Effect of the Exact Center of Mass Correction on the Longitudinal Form Factors for Neutron Rich 12,14,18N Isotopes

AbstractBy considering energy-dependent form factors extracted from generalized Chou–Yang model, root mean square (rms) charge radii of deuteron and helium nuclei (alpha) are predicted at different values of center of mass energy which are in good agreement with theoretical predictions and experimental results. The rms radius is inversely proportional to mass of nuclei. Besides, the relationship between radii and energy are also derived.

Download Full-text

Studying time-like electromagnetic baryonic transitions with HADES in pion induced reactions

EPJ Web of Conferences ◽

10.1051/epjconf/202024101012 ◽

2020 ◽

Vol 241 ◽

pp. 01012

Author(s):

Béatrice Ramstein

Keyword(s):

Center Of Mass ◽

Quantitative Description ◽

Form Factors ◽

Resonance Region ◽

Partial Wave Analysis ◽

Real Photon ◽

Pion Beam ◽

Dalitz Decay ◽

Covariant Model ◽

Proton Induced Reactions

A dedicated programme aiming at studying electromagnetic baryonic transitions in the time-like region has started at GSI using the pion beam and the High Acceptance Di-Electron Spectrometer (HADES) set-up. A pioneering experiment has been carried out in the second resonance region, at a center-of-mass energy of 1.49 GeV, using carbon and polyethylene targets, allowing for an analysis of the inclusive e+e- production and of the exclusive quasi-free π-p → ne+e- reaction, in complement to hadronic channels. Predictions for the Dalitz decay of N(1520) and N(1535) based on real photon couplings strongly underestimate the e+e- yield at invariant masses larger than 300 MeV/c2, which signals effects of time-like baryon transition form factors, in qualitative agreement with the Vector Dominance Models (VDM). A quantitative description of the observed e+e- yield is achieved by taking into account the contribution from off-shell ρs. The latter was provided by the preliminary results of a Bonn-Gatchina Partial Wave Analysis of the two-pion production channels, which were measured simultaneously in our experiment. A good agreement is also obtained using a covariant model for the time-like electromagnetic form factors for the N-N(1520) transition. The angular distributions for the e+e- production contain additional selective information on the spin structure of the different transitions. The measurements with the pion beam will be extended in future in the third resonance region. Hyperon Dalitz decay studies in proton induced reactions are also foreseen.

Download Full-text

Measurement of hadronic form factors at BESIII

EPJ Web of Conferences ◽

10.1051/epjconf/201817203002 ◽

2018 ◽

Vol 172 ◽

pp. 03002

Author(s):

Haiming HU

Keyword(s):

Form Factor ◽

Cross Section ◽

Center Of Mass ◽

Polar Angle ◽

Form Factors ◽

Pion Form Factor ◽

Angle Distribution ◽

Data Set ◽

Center Of Mass Energy ◽

The Cross

The measurements of hadronic form factors of three modes using the data samples collected with the BESIII detector at BEPCII collider are presented. The cross section of e+e- → p p̅ at 12 energies from 2232.4 to 3671.0 MeV are measured, the electromagnetic form factor is deduced, and the ratio |GE/GM| is extracted by fitting the polar angle distribution. The preliminary results about the form factors of e+e- → ∧c+ ⊼c- will also be described. The cross section of e+e- → π+ π-between effective center-of-mass energy 600 and 900 MeV is measured by the ISR return method using the data set with the integrated luminosity of 2.93 fb-1 taken at ψ(3773) peak, the pion form factor is extracted.

Download Full-text

MEASUREMENT OF THE PROTON ELECTROMAGNETIC FORM FACTORS AT BABAR

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194514604256 ◽

2014 ◽

Vol 35 ◽

pp. 1460425

Author(s):

V. P. DRUZHININ ◽

Keyword(s):

Center Of Mass ◽

Form Factors ◽

Mass Range ◽

Initial State Radiation ◽

Electromagnetic Form Factors ◽

Initial State ◽

State Radiation ◽

Radiation Technique ◽

Babar Detector ◽

Integrated Luminosity

The process [Formula: see text] has been studied in the [Formula: see text] mass range from threshold to 6.5 GeV/c2 using the initial-state-radiation technique with both detected and undetected photon. The analysis is based on 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider at e+e- center-of-mass energies near 10.6 GeV.

Download Full-text

A QUARK-MODEL FIT FOR THE ELECTROMAGNETIC PROPERTIES OF OCTET BARYONS

International Journal of Modern Physics A ◽

10.1142/s0217751x92001289 ◽

1992 ◽

Vol 07 (12) ◽

pp. 2841-2861 ◽

Cited By ~ 11

Author(s):

S. N. JENA ◽

S. PANDA

Keyword(s):

Quark Model ◽

Magnetic Moments ◽

Center Of Mass ◽

Axial Vector ◽

Form Factors ◽

Electromagnetic Properties ◽

Coupling Constant ◽

Vector Coupling ◽

Pion Nucleon ◽

Octet Baryons

A simple independent-quark model based on the Dirac equation with an equally mixed scalar–vector linear confining potential model is used to obtain a fit for the electromagnetic properties — like the magnetic moments, charge radii and axial-vector coupling-constant ratios — of octet baryons, taking into account the appropriate center-of-mass corrections. This fit is extended to include the quark-core contributions to the nucleon electromagnetic form factors [Formula: see text], [Formula: see text], [Formula: see text] and the axial-vector form factor GA(q2). The respective root-mean-square radii associated with [Formula: see text] and GA(q2) come out as [Formula: see text] and [Formula: see text]. The possibility of restoring in this model the chiral symmetry in the usual way is discussed and the pion-nucleon coupling constant is found as gπ NN = 13.72 as compared to (gπ NN ) exp ≃ 13.

