Spectral clustering for jet physics

Abstract

Abstract We present a new approach to jet definition alternative to clustering methods, such as the anti-kT scheme, that exploit kinematic data directly. Instead the new method uses kinematic information to represent the particles in a multidimensional space, as in spectral clustering. After confirming its Infra-Red (IR) safety, we compare its performance in analysing gg → H 125 GeV → H 40 GeV H 40 GeV → b b ¯ b b ¯ $$ b\overline{b}b\overline{b} $$ , gg → H 500 GeV → H 125 GeV H 125 GeV → b b ¯ b b ¯ $$ b\overline{b}b\overline{b} $$ and gg, q q ¯ $$ q\overline{q} $$ → t t ¯ $$ t\overline{t} $$ → b b ¯ W + W − $$ b\overline{b}{W}^{+}{W}^{-} $$ → b b ¯ jj ℓ v ℓ $$ b\overline{b} jj\mathrm{\ell}{v}_{\mathrm{\ell}} $$ events from Monte Carlo (MC) samples, specifically, in reconstructing the relevant final states, to that of the anti-k T algorithm. Finally, we show that the results for spectral clustering are obtained without any change in the parameter settings of the algorithm, unlike the anti-k T case, which requires the cone size to be adjusted to the physics process under study.

Keywords

• Jets
• QCD Phenomenology