Direct observation of the dead-cone effect in quantum chromodynamics

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F22%3A00558284" target="_blank" >RIV/68378271:_____/22:00558284 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61389005:_____/22:00558284 RIV/68407700:21340/22:00363955

Výsledek na webu

<a href="https://doi.org/10.1038/s41586-022-04572-w" target="_blank" >https://doi.org/10.1038/s41586-022-04572-w</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1038/s41586-022-04572-w" target="_blank" >10.1038/s41586-022-04572-w</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Direct observation of the dead-cone effect in quantum chromodynamics

Popis výsledku v původním jazyce

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 shower(2), 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 m(Q) and energy E, within a cone of angular size m(Q)/E around the emitter(3). 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 techniques(4,5) 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.

Název v anglickém jazyce

Direct observation of the dead-cone effect in quantum chromodynamics

Popis výsledku anglicky

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 shower(2), 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 m(Q) and energy E, within a cone of angular size m(Q)/E around the emitter(3). 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 techniques(4,5) 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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10303 - Particles and field physics

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Nature

ISSN

0028-0836

e-ISSN

1476-4687

Svazek periodika

605

Číslo periodika v rámci svazku

7910

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

9

Strana od-do

440-446

Kód UT WoS článku

000797641900017

EID výsledku v databázi Scopus

2-s2.0-85130231262