摘要:

We study the effect of a surrounding Fermi sea of non‐interacting nucleons on the &Dgr;‐isobar, in a simple model, derived from Chew‐Low theory.

ISSN:0094-243X    

DOI:10.1063/1.30831

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30832

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A calculation of the pion‐nucleon interaction in nuclear matter including effects of propagator modification results in a significant damping width for the (3,3) resonance.

ISSN:0094-243X    

DOI:10.1063/1.30833

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30834

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

It was recently reported that contributions of meson‐exchange currents, i.e., one‐pion exchange and &rgr; (&ohgr;)−&pgr; exchange, were significant to the electromangnetic form factors of the two‐ and three‐nucleon systems [1]. In the framework of the independent pair model [2], we have investigated the contributions of the meson‐exchange currents to the charge density and rms radius of16O. The distribution of the center‐of‐mass of the nucleon pair was assumed to be the same as the proton distribution obtained by the Hartree‐Fock calculation [3]. Our numerical results show that that one‐pion exchange current is very important in calculation of the nuclear charge density. In calculation of ‐&rgr;n(r), we used the dipole type distribution for the neutron charge [4]. The rms radius of16O is suppressed by 8.93%, 0.81% and 0.25%, respectively by the contributions of one‐pion exchange current, neutron charge and &rgr;‐&pgr; exchange currents. Hence, it turns out that the meson exchange currents should be included in the Hartree‐Fock calculation of the nuclear charge density.

ISSN:0094-243X    

DOI:10.1063/1.30835

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30836

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Some more refined methods than simple forward dispersion relations are suggested for studying the pion‐nucleus scattering.

ISSN:0094-243X    

DOI:10.1063/1.30837

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The new threshold expansion of the crossing‐symmetrics‐wave scattering amplitude is qualitatively confirmed by means of dispersion relations for the forward scattering amplitude.

ISSN:0094-243X    

DOI:10.1063/1.30838

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

In connection with the puzzle of the missing solar neutrinos, it is important to know whether current theoretical estimates of the rate of the unmeasurably slow proton‐proton reaction, p+p →2H+e++&ngr;e, are reliable to within 10%, as assumed in construction of solar models. I find that a unitary transform of range 1 fm applied to typical phenomenological1S0p‐p and3D1deuteron radial functions can increase the S‐D non‐Born pionic exchange‐current term, which dominates the interaction‐current correction to the impulse approximation, by a factor of five. The resulting rate is 40% higher than the presently accepted value.

ISSN:0094-243X    

DOI:10.1063/1.30839

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

We have examined the effect of anti‐symmetrized p‐p amplitude on the p‐d scattering and found that the back angle scattering must be treated more carefully than having been done in the conventional approach.

ISSN:0094-243X    

DOI:10.1063/1.30840

出版商:AIP    

年代:1976

数据来源: AIP