How precisely will the total cross section be measured at the Large Hadron Collider?

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The CERN Large Hadron Collider (LHC) is poised to explore a new regime of hadronic scattering.
• Approaching the black-disk limit in scattering suggests significant changes in amplitude behavior.
• Existing methods for measuring total cross-sections may be susceptible to biases in this new regime.

Purpose of the Study:

• To investigate the impact of reaching the black-disk limit on elastic scattering amplitudes.
• To analyze potential biases in total cross-section measurements due to these amplitude changes.
• To propose and evaluate novel strategies for validating total cross-section measurements.

Main Methods:

• Theoretical analysis of elastic scattering amplitudes in the context of the black-disk limit.
• Simulations exploring the t-dependence of scattering parameters.
• Development and assessment of new methodologies for cross-section measurement reliability.

Main Results:

• The study predicts significant alterations in the t-dependence of the real part and slope of the elastic scattering amplitude.
• These changes are identified as a potential source of systematic bias in total cross-section measurements.
• Proposed strategies offer enhanced reliability for future measurements.

Conclusions:

• Hadronic scattering at the LHC is likely entering a regime where the black-disk limit impacts scattering dynamics.
• Careful consideration and new strategies are essential to mitigate biases and ensure accurate total cross-section measurements.
• The findings provide crucial guidance for experimentalists at the LHC and future colliders.