Article

Exclusive neutrino-induced production of pseudoscalar mesons in the neutral currents

Authors:

Institut National de Physique Nucléaire et de Physique des Particules

A study is made of exclusive processes of production of the pseudoscalar ..pi..Â°, eta, and eta' mesons in the weak neutral currents, due to scattering of a neutrino: a) by virtual mesons (Reggeons) at the periphery of a nucleon; b) in the Coulomb field of a proton (nucleus). The study of such processes will make it possible to obtain information about the weak transitions meson (Reggeon)..--> pi..Â°(eta,eta') and about the effects of the isoscalar axial current.

ResearchGate has not been able to resolve any citations for this publication.

ResearchGate has not been able to resolve any references for this publication.

Article

Inclusive pion production in proton and ion collisions with nuclei

July 1979

Rubin H. Landau

Inclusive pion production in nuclear collisions is examined with models for hard scattering from single nucleons or clusters within the nucleus. The occurrence of scaling and the shapes of the forward and backward pion spectrums are examined.

Article

Antisymmetrization in the multicluster dynamical model of nuclei and nucleon-exchange effects

January 1999 · Physics of Atomic Nuclei

A modified version of the multicluster dynamical model of nuclei is proposed to construct completely antisymmetrized wave functions of multicluster systems. An overlap kernel operator is introduced to renormalize the total wave function after antisymmetrization with respect to nucleons belonging to different clusters. A group-theoretical method is developed to analyze the role of exchange effects ... [Show full abstract] that arise in calculating various observables of multicluster systems due to this antisymmetrization. The antisymmetrized version of the multicluster dynamical model is applied to six-nucleon systems treated as α-2N ones. For six-nucleon systems, the static and dynamical characteristics that manifest themselves in electron and π-meson scattering, muon capture, β decay, pion photoproduction, etc., are calculated. Significant advances are made in describing a variety of dynamical observables of six-nucleon systems in relation to the multicluster dynamical model. In the majority of cases, the calculated static and especially dynamical features comply well with available experimental data.

Article

Strong Cancellations of Neutron and Proton Transition Amplitudes Observed in Pion Inelastic Scatteri...

July 1981 · Physical Review Letters

Differential cross sections were measured for inelastic scattering of 164-MeV ${$\pi${}}^{+}$ and ${$\pi${}}^{$-${}}$ from $^{14}\mathrm{C}$. Large cross-section ratios, $R=\frac{$\sigma${}({$\pi${}}^{+})}{$\sigma${}({$\pi${}}^{$-${}})}$ (or ${R}^{$-${}1}$), were observed, two being significantly larger than the free $$\pi${}$-nucleon value. Lower limits are $R>26$, ${R}^{$-${}1}>17$, and $R>11$ ... [Show full abstract] for states at 8.32 MeV (${2}^{+}$), 11.67 MeV (${4}^{$-${}}$), and 17.26 MeV (${4}^{$-${}}$), respectively. These values are interpreted as being due to strong cancellations of the neutron and proton components of the transition amplitudes.

Article

Full-text available

The 3D Structure of the Proton

September 2012 · Journal of Physics Conference Series

Ralf Kaiser

When Rutherford, Geiger and Marsden discovered the atomic nucleus in 1909 in Manchester, they at the same time also laid the foundations for the most successful method to study the structure of nuclei and nucleons. They found a point-like scattering centre inside the atom and identified it with the atomic nucleus and the theoretical description of this process has been known as Rutherford ... [Show full abstract] scattering ever since. The deviation between the theoretical description for a point-like scattering centre and experimental data has since been used to reveal information about the structure of the nucleus as well as the nucleon. There has been a continuous development from Hofstadters experiments in the 1950s, over the SLAC experiments in the 60s and 70s to the the HERA experiments at DESY and the experimental programme at Jeffersonlab. In this paper I am presenting the most recent results in Deeply Virtual Compton Scattering from the Hermes experiment at DESY, taken with a high density unpolarised target and a recoil detector in 2006/7.

Article

Electron quasi-elastic scattering and. Delta. production from sup 3 H and sup 3 He

Electron quasi-elastic scattering and Î production cross sections of Â³H and Â³He are presented for E{sub i} from 109 MeV to 789 MeV at Î¸ = 54.0Â°, E{sub i} from 99 MeV to 507 MeV at Î¸ = 134.5Â°. The longitudinal and the transverse response functions were obtained using Rosenbluth separation with {vert bar}{rvec q}{vert bar} from 150 MeV/c to 700 MeV/c. The results in the quasi-elastic ... [Show full abstract] scattering region are compared with the calculation using spectral function obtained from the 3-nucleon wave function calculated for the Reid soft core potential with the Fadeev technique. Discrepancies are seen between the experimental longitudinal response functions and the calculations. The transverse response functions agree, in general, with the calculations. The nucleon form factors modified by the nuclear medium, the nucleon-nucleon pair correlations, final state interactions, meson exchange effects and pion productions are considered as the contributions to the discrepancies. The Coulomb sum rules for both Â³H and Â³He are obtained with model independent approach. The Coulomb sums are shown saturated at 85% as {vert bar}{rvec q}{vert bar} > 350 MeV/c. Â³He displays a larger nucleon-nucleon pair correlation than Â³H. The phenomena of y-scaling are also studied with the total cross sections and the separated longitudinal and transverse cross sections in the quasi-elastic scattering region. In the Î peak region, the cross sections of Â³H and Â³He are identical with experimental uncertainty, which indicates that the electro-Î production mechanisms from proton and neutron in the nucleus are the same.

Article

Validity of the one-photon exchange approximation in inelastic scattering of electrons and positrons...

