The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Peter Christiansen Profile

Peter Christiansen

Professor

Peter Christiansen Profile

Direct observation of the dead-cone effect in quantum chromodynamics

Author

  • S. Acharya
  • J. Adolfsson
  • S. Basu
  • P. Christiansen
  • O. Matonoha
  • A.F. Nassirpour
  • A. Ohlson
  • A. Oskarsson
  • T. Richert
  • O.V. Rueda
  • D. Silvermyr
  • N. Zurlo
Show all

Summary, in English

In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD)1. These partons subsequently emit further partons in a process that can be described as a parton shower2, which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass mQ and energy E, within a cone of angular size mQ/E around the emitter3. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques4,5 to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics. © 2022, The Author(s).

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2022

Language

English

Pages

440-446

Publication/Series

Nature

Volume

605

Issue

7910

Document type

Journal article

Publisher

Nature Publishing Group

Topic

  • Subatomic Physics

Keywords

  • experimental study
  • momentum transfer
  • observational method
  • physics
  • article
  • gluon
  • hadron
  • plant cone
  • quark
  • food
  • motion
  • Food
  • Motion
  • Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0028-0836