摘要:

The results of recent low‐energy nucleon‐nucleon scattering are summarized. New p‐p cross section experiments below 20 MeV have resolved some of the inconsistencies in earlier cross section data and lead to a low energy behavior of the3Pcphase shift combination consistent with the analysis of higher energy data. Accurate polarization measurements in p‐p scattering permit a model independent determination of all p‐wave phase shifts at 10 MeV. New measurements of the n‐p cross section at 50 MeV resolve an inconsistency in the1P1phase shift at that energy. New n‐p polarization measurements near 25 MeV and measurements of the spin correlation parameter at 50 MeV resolve the problem of the low energy behavior of the S‐D coupling parameter &egr;1. The last section mentions other types of experiments related to the nucleon‐nucleon interaction, i.e. study of the three‐body problem and of the deuteron D‐state.

ISSN:0094-243X    

DOI:10.1063/1.31189

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

This paper describes measurements, made at TRIUMF, of triple scattering parameters in proton‐proton and neutron‐proton elastic scattering.

ISSN:0094-243X    

DOI:10.1063/1.31188

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Elastic differential cross‐sections for neutron‐proton scattering in the range 200−1000 MeV are reviewed. Recent high statistics, backward‐angle experiments at Saclay and LAMPF are in agreement, but disagree with previous measurements from PPA and Dubna. With few exceptions, data come from older, lower statistics experiments done with poor quality neutron beams. The study of neutron‐proton interactions requires more high‐rate measurements of complete angular distributions, which can be performed using recently developed accelerator facilities. Preliminary measurements at LAMPF of 800 MeV np scattering at back angles and forward angles are presented. The latter is the first such high statistics experiment at medium energies.

ISSN:0094-243X    

DOI:10.1063/1.31203

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

An experiment for the determination of the Wolfenstein parameters P, D, R and A in p‐p elastic scattering in an angular domain covering the Coulomb interference region was running at SIN. Preliminary results are presented at 310, 390 and 490 MeV incident kinetic energy for 20?&Vthgr;lab?80. These are in fair agreement with the phase shift predictions.

ISSN:0094-243X    

DOI:10.1063/1.31218

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Results of various asymmetry measurements in nucleon‐nucleon scattering with polarized beams and targets at ZGS energies are presented. A possible direct‐channel resonance in the pp system is discussed. Most of the discussion above ZGS energies are aimed at future measurements.

ISSN:0094-243X    

DOI:10.1063/1.31268

出版商:AIP    

年代:1978

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.31269

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We report on our measurements of n‐p scattering observables at 50 MeV, most notably the recent measurement of the spin‐correlation parameter, Ayy. This measurement is sensitive to the phase shift parameters ?1and &dgr; (1P1), for which early phase shift analyses gave poorly determined or ’’unphysical’’ values. The results of our measurements are incorporated in a phase shift analysis to determine or ’’unphysical’’ values. The results of our measurements are incorporated in a phase shift analysis to determine current best‐fit values of 50 MeV n‐p phase shifts.

ISSN:0094-243X    

DOI:10.1063/1.31270

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The experimental results on p‐p scattering at Fermilab for &sgr;total, &sgr;elastic, &sgr;inelasticand &sgr;inelasticand &sgr;diffractiveare synthesized. Their implications, as well as that of the future data inputs on the fundamental structure of the proton, are discussed.

ISSN:0094-243X    

DOI:10.1063/1.31271

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Four recent measurements in p‐p and n‐p scattering below 520 MeV are used to indicate the influence that new experiments can have upon phase parameters derived from the expanded data base. The cases are described separately and the collective effect upon energy dependent analyses is discussed. The representations used in this discussion are from the recent VPI analyses of 1135 pp data from 1 to 500 MeV, and 1386 np data from 0 to 425 MeV.1The analyses consisted of an Energy Dependent Analysis (EDA) involving 46 variable parameters and producing an overall &khgr;2of 2815 for the 2670 data. The EDA was complemented by single Energy Analyses (SEA) of data binned around 7 energies. The local energy dependence within a bin was that given by the EDA; some results of those analyses are given in Table I of Ref. 1 which summarizes the binning and fitting through SEA’s and Table II which gives the resultant phase parameters at 7 energies. Some indication of how well the SEA minima could be described by a quadratic expansion in the parameter space (the usual error matrix approximation) can be seen in the last column of Table I, where the 2n derivative matrix was used to predict &khgr;2for the binned data and the EDA fit; it compares favorably to the actural (data) values. Figure 4, Ref. 1, indicates the distribution of n−p scattering data which is used for the determination of I=0 phases. It is certainly the weaker component of the data base consisting almost entirely of &sgr; (&Vthgr;), &sgr;Tand P with larger experimental uncertainties than for corresponding p‐p quantities.Although we use these particular analyses to measure the effect of newer data, the conclusions are certain to be generally valid when applied to other analyses. The results of these studies, which are based upon preliminary data, should not be taken as a final indication of the phase parameters which will be obtained when the data is properly incorporated into the data base.

ISSN:0094-243X    

DOI:10.1063/1.31181

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

In this paper we discuss a new phase shift analysis and give some results for pp and np scattering. An improvement over the standard method of phase shift analysis is presented by the inclusion of the cut for 4m&pgr;?t≲45m&pgr;2. Unitarization is achieved through application of a K‐matrix formalism where we employ for the first time in NN, the ’’derivative amplitudes’’. We compare the theoretical predictions for the peripheral waves with the trends predicted by a new version of Optimal Polynomial Theory (OPT). With the analysis described here we aim at better determination of non‐peripheral phase shifts and a smooth transition between peripheral and non‐peripheral phases.

ISSN:0094-243X    

DOI:10.1063/1.31182

出版商:AIP    

年代:1978

数据来源: AIP