Author: Mikael Mieskolainen, CERN [25'-]; Imperial College London, Blackett Laboratory [20-25']; University of Helsinki, Department of Physics [17-19'], mikael.mieskolainen@cern.ch
References: arXiv:1910.06300 | arXiv:2304.06010 [hep-ph]
Physics simulation, synthesis and event generation
- pp: Central exclusive Pomeron-Pomeron, Gamma-Pomeron, Gamma-Gamma (kt-EPA), Durham QCD/KMR (gg) processes
- Forward proton excitation (N*)
- A user extendable set of scattering amplitudes with helicity amplitudes e.g. from MadGraph
- Differential eikonal event-by-event Pomeron loop integral screening (absorption) with numerical Fourier-Bessel transform
Durham QCD loop framework with spin-parity projection and a generalized gluon pdf transformation (Shuvaev transform+Sudakov suppression)Tensor Pomeron model scattering amplitudes for continuum + resonances- Arbitrary Jacob-Wick helicity decay 1 → 2 amplitudes with any spin and cascade spin correlations, polarization parametrized via spin density matrices and 'Glueball filter dynamics'
- Exact 2 → N relativistic kinematics with different phase space composition options, automated Lorentz scalars and 4-momenta for arbitrary amplitudes
- Arbitrary wide/deep decay chains according to the phase space with interpreter syntax
- Elastic scattering through the eikonal screening amplitude
- Single and Double Diffraction (triple Pomeron) and soft Non-Diffractive (with a 'Retro style' KISS fragmentation) - as a simple reference
Spin-2 couplings (left), central exclusive production pp → p + X + p spectrums (right)
Physics analysis, inference and inversion
- Ultrafast and automated fiducial observable studies (tracking cuts, forward vetos) - physics in 5 minutes
- Spin studies: 2-body final state angular distribution Laplace's spherical harmonics expansion (to arbitrary order in LM) and inversion via an extended Maximum Likelihood fit and closed-form algebraic inversion - including multistep factorization of fiducial acceptance and efficiency via moment mixing matrices (1. detector, 2. fiducial and 3. flat phase space)
Spherical moments in fidual phase space (left) vs after inversion in flat phase space (right)
- Glueball domain central production fit tool (continuum + interfering resonances) using arbitrary differential distributions
- Eikonal Pomeron model fit tool using differential elastic dσ/dt data
- Use
DREM-PID for optimal final state particle and decay channel identification - Use
DeepEfficiency for minimally biased fiducial measurement efficiency corrections - Use
Diffractive Combinatorics for novel fiducial measurements of inclusive diffraction - Output directly to Rivet via HepMC - robust check of the generator output, measurement definition and projections against existing fiducial measurements
Decay angles in Collins-Soper, Helicity, Lab, Gottfried, Pseudo-Gottfried, Non-rotated rest frame
Technology
- Fully multithreaded (max CPU) VEGAS importance sampling Monte Carlo engine; weighted and unweighted event generation
- High performance computing (HPC) type distributed and scalable MC model tuning with
RAY , steered via Python 3 -
JSON object file (partial JSON5) and commandline control - HepMC3, HepMC2 and HEPEVT event record output, HepMC3 to LHE converter
- Autotesting and comparison with LHC/Tevatron/RHIC measurements
- Automatic version update notifications
- Based on modern
C++17 language
