CMS-PAS-GEN-19-001 | ||

Extraction and validation of a set of HERWIG 7 tunes from CMS underlying-event measurements | ||

CMS Collaboration | ||

May 2020 | ||

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Abstract:
This note presents a new set of parameters ("tunes") for the underlying-event model of the HERWIG 7 event generator. The parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG 7, and are obtained from a fit to underlying-event and minimum-bias data collected by the CMS experiment at $\sqrt{s}=$ 0.9, 7, and 13 TeV. The tunes are based on the NNPDF3.13.1 next-to-next-to-leading-order PDF set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event-shape observables, and minimum-bias, dijet, top quark pair, and weak boson events, and are compared to data. Each of the new tunes describe the data to a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI are found to provide the best description of the data.
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Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, EPJC 81 (2021) 312.The superseded preliminary plots can be found here. |

Figures | |

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Figure 1:
Illustration of the different $\phi $ regions, with respect to the leading object in an event, used to probe the properties of the UE in experimental measurements. |

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Figure 2:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${\frac {dN_{\mathrm {ch}}}{d\eta}}$, the pseudorapidity of charged hadrons [26]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 3:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 3-a:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 3-b:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 3-c:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 3-d:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 4:
CMS data at $ {\sqrt {s}} = $ 7 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [22]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 4-a:
CMS data at $ {\sqrt {s}} = $ 7 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [22]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 4-b:
CMS data at $ {\sqrt {s}} = $ 7 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [22]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 4-c:
CMS data at $ {\sqrt {s}} = $ 7 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [22]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 4-d:
CMS data at $ {\sqrt {s}} = $ 7 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [22]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 5:
CMS data at $ {\sqrt {s}} = $ 0.9 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the transverse regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track jet, ${p_{\mathrm {T}}^{\mathrm {jet}}}$ [24]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 5-a:
CMS data at $ {\sqrt {s}} = $ 0.9 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the transverse regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track jet, ${p_{\mathrm {T}}^{\mathrm {jet}}}$ [24]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 5-b:
CMS data at $ {\sqrt {s}} = $ 0.9 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the transverse regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track jet, ${p_{\mathrm {T}}^{\mathrm {jet}}}$ [24]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 6:
CDF data at $ {\sqrt {s}} = $ 1.96 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [28]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 6-a:
CDF data at $ {\sqrt {s}} = $ 1.96 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [28]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 6-b:
CDF data at $ {\sqrt {s}} = $ 1.96 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [28]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 6-c:
CDF data at $ {\sqrt {s}} = $ 1.96 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [28]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 6-d:
CDF data at $ {\sqrt {s}} = $ 1.96 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [28]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 7:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH1 and CH3 tunes, and from PYTHIA 8, with the CP1 and CP5 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 7-a:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH1 and CH3 tunes, and from PYTHIA 8, with the CP1 and CP5 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 7-b:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH1 and CH3 tunes, and from PYTHIA 8, with the CP1 and CP5 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 7-c:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH1 and CH3 tunes, and from PYTHIA 8, with the CP1 and CP5 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 7-d:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH1 and CH3 tunes, and from PYTHIA 8, with the CP1 and CP5 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

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Figure 8:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${\frac {dN_{\mathrm {ch}}}{d\eta}}$, the pseudorapidity of charged hadrons [26]. The data are compared to predictions from HERWIG 7, with the CH1 and CH3 tunes, and from PYTHIA 8, with the CP1 and CP5 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 9:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. The grey shaded band corresponds to the envelope of the "up" and "down" variations of the CH3 tune. |

png pdf |
Figure 9-a:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. The grey shaded band corresponds to the envelope of the "up" and "down" variations of the CH3 tune. |

png pdf |
Figure 9-b:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. The grey shaded band corresponds to the envelope of the "up" and "down" variations of the CH3 tune. |

png pdf |
Figure 9-c:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. The grey shaded band corresponds to the envelope of the "up" and "down" variations of the CH3 tune. |

png pdf |
Figure 9-d:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (upper) and ${N_{\mathrm {ch}}}$ (lower) distributions in the transMin (left) and transMax (right) regions, as a function of the ${p_{\mathrm {T}}}$ of the leading track, ${p_{\mathrm {T}}^{\mathrm {max}}}$ [23]. The data are compared to predictions from HERWIG 7, with the CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. The grey shaded band corresponds to the envelope of the "up" and "down" variations of the CH3 tune. |

