Neleptonski B raspadi bez promjene sarma i stranosti

Decay rates of the B-meson are studied through charmless and strangless transitions into π, ρ , ω and γ systems. The important features of these modes are their clean signatures. The CLEO II collaboration has recently reported the value BR(B0 → π +π −) = (1.3 +0.8 −0.6 ± 0.2) × 10−5 . This value is tests our approach to nonleptonic B-decays within the standard model (SM). Since B → γγ is far beyond our experimental reach, we believe that the correct determination of the order of magnitude ∼ 10−10 for BR(B → γγ) provides the most reliable value needed at this moment. The most recent experimental report by the CLEO collaboration on BR(B → K∗γ) = (4.5 ± 1.5 ± 0.9) × 10−5 represents a confirmation of our SM prediction for the B → K∗γ decay. This experimental result, despite of its great importance for the SM and the physics beyond the SM, enables us to predict the value BR (B → ργ) ∼= (3.5 ± 3.3) × 10−6 .Proučavani su raspadi B-mezona bez promjene šarma i stranosti u π, ρ, ω i γ konačna stanja. Važna osobina ovih modova su njihovi čisti eksperimentalni signali. CLEO II kolaboracija nedavno je objavila vrijednost BR(B0 → π +π −) = (1.3 +0.8 −0.6 ± 0.2) × 10−5 . Ta se vrijednost može upotrijebiti za test našeg pristupa objašnjenju neleptonskih B-raspada unutar standardnog modela (SM). Budući je B → γγ daleko izvan našeg eksperimentalnog dosega, vjerujemo da korektno određeni red veličine ∼ 10−10 za BR(B → γγ) predstavlja najrealniju vrijednost potrebnu u ovom trenutku. Najnoviji eksperimentalni izvještaj CLEO kolaboracije o mjerenju BR(B → K∗γ) = (4.5 ± 1.5 ± 0.9) × 10−5 predstavlja potvrdu naše teoretske (SM) predikcije B → K∗γ raspada. Taj eksperimentalni rezultat i pored važnosti za standardni model i fiziku izvan tog modela omogućuje nam predikciju jakosti raspada BR(B → ργ) ≃ (3.5 ± 3.3) × 10−6

Neleptonski B raspadi bez promjene sarma i stranosti

Decay rates of the B-meson are studied through charmless and strangless transitions into π, ρ , ω and γ systems. The important features of these modes are their clean signatures. The CLEO II collaboration has recently reported the value BR(B0 → π +π −) = (1.3 +0.8 −0.6 ± 0.2) × 10−5 . This value is tests our approach to nonleptonic B-decays within the standard model (SM). Since B → γγ is far beyond our experimental reach, we believe that the correct determination of the order of magnitude ∼ 10−10 for BR(B → γγ) provides the most reliable value needed at this moment. The most recent experimental report by the CLEO collaboration on BR(B → K∗γ) = (4.5 ± 1.5 ± 0.9) × 10−5 represents a confirmation of our SM prediction for the B → K∗γ decay. This experimental result, despite of its great importance for the SM and the physics beyond the SM, enables us to predict the value BR (B → ργ) ∼= (3.5 ± 3.3) × 10−6 .Proučavani su raspadi B-mezona bez promjene šarma i stranosti u π, ρ, ω i γ konačna stanja. Važna osobina ovih modova su njihovi čisti eksperimentalni signali. CLEO II kolaboracija nedavno je objavila vrijednost BR(B0 → π +π −) = (1.3 +0.8 −0.6 ± 0.2) × 10−5 . Ta se vrijednost može upotrijebiti za test našeg pristupa objašnjenju neleptonskih B-raspada unutar standardnog modela (SM). Budući je B → γγ daleko izvan našeg eksperimentalnog dosega, vjerujemo da korektno određeni red veličine ∼ 10−10 za BR(B → γγ) predstavlja najrealniju vrijednost potrebnu u ovom trenutku. Najnoviji eksperimentalni izvještaj CLEO kolaboracije o mjerenju BR(B → K∗γ) = (4.5 ± 1.5 ± 0.9) × 10−5 predstavlja potvrdu naše teoretske (SM) predikcije B → K∗γ raspada. Taj eksperimentalni rezultat i pored važnosti za standardni model i fiziku izvan tog modela omogućuje nam predikciju jakosti raspada BR(B → ργ) ≃ (3.5 ± 3.3) × 10−6

High energy Compton scattering in the NCQED

We discuss the behavior of head-to-head $e\gamma\to e\gamma$ scattering process in the noncommutative quantum electrodynamics on the Moyal space amid its unresolved forward scattering singularity. We model the effect of the currently unknown resolution to this collinear singularity by cut-offs which are functions of the control variable $s/\Lambda_{\rm NC}^2$ and find that such cut-off functions can suppress NC corrections to the inverse Compton scattering to negligible. We also notice that such cut-offs leave the 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 scale of noncommutativity $\Lambda_{\rm NC}\gtrsim1$ TeV.Comment: 4 pages, 1 figur

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.Comment: 11 pages, 10 figures. Version to be published in Phys. Rev.

Seiberg-Witten map Invariant Scatterings

We investigate Scattering amplitudes of the reversible $\theta$-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 M\"oller, Bhabha, Compton, pair annihilation, pair production and light-by-light $(\gamma\gamma\to\gamma\gamma)$ scatterings. We apply our NCQED results to the $\gamma\gamma\to\gamma\gamma$ and $\gamma\gamma\to\ell^+\ell^-$ exclusive processes, convoluted to the ultraperipheral lead $^{208}$Pb ion-ion collisions, recently measured by the ATLAS collaboration at LHC. We demonstrate that $\gamma\gamma\to\gamma\gamma$ is the more appropriate channel to probe NC scale $\Lambda_{\rm NC}$ while both are less efficient than some other probes.Comment: 54 pages, 15 figures. Version, to be published in Phys. Rev. D, containing important angular distributions of light-by-light scatterings in the PbPb collision at the ATLAS and the next-generation collider experiments like FC

Equivalence of quantum field theories related by the θ-exact Seiberg-Witten map

The equivalence of the noncommutative U(N) quantum field theories related by the θ-exact Seiberg-Witten maps is, in this paper, proven to all orders in the perturbation theory with respect to the coupling constant. We show that this holds for super Yang-Mills theories with N=0, 1, 2, 4 supersymmetry. A direct check of this equivalence relation is performed by computing the one-loop quantum corrections to the quadratic part of the effective action in the noncommutative U(1) gauge theory with N=0, 1, 2, 4 supersymmetry

Spacetime Deformation Effect on the Early Universe and the PTOLEMY Experiment

Using a fully-fledged formulation of gauge field theory deformed by the spacetime noncommutativity, we study its impact on relic neutrino direct detection, as proposed recently by the PTOLEMY experiment. The noncommutative background tends to influence the propagating neutrinos by providing them with a tree-level vector-like coupling to photons, enabling thus otherwise sterile right-handed (RH) neutrinos to be thermally produced in the early universe. Such a new component in the universe's background radiation has been switched today to the almost fully active sea of non-relativistic neutrinos, exerting consequently some impact on the capture on tritium at PTOLEMY. The peculiarities of our nonperturbative approach tend to reflect in the cosmology as well, upon the appearances of the coupling temperature, above which RH neutrinos stay permanently decoupled from thermal environment. This entails the maximal scale of noncommutativity as well, being of order of 10^{; ; −4}; ; M_{; ; Pl}; ; , above which there is no impact whatsoever on the capture rates at PTOLEMY. The latter represents an exceptional upper bound on the scale of noncommutativity coming from phenomenology