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Josip Trampetić

Publications and source records attributed to Josip Trampetić.

6 recordsLinked to original sources

Remarks on Compton forward scattering singularity in the NCQED

We investigate the behaviour of head-to-head high energy Compton scattering in the $θ$-exact noncommutative (NC) quantum electrodynamics (QED) on the Moyal space (NCQED) in the amid its unresolved forward scattering singularity. We model the effect of the currently unknown resolution to this unavoidable collinear singularity by cut-offs which are functions of the control variable $s/Λ_{\rm NC}^2$, and find that such cut-off functions can suppress NC corrections to the inverse Compton scattering to negligible. Discussed cut-offs leave the unpolarised integral cross section of the forward region larger than the backward region all the time, making the former potentially easier to observe. Our estimations indicate that such an effect may be visible in the future collider experiments when the NC scale $Λ_{\rm NC}\gtrsim1$ TeV.

hep-ph↗

Seiberg-Witten map Invariant Scatterings

We investigate Scattering amplitudes of the reversible $θ$-exact Seiberg-Witten (SW) map based noncommutative (NC) quantum electrodynamics, and show explicitly the SW map invariance for all tree-level NCQED $2\to2$ proceses, including Möller, Bhabha, Compton, pair annihilation, pair production and light-by-light $(γγ\toγγ)$ scatterings. We apply our NCQED results to the $γγ\toγγ$ and $γγ\to\ell^+\ell^-$ exclusive processes, convoluted to the ultraperipheral lead $^{208}$Pb ion-ion collisions, recently measured by the ATLAS collaboration at LHC. We demonstrate that $γγ\toγγ$ is the more appropriate channel to probe NC scale $Λ_{\rm NC}$ while both are less efficient than some other probes.

hep-ph↗

Revisiting NCQED and scattering amplitudes

Research progresses on the noncommutative gauge theories on the Moyal space are discussed in this minireview. We first present a brief overview on the development of gauge theories on Moyal space, with an emphasis on the role of Seiberg-Witten maps. Two important relations induced by reversible Seiberg-Witten maps, namely the formal equivalence of on-shell DeWitt background field effective action in general and explicit identical relation between tree level scattering amplituded in noncommutative quantum electrodynamics (NCQED), are described in some details. We then proceed to the properties of the tree level two-by-two scattering amplitudes in NCQED, including a forward scattering singularity in NCQED Compton scattering. After covering some phenomenological perspectives of NCYM based models, outlooks into the future are given at the end.

hep-th↗

Seiberg-Witten maps and scattering amplitudes of NCQED

The connection between tree-level scattering amplitudes and the Seiberg-Witten (SW) map in the Moyal deformed U(1) noncommutataive quantum electrodynamics (NCQED) is studied. We show that in the minimal U(1) NCQED based on a reversible Seiberg-Witten (SW) map, SW map induced interactions cancel each other in all tree-level scattering amplitudes and leave them identical to the Moyal NCQED without SW map. On the other hand, the two-by-two Compton and light-by-light scattering amplitudes deviate from minimal model when irreversible SW map is used. Therefore the risibility of SW map and equivalence between NCQED before and after SW map manifest themselves as an identity between the tree-level scattering amplitudes.

hep-th↗

UV/IR mixing in Noncommutative SU(N) Yang-Mills theory

We show that there are one-loop IR singularities arising from UV/IR mixing in noncommutative SU(N) Yang-Mills theory defined by means of the $θ$-exact Seiberg-Witten map. This is in spite of the fact that there are no ordinary U(1) gauge fields in the theory and this is at variance with the noncommutative U(N) case, where the two-point part of the effective action involving the ordinary SU(N) fields do not suffer from those one-loop IR singularities.

hep-th↗

Photon self-interaction on deformed spacetime

A novel nonlocal four-photon interaction on the deformed spacetime is derived and studied in the three selected models (I, II, III). The first two models (I, II) are obtained via two distinct second-order $θ$-exact Seiberg-Witten maps of the noncommutative U(1) gauge field strength on Moyal space. The third one (III), inspired by the manifestly gauge invariant structures emerging in the first two, due to the model generality has been constructed with a different set of freedom parameters. The physical relevancy of all models is analyzed by evaluating the four-photon-tadpole diagram, which, when combined with the bubble graph, enables us to fully consider all contributions to the one-loop photon polarization tensor. For an arbitrary noncommutative matrix theta^μν, the full quadratic IR divergence cancellation in the one-loop photon two-point function is obtained with particular combinations of Seiberg-Witten map/gauge-symmetry freedom parameters in models I and II. Finally, our model III enables complete elimination of all pathological terms in the photon polarization tensor at one-loop order if a special value for the theta matrix is chosen.

hep-th↗