png pdf |
Figure 10:
CMS data at $ {\sqrt {s}} = $ 13 TeV on the ${\frac {dN_{\mathrm {ch}}}{d\eta}}$, the pseudorapidity of charged hadrons [26]. The data are compared to predictions from HERWIG 7, with the CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. The grey shaded band corresponds to the envelope of the "up" and "down" variations of the CH3 tune. |

png pdf |
Figure 11:
ALEPH data at $ {\sqrt {s}} = $ 91.2 GeV showing the T (upper left), T$_{\mathrm {major}}$ (upper right), {O} (lower left), and {S} (lower right) event-shape observables [29]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tune. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 11-a:
ALEPH data at $ {\sqrt {s}} = $ 91.2 GeV showing the T (upper left), T$_{\mathrm {major}}$ (upper right), {O} (lower left), and {S} (lower right) event-shape observables [29]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tune. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 11-b:
ALEPH data at $ {\sqrt {s}} = $ 91.2 GeV showing the T (upper left), T$_{\mathrm {major}}$ (upper right), {O} (lower left), and {S} (lower right) event-shape observables [29]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tune. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 11-c:
ALEPH data at $ {\sqrt {s}} = $ 91.2 GeV showing the T (upper left), T$_{\mathrm {major}}$ (upper right), {O} (lower left), and {S} (lower right) event-shape observables [29]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tune. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 11-d:
ALEPH data at $ {\sqrt {s}} = $ 91.2 GeV showing the T (upper left), T$_{\mathrm {major}}$ (upper right), {O} (lower left), and {S} (lower right) event-shape observables [29]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tune. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 12:
CMS data at $ {\sqrt {s}} = $ 13 TeV [35,38] of the ${p_{\mathrm {T}}}$ (upper left) and rapidity $y$ (upper right) of the hadronically decaying top quark, the invariant mass of the ${\mathrm{t} {}\mathrm{\bar{t}}}$ system (middle left), and the additional jet multiplicity (middle right). The ${H_{\mathrm {T}}}$ (lower left) and ${{p_{\mathrm {T}}} ^\text {miss}}$ (lower right) in single-leptonic ${\mathrm{t} {}\mathrm{\bar{t}}}$ events are also shown. The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 12-a:
CMS data at $ {\sqrt {s}} = $ 13 TeV [35,38] of the ${p_{\mathrm {T}}}$ (upper left) and rapidity $y$ (upper right) of the hadronically decaying top quark, the invariant mass of the ${\mathrm{t} {}\mathrm{\bar{t}}}$ system (middle left), and the additional jet multiplicity (middle right). The ${H_{\mathrm {T}}}$ (lower left) and ${{p_{\mathrm {T}}} ^\text {miss}}$ (lower right) in single-leptonic ${\mathrm{t} {}\mathrm{\bar{t}}}$ events are also shown. The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 12-b:
CMS data at $ {\sqrt {s}} = $ 13 TeV [35,38] of the ${p_{\mathrm {T}}}$ (upper left) and rapidity $y$ (upper right) of the hadronically decaying top quark, the invariant mass of the ${\mathrm{t} {}\mathrm{\bar{t}}}$ system (middle left), and the additional jet multiplicity (middle right). The ${H_{\mathrm {T}}}$ (lower left) and ${{p_{\mathrm {T}}} ^\text {miss}}$ (lower right) in single-leptonic ${\mathrm{t} {}\mathrm{\bar{t}}}$ events are also shown. The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 12-c:
CMS data at $ {\sqrt {s}} = $ 13 TeV [35,38] of the ${p_{\mathrm {T}}}$ (upper left) and rapidity $y$ (upper right) of the hadronically decaying top quark, the invariant mass of the ${\mathrm{t} {}\mathrm{\bar{t}}}$ system (middle left), and the additional jet multiplicity (middle right). The ${H_{\mathrm {T}}}$ (lower left) and ${{p_{\mathrm {T}}} ^\text {miss}}$ (lower right) in single-leptonic ${\mathrm{t} {}\mathrm{\bar{t}}}$ events are also shown. The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 12-d:
CMS data at $ {\sqrt {s}} = $ 13 TeV [35,38] of the ${p_{\mathrm {T}}}$ (upper left) and rapidity $y$ (upper right) of the hadronically decaying top quark, the invariant mass of the ${\mathrm{t} {}\mathrm{\bar{t}}}$ system (middle left), and the additional jet multiplicity (middle right). The ${H_{\mathrm {T}}}$ (lower left) and ${{p_{\mathrm {T}}} ^\text {miss}}$ (lower right) in single-leptonic ${\mathrm{t} {}\mathrm{\bar{t}}}$ events are also shown. The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 12-e:
