| DATE: |
2007-03-12 11:00 - 12:00 |
| PLACE: |
Kenkyu Honkan 2F RM 220 |
| TITLE: |
Twistor Spinoffs for Collider Physics |
| CONTACT: |
tsuda |
| SPEAKER: |
Lance Dixon (Stanford Linear Accelerator Center (SLAC)) |
| LANGUAGE: |
English |
| ABSTRACT: |
In the search for new physics at the LHC, precise predictions for Standard Model backgrounds will be essential, and this generally means going to next-to-leading order in QCD. A major bottleneck is in the computation of loop amplitudes for processes with many external partons. In the past few years, spinoffs from a new theory, "twistor string theory", have led to efficient alternatives to Feynman diagrams, and new calculational insights. Many of the techniques exploit the analytic properties of amplitudes, particularly unitarity and factorization. I'll describe a "unitarity-recursive" bootstrap method which has been used to compute particular infinite sequences of QCD loop amplitudes, and which promises to make such loop computations more efficient in general.
Refs.
* C.F. Berger, Z. Bern, L.J. Dixon, D. Forde and D.A. Kosower, ``All one-loop maximally helicity violating gluonic amplitudes in QCD,'' Phys. Rev. D75, 016006 (2007) [hep-ph/0607014], and ``Bootstrapping one-loop QCD amplitudes with general helicities,'' Phys. Rev. D74, 036009 (2006) [hep-ph/0604195].
* Z. Bern, L.J. Dixon and D.A. Kosower, ``Bootstrapping multi-parton loop amplitudes in QCD,'' Phys. Rev. D73, 065013 (2006) [hep-ph/0507005].
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