The real part of the amplitude of proton-proton scattering at an energy of 3 GeV

Measurement of the differential cross-sections of proton-proton scattering at an energy of 3 GeV is described. The measurement was performed in the region of angles from 2·4° to 16·2°. Analysis of the experimental data shows that besides the imaginary scattering amplitude a real part is also necessary in order to describe elastic scattering at an energy of 3 GeV; the magnitude of the real part is 24% of the magnitude of the imaginary part.It is the authors' pleasant duty to thank V. Sviridov, V. Nikitin, M. afranova and L. Kirillova from the High Energy Laboratory of the Joint Institute of Nuclear Research in Dubna for their help in irradiating the emulsions and monitoring the primary proton beam, and also to Prof. V. Petrílka for stimulating interest and suport in the work.     

Determination of the real part of elastic proton-neutron scattering at an energy of 8 GeV

Elastic pd scattering at an energy of 8 GeV was studied by means of the improved method of the multiple passage of protons through a target 0·6 m thick, made of (CD₂) _n . It was determined from an analysis of the differential cross-section that the magnitude of the real part of the amplitude is 26% of the magnitude of the imaginary part. The real part of the elastic pn scattering amplitude was calculated using the results of the study of the elastic pp scattering at an energy of 8 GeV; its magnitude is 30% of the magnitude of the imaginary part.The authors thank the Directorate of the Joint Institute of Nuclear Research in Dubna for enabling the experiment to be made and the group of experts of the High Energy Laboratory (V. A. Sviridov, V. A. Nikitin, M. G. afranova, L. F. Kirilova and many others) for their collaboration in carrying out the experiment, numerous advice and valuable discussions. The authors also wish to thank Prof. V. Petrílka for his constant interest in this work and all-round help.Their thanks are due to the team of laboratory workers of the Department of Nuclear Physics of the Faculty of Nuclear and Technical Physics for scanning and measuring the nuclear emulsions and other work.     

An application of dispersion relations to Kaon-nucleon scattering

In this paper we have made predictions for the invariant KN and $\text{K}$N scattering amplitudes in the kinematical region q_lab < 15 GeV/c and 0 >; t > -0.7 (GeV/c)².We have performed a direct fit to medium and high-energy data using a parametrization where the imaginary part of the amplitudes for energies above the phase-shift region is identical with the imaginary part of a Regge-pole amplitude, and the real part of the amplitudes has been obtained from a dispersion relation.The s-channel helicity amplitudes are compared with their counterparts in pion-nucleon scattering and other reactions. Exact exchange degeneracy can not be verified.Also the real part of the amplitudes are compared with the real part of phase-shift solutions. There is a qualitative agreement between these two real parts even though they differ in detail.     

The elastic scattering of proton on proton at an energy of 8 GeV

The paper describes the measurement of the differential cross-section for pp scattering at an energy of 8 GeV. The results of the paper agree well with the assumption that there exists a real part of the scattering amplitude that is 33% of the imaginary part.     

Determination of the πN charge exchange scattering amplitude from the experimental data at high energies

The difference between theπ ⁺ p andπ ^? p diffraction peaks is used for an estimate of the imaginary part of the charge exchange scattering amplitude. The imaginary part has a narrow peak in the forward direction and passes over to negative values at a momentum transfert of about ?0.15(GeV/c)². If the charge exchange amplitude is dominated by the contribution of theρ Regge pole, the peak is mainly due to thet-dependence of the residue function and a narrow forward peak is expected in the charge exchange angular distribution.     

