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Direct observation of the dead-cone effect in quantum chromodynamics

Acharya, S. ; Adolfsson, J. LU ; Basu, S. LU orcid ; Christiansen, P. LU ; Matonoha, O. LU ; Nassirpour, A.F. LU orcid ; Ohlson, A. LU ; Oskarsson, A. LU ; Richert, T. LU and Rueda, O.V. LU , et al. (2022) In Nature 605(7910). p.440-446
Abstract
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... (More)
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). (Less)
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publishing date
type
Contribution to journal
publication status
published
subject
keywords
experimental study, momentum transfer, observational method, physics, article, gluon, hadron, plant cone, quark, food, motion, Food, Motion, Physics
in
Nature
volume
605
issue
7910
pages
7 pages
publisher
Nature Publishing Group
external identifiers
  • scopus:85130231262
  • pmid:35585340
ISSN
0028-0836
DOI
10.1038/s41586-022-04572-w
language
English
LU publication?
yes
additional info
Number of authors = 1026 EID = 85130231262 Start page = 440 End page = 446 Affiliation = Acharya, S., Variable Energy Cyclotron Centre, Homi Bhabha National Institute, Kolkata, India Affiliation = Zurlo, N., INFN, Sezione di Pavia, Pavia, Italy, Universita di Brescia, Brescia, Italy Affiliation = ALICE Collaboration
id
aec6c764-3a63-4878-a01f-364e4d90ff47
date added to LUP
2022-09-12 12:23:50
date last changed
2023-05-11 09:21:57
@article{aec6c764-3a63-4878-a01f-364e4d90ff47,
  abstract     = {{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).}},
  author       = {{Acharya, S. and Adolfsson, J. and Basu, S. and Christiansen, P. and Matonoha, O. and Nassirpour, A.F. and Ohlson, A. and Oskarsson, A. and Richert, T. and Rueda, O.V. and Silvermyr, D. and Zurlo, N.}},
  issn         = {{0028-0836}},
  keywords     = {{experimental study; momentum transfer; observational method; physics; article; gluon; hadron; plant cone; quark; food; motion; Food; Motion; Physics}},
  language     = {{eng}},
  number       = {{7910}},
  pages        = {{440--446}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Nature}},
  title        = {{Direct observation of the dead-cone effect in quantum chromodynamics}},
  url          = {{http://dx.doi.org/10.1038/s41586-022-04572-w}},
  doi          = {{10.1038/s41586-022-04572-w}},
  volume       = {{605}},
  year         = {{2022}},
}