Speaker
Description
The first measurement of $anti-k_{T}$ jets and two-particle angular correlations of charged particles emitted in high energy $e^+e^−$ annihilation is presented. The archived data at a center-of-mass energy of 91-209 GeV were collected with the ALEPH detector at LEP between 1992 and 2000.
At 91 GeV, no significant long-range correlation was observed in either the lab coordinate analysis or the thrust coordinate analysis, where the latter is sensitive to a medium expanding transverse to the color string between the outgoing $q\bar{q}$ pair from Z boson decays. We also present the first measurement of anti-$k_{T}$ jet energy spectra and substructures compared to various event generators, NLO, and NLL'+R resummation calculations.
The correlation functions are measured over a broad range of pseudorapidity and full azimuth as a function of charged particle multiplicity for the first time with LEP2 data. This data set provides higher event multiplicity reach up to around 50 and a chance to sample different underlying hard-scattering processes. Studies of the high energy annihilation data will expand our search for collective phenomena in $e^+e^−$ collisions to a new phase space for a potential discovery.
