Comparison of quark and gluon jets produced in high-energye+e−annihilations

Abstract

Three-jet events produced in e + e ~ annihilations are used to provide comparisons between quark and gluon jets. Differences between quark-induced and gluon-induced jets are observed. Quark jets tend to have a more tightly collimated structure than gluon jets, which is reflected in the concentration of a larger fraction of the jet's energy near the jet axis. PACS numbers: 13.87.Fh, 12.38.Qk, 13.65.+i Quantum chromodynamics (QCD) has been proposed as a theory for the strong interactions. 1 In this theory, the strong force is mediated by the exchange of massless vector gluons between quarks, the fundamental constituents of strongly interacting particles. The coupling of quarks to gluons is expected to decrease with increasing momentum transfer so that in high-g 2 processes calculations based on perturbation theory are valid. However, in applications of QCD to experimental situations, effects of the transition from the unobservable quarks and gluons to the physically observable hadrons (the socalled hadronization process) are unavoidable. This is a complex sequence of low-g 2 processes for which the techniques of perturbative QCD are not applicable and phenomenological models must be used. Uncertainties in these models present a major obstacle to the detailed testing of QCD. It is thus important to obtain experimental insight into the hadronization process using reactions where the primary parton dynamics are well understood. High-energy e + e ~ annihilations, because of their basic simplicity, are well suited for these purposes. e + e~ annihilation into three jets of hadrons, which is most simply interpreted as consisting of two quark jets and one gluon jet, provides an opportunity for direct 1772

Measurement of the charged-particle multiplicity inside jets from $$\sqrt{s}=8$$ s = 8 $${\mathrm{TeV}}$$ TeV pp collisions with the ATLAS detector

“…The measurement of the charged-particle multiplicity inside jets has a long history from the SPS [7–9], PETRA [10, 11], PEP [12–15], TRISTAN [16], CESR [17], LEP [18–29], and the Tevatron [30]. At the LHC, both ATLAS [31, 32] and CMS [33] have measured the charged-particle multiplicity inside jets at .…”

Simulation studies of R2(Δη,Δφ) and P2(Sahoo1, Nandi2, Pujahari3 et al. 2019Phys. Rev. C6040View full textAdd to dashboardCite

“…This behavior likely stems from the fact that high-multiplicity events favor gluon jets. These are less collimated than quark jets and feature softer particles on average [52]. Evidently, such variations are not possible with the R CI 2 correlators.…”

Hadron Production in Quark, Antiquark, and Gluon Jets from Electron-Positron Interactions at the Z0 Pole

“…The results from these experiments were inconsistent. Some of them (HRS [96], MARK II [97], UA2 [98], UA1 [99], PLUTO [100], AMY [101]) showed small differences between quark and gluon jets, and some of them (TASSO [102], JADE [103], CELLO [104]) did not show any difference, so the interpretation of the results was inconclusive.…”