Elastic pp and \bar pp scattering in the modified additive quark model

The modified additive quark model, proposed recently, allows one to improve the agreement of the standard additive quark model with the data on the and total cross-sections, as well as on the ratios of real to imaginary part of the pp and amplitudes att=0. Here, we extend this model to non-forward elastic scattering of protons and antiprotons. A high quality reproduction of the angular distributions at 19.4 GeV GeV is obtained. A zero at small in the real part of the even amplitude in accordance with a recently proved general high energy theorem is found. Received: 26 April 2000 / Revised version: 21 September 2000 / Published online: 8 December 2000     

Structure of 6Li from high-energy proton scattering

The elastic and inelastic (2.189 MeV level) scattering of 1 GeV protons from ⁶Li is predicted using Glauber multiple-scattering theory in conjunction with an α-d cluster model capable of fitting quantitatively a large number of measured form factors, in particular the most recent high-momentum-transfer electron scattering data. The predictions, especially in the inelastic channel, are quite sensitive to the parameters of the model. A valuable opportunity is thus provided via experiments well within the capabilities of LAMPF for comparison of structure information obtained from proton scattering with that from other sources in the case of a “test” nucleus whose properties are relatively well determined and unambiguous. Moreover, proton scattering goes beyond electron scattering in possibly providing information about the effective real part of the proton-deuteron cluster amplitude, and thus indirectly about D-state effects in the deuteron cluster.     

Physics (and technique) of gas jet experiments

Recently gas jet targets have been used for the study of small momentum transfer p-p and p-d elastic and inelastic scattering. In these experiments, which were performed at Serpukhov in the USSR and at the Fermilab in the USA, the gas jet is introduced in the main ring of the accelerator. We review the techniques associated with these measurements and summarize the published results which cover 4-momentum transfers 0.001< |t|< 0.12 (GeV/c)^?2 and incident energies 8<E< 400 GeV. Elastic scattering data have yielded precise values for the slope of the nuclear scattering amplitude and for the ratio of the real to imaginary part as a function of energy. The implications of these data on the understanding of high energy hadronic interactions are discussed in some detail. We also present and discuss information on the diffractive dissociation of the proton to low mass states, obtained from inelastic scattering using the gas jet target.     

Model-independent result for the imaginary part of forward πHe4 scattering amplitude in unphysical region

Evaluation of contributions from dispersion integrals to the real part of forwardHe⁴ scattering amplitude is reconsidered. By application of a generalized mean-value theorem to the dispersion integral from the lowest branch point to the elastic threshold, a model-independent conclusion on the imaginary part of forwardHe⁴ scattering amplitude in unphysical region is drawn.     

High-energy elastic scattering near 90 °

The Euler-Maclaurin summation equation is used to sum the scattering-amplitude series near 90 ° for high energies. With certain plausible assumptions regarding the behavior of the partial amplitudes the cross section for scattering near 90 ° is described by two parameters which also describe the cross section for scattering near 180 °. The calculated results are compared with results found in ⁺p scattering at a momentum of 3 GeV/c.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 12, No. 6, pp. 61–64, June, 1969.     

Measurement of the transverse beam spin asymmetry in elastic electron-proton scattering and the inelastic contribution to the imaginary part of the two-photon exchange amplitude

We report on a measurement of the asymmetry in the scattering of transversely polarized electrons off unpolarized protons, A( perpendicular), at two Q2 values of 0.106 and 0.230 (GeV/c)(2) and a scattering angle of 30 degrees 相似文献   

On the real part of the amplitude of elastic scattering of proton on deuteron at an energy of 8 GeV

The elastic scattering of a proton on a deuteron at an energy of 8 GeV is studied by the method of multiple transitions of protons through a target 1·5 μ thick, made from (CD ₂)_n. Altogether 27,385 reflected deuterons were recorded and measured by means of nuclear emulsions. From an analysis of the course of the differential cross-section as a function of the scattering angle in the limits of 1·4° to 8·9° (¦t¦= 0·0042 – 0·1750 (GeV/c)²) we determined the ratio of the real and imaginary parts of the scattering amplitude

$$\alpha = \frac{{\operatorname{Re} A(0)}}{{\operatorname{Im} A(0)}} = - 0 \cdot 36 \pm 0 \cdot 08$$     

Total cross sections,real part of the amplitude,and slope of diffraction cones of the pp and ¯pp forward scattering

In the framework of the model described in [6], analytic expressions are obtained for the ratio of the real part of the forward scattering amplitude to its imaginary part, and for the total cross sections and the slopes of diffraction cones for hadron-hadron and hadron-antihadron interactions. A comparison with the existing experimental data for pp and pp interaction shows that that the computed values of parameters of the elastic scattering are in good qualitative and fair quantitative agreement with their observed values in a wide range of energies s = 5 to 546 GeV.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 65–70, May, 1990.     