CMS data at $ {\sqrt {s}} = $ 13 TeV [35,38] of the ${p_{\mathrm {T}}}$ (upper left) and rapidity $y$ (upper right) of the hadronically decaying top quark, the invariant mass of the ${\mathrm{t} {}\mathrm{\bar{t}}}$ system (middle left), and the additional jet multiplicity (middle right). The ${H_{\mathrm {T}}}$ (lower left) and ${{p_{\mathrm {T}}} ^\text {miss}}$ (lower right) in single-leptonic ${\mathrm{t} {}\mathrm{\bar{t}}}$ events are also shown. The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 12-f:
CMS data at $ {\sqrt {s}} = $ 13 TeV [35,38] of the ${p_{\mathrm {T}}}$ (upper left) and rapidity $y$ (upper right) of the hadronically decaying top quark, the invariant mass of the ${\mathrm{t} {}\mathrm{\bar{t}}}$ system (middle left), and the additional jet multiplicity (middle right). The ${H_{\mathrm {T}}}$ (lower left) and ${{p_{\mathrm {T}}} ^\text {miss}}$ (lower right) in single-leptonic ${\mathrm{t} {}\mathrm{\bar{t}}}$ events are also shown. The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 13:
CMS data at $ {\sqrt {s}} = $ 13 TeV [39] of several jet substructure observables: the charged-particle multiplicity (upper left), the eccentricity (upper right), the groomed momentum fraction (lower left), and angle between the groomed subjets (lower right). The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 13-a:
CMS data at $ {\sqrt {s}} = $ 13 TeV [39] of several jet substructure observables: the charged-particle multiplicity (upper left), the eccentricity (upper right), the groomed momentum fraction (lower left), and angle between the groomed subjets (lower right). The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 13-b:
CMS data at $ {\sqrt {s}} = $ 13 TeV [39] of several jet substructure observables: the charged-particle multiplicity (upper left), the eccentricity (upper right), the groomed momentum fraction (lower left), and angle between the groomed subjets (lower right). The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 13-c:
CMS data at $ {\sqrt {s}} = $ 13 TeV [39] of several jet substructure observables: the charged-particle multiplicity (upper left), the eccentricity (upper right), the groomed momentum fraction (lower left), and angle between the groomed subjets (lower right). The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 13-d:
CMS data at $ {\sqrt {s}} = $ 13 TeV [39] of several jet substructure observables: the charged-particle multiplicity (upper left), the eccentricity (upper right), the groomed momentum fraction (lower left), and angle between the groomed subjets (lower right). The data are compared to predictions from {powheg} + HERWIG 7, with the SoftTune, CH1, CH2, and CH3 tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 14:
CMS dijet data at $ {\sqrt {s}} = $ 7 TeV on ${\rho (\mathrm {r})}$ and ${< \delta R^2 >} [40]$. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 14-a:
CMS dijet data at $ {\sqrt {s}} = $ 7 TeV on ${\rho (\mathrm {r})}$ and ${< \delta R^2 >} [40]$. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 14-b:
CMS dijet data at $ {\sqrt {s}} = $ 7 TeV on ${\rho (\mathrm {r})}$ and ${< \delta R^2 >} [40]$. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 14-c:
CMS dijet data at $ {\sqrt {s}} = $ 7 TeV on ${\rho (\mathrm {r})}$ and ${< \delta R^2 >} [40]$. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 15:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the towards (upper), away (middle), and transverse (lower) regions, as a function of the ${p_{\mathrm {T}}}$ of the two muons, ${{p_{\mathrm {T}}} (\mu \mu)}$ [42]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 15-a:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the towards (upper), away (middle), and transverse (lower) regions, as a function of the ${p_{\mathrm {T}}}$ of the two muons, ${{p_{\mathrm {T}}} (\mu \mu)}$ [42]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 15-b:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the towards (upper), away (middle), and transverse (lower) regions, as a function of the ${p_{\mathrm {T}}}$ of the two muons, ${{p_{\mathrm {T}}} (\mu \mu)}$ [42]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 15-c:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the towards (upper), away (middle), and transverse (lower) regions, as a function of the ${p_{\mathrm {T}}}$ of the two