Measurement of the underlying event activity in pp collisions at $ \sqrt {s} = 0.9 $ and 7 TeV with the novel jet-area/median approach

Abstract

Measurement of the underlying event activity in pp collisions at √ s = 0.9 and 7 TeV with the novel jet-area/median approach The CMS collaboration Abstract: The first measurement of the charged component of the underlying event using the novel "jet-area/median" approach is presented for proton-proton collisions at centre-ofmass energies of 0.9 and 7 TeV. The data were recorded in 2010 with the CMS experiment at the LHC. A new observable, sensitive to soft particle production, is introduced and investigated inclusively and as a function of the event scale defined by the transverse momentum of the leading jet. Various phenomenological models are compared to data, with and without corrections for detector effects. None of the examined models describe the data satisfactorily.

Energy correlation functions for jet substructure

“…On the theoretical side, there has been substantial progress in computing and understanding these observables and procedures in perturbative QCD [15][16][17][18][19][20][21][22][23]. On the experimental side, the ATLAS and CMS experiments at the Large Hadron Collider (LHC) have begun measuring and testing jet substructure ideas [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], with pile-up suppression becoming increasingly important at higher luminosities. With the recent discovery of a Higgs-like particle [40,41], jet substructure methods for identifying the H → bb decay mode [5] (and potentially the H → gg decay mode) could be vital for testing Higgs properties.…”

Soft and Semi-hard QCD Dynamics in <span class="cmmi-10">p</span>–<span class="cmmi-10">p </span>Collisions with the CMS Detector

“…3. Left: Mean values of the corrected ρ distributions versus leading chargedparticle jet transverse momentum at √ s = 7 TeV in comparison to the predictions by the different generator tunes [30]. The ρ distributions in each slice are unfolded with the Bayesian method.…”

“…In addition to a charged particle counting, a novel approach based on the Jet Area [35] has been applied as well [30]. The jet area is essentially defined as the area in the η-φ plane in which a given jet clustering algorithm picks up random ghots particles with very small momenta that are uniformly scattered in this plane.…”

Analysis of b jets in p–Pb collisions at $\sqrt{sNN}$ = 5 TeV with ALICE

“…The pseudorapidity of the jets was constrained to |η jet | < 0.5. The p T spectrum of the jets was corrected for the underlying event density with the method described in [7].…”