Proton Electromagnetic Form Factors Data Are in Disagreement with New Electron-Positron Annihilation into Proton-Antiproton Pair Total Cross Section Measurements

Anna Zuzana Dubnickova,Stanislav Dubnicka

doi:10.11648/j.ajmp.20211003.11

Anna Zuzana Dubnickova, Stanislav Dubnicka

Open Access

https://doi.org/10.11648/j.ajmp.20211003.11

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Abstract

In this paper a consistency of new very precise data on electron-positron annihilation into proton-antiproton pair total cross section with existing proton and neutron electromagnetic form factors data is investigated. First, the result is represented by a theoretically predicted dashed line for the total cross section obtained in the simultaneous analysis of the proton and neutron form factors data by the advanced nucleon electromagnetic structure Unitary and Analytic model, and then, as the neutron data are always less precise from objective reasons than the proton data, the result is also represented by a theoretically predicted full line for the total cross section obtained in the analysis of only the proton form factors data in space-like and time-like regions by the advanced proton electromagnetic structure Unitary and Analytic model. In both cases one finds disagreement between the electron-positron annihilation into proton-antiproton pair total cross section data and the corresponding form factors data, which is demonstrated by a disagreement of the dashed and full curves representing theoretically predicted electron-positron annihilation into proton-antiproton pair total cross sections behaviors.

Highlights

The electromagnetic (EM) structure of the nucleon is completely described theoretically by two independent functions of one variable, the Dirac F1N (t) and Pauli F2N (t) form factors (FFs), which naturally appear in a decomposition of the nucleon matrix element of the EM current JμEM (0) as coefficients of two linearly independent covariants constructed from the four momenta p, p, γ-matrices and Dirac bi-spinors
A description of EM structure of the nucleon is even improved if mixed transformation properties of the EM current JμEM (0) under the rotation in the isospin space is utilized
F1n(t) = [F1Ns (t) − F1Nv (t)], F2n(t) = [F2Ns (t) − F2Nv (t)], whereby the sign between them is specified by the sign of the third component of the isospin of the concrete nucleon under

Summary

Introduction

The electromagnetic (EM) structure of the nucleon (isodoublet compound of the proton and neutron) is completely described theoretically by two independent functions of one variable, the Dirac F1N (t) and Pauli F2N (t) form factors (FFs), which naturally appear in a decomposition of the nucleon matrix element of the EM current JμEM (0) as coefficients of two linearly independent covariants constructed from the four momenta p, p , γ-matrices and Dirac bi-spinors. A description of EM structure of the nucleon is even improved if mixed transformation properties of the EM current JμEM (0) under the rotation in the isospin space is utilized. A part of JμEM (0) transforms as an isoscalar and its another part as the third component of isovector. The latter leads to a splitting of the proton and neutron Dirac and Pauli. EM FFs to flavour-independent isoscalar and isovector parts F1Ns (t), F1Nv (t), F2Ns (t), F2Nv (t) as follows. F1n(t) = [F1Ns (t) − F1Nv (t)], F2n(t) = [F2Ns (t) − F2Nv (t)], whereby the sign between them is specified by the sign of the third component of the isospin of the concrete nucleon under

42 Anna Zuzana Dubnickova and Stanislav Dubnicka

Experimental Information on Nucleon EM FFs and Its Analysis

Conclusions