muons, ${{p_{\mathrm {T}}} (\mu \mu)}$ [42]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 15-d:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the towards (upper), away (middle), and transverse (lower) regions, as a function of the ${p_{\mathrm {T}}}$ of the two muons, ${{p_{\mathrm {T}}} (\mu \mu)}$ [42]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 15-e:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the towards (upper), away (middle), and transverse (lower) regions, as a function of the ${p_{\mathrm {T}}}$ of the two muons, ${{p_{\mathrm {T}}} (\mu \mu)}$ [42]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 15-f:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV on the ${p_{\mathrm {T}}^{\mathrm {sum}}}$ density (left) and ${N_{\mathrm {ch}}}$ (right) distributions in the towards (upper), away (middle), and transverse (lower) regions, as a function of the ${p_{\mathrm {T}}}$ of the two muons, ${{p_{\mathrm {T}}} (\mu \mu)}$ [42]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 16:
The exclusive jet multiplicity in Z (left) and W (right) boson events, measured by CMS at $ {\sqrt {s}} = $ 13 TeV [43,44]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 16-a:
The exclusive jet multiplicity in Z (left) and W (right) boson events, measured by CMS at $ {\sqrt {s}} = $ 13 TeV [43,44]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 16-b:
The exclusive jet multiplicity in Z (left) and W (right) boson events, measured by CMS at $ {\sqrt {s}} = $ 13 TeV [43,44]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 17:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV showing the measured distributions of ${{p_{\mathrm {T}}} ({\mathrm{Z}})}$ (upper left), ${{p_{\mathrm {T}}} ^{\mathrm {bal}}}$ (upper right), and JZB (lower) [43]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 17-a:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV showing the measured distributions of ${{p_{\mathrm {T}}} ({\mathrm{Z}})}$ (upper left), ${{p_{\mathrm {T}}} ^{\mathrm {bal}}}$ (upper right), and JZB (lower) [43]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 17-b:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV showing the measured distributions of ${{p_{\mathrm {T}}} ({\mathrm{Z}})}$ (upper left), ${{p_{\mathrm {T}}} ^{\mathrm {bal}}}$ (upper right), and JZB (lower) [43]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 17-c:
CMS data on Z boson production at $ {\sqrt {s}} = $ 13 TeV showing the measured distributions of ${{p_{\mathrm {T}}} ({\mathrm{Z}})}$ (upper left), ${{p_{\mathrm {T}}} ^{\mathrm {bal}}}$ (upper right), and JZB (lower) [43]. The data are compared to predictions from MG5_aMC@NLO + HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 18:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 18-a:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 18-b:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 18-c:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 18-d:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 19:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 19-a:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 19-b:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 19-c:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 19-d:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the pseudorapidity of charged particles for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left), $ {N_{\mathrm {ch}}} \ge $ 20 (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 20:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 20-a:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 20-b:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 20-c:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 20-d:
ATLAS data at $ {\sqrt {s}} = $ 900 GeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 21:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 21-a:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 21-b:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 21-c:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 21-d:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV [45] on the charged-particle ${p_{\mathrm {T}}}$ for $ {N_{\mathrm {ch}}} \ge $ 1 (upper left), $ {N_{\mathrm {ch}}} \ge $ 2 (upper right), $ {N_{\mathrm {ch}}} \ge $ 6 (lower left). The mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity is also shown (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 22:
