Tuning and test of fragmentation models based on identified particles and precision event shape data

Abstract

Event shape and charged particle inclusive distributions are measured using 750000 decays of the Z to hadrons from the DELPHI detector at LEP. These precise data allow a decisive confrontation with models of the hadronization process. Improved tunings of the JETSET, ARIADNE and HERWIG parton shower models and the JETSET matrix element model are obtained by tting the models to these DELPHI data as well as to identi ed particle distributions from all LEP experiments. The description of the data distributions by the models is critically reviewed with special importance attributed to identi ed particles.(To be submitted to Zeit. Phys. C) ii

Logarithmic accuracy of angular-ordered parton showers

“…In order to tune the shower and light quark hadronization parameters we used data on jet rates and event shapes for centre-of-mass energies between 14 and 44 GeV [40][41][42][43], at LEP1 and SLD [42][43][44][45][46][47] and LEP2 [42,43,46,47], particle multiplicities [44,45] and spectra [44,45,[48][49][50][51][52][53][54][55][56][57][58][59][60] at LEP 1, identified particle spectra below the Υ(4S) from Babar [61], the charged particle multiplicity and distributions from [62][63][64][65][66][67] for centre-of-mass energies between 14 and 61 GeV, the charged particle multiplicity [68,69] and particle spectra [68,70,71] in light quark events at LEP1 and SLD, the charged particle multiplicity in light quark events at LEP2 [72,73], the cha...…”

“…The hadronization parameters for charm quarks were tuned using the charged multiplicity in charm events at HRS [64], SLD [69] and LEP2 [72,73], the light hadron spectra in charm events at LEP1 and SLD [68,70,71], the multiplicities of charm hadrons at the Z-pole [44,77], and charm hadron spectra below the Υ(4S) [80][81][82] and at LEP1 [83].…”

CMS Physics Technical Design Report, Volume II: Physics Performance

“…PARJ ( Alternatively, or additionally, it would also be important to compare pythia with herwig with consistent tunings from LEP [787][788][789]; in doing so it is important to factorise the UE description (see next section) that can induce important differences in the results.…”

Rivet user manual

“…• Running analyses: rivet -a DELPHI_1996_S3430090 fifo.hepmc will run the Rivet DELPHI_1996_S3430090 [10] analysis on the events in the fifo.hepmc file (which, from the name, is probably a filesystem named pipe rather than a normal file). This analysis is the one originally used for the Delphi "Professor" generator tuning.…”