Neglecting spin effects, one introduces here a subtle approximation for the scattering angle, which allows the obtaining of a logarithmic leading Regge pole, consistent with the Froissart-Martin bound. A simple parameterization is also introduced for the proton-proton total cross section. Fitting procedures are implemented only for the highest energy experimental data available. The intercept for a linear approach is obtained, indicating the presence of a soft pomeron. The Tsallis entropy in the impact parameter space is calculated using the Regge pole formalism. This entropy depends on a free parameter, whose value implies the existence of a central or non-central maximum value for the entropy. The hollowness effect is discussed in terms of this parameter.
The high-energy limit of gauge-theory amplitudes features both a Regge pole and Regge cuts. We show how to disentangle these, and hence how to determine the Regge trajectory beyond two loops. While the nonplanar part of multiple Reggeon $t$-channel exchange forms a Regge cut, the planar part contributes to the pole along with the single Reggeon. With this, we find that the infrared singularities of the trajectory are given by the cusp anomalous dimension. By matching to recent QCD results, we determine the quark and gluon impact factors to two loops and the Regge trajectory to three loops.
The Regge limit of gauge-theory amplitudes and cross sections is a powerful theory tool for the study of fundamental interactions. