A diffractive model including spin for pp elastic scattering at very high energy

In this paper we present a theoretical diffractive model for spin-dependent proton-proton scattering at very high energies using an extended version of the Chou-Yang model. The model describes a wide t range, but in this paper we use it for small t values. We obtain estimates of the ratio of spin-dependent to spin-independent amplitudes, β, consistent with a previous phenomenological analysis. Next we estimate the asymmetry, Σ, expected in a certain polarized inclusive process at high energy. We then compute the size of polarization effects in pp total cross-section measurements, using polarized beam and target at very high energy. Our estimates of the latter two quantities indicate that their measurement would not provide a sensitive test of pomeron factorization.     

Sum rules for forward elastic pion-nucleon scattering

A number of energy weighted sum rules relating amplitudes and differential cross sections for forward elastic and charge exchange scattering to the total pion-nucleon cross section are derived from dispersion relations.     

The odderon in high energy elastic pp scattering

We study the odderon contribution to elastic pp and scattering at high energies. Different models for the odderon–proton coupling are considered and their effects on the differential cross section in the dip region are investigated. We use a Regge fit by Donnachie and Landshoff as a framework and replace its odderon contribution by the different models. We consider two models for the odderon–proton impact factor proposed by Fukugita and Kwieciński and by Levin and Ryskin. In addition we construct a geometric model of the proton which allows us to put limits on the size of a possible diquark cluster in the proton. All models are able to describe the data well. The two models for the impact factor require the strong coupling constant to be fixed rather precisely. In the geometric model a relatively small diquark size is required to describe the data. Received: 1 February 2002 / Published online: 14 June 2002     

Regge-eikonal model for high energy elastic diffractive nucleon-nucleon scattering with a minimum number of reggeons

A phenomenological Regge-eikonal model with nonlinear monotonic parameterizations for Regge trajectories in which their asymptotic behavior in the perturbative region is taken into account explicitly is proposed. It is shown with the example of elastic proton-(anti)proton scattering that in the kinematic region \(\sqrt s \) > 23 GeV, 0.005 GeV² < ?t < 3 GeV², the diffraction pattern is mainly determined by only three Regge trajectories.     

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.     

Intermediate changes in high energy elastic scattering from atoms

Correction of the Glaubner T-matrix to account for target particle motion and energy change in elastic scattering of charged particles from atomic systems is found to vanish to leading order.     

Differential cross sections for high energy elastic hadron-hadron scattering in nonperturbative QCD

Total and differential cross sections for high energy and small momentum transfer elastic hadron-hadron scattering are studied in QCD using a functional integral approach. The hadronic amplitudes are governed by vacuum expectation values of lightlike Wegner-Wilson loops, for which a matrix cumulant expansion is derived. The cumulants are evaluated within the framework of the Minkowskian version of the model of the stochastic vacuum. Using the second cumulant, we calculate elastic differential cross sections for hadron-hadron scattering. The agreement with experimental data is good. Received: 3 September 1998 / Published online: 19 November 1998     

Simple regge pole model for neutron-proton elastic scattering at high energies

It is shown that, by a phenomenological choice of residue functions, the most recent measurements of the differential cross section, the total cross section and the slope fornp elastic scattering from 70 to 400 GeV/c can be explained on simple Reggepole model. The predictions are also made regarding the energy dependence of dip and bump structure.     

A search at high energies for antineutrino-electron elastic scattering

We have searched for candidates for the weak neutral leptonic current reaction $\text{ν}{}_{\mathrm{\mu }}\text{+}\text{e}{}^{\mathrm{?}}\text{→}\text{ν}{}_{\mathrm{\mu }}\text{+}\text{e}{}^{\mathrm{?}}$ in the Fermilab 15 ft bubble chamber filled with a heavy neon-hydrogen mix. Based on zero observed events of this type we find the 90% confidence level upper limit for the rate for this reaction relative to the total antineutrino charged current rate to be 3.9 × 10^?4 and, in the Weinberg-Salam model, sin²θ_W ? 0.37.     

Straight-line path approximation for high energy elastic and inelastic scattering in quantum gravity

The asymptotic behavior of Planck energy elastic and inelastic amplitudes in quantum gravity is studied by means of the functional integration method. A straight-line path approximation is used to calculate the functional integrals which arise. Closed relativistically invariant expressions are obtained for the two “nucleons” elastic and inelastic amplitudes including the radiative corrections. Under the requirement of “softness” of the secondary gravitons a Poisson distribution for the number of particles emitted in the collision is found. Received: 6 December 1999 / Published online: 6 July 2000     

Some implications of the quark model for high energy scattering

The expressions for total scattering cross sections obtained from the quark model are expressed in a simple form which shows the dependence of the results on the assumptions. The results are shown to depend only on the value of six constants or “charges” defined for each hadron and to be otherwise independent of the structure. Any model which gives the same values of these charges gives the same result as the quark model. In particular, the results for processes which have odd signature t-channel quantum numbers hold in a quark model even with arbitrary mixtures of additional quarkantiquark pairs in the hadron wave function, provided that B, Y, and I are conserved.     

Physical meaning of the phase of high energy elastic scattering amplitude

The influence of the phaset-dependence on the profiles of high energy elastic hadron scattering in the impact-parameter plane are discussed. The analysis of interference experimental data concerning pp, ¯pp and p⁴He scattering is summarized. It is shown that in all these cases the high-energy elastic scattering can be interpreted as a peripheral process.Dedicated to Academician Václav Votruba on the occasion of his eightieth birthday.     

A possible mechanism for spin effects in large anglep−p elastic scattering

We propose a simple parton model interpretation of large anglep?p elastic scattering in terms of elementaryq?q scattering. We formulate the model and give some numerical estimates which qualitatively explain the most important spin effects. We do not assume any particular quark recombination mechanism but we stress the importance of the proton wave function. Comparisons with other models are made.     

Measurement of spin observables in neutron-proton elastic scattering

The spin correlation parameters and the analyzing power have been measured in free np elastic scattering at kinetic energies of 260, 315, 380, 460 and 535 MeV in the c.m. angle range from 60° to 164°. The experiment was performed at the Paul-Scherrer-Institut (PSI) using a polarized neutron beam with continuous energy incident on a polarized proton target. These data will contribute significantly to the determination of the isospin I=0 nucleon-nucleon amplitudes. Received: 24 May 2000 / Published online: 31 August 2000     

A new measurement of the51V spin dependent scattering length

The method of pseudomagnetic slow neutron precession has been used to obtain the spin-dependent (incoherent) scattering length of⁵¹V with a better precision than obtained before by other methods. The result,b ⁺ ?b ^?=12.81±0.08 fm, is consistent with the earlier values.