anomalously large. Different experiments have made different assumptions for the value of $R$ used in extracting ${F}_{2}$ from their data. We show that these differences can account for the discrepancies in the relative normalizations of ${F}_{2}$ from these experiments and also can have a significant effect on the value of $\ensuremath{\Lambda}$ obtained.

R. Michael Barnett

Papers

Review of particle properties. Particle Data Group

Ultra-heavy particle production from heavy partons at hadron colliders

Discovering supersymmetry with like-sign dileptons

The effect of 1Q2 and αs corrections on tests of QCD

Quantum-chromodynamic analysis of eN deep-inelastic scattering data