Electromagnetic form factors of neutron and neutral hyperons in the oscillating point of view *

Abstract

Based on the recently precise measurements of the electron-positron annihilation reactions into a neutron and anti-neutron pair by BESIII collaboration, the effective form factor of neutron was determined in the time like region, and it was found that the effective form factor of neutron is smaller than the ones of proton. The effective form factors of neutron shows a periodic behaviour, similar to the case of proton. Here, a compared analysis for $\Lambda$, $\Sigma^0$ and $\Xi^0$ is performed. Fits of the available data on the effective form factors of $\Lambda$, $\Sigma^0$ and $\Xi^0$ with charge zero, allow to show an interesting phenomenon of the oscillation behavior in their effective form factors. However, this needs to be confirmed by future precise experiments. Both theoretical and experimental investigations of this phenomenon can shed light on the reaction mechanisms of the electron-positron annihilation process. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Measurements of Σ+ and Σ− time-like electromagnetic form factors for center-of-mass energies from 2.3864 to 3.0200 GeV

“…The relative phase of the Λ EMFFs was extracted by fitting the angular distributions [21]. Many theoretical activities [30][31][32][33][34][35] arose after this measurement. In Ref.…”

e+e−→Λc+Λ¯c− Cross Sections and the Λc+ Electromagnetic Form Factors within the Extended Vector Meson Dominance Model

“…= 0.6. The fitted result for the parameter 𝛾 is 0.147 ± 0.017 GeV −2 , which is smaller than the typical values for the light baryons nucleon, [47,48] 𝛬, [14,47] 𝛴, [12,47] and 𝛯. [12] Table 2 Fig.…”

“…[21], does not exhibit oscillatory behavior, in contrast to the findings in the nucleon case. [47,[49][50][51][52][53][54] This may be attributed to the limited energy range considered for the 𝑒 + 𝑒 − → 𝛬 + 𝑐 Λ− 𝑐 reaction. The range from the reaction threshold to 4.95 GeV is only about 350 MeV.…”

The $Σ$ and $Ξ$ electromagnetic form factors in the extended vector meson dominance model

“…In the vector meson dominance model for studying the electromagnetic form factors of baryons, there is a phenomenological intrinsic form factor g(q 2 ). From these studies of the nucleon and hyperon EMFFs [17][18][19][20][21][22][23][24][25][26][27][28][29], it is found that a better choice of g(q 2 ) is the dipole form…”

“…For a long time, the simple dipole form paremetrization is very useful for the discussion of different baryons. For example, the dipole form of g(q 2 ) can well describe the effective form factors of Λ [20,21], Σ [32], and Ξ [27]. While for the nucleon, a good general review is given in Refs.…”