CMS-PAS-SMP-22-015

CMS-PAS-SMP-22-015
Measurement of energy correlators inside jets and determination of the strong coupling constant
CMS Collaboration
2 August 2023

Abstract: We measure the two-point and three-point energy correlator jet substructure observables (E2C and E3C), using LHC 13 TeV data collected by the CMS experiment. These measurements reveal in a straightforward way the two most important features of strong interactions, confinement and asymptotic freedom. The E2C and E3C distributions show a sharp transition from the falling scaling behavior characterizing the quantum interactions of quarks and gluons to an integer power law reflective of classical noninteracting hadrons. The ratio of E3C/E2C is directly proportional to the strong coupling constant $ \alpha_S $. The slopes of the ratio of the distribution of E3C and E2C are measured in multiple jet transverse momentum regions, consistent with the expected decrease of $ \alpha_S $ with increasing energy due to asymptotic freedom. Measurements of scaling behavior are compared to theoretical predictions with all-orders resummation at next-to-next-to-leading logarithmic accuracy matched to a fixed-order next-to-leading order calculation, yielding an $ \alpha_S (m_{\mathrm{Z}}) $ value of 0.1229$ ^{+0.0040}_{-0.0050} $. This is the most precise extraction of $ \alpha_S (m_{\mathrm{Z}}) $ using jet substructure observables to date.
Links: CDS record (PDF) ; Physics Briefing ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to PRL. The superseded preliminary plots can be found here.

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