Invariance Conditions on the Scattering Amplitudes for Spin ½ Particles

We derive and calculate the multiple scattering expansion of the Kerman-McManus-Thaler optical potential to second order in the free nucleon-nucleon transition amplitude and clarify the physical content of the interaction. Calculations are presented for the elastic scattering of protons from ' 0 at 135, 200, and 300 MeV incident energies, paying particular attention to the nonlocalities inherent in the second-order potential. It is shown that these effects result in a significant reduction in the proton-target absorption.PACS number 24.10.Ht, 24.70.+s, 25.40.Cm

show abstract

“…We therefore proceed to calculate the KMT potential in the form of Eqs. (9) and (10) [27] M=A+X(op n)(cr, n)+C(op+o, ).n…”

Section: The Optical Potentialmentioning

confidence: 99%

Multiple scattering theory of proton elastic scattering at intermediate energies

1992

View full text Add to dashboard Cite

show abstract

“…Any NN observable is expressed by the M matrix and nucleon spin operators σ (1) and σ (2) [3][4][5]. Due to (5) all observables can also be expressed in terms of the Wolfenstein parameters W k .…”

Section: Solution For Wolfenstein Parametersmentioning

confidence: 99%

“…The Wolfenstein parameters W k for NN scattering are labeled as a, c, g, h and m and they parametrize linearly the NN M matrix [3,4]:…”

Section: Solution For Wolfenstein Parametersmentioning

confidence: 99%

Determination of Wolfenstein Parameters in NN Scattering Directly from Observables

et al. 2011

View full text Add to dashboard Cite

The Wolfenstein parameters are for the first time obtained analytically in terms of observables. It is shown that a set of ten nucleon-nucleon (NN) observables, which contains polarization observables together with the differential cross section, determines uniquely the solution for Wolfenstein parameters except for a common insignificant phase. Using such analytical solutions one expects to get more accurate theoretical parameters for the potential models by χ 2 fitting to the resulting Wolfenstein parameter data than the standard manner of a phase-shift analysis. An example of fixing a unique set of physical solutions for the Wolfenstein parameters from a set of 16 solutions based on nine observables alone and adding one more observable is illustrated using pseudo data generated by the CD Bonn potential.

show abstract

“…While careful applications of each of these approaches have been able to describe the existing data with reasonable accuracy, differing predictions are obtained for those observables which depend on initial state spin [4,6]. There has also been growing interest in the relevance of the spin structure ofpp →ΛΛ to the question of the strangeness component of the nucleon [8,9].The formalism for scattering two spin-1 2 particles to two spin-1 2 particles has been well developed in both the general case and in application to thepp →Ȳ Y reaction [10][11][12][13]. The implications of this application of the formalism must be carefully explored for the larger set of observables available to PS185/3 [14,15].…”

mentioning

confidence: 99%

“…The formalism for scattering two spin-1 2 particles to two spin-1 2 particles has been well developed in both the general case and in application to thepp →Ȳ Y reaction [10][11][12][13]. The implications of this application of the formalism must be carefully explored for the larger set of observables available to PS185/3 [14,15].…”

mentioning

confidence: 99%

Spin observables in with a transverse initial state polarization

Paschke

Quinn

2000

Physics Letters B

View full text Add to dashboard Cite

The formalism describing the scattering of two spin-1 2 objects is reviewed for the case ofpp →ΛΛ. It is shown that an experiment utilizing a transverse target polarization can, in principle, completely determine the spin structure of the reaction. Additional measurements, even those using both beam and target polarizations, would not be sensitive to any additional spin dynamics. Thus, the transverse target polarization allows access to the complete set of spin observables, not just the subset upon which the literature has previously focused. This discussion is especially relevant in light of the data collected by PS185/3 at LEAR.Exclusive production of antihyperon-hyperon states from antiproton-proton annihilation (pp → Y Y ) has been extensively studied near threshold by the PS185 collaboration throughout the 13 year lifetime of LEAR at CERN [1,2]. Results for the total and differential cross-sections and those spin observables depending only on final state spins have been published for a range of energies and channels. In 1996, an upgraded version of the experiment, PS185/3, incorporated a transverse target polarization to allow sensitivity to a wider range of spin observables in the reactionpp →ΛΛ [3].There is significant interest in the results of this measurement. Two types of models with different physical motivations have been successfully used to describe the reaction in this energy regime: K and K * meson exchange [4,5] and effective quark models [6,7]. While careful applications of each of these approaches have been able to describe the existing data with reasonable accuracy, differing predictions are obtained for those observables which depend on initial state spin [4,6]. There has also been growing interest in the relevance of the spin structure ofpp →ΛΛ to the question of the strangeness component of the nucleon [8,9].The formalism for scattering two spin-1 2 particles to two spin-1 2 particles has been well developed in both the general case and in application to thepp →Ȳ Y reaction [10][11][12][13]. The implications of this application of the formalism must be carefully explored for the larger set of observables available to PS185/3 [14,15]. The recent literature discussing the strangeness production dynamics has focused on the depolarization D nn , and, to a lesser extent, other rank-2 spin observables to which PS185/3 is directly sensitive [3,4,6,8,14]. As will be shown below, the use of a transverse target polarization, in principle, allows the complete determination of the spin structure of the reaction. This then permits model independent predictions of the full set of spin observables, including those that were not directly measured. This is the first demonstration of the feasibility of such an analysis for pp →ΛΛ, although this possibility had been hinted at by previous publications [13].In discussing spin-1 2 particle scattering it is common to parameterize the spin structure of the transition matrix M explicitly. Forpp →ΛΛ, the transition matrix M can be written 1

show abstract

Invariance Conditions on the Scattering Amplitudes for Spin ½ Particles

Cited by 262 publications

References 4 publications

Multiple scattering theory of proton elastic scattering at intermediate energies

Multiple scattering theory of proton elastic scattering at intermediate energies

Determination of Wolfenstein Parameters in NN Scattering Directly from Observables

Spin observables in with a transverse initial state polarization

Contact Info

Product

Resources

About