Transverse-momentum-ordered showers and interleaved multiple interactions

By Torbjörn Sjöstrand, Peter Z. Skands. 2004

408 citations recorded by the source corpus.

Abstract.We propose a sophisticated framework for high-energy hadronic collisions, wherein different QCD physics processes are interleaved in a common sequence of falling transverse-momentum values. Thereby phase-space competition is introduced between multiple parton-parton interactions and initial-state radiation. As a first step we develop new transverse-momentum-ordered showers for initial- and final-state radiation, which should be of use also beyond the scope of the current article. These showers are then applied in the context of multiple interactions, and a few tests of the new model are presented. The article concludes with an outlook on further aspects, such as the possibility of a shower branching giving partons participating in two different interactions.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/514ae0fa2fa57c406726a5adb334decd3fca8ff7

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In Nuclear and High Energy Physics

Citations in the corpus

String formation beyond leading colour (2015, methodology): “In the new (interleaved) MPI model in PYTHIA 6 [14, 28], showers and MPI were carried out in parallel, with physical colour flows.”
A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector (2015, neutral): “The baseline samples use PYTHIA for the 2 → 2 matrix element calculation, as well as pT-ordered parton showers [12] and the Lund string model [13] for hadronization.”
Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report (2016, background): “The evolution variable p⊥ is defined in Pythia as: p2⊥,evol = p2⊥ = { (1− z)Q2 for ISR z(1− z)Q2 for FSR (V.8) where Q2 > 0 is the virtuality of the branching parton.”
Coherent parton showers with local recoils (2009, background): “ed in order to take into account mass eﬀects and improve the phase space coverage [8] or to incorporate intertwined interactions with partons from additional hard interactions in the underlying event [9]. Other developments try to incorporate quantum interference eﬀects or subleading terms in the ex”
Jet energy measurement and its systematic uncertainty in proton–proton collisions at $$\sqrt{s}=7$$s=7 TeV with the ATLAS detector (2015, methodology): “The modelling of non-perturbative physics effects arising in MPI, fragmentation, and hadronisation is based on the ATLAS AUET2B MRST LO** tune.”
QCD matrix elements and truncated showers (2009, methodology): “There is the class of PYTHIA-like parton showers using either virtuality [51] or transverse momentum [52] as evolution variable.”
The midpoint between dipole and parton showers (2015, positive): “The two event generation frameworks Pythia [5,6] and Sherpa [7,8] are used to construct two entirely independent Monte Carlo programs.”
Towards an understanding of jet substructure (2013, background): “The top-left plot of figure 16 shows the comparison between the different showers in Pythia 6 and Pythia 8: the virtuality-ordered one in Pythia 6, our default, and the ptordered one in Pythia 6 [70] (in the Perugia 2011 [71] tune) and the pt-ordered shower from Pythia 8 [18] (in the 4C tune [72]).”
Colour reconnections in Herwig++ (2012, background): “r but will be replaced by a new approach [20]. The current model in Pythia diers from the original development in some details and follows the idea of interleaved partonic interactions and showering [21,22]. In the recent releases of Herwig an MPI model is also included [23]. It comes with two main ”
Les Houches 2017: Physics at TeV Colliders Standard Model Working Group Report (2017, methodology): “Both generators provide an option for using different shower modules, however at this stage of the project we only use default parton showers algorithms5: the angular ordered shower in HERWIG [702] and p⊥-ordered shower in PYTHIA [1013].”
Parton Shower Uncertainties in Jet Substructure Analyses with Deep Neural Networks (2016, background): “[61] T.”