ATLAS data at $ {\sqrt {s}} = $ 13 TeV [46]. The upper row shows the pseudorapidity of charged particles for $|\eta | < 2.5$ (upper left), and $|\eta | < 0.8$ (upper right). The middle row shows the charged-particle ${p_{\mathrm {T}}}$ for $|\eta | < 2.5$ (middle left), and $|\eta | < 0.8$ (middle right). The final row shows the mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity the for $|\eta | < 2.5$ (lower left), and $|\eta | < 0.8$ (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 22-a:
ATLAS data at $ {\sqrt {s}} = $ 13 TeV [46]. The upper row shows the pseudorapidity of charged particles for $|\eta | < 2.5$ (upper left), and $|\eta | < 0.8$ (upper right). The middle row shows the charged-particle ${p_{\mathrm {T}}}$ for $|\eta | < 2.5$ (middle left), and $|\eta | < 0.8$ (middle right). The final row shows the mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity the for $|\eta | < 2.5$ (lower left), and $|\eta | < 0.8$ (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 22-b:
ATLAS data at $ {\sqrt {s}} = $ 13 TeV [46]. The upper row shows the pseudorapidity of charged particles for $|\eta | < 2.5$ (upper left), and $|\eta | < 0.8$ (upper right). The middle row shows the charged-particle ${p_{\mathrm {T}}}$ for $|\eta | < 2.5$ (middle left), and $|\eta | < 0.8$ (middle right). The final row shows the mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity the for $|\eta | < 2.5$ (lower left), and $|\eta | < 0.8$ (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 22-c:
ATLAS data at $ {\sqrt {s}} = $ 13 TeV [46]. The upper row shows the pseudorapidity of charged particles for $|\eta | < 2.5$ (upper left), and $|\eta | < 0.8$ (upper right). The middle row shows the charged-particle ${p_{\mathrm {T}}}$ for $|\eta | < 2.5$ (middle left), and $|\eta | < 0.8$ (middle right). The final row shows the mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity the for $|\eta | < 2.5$ (lower left), and $|\eta | < 0.8$ (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 22-d:
ATLAS data at $ {\sqrt {s}} = $ 13 TeV [46]. The upper row shows the pseudorapidity of charged particles for $|\eta | < 2.5$ (upper left), and $|\eta | < 0.8$ (upper right). The middle row shows the charged-particle ${p_{\mathrm {T}}}$ for $|\eta | < 2.5$ (middle left), and $|\eta | < 0.8$ (middle right). The final row shows the mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity the for $|\eta | < 2.5$ (lower left), and $|\eta | < 0.8$ (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 22-e:
ATLAS data at $ {\sqrt {s}} = $ 13 TeV [46]. The upper row shows the pseudorapidity of charged particles for $|\eta | < 2.5$ (upper left), and $|\eta | < 0.8$ (upper right). The middle row shows the charged-particle ${p_{\mathrm {T}}}$ for $|\eta | < 2.5$ (middle left), and $|\eta | < 0.8$ (middle right). The final row shows the mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity the for $|\eta | < 2.5$ (lower left), and $|\eta | < 0.8$ (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 22-f:
ATLAS data at $ {\sqrt {s}} = $ 13 TeV [46]. The upper row shows the pseudorapidity of charged particles for $|\eta | < 2.5$ (upper left), and $|\eta | < 0.8$ (upper right). The middle row shows the charged-particle ${p_{\mathrm {T}}}$ for $|\eta | < 2.5$ (middle left), and $|\eta | < 0.8$ (middle right). The final row shows the mean charged-particle ${p_{\mathrm {T}}}$ as a function of the charged-particle multiplicity the for $|\eta | < 2.5$ (lower left), and $|\eta | < 0.8$ (lower right). The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 23:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV on the ${F(z)}$ and ${f(p_{\mathrm {T}}^{\mathrm {rel}}})$ distributions [47]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 23-a:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV on the ${F(z)}$ and ${f(p_{\mathrm {T}}^{\mathrm {rel}}})$ distributions [47]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 23-b:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV on the ${F(z)}$ and ${f(p_{\mathrm {T}}^{\mathrm {rel}}})$ distributions [47]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 23-c:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV on the ${F(z)}$ and ${f(p_{\mathrm {T}}^{\mathrm {rel}}})$ distributions [47]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