Forward elastic scattering of light on light, \gamma+\gamma\rightarrow\gamma+\gamma

The forward elastic scattering of light on light, i.e., the reaction in the forward direction, is analyzed utilizing real analytic amplitudes. We calculate , the ratio of the real to the imaginary portion of the forward scattering amplitude, by fitting the total cross section data in the high energy region 5 GeV GeV, assuming a cross section that rises asymptotically as ln² s. We then compare , the ratio of the even portions of the pp and forward scattering amplitudes, as well as to [1], the value for Compton scattering. Within errors, we find that the three -values in the c.m.s. energy region 5 GeV 130 GeV are the same, as predicted by a factorization theorem of Block and Kaidalov [2]. Received: 18 June 2002 / Published online: 9 August 2002     

The pion-nucleon forward scattering amplitude

The pion-nucleon forward scattering amplitude has been calculated from new data of the total cross sections, using several assumptions on the energy dependence above 20 GeV. The results are presented as complex diagrams of the forward amplitude, which are of interest for the discussion of the nucleonic resonances and the non-resonant background scattering. In addition the predictions for the elastic forward cross sections are given as well as the contributions of the real parts to this quantity. A comparison with the new Saclay data of the charge exchange forward cross section leads to the estimate αρ≈0.6, if a Regge behaviour is assumed above 20 GeV. There are indications in favour of a new\(T = \tfrac{1}{2}\) resonance at the total c.m. energyW≈2.8 GeV.     

Measurements of the spin rotation parameterR in high energy elastic scattering and helicity amplitudes at Serpukhov energies

The spin rotation parameterR in pp and ⁺ p elastic scattering at 45 GeV/c has been measured at the Serpukhov accelerator, for ¦t¦ ranging from 0·2 to 0·5 (GeV/c)². The results are presented, together with previousR measurements at lower energies, and are compared with the predictions of Regge pole models. The equality of the values forR in proton-proton and pion-proton scattering, within the experimental errors, is a test of factorization of the residues.Ans-channel helicity amplitude analysis for pion-nucleon scattering at 40 GeV/c is made using all available data, Significant results are obtained for the isoscalar exchange amplitudes. The helicity flip in isoscalar exchange is non negligible. The energy dependence of this amplitude, at 6, 16 and 40 GeV/c, is compared with predictions of Reggs pole models.Presented by L.van Rossum at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.     

Antinucleon- and pion-nucleus interactions and black nucleus model

Analytical expressions for eikonal scattering amplitude, total and reaction cross sections are obtained in a strong absorption case. Different version of the black nucleus model are derived in connection with antiproton- and pion-nucleus data. Non-eikonal corrections to imaginary part of amplitude are found to be small even at low energies.Presented at the symposium Mesons and Light Nuclei, Bechyn, Czechoslovakia, May 27–June 1, 1985.     

Measurement of the real part of the forward scattering amplitude in K±p elastic scattering at 10.4 and 14 GeV/c

The differential cross section for K^±p elastic scattering has been measured in the very low t region (0.003 < t < 0.2 GeV²) in a wire chamber spectrometer experiment at 10.4 and 14 GeV/c. The interference effect observed between the Coulomb and the nuclear interaction has been used to determine α, the ratio of real to imaginary part of the forward scattering amplitude. At 10.4 GeV/c we measure α(K⁺p) = ?0.21 ± 0.06 and α(K^?p = 0.08 ± 0.04, and at 14 GeV/c, α(K⁺p) = ? 0.13 ± 0.03 and α(K^?p) = 0.000 ± 0.04 in agreeement with the predictions of dispersion theory calculation.