Physics:Quantum data analysis/Particle Decays: Difference between revisions
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'''Particle decays''' are transformations in which an unstable particle produces lighter final-state particles according to the allowed quantum numbers and interaction strengths. In experiments, decays provide the signatures used to discover particles, measure lifetimes, identify flavor, and test the Standard Model. Data analysis treats decays as both physics processes and reconstruction patterns made of tracks, vertices, showers, and missing energy.<ref name="pdg2024">{{cite journal |collaboration=Particle Data Group |title=Review of Particle Physics |journal=Physical Review D |volume=110 |issue=3 |pages=030001 |year=2024 |doi=10.1103/PhysRevD.110.030001}}</ref> | |||
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[[File:Quantum_data_analysis_particle_decays_yellow.png|thumb|280px|Particle | [[File:Quantum_data_analysis_particle_decays_yellow.png|thumb|280px|Particle decays represented as branching topologies in a yellow data-analysis diagram.]] | ||
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== Lifetime and width == | |||
The lifetime of an unstable state is related to its decay width. Very short-lived resonances are reconstructed statistically from invariant-mass peaks, while longer-lived particles may produce displaced vertices or visible flight paths.<ref name="griffiths">{{cite book |last=Griffiths |first=David J. |title=Introduction to Elementary Particles |edition=2nd |publisher=Wiley-VCH |year=2008 |isbn=978-3-527-40601-2}}</ref> | |||
== Branching fractions == | |||
A branching fraction is the probability that a particle decays through a particular channel. Measurements of branching fractions test couplings, symmetries, forbidden processes, and possible contributions from new physics.<ref name="pdg2024">{{cite journal |collaboration=Particle Data Group |title=Review of Particle Physics |journal=Physical Review D |volume=110 |issue=3 |pages=030001 |year=2024 |doi=10.1103/PhysRevD.110.030001}}</ref> | |||
== Reconstruction use == | |||
Decay chains are used to identify parent particles and suppress backgrounds. Constraints from known masses, vertex fits, charge combinations, and angular distributions improve reconstruction and interpretation.<ref name="leo">{{cite book |last=Leo |first=William R. |title=Techniques for Nuclear and Particle Physics Experiments |publisher=Springer |year=1994 |isbn=978-3-540-57280-0}}</ref> | |||
=See also= | =See also= | ||
Revision as of 20:57, 19 May 2026
Particle decays are transformations in which an unstable particle produces lighter final-state particles according to the allowed quantum numbers and interaction strengths. In experiments, decays provide the signatures used to discover particles, measure lifetimes, identify flavor, and test the Standard Model. Data analysis treats decays as both physics processes and reconstruction patterns made of tracks, vertices, showers, and missing energy.[1]
Lifetime and width
The lifetime of an unstable state is related to its decay width. Very short-lived resonances are reconstructed statistically from invariant-mass peaks, while longer-lived particles may produce displaced vertices or visible flight paths.[2]
Branching fractions
A branching fraction is the probability that a particle decays through a particular channel. Measurements of branching fractions test couplings, symmetries, forbidden processes, and possible contributions from new physics.[1]
Reconstruction use
Decay chains are used to identify parent particles and suppress backgrounds. Constraints from known masses, vertex fits, charge combinations, and angular distributions improve reconstruction and interpretation.[3]
See also
Table of contents (60 articles)
Index
Full contents
References
- ↑ 1.0 1.1 "Review of Particle Physics". Physical Review D 110 (3): 030001. 2024. doi:10.1103/PhysRevD.110.030001.
- ↑ Griffiths, David J. (2008). Introduction to Elementary Particles (2nd ed.). Wiley-VCH. ISBN 978-3-527-40601-2.
- ↑ Leo, William R. (1994). Techniques for Nuclear and Particle Physics Experiments. Springer. ISBN 978-3-540-57280-0.
Source attribution: Physics:Quantum data analysis/Particle Decays
