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Two-Loop Four-Gluon Amplitudes from Numerical Unitarity.

S Abreu1, F Febres Cordero1, H Ita1

  • 1Physikalisches Institut, Albert-Ludwigs-Universität Freiburg D-79104 Freiburg, Germany.

Physical Review Letters
|October 21, 2017
PubMed
Summary
This summary is machine-generated.

This study introduces a novel numerical approach for calculating two-loop amplitudes, a crucial step in understanding particle interactions. The method successfully computes the four-gluon process, paving the way for automated, complex calculations in high-energy physics.

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Area of Science:

  • High Energy Physics
  • Computational Physics
  • Quantum Field Theory

Background:

  • Calculating multi-loop amplitudes is essential for precise predictions in particle physics.
  • The unitarity method offers a powerful framework for amplitude calculations.
  • Numerical approaches are needed to handle the complexity of multi-loop computations.

Purpose of the Study:

  • To present the first numerical computation of two-loop amplitudes using the unitarity method.
  • To demonstrate the method's capability by computing the four-gluon process.
  • To establish a universal and automatable numerical framework for multi-loop calculations.

Main Methods:

  • The unitarity method was employed for numerical computation.
  • The leading-color approximation was used for the four-gluon process.
  • The numerical results were used to reconstruct the analytic form of the amplitudes.

Main Results:

  • The first numerical computation of two-loop amplitudes was successfully achieved.
  • The four-gluon process was computed as a proof of principle.
  • The numerical method demonstrated its universality and potential for automation.

Conclusions:

  • The developed numerical method is a significant advancement for two-loop amplitude calculations.
  • This approach can be automated for complex, multi-scale computations relevant to hadron colliders.
  • The method opens new avenues for precision physics at the LHC and future colliders.