In Nima's lectures on the 'Twistor Uprising' (for example here), he gushes about about new powerful techniques for calculating amplitudes, such as summing Feynman diagrams using 'BCFW recursion.' He makes it sound like there should be practical results, like new QCD amplitudes for use in Monte Carlo generators, etc. Are there any, or are any on the horizon? Or does he overstate the power of these new techniques?

EDIT: There is a recent blog post by Matt Strassler seeming to imply that BlackHat (a program that computes QCD amplitudes) uses some of these techniques.

  • $\begingroup$ Here is a link from 2007 physics.ox.ac.uk/pp/seminars/… "Twistor inspired developments in perturbative QCD". Mind you, I have sat through a phenomenology lecture which was using similar methods but did not call it "twistor". It may be calculations are implemented in the LHC monte carlos but called something else.(NNLO?) $\endgroup$
    – anna v
    Apr 25, 2012 at 13:45

1 Answer 1


The N=4 planar YM techniques are very close to describing actual Standard Model scattering amplitudes, and far more elegantly than Feynman methods. He is not overstating their importance. Note that Dixon, Bern et al were studying real QCD, and Parke and Taylor came up with the original MHV amplitudes without modern twistor methods. Moreover, the new techniques clearly show how the assumption of locality in the 20th century methods complicates the answer needlessly, and why BCFW is so important. All particle physicists should now be studying these methods. Moreover N=8 SUGRA is also being sorted out this way.

QCD is still a problem tho. But there is a great deal of new mathematics in the most recent combinatorial results, and it won't be long before some amazing progress is made in QCD itself. Probably.


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