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Measurement of spin correlation in tt production using a matrix element approach
V M Abazov1, B Abbott, B S Acharya
1Joint Institute for Nuclear Research, Dubna, Russia.
Physical Review Letters
|August 16, 2011
Summary
This study investigated top quark (tt) spin correlation in proton-antiproton collisions. Results confirm the Standard Model prediction, excluding uncorrelated tt spin at 97.7% confidence.
Area of Science:
- High Energy Physics
- Particle Physics
- Quantum Chromodynamics
Background:
- Top quarks are the heaviest known elementary particles.
- Understanding top quark spin correlation is crucial for testing the Standard Model (SM).
- Previous studies have explored tt spin correlation with varying methodologies.
Purpose of the Study:
- To determine the fraction of tt events with spin correlation.
- To test the Standard Model prediction of correlated tt spin.
- To exclude the hypothesis of uncorrelated tt spin.
Main Methods:
- Utilized a matrix-element-based approach for the first time to study tt spin correlation.
- Analyzed tt → W+ b W- b → ℓ+ νbℓ- ν b final states (where ℓ is an electron or muon).
- Used data from proton-antiproton collisions at √s = 1.96 TeV collected by the D0 detector at the Fermilab Tevatron collider, with an integrated luminosity of 5.4 fb⁻¹.
Main Results:
- The measured fraction of tt events with spin correlation agrees with the Standard Model prediction.
- The hypothesis of uncorrelated tt spin was excluded at the 97.7% confidence level (C.L.).
Conclusions:
- The study provides strong evidence supporting the Standard Model's prediction of top quark spin correlation.
- The exclusion of uncorrelated spin significantly advances our understanding of top quark properties and interactions.
- This matrix-element-based approach offers a powerful new tool for future precision measurements in particle physics.
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