Download Free Study Of The Phi Decays Into Pi Pi Gamma Pi 0 Pi 0 Gamma And Etapi 0 Gamma Final States Book in PDF and EPUB Free Download. You can read online Study Of The Phi Decays Into Pi Pi Gamma Pi 0 Pi 0 Gamma And Etapi 0 Gamma Final States and write the review.

It is proposed to use the Charged and Neutral Spectrometer in Beam 8 to study the reactions ..pi..−p ..-->.. ..pi ... pi..−3..gamma..n and ..pi..−p ..-->.. ..pi..+..pi..−4..gamma..n at 8.5 GeV/c. Improvements to the spectrometer will allow a data collection rate 4 to 5 times better than achieved for these reactions in E-397. Of particular interest are the radiative decays eta' ..-->.. ..omega gamma.., ..omega.. ..-->.. eta..gamma.., rho ..-->.. eta..gamma..; the decay f ..-->.. ..pi../sup +/..pi..−..pi..°..pi..°, in which A1..pi.. may occur; the decay A2 ..-->.. ..omega pi../sup +/..pi..−, in connection with an isoscalar under the A2; study/search for B° and delta°; rare final states such as eta eta, eta..omega.., eta'..pi..° and eta'eta.
We discuss the relevance of a dedicated measurement of exclusive production of a pair of neutral pions in a hard [gamma]*[gamma] scattering at small momentum transfer. In this case, the virtuality of one photon provides us with a hard scale in the process, enabling us to perform a QCD calculation of this reaction rate using the concept of Transition Distribution Amplitudes (TDA). Those are related by sum rules to the pion axial form factor F{sub A}{sup [pi]} and, as a direct consequence, a cross-section measurement of this process at intense beam electron-positron colliders such as CLEO, KEK-B and PEP-II, or Super-B would provide us with a unique measurement of the neutral pion axial form factor F{sub A}{sup [pi]0} at small scale. We believe that our models for the photon to meson transition distribution amplitudes are sufficiently constrained to give reasonable orders of magnitude for the estimated cross sections. Cross sections are large enough for quantitative studies to be performed at high luminosity ee− colliders. After verifying the scaling and the [phi] independence of the cross section, one should be able to measure these new hadronic matrix elements, and thus open a new gate to the understanding of the hadronic structure. In particular, we argued here that the study of [gamma]*[gamma] 2![pi]°{pi}° in the TDA regime could provide with a unique experimental measurement of the {pi}° axial form factor.
Abstract: The Standard Model is the best current description of fundamental interactions and particles; however, the Standard Model has certain shortcomings which have driven particle physicists for the last 30 years to search for phenomena which provide evidence for the next theory beyond the Standard Model. To this end, using the BaBar detector, we search for evidence of the rare decay D* -> D0[pi];D0->[gamma][gamma]. The branching fraction of this decay is enhanced up to 200 times the standard model prediction in certain beyond-the-Standard-Model theories. A measurement of a significant branching fraction would provide evidence for a new theory of particle physics. We describe our search for this rare decay and an improved measurement of the associated decay, B(D0-> [pi]0 [pi]0) using an integrated luminosity corresponding to 470.5 fb−1 of e e− data collected by the BaBar detector at the PEP-II asymmetric ee− collider at SLAC from 1999-2007. We place an upper limit of B(D0->[gamma][gamma]) 2.51 X 10−6 at 90% confidence level and find B(D0-[pi]0[pi]0) = (8.4 " 0.1 " 0.4 " 0.3) X 10−4.
The pi° --> gamma gamma decay width is analyzed within the combined framework of Chiral Perturbation Theory and the 1/N{sub c} expansion up to order(p6) and order(p4 x 1/N{sub c}) in the decay amplitude. The eta' is explicitly included in the analysis. It is found that the decay width is enhanced by about 4% due to the isospin-breaking induced mixing of the pure U(3) states. This effect, which is of leading order in the low energy expansion, is shown to persist nearly unchanged at next to leading order. The chief prediction Gamma{sub pi}0{sub {yields}gamma gamma} = 8.10 eV is estimated to have an uncertainty of less than 1%. Observations on the eta and eta' can also be made, especially about their mixing, which is shown to be significantly affected by next to leading order corrections.
The NA48/2 experiment at the CERN SPS has collected a large sample of K to pi pi0 gamma decays.Two amplitudes contribute to these decays. The dominant one comes from Inner Bremsstrahlung (IB) in the K to pi pi0 process. The second one is given by the Direct Emission (DE) of the photon at the weak vertex from an intermediate state of the decay. The simplest radiative transitions are electric dipole (E1) and magnetic dipole (M1). Electric amplitudes can interfere with IB, and CP violation and possible non-SM effects can show up in th e corresponding interference (INT) term.In this work a sub sample of the data has been analyzed. About 120000 K to pi pi0 gamma decays, with negligible background contamination have been reconstructed in the ranges 0.2