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LPAIR-like steering cards

The second (and simplest one), inherited from LPAIR and PPtoLL, only allows to set a well-defined set of parameters through a key → value scheme. All keys currently handled by this parser are listed below, along with their default value (if not retrieved from the steering card).

General parameters

  • PROC: Process to generate (complete list here)
  • MODE (default: 1 = elastic-elastic): Subprocess’ mode
  • NGEN (default: 0): Number of unweighted events to generate
  • NTRT (default: 1): Flag to specify if the integrant is required to be smoothed
  • DEBG (default: 2 = warning): Debugging verbosity

Vegas integration parameters

  • NCVG (default: 1D5): Number of function calls
  • NCSG (default: 100): Number of points to probe
  • ITVG (default: 10): Number of iterations for the integration

Output module parameters

  • OUTP (default: none): Type of output module to configure
  • OUTF (default: none, module-dependent): Output file name

Kinematics parameters

Incoming state

  • IN1P|INPP (default: 6500.0): First incoming particle’s momentum, in GeV
  • IN2P|INPE (default: 6500.0): Second incoming particle’s momentum, in GeV
  • PMOD (default: 2 = elastic): First incoming particle’s remnant mode or structure functions modelling
  • EMOD (default: 2 = elastic): Second incoming particle’s remnant mode or structure functions modelling
  • Q2MN&Q2MX (default: 0.0 → 1D5): Q² range for the exchanged parton, in GeV²

Central system

  • PAIR (default: 13 = $\mu$): Outgoing leptons’ PDG identifier
  • PTCT (default: 3.0): Minimal transverse momentum for any single central particle, in GeV/c
  • MSCT (default: 0.0): Minimal central system mass, in GeV/c²
  • ECUT (default: 0.0): Minimal energy for any single central particle, in GeV
  • ETMN&ETMX (default: -2.5 → 2.5): Pseudo-rapidity range for central outgoing particles
  • YMIN&YMAX (default: -5.0 → 5.0): Rapidity range for central outgoing particles

Outgoing protons / remnants

  • HADR: Hadronisation algorithm
  • MXMN & MXMX (default: 1.07 $=m_p+m _ {\pi^{0}}$ → 320.0): Invariant mass range of proton remnants, in GeV/c²
  • XIMN & XIMX (default: 0.0 → 1.0): Fractional longitudinal momentum loss $\xi = \Delta p/p$

(configuration-card-example-lpair)=

Configuration card example

The generation of 100k single-dissociative $\gg{\mu^+\mu^-}$ events at 13 TeV with the LPAIR matrix element implementation with the following phase space cuts:

  • $\pt(\mu^\pm)&gt;$ 25 GeV, $\lvert\eta(\mu^\pm)\rvert< $ 2.5
  • 1.07 $&lt; M_X &lt;$ 1000 GeV

can be steered using the following card:

PROC lpair
MODE 3      ! inelastic-elastic
PAIR 13     ! muons
IN1P 6500.
IN2P 6500.
PMOD 11     ! Suri-Yennie
PTCT 25.
ETMN -2.5
ETMX 2.5
ECUT 0.
MXMN 1.07
MXMX 1000.
NGEN 100000 ! generate 100k events
OUTP lhef
OUTF lpair-example.lhe

This configuration is equivalent to the Python card shown here.