Nullification of threshold amplitudes
نویسندگان
چکیده
منابع مشابه
On threshold amplitudes II: Amplitudes nullification via classical symmetries
The Ward identities for amplitudes at the tree level are derived from symmetries of the corresponding classical dynamical systems. The result are aplied to some 2 → n amplitudes supported by the Lódź University grant No. 269. supported by KBN grant No. 5 P03B 060 21 1 I Introducion Threshold amplitudes provide one of the rare examples of problems in quantum field theory which are both interesti...
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We construct the set of theories which share the property that the tree-level threshold amplitudes nullify even if both initial and final states contain the same type of particles. The origin of this phenomenom lies in the fact that the reduced classical dynamics describes isochronic systems. supported by the Lódź University grant No. 269 supported by KBN grant No. 5 P03B 060 21 1 The problem o...
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We present exact tree-order amplitudes for H → n H , for final states containing one or two particles with non-zero three-momentum, for various interaction potentials. We show that there are potentials leading to tree amplitudes that satisfy unitarity, not only at threshold but also in the above kinematical configurations and probably beyond. As a by-product, we also calculate 2 → n tree amplit...
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The threshold amplitude for subcritical transition in Poiseuille and Couette ows is investigated. For Poiseuille ow we present examples where the threshold scales like R ?7=4 for 1500 R 5000, where R is the Reynolds number. For Couette ow we present an example where the threshold scales like R ?5=4 for 500 R 2000.
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where D is a partition of {1 . . . n} into 4 nonempty sets, P i is the sum of momenta in i ∈ D and D0 a scalar box. In other words, scalar one-loop integrals (up to boxes) form a basis. Thus, coefficients in the expansion (BD etc.) are uniquely determined, although some reduction method can be more efficient than others. However, troublesome points where the numerical stability of the result is...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 2002
ISSN: 0556-2821,1089-4918
DOI: 10.1103/physrevd.66.105010