March 1976 · Lettere al Nuovo Cimento

In the analysis of elastic and inelastic electron scattering data on nucleons one assumes that thc one-photon exchange approximation is valid, since higher-order diagrams should be smaller by a factor a ~ 1/137. For elastic scattering an upper limit of 2% for the real part of the two-photon exchange amplitude can be derived in the whole kinematic region explored up to now (~). In the inelastic ... [Show full abstract] region two measurements at a primary energy of E = 10 GeV and scattering angles of 2.6 ~ and 5 ~ have been published for the electron-proton and positron-proton scattering (2). In addition measurements with lower statistics using muon beams have been performed (a). Since the linear relationship between the structure functions W~(q 2, v), W2(q 2, v), which describe the coupling between the virtual photon and the hadron, and the measured twofold cross-section

Article

Development of cluster ideas in the physics of multinucleon and multiquark systems

June 2006 · Physics of Atomic Nuclei

V. G. Neudatchin

We review the development of cluster ideas in the following directions: the structural forbiddenness of heavy-nucleus fragmentation, the possibility of “seeing” virtual excited clusters in a nucleus during the quasi-elastic knockout of clusters by ∼1-GeV protons; the role of two-step mechanisms in direct nuclear reactions with clusters; the cluster-cluster potentials with forbidden states; the ... [Show full abstract] Moscow NN-interaction potential and quark microscopics; and the quasi-elastic knockout of mesons from a nucleon by high-energy electrons in quark microscopics.

Article

Quasielastic Ca40(e,e'p) cross sections in a many-particle self-consistent Hartree model

May 1993 · Physical Review C

A fully distorted partial-wave calculation is presented for the reaction [sup 40]Ca([ital e],[ital e][prime][ital p])[sup 39]K which uses relativistic self-consistent Hartree wave functions for both the target nucleus and the residual nucleus. The final state interaction of the knocked-out nucleon is described by an optical potential and the Coulomb distortion of the electron wave functions is ... [Show full abstract] also included. We assume standard values for meson coupling constants and masses in the Hartree calculations and the optical potential used comes from global fits to elastic proton scattering; hence, this calculation is a description of ([ital e],[ital e][prime][ital p]) reactions with no free parameters. We examine the proton knocked-out from the [ital d][sub 3/2] state of [sup 40]Ca which leaves the residual nucleus [sup 39]K in its ground state. Agreement with the experimental data of NIKHEF is good and the calculated spectroscopic factor agrees very well with the one extracted from experiment. There seems to be no need to make the assumption that the [ital d][sub 3/2] state is appreciably depleted. We also calculate the ([ital e],[ital e][prime][ital p]) cross section from the 2[ital s][sub 1/2] and 1[ital f][sub 7/2] orbitals. For the 2[ital s][sub 1/2] orbital the shape does not agree so well with the experimental data. The [ital f][sub 7/2] orbital leads to approximately the correct shape and we extract a spectroscopic factor of 3.7%.

Article

Low-lying states in 32Mg studied by proton inelastic scattering

May 2009 · Physical Review C

Proton inelastic scattering on the neutron-rich nucleus 32Mg has been studied at 46.5 MeV/nucleon in inverse kinematics. Populated states were identified by measuring de-excitation γ rays, in which five new states were found by γ-γ coincidence analyses. By analyzing the angular differential cross sections via coupled-channel calculations, their spins and parities were constrained and the ... [Show full abstract] amplitudes for each transition were extracted. The spin and parity of the 2321-keV state was assigned as 41+. The ratio between the energies of the 21+ and 41+ states indicates that 32Mg is a transitional nucleus rather than an axially deformed rigid rotor. The collectivities in the nucleus 32Mg with N=20 are discussed based on the results obtained in the present experiment.

Article

Analysis of π - MMMesonic atoms

April 1967 · Physical Review

A phenomenological analysis of the pi--mesonic atom in light nuclei has been made by use of a new approximation technique for the exterior wave function outside of the region of strong interaction. This approximation is a series expansion of the Coulomb wave function in terms of the energy-level-shift ratio DeltaE1SE1S. From the new measurements of Jenkins, Kunselman, Simmons, and Yamazaki of the ... [Show full abstract] shifts and spreads of the 2P-->1S transition energy in pi--mesonic atoms, we have calculated the complex pi--nucleus potential and the exact pi--nucleus scattering length. The pi--nucleus scattering lengths are found not to satisfy the hypothesis that they are the sums of pi--nucleon scattering lengths. Also the scattering lengths do not exhibit any apparent isotopic-spin dependence. It is also found that level shift depends only on the volume integral of the potential and not on its shape. Using this potential, the pi--mesonic wave function inside the nucleus is obtained in analytic form, and it is found that the probability that the pi--meon is inside the nucleus has only about half the value given by a first-order perturbation calculation.

Article

Full-text available

Hard exclusive pion electroproduction at backward angles with CLAS

November 2017

We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, $e p \to e^\prime n \pi^+$, above the resonance region at backward pion center-of-mass angles. The $\varphi^*_{\pi}$-dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with ... [Show full abstract] calculations based on nucleon-to-pion transition distribution amplitudes (TDAs) and shed new light on nucleon structure.

Article

Nuclear response in electromagnetic quasi-free knockout including two-body currents

May 1991 · Nuclear Physics A

The nuclear response is considered for the outgoing nucleon knocked out in quasi-free scattering with polarized electrons. In the framework of the one-photon exchange approximation, the resulting five structure functions are calculated with an electromagnetic current of the target nucleus which includes two-body contributions coming from meson-exchange currents and isobar configurations in ... [Show full abstract] intermediate nuclear states. Specific calculations are presented for both proton and neutron knockout in the case of a 16O target nucleus. The sensitivity to final state interactions, mesonic effects and isobaric configurations is discussed.

Last Updated: 05 Jul 2022