CMS-PAS-FSQ-12-022 | ||
Jet properties in low and high multiplicity events in p-p collisions at 7 TeV | ||
CMS Collaboration | ||
2013 | ||
Abstract: The characteristics of multi-particle production in p-p collisions at $\sqrt{s}=7$ TeV arestudied as a function of the event charged particle multiplicity ($N_{\rm ch}$), by classifying the measured tracks into two distinct classes, those belonging to jets and those belonging to the underlying event (UE). Charged tracks are measured within pseudorapidity $|\eta|<$ 2.4 and transverse momenta above $p_{T}$~=~0.25~GeV/c, and charged-particle jets are reconstructed above $p_{T}$~=~5~GeV/c with track-only information. The distributions of jet $p_{T}$, average $p_{T}$ of UE tracks and jets, jet rates, and jet shapes are studied as a function of $N_{\rm ch}$ and are compared to the predictions of the \textsc{pythia} and \textsc{herwig} Monte Carlo (MC) event generators. As the event-multiplicity increases, \textsc{pythia} systematically predicts higher jet rates and harder $p_{T}$ spectra than seen in the data, whereas \textsc{herwig} shows the opposite trend. Predictions without multi-parton interactions fail completely to describe the data. In the lowest-multiplicity events, the data show narrower jets than predicted by both MC generators. | ||
Links:
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These preliminary results are superseded in this paper, EPJC 73 (2013) 2674. The superseded preliminary plots can be found here. |
Compact Muon Solenoid LHC, CERN |