Coulomb amplitude representation and nuclear diffraction and refraction

A new, consistent with wave-optics, method of treating diffraction and refraction in nuclear elastic scattering, is proposed and discussed. The method is based on the decomposition of the total elastic-scattering amplitude, written in a different form than usual, into the amplitude describing pure diffraction, and the rest, i.e., refraction and reflection. It is shown that nuclear diffraction is due to incompleteness of the Coulomb-scattering amplitude and is described by it. It is show that diffraction can be regarded as a kind of ``background'' always present, irrespective of the system being studied. PACS Nos.: 24.10.Ht, 42.25.Fx, 42.25.Gy

Coulomb–Nucleon Phase and Spin Effects in the Diffraction Dip Domain

A new form for the Coulomb–hadron phase which can be used in a wide region of transfer momenta is obtained. The total phase of the Coulomb–hadron interaction is calculated with the true hadron scattering amplitude and with the Coulomb amplitude including the form factor of hadrons. As an example, the additional contribution to analyzing power AN owing to the Coulomb–hadron interference is calculated in the whole diffraction dip domain of high–energy elastic hadron scattering.

PHASE OF THE COULOMB AMPLITUDE IN THE SECOND BORN APPROXIMATION

The method of calculating the Coulomb phase in the second Born order with allowance for the hadron form factor is presented. The phase of the modified Coulomb amplitude can be calculated exactly by taking account of the form factor of hadrons. The phase with the dipole form factor is estimated; as a result, the behavior of the total phase of the Coulomb-hadron interference changes as a function of the transfer momentum.

A HYPOTHETICAL, ATTRACTIVE LONG-RANGE FORCE FROM TWO-GLUON EXCHANGE, AND THE MEASUREMENT OF ρ IN HIGH ENERGY $\bar p p$ ELASTIC SCATTERING

The dynamical question is raised of the possible existence of long-range, residual attractive forces between hadrons due to the overall color-neutral exchange of two, massless transverse gluons between their constituents. Such a force between fermionic constituents would behave as 1/R6. We discuss the experiments which measure the real part of the nuclear amplitude, through its interference with the Coulomb amplitude in high energy [Formula: see text] elastic scattering at very small momentum transfers. We show that on-going [Formula: see text] experiments at [Formula: see text] and at 1800 GeV are sensitive to the scattering amplitude from a residual long-range force.