png pdf |
Figure 23-d:
ATLAS data at $ {\sqrt {s}} = $ 7 TeV on the ${F(z)}$ and ${f(p_{\mathrm {T}}^{\mathrm {rel}}})$ distributions [47]. The data are compared to predictions from HERWIG 7, with the SoftTune and CH tunes. The coloured band in the ratios of the different predictions from simulation to the data represents the total experimental uncertainty in the data. |

Tables | |

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Table 1:
Parameters considered in the tuning, and their allowed ranges in the fit. |

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Table 2:
Values of the parameters for SoftTune [12,3], CH1, CH2, and CH3. |

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Table 3:
Parameters of the central, "up", and "down" variations of the CH3 tune. |

Summary |

Three new tunes for the multiple-parton interaction (MPI) model of the HERWIG 7 generator have been derived from minimum-bias (MB) and underlying-event (UE) data collected by the CMS experiment. These tunes are based on the NNPDF3.1 PDF sets, and are labelled CH1, CH2, and CH3. All of the CH tunes are based on the NNLO NNPDF3.1 set for the simulation of the parton shower (PS) in HERWIG 7, and the value of the strong coupling is ${\alpha_S}(m_{\mathrm{Z}})=$ 0.118 with a two-loop evolution of ${\alpha_S}$. The configuration of the tunes differ in the PDF used for the simulation of MPI and beam remnants. The tune CH1 uses the same NNLO PDF set for these aspects of the HERWIG 7 simulation, whereas CH2 and CH3 use LO versions of the PDF set. The tune CH2 is based on a LO PDF set that was derived assuming ${\alpha_S}(m_{\mathrm{Z}})=$ 0.118, and CH3 on a LO PDF set assumixng ${\alpha_S}(m_{\mathrm{Z}})=$ 0.130. The parameters of the MPI model were optimised for each tune with the PROFESSOR framework to describe MB and UE data collected by CMS. The predictions using the tunes CH2 and CH3, where a LO PDF was used for the simulation of MPI, were found to provide the best description of the data. Furthermore, the differences in the predictions of CH2 and CH3 were observed to be small. Given the configuration of PDF sets in the tune CH3, where the LO PDF used for the simulation of MPI was derived with a value of ${\alpha_S}$ typically associated with LO PDF sets, this tune is the preferred choice between the two tunes CH2 and CH3. Two alternative tunes representing the uncertainties in the tuned parameters of CH3, based on the eigentunes provided by PROFESSOR from the tuning procedure, are also provided. These tunes allow the uncertainty in predictions using the CH3 tune to be estimated. Predictions using the three CH tunes are compared against a range of data beyond MB and UE events : event-shape data from LEP; data enriched in top quark pairs and weak bosons; and inclusive jet data. This validated the performance of HERWIG 7 using these tunes against a wide range of data sensitive to various aspects of the modelling by HERWIG 7, and in particular the modelling of the UE. Comparisons against event-shape observables measured at LEP, which are sensitive to the modelling of final-state radiation, are well described by HERWIG 7 with the new tunes. Predictions using the new tunes were also shown to describe the UE in events containing Z bosons, demonstrating the universality of the UE modelling in HERWIG 7 at different energy scales. The kinematics of top quarks, and the modelling of jets in $ \mathrm{t\bar{t}}$, Z boson, W boson, and inclusive dijet data was also shown to be well described by predictions using the new tunes. In general, predictions with the new CH tunes derived in this note provide a better description of measured observables than those using one of the default tunes available in HERWIG 7 referred to as SoftTune. |

References | ||||

1 |
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2 |
J. Bellm et al. | HERWIG 7.0/HERWIG++ 3.0 release note | EPJC 76 (2016) 196 | 1512.01178 |

3 |
J. Bellm et al. | HERWIG 7.1 release note | 1705.06919 | |

4 |
T. Sjostrand et al. | An introduction to PYTHIA 8.2 | CPC 191 (2015) 159 | 1410.3012 |

5 |
S. Platzer and S. Gieseke | Dipole showers and automated NLO matching in HERWIG++ | EPJC 72 (2012) 2187 | 1109.6256 |

6 |
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Compact Muon Solenoid LHC, CERN |