arXiv subjects

Flavio Pereira

Publications and source records attributed to Flavio Pereira.

3 recordsLinked to original sources

arXiv2007

Gauge-invariant soft modes in Yang-Mills theory

A gauge-invariant saddle point expansion for the Yang-Mills vacuum transition amplitude on the basis of the squeezed approximation to the vacuum wave functional is outlined. This framework allows the identification of gauge-invariant infrared degrees of freedom which arise as dominant sets of gauge field orbits and provide the principal input for an essentially analytical treatment of soft amplitudes. The analysis of the soft modes sheds new light on how vacuum fields organize themselves into collective excitations and yields a gauge-invariant representation of instanton and meron effects as well as a new physical interpretation for Faddeev-Niemi knots.

hep-th↗

arXiv1999

Zeros, Dips and Signs in pp and p$\rm\bf\bar p$ Elastic Amplitudes

The dips observed in the differential cross sections of elastic pp and p$\bar{\rm p}$ scattering are studied in terms of the locations of the zeros of the real and imaginary parts of the amplitude and of the sign of real part at large $|t|$. It is confirmed that the differences in shapes of the dips in the pp and p$\bar{\rm p}$ systems are determined by a change of sign of the real tail, which seems to be determined by perturbative QCD contributions.

hep-ph↗

arXiv1998

Eikonal profile functions and amplitudes for $\rm pp$ and $\bar{\rm p}{\rm p}$ scattering

The eikonal profile function $J(b)$ obtained from the Model of the Stochastic Vacuum is parametrized in a form suitable for comparison with experiment. The amplitude and the extended profile function (including imaginary and real parts) are determined directly from the complete pp and $\bar{\rm p}$p elastic scattering data at high energies. Full and accurate representation of the data is presented, with smooth energy dependence of all parameters. The changes needed in the original profile function required for description of scattering beyond the forward direction are described.

hep-ph↗