Download Full-text

Consequences of the center–of–mass correction in nuclear mean–field models

The European Physical Journal A ◽

10.1007/pl00013645 ◽

2000 ◽

Vol 7 (4) ◽

pp. 467-478 ◽

Cited By ~ 88

Author(s):

M. Bender ◽

K. Rutz ◽

P.-G. Reinhard ◽

J.A. Maruhn

Keyword(s):

Center Of Mass ◽

Mean Field ◽

Mean Field Models ◽

Mass Correction

Download Full-text

MAGNETIC MOMENTS OF OCTET BARYONS IN A RELATIVISTIC QUARK MODEL WITH CHIRAL SYMMETRY

International Journal of Modern Physics A ◽

10.1142/s0217751x93001831 ◽

1993 ◽

Vol 08 (25) ◽

pp. 4563-4576 ◽

Cited By ~ 2

Author(s):

S.N. JENA ◽

S. PANDA

Keyword(s):

Quark Model ◽

Chiral Symmetry ◽

Effective Potential ◽

Magnetic Moments ◽

Center Of Mass ◽

Relativistic Quark Model ◽

First Approximation ◽

Mass Correction ◽

Experimental Values ◽

Octet Baryons

Under the assumption that baryons are an assembly of independent quarks confined in a first approximation by an effective potential [Formula: see text], which presumably represents the nonperturbative gluon interactions, the magnetic moments of octet baryons have been calculated by considering perturbatively the contributions of the residual quark-pion coupling arising out of the requirement of chiral symmetry over and above the necessary center-of-mass correction. The results so obtained agree quite well with the corresponding experimental values.

Download Full-text

Hadron Form Factors at BESIII

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194518600273 ◽

2018 ◽

Vol 46 ◽

pp. 1860027

Author(s):

Zhaoxia Meng

Keyword(s):

Cross Section ◽

Center Of Mass ◽

Polar Angle ◽

Form Factors ◽

Angle Distribution ◽

Initial State ◽

Fundamental Information ◽

Born Cross Section ◽

Effective Form ◽

State Radiation

Form factors of hadron provide fundamental information about its structure and dynamics. They constitute a rigorous test of non-perturbative QCD as well as of phenomenological models. Based on data samples collected with BESIII detector at BEPCII collider, born cross section of [Formula: see text] and proton effective form factors are measured at 12 center-of-mass energies between 2.2324 and 3.671 GeV. The ratio [Formula: see text]s are extracted by fitting polar angle distribution of proton for data samples with large statistics. For data between 3.773 and 4.6 GeV, we use initial state radiation (ISR) method to study [Formula: see text] by tagged or un-tagged ISR photon, where the pair cross section, effective form factors and [Formula: see text]s are obtained from proton pair threshold to about 3 GeV. For [Formula: see text] and [Formula: see text], the pair cross section and [Formula: see text] form factors are measured near threshold. With data scanned in 2015 from 2-3.08 GeV, charged Kaon pair cross section and form factors are measured at 21 center-of-mass energies.

Download Full-text

Measurement of hadron form factors at BESIII

EPJ Web of Conferences ◽

10.1051/epjconf/201819200023 ◽

2018 ◽

Vol 192 ◽

pp. 00023

Author(s):

Christoph Florian Redmer

Keyword(s):

Center Of Mass ◽

Form Factors ◽

Large Data ◽

Pion Form Factor ◽

Data Sets ◽

Intermediate Energies ◽

Physics Program ◽

Important Input ◽

Electro Magnetic ◽

Key Aspects

The BESIII experiment, operated at the BEPCII e+e- collider in Beijing, has acquired large data sets at center-of-mass energies between 2.0 GeV and 4.6 GeV. One of the key aspects of the physics program of the BESIII collaboration is to test the understanding of QCD at intermediate energies. Applying different experimental techniques, form factors of hadrons are measured. Among these are the pion form factor, as an important input to the (g - 2)μ puzzle, and the electro-magnetic form factors of nucleons and hyperons in the time-like regime. An overview of the recent results and some ongoing studies at BESIII is provided.

Download Full-text

Charm Meson Physics at BESIII

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194518600637 ◽

2018 ◽

Vol 46 ◽

pp. 1860063

Author(s):

Lei Li

Keyword(s):

Decay Constant ◽

Phase Measurement ◽

Center Of Mass ◽

Form Factors ◽

Mass Energy ◽

Text Data ◽

Strong Phase ◽

Center Of Mass Energy ◽

Plot Analysis ◽

Mixing Parameter

Based on 2.93 fb[Formula: see text] data taken at the center-of-mass energy of [Formula: see text] GeV with the BESIII detector at the BEPCII collider, we report the precise measurements of the decay constant [Formula: see text], the form factors of [Formula: see text] semileptonic decays [Formula: see text] and [Formula: see text], the Dalitz plot analysis of [Formula: see text], the strong phase measurement in [Formula: see text] and the [Formula: see text] mixing parameter [Formula: see text].

Download Full-text