The DNA of Particle Scattering

<!--HTML--><p>Scattering amplitudes are where quantum field theory meets particle experiments, especially at the LHC where the copious scattering of quarks and gluons in QCD produces Higgs bosons and many backgrounds to new physics searches.&nbsp; For decades, it has been realized that the scattering of particles in gauge theories like QCD is far simpler than standard perturbative approaches would suggest. New approaches based on unitarity and bootstrapping have massively simplified many computations previously done with Feynman diagrams.&nbsp; Still, the final results are often highly intricate, multivariate mathematical functions, which are difficult to describe, let alone compute.&nbsp; In many cases, the functions have a "genetic code" underlying them, called the symbol, which reveals their structure. The symbol of such a function is a linear combination of words, sequences of letters analogous to sequences of DNA base pairs.&nbsp; Understanding the alphabet, and then reading the code, exposes the physics and mathematics underlying the scattering process.&nbsp; Remarkably, the two scattering amplitudes known to the highest orders in perturbation theory (7 and 8 loops, in planar N=4 super-Yang-Mills theory) are related to each other by a mysterious antipodal duality, which involves reading the code backwards as well as forwards. This duality can now be embedded in a larger, but still mysterious, "antipodal self-duality".</p>