Collider-independent tt forward-backward asymmetries

Area of Science:

• High Energy Physics
• Particle Physics
• Collider Physics

Background:

• The top quark is the heaviest known elementary particle.
• Observed anomalies in top quark production at the Tevatron suggest potential new physics beyond the Standard Model.
• Discrepancies exist between forward-backward asymmetry measurements at the Tevatron and charge asymmetry measurements at the LHC.

Purpose of the Study:

• Introduce novel, collider-independent observables, A(u) and A(d), for top quark pair production (uū → tt and dd → tt).
• Provide a framework to extract these asymmetries from experimental data.
• Investigate the nature of the anomalous forward-backward asymmetry observed at the Tevatron and its relation to LHC measurements.

Main Methods:

• Definition of new asymmetry observables A(u) and A(d) for specific quark-antiquark initial states.
• Discussion of data analysis strategies for extracting these asymmetries at hadron colliders.
• Model-independent analysis to compare theoretical expectations with experimental results.

Main Results:

• A(u) and A(d) are independent of collider energy and center-of-mass energy.
• These observables directly relate to experimentally measured forward-backward and charge asymmetries.
• The framework demonstrates compatibility between a large Tevatron asymmetry and a small LHC asymmetry within a model-independent approach.

Conclusions:

• The proposed asymmetries offer a powerful tool to probe new physics in top quark production.
• Measuring A(u) and A(d) at both the Tevatron and LHC can resolve the discrepancy in top quark production asymmetries.
• The study reconciles seemingly contradictory results from different experiments, supporting the Standard Model or constraining new physics scenarios.