engleski

Light-by-light scattering and spacetime noncommutativity

The aim of this article is to explore a potential usability of a photon-photon self- interaction from the noncommutative quantum electrodynamics (NCQED) in the case of light-by- light scattering (γγ→γγ) in ultraperipheral Pb+Pb collisions, a reaction measured recently by ATLAS and planned for future experiments in hadron-hadron colliders. We compute the total cross section from both, the full one-loop standard model (SM) and the tree- level NCQED amplitudes, in the equivalent photon approximation with impact parameters, for various noncommutative scales, ΛNC, and incoming nuclear spin-energy combinations. We find that NCQED contribution to the cross section has considerable increase at diphoton invariant mass range higher than ΛNC, while the SM contribution is strongly suppressed in such region. Our results show that the current ATLAS √sNN=5.02 TeV experiment can only probe ΛNC<100 GeV region. On the other hand, future hadron-hadron collider proposals could have the potential to extend to ΛNC≲300 GeV region, making the performance of PbPb→PbPbγγ scattering on testing space-time noncommutativity close to that of the previously proposed photon-photon mode of linear electron- positron collider.

Electroweak interaction ; Gauge theories ; Noncommutative field theories ; Quantum field theory

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