Regge pole plus cut model for proton-antiproton elastic scattering at collider and tevatron energies

The Regge pole plus cut model has been used to explain the data at the collider energies √s=546 and 630 GeV and the most recent differential cross-section results at √s=1.8 TeV. Predictions of the model at 1.8 and 40 TeV are compared with those of Bourrelyet al.     

Single Regge pole model for large angle elasticp-p scattering at high energies

The elastic proton-proton angular distribution at large momentum transfers (?t?8 (GeV/c)²) and energies above 10 GeV laboratory momentum can be understood in the framework of a single Regge pole model.     

Possibility that the Pomeron-Reggeon cut contains the Regge pole

Using the triple Regge formalism for the sum over intermediate states it is shown that the Reggeon-Pomeron cut inherits the Regge pole. This pole dominance of the cut is experimentally verified for non-Pomeron exchanges involving vector and tensor trajectories. Consequences of t-channel unitarity are discussed.     

Logarithmic Regge pole

This work presents the subtraction procedure and the Regge cut in the logarithmic Regge pole approach. The subtraction mechanism leads to the same asymptotic behavior as previously obtained in the non-subtraction case. The Regge cut, in contrast, introduces a clear role to the non-leading contributions for the asymptotic behavior of the total cross-section. From these results, some simple parameterization is introduced to fit the experimental data for the proton-proton and antiproton-proton total cross-section above some minimum value up to the cosmic-ray. The fit parameters obtained are used to present predictions for the begin{document}$ rho(s)$end{document}-parameter as well as to the elastic slope begin{document}$ B(s)$end{document} at high energies.     

Upsilon production at Fermilab Tevatron and LHC energies

We update the theoretical predictions for direct Upsilon(nS) hadroproduction in the framework of nonrelativistic QCD. We show that the next-to-leading order corrections in alpha(S) to the color-singlet transition significantly raise the differential cross section at high p(T) and substantially affect the polarization of the Upsilon. Motivated by the remaining gap between the next-to-leading order yield and the cross-section measurements at the Fermilab Tevatron, we evaluate the leading part of the alpha(S)(5) contributions, namely, those coming from Upsilon(nS) associated with three light partons. The differential color-singlet cross section at alpha(S)(5) is in substantial agreement with the data, so that there is no evidence for the need of color-octet contributions. Furthermore, we find that the polarization of the Upsilon(nS) is longitudinal. We also present our predictions for Upsilon(nS) production at the LHC.     

Neutron total cross sections on nuclei at Fermilab energies

We have measured total cross sections for neutrons on protons, deuteriom, beryllium, carbon, aluminium, iron, copper, cadmium, tungsten, lead, and uranium for momenta between 30 and 300 GeV/c. The measurements were carried out in a small-angle neutral beam at Fermilab. Typical accuracy of the data is 0.5 to 1%. The cross sections are consistent with an A^0.77±0.01 dependence over the entire momentum range. The cross sections are compared with theoretical predictions. Agreement is found only if inelastic screening is included. Nuclear radii obtained from our data are in good agreement with previous determinations.     

Regge behaviour at high energy and more on boson-fermion interaction

Our approach to the problem of boson-fermion interaction in the conventional RFT stems from a model of super-symmetric version in 2-space and 1 time world. Basically it is stressed here that at super high energy there may not be any distinction between the bosonic and fermionic modes and may be treated on a common footing. Usual renormalization group approach for the vertex function has been adopted and the characteristic functionsβ ₁ andβ ₂ are calculated and the possibility of having stable points in the theory has been studied.     

A model for Regge cuts with pole enhancement

It is argued that, since hadronic processes show Regge shrinkage even at large ∣t∣, Regge-cut discontinuities must be enhanced in the region of J near the Regge poles (as suggested by some recent theoretical work on the weak-coupling solution to the “infrared problem” in the reggeon calculus) so that the dominant Regge-cut contribution (at current energies) does not come from the region of the discontinuity near the branch point (as it does in eikonal and absorption models). In particular we show that this hypothesis works well for π^?p→π⁰n. However, there is less shrinkage in photoproduction processes at large ∣t∣, and we find that in γp→π⁰p (and related processes) there is no pole enhancement of the cuts. We connect this fact with the absence of t-channel unitarity constraints for electromagnetic processes and more speculatively with the possibility that a scaling behaviour due to Regge cuts develops at large ∣t∣ as the mass of the external particle is decreased.     

Regge approach to charged pion photoproduction at invariant energies above 2 GeV

A Regge model with absorptive corrections is employed in a global analysis of the world data on positive and negative pion photoproduction for photon energies from 3 to 8GeV. In this region resonance contributions are expected to be negligible so that the available experimental information on differential cross-sections and single polarization observables at - t ⩽ 2 GeV^2 allows us to determine the non-resonant part of the reaction amplitude reliably. The model amplitude is then used to predict observables for photon energies below 3GeV. Differences between our predictions and data in this energy region are systematically examined as possible signals for the presence of excited baryons. We find that the data available for the polarized photon asymmetry show promising resonance signatures at invariant energies around 2GeV. With regard to differential cross-sections the analysis of negative pion photoproduction data, obtained recently at JLab, indicates likewise the presence of resonance structures around 2GeV.     

量子力学中的复角动量理论及其应用

介绍了量子力学中散射振幅分波展开在复角动量平面中的解析延拓问题,讨论了Regge极点的物理意义及其应用.     

Regge pole model for invariant functions. V

The total cross section, the differential cross section and the polarization data ofπN charge exchange as well as elastic scattering is described by the fourρ, ρ′, P, P′ Regge type poles in good agreement with experiment.     

Analytic continuation of the Regge pole residue function

We show that the Regge residue functiony(s) is particularly well suited for performing unitarity bootstrap calculations. The reason is that firstlyy(s) has only one, viz. the right hand, cut along which its value can be evaluated from direct channel unitarity using a parameterfree representation for the partial wave amplitudeS(l, s). Secondly its values for negative real argument follow directly from large-energy scattering with the exchange of one Regge pole in the crossed channel. These values can be evaluated from the sameS(l, s) representation by partial wave sums. Then all one needs for a bootstrap system is an analytic connection of these 2 different pieces of information. We show that this can be achieved by logarithmic dispersion relations. This bootstrap system is supposed to compete favorably with the old unitaryN/D calculations. We finally also propose a new parameter free representation ofS(l, s) which applies equally well as that of Cheng. One main result is that Im α(s) has to decrease exponentially for larges.     

Regge pole model for invariant functions. IV

TheNN→NN andγN→πN differential cross sections for polarized targets are discussed in terms of invariant functions. In former fits of high energy experimental data certain of these invariant functions came out to be small. Based on these fits thepn→np,p¯p→ n¯n, γp→ nπ ⁺ andγn→ pπ ^? differential cross sections are predicted to be independent of the target polarization.     

Triple Regge behaviour in inclusive reactions

Prominent features associated with a triple Reggeon formula are found to meet the low momentum transfer domain of the K⁺p(K^o) inclusive reaction.