Charged-particle production as a function of multiplicity and transverse spherocity in pp collisions at √s=5.02 and 13 TeV

Abstract

Abstract We present a study of the inclusive charged-particle transverse momentum ( $$p_{\mathrm{T}}$$ p T ) spectra as a function of charged-particle multiplicity density at mid-pseudorapidity, $$\mathrm{d}N_{\mathrm{ch}}/\mathrm{d}\eta $$ d N ch / d η , in pp collisions at $$\sqrt{s}=5.02$$ s = 5.02 and 13 TeV covering the kinematic range $$|\eta | | η | 0.8 and $$0.15 0.15 p T 20 GeV/ c . The results are presented for events with at least one charged particle in $$|\eta | | η | 1 (INEL $$\,>0$$ > 0 ). The $$p_\mathrm{T}$$ p T spectra are reported for two multiplicity estimators covering different pseudorapidity regions. The $$p_{\mathrm{T}}$$ p T spectra normalized to that for INEL $$\,>0$$ > 0 show little energy dependence. Moreover, the high- $$p_{\mathrm{T}}$$ p T yields of charged particles increase faster than the charged-particle multiplicity density. The average $${ p}_{\mathrm{T}}$$ p T as a function of multiplicity and transverse spherocity is reported for pp collisions at $$\sqrt{s}=13$$ s = 13 TeV. For low- (high-) spherocity events, corresponding to jet-like (isotropic) events, the average $$p_\mathrm{T}$$ p T is higher (smaller) than that measured in INEL $$\,>0$$ > 0 pp collisions. Within uncertainties, the functional form of $$\langle p_{\mathrm{T}} \rangle (N_{\mathrm{ch}})$$ ⟨ p T ⟩ ( N ch ) is not affected by the spherocity selection. While EPOS LHC gives a good description of many features of data, PYTHIA overestimates the average $$p_{\mathrm{T}}$$ p T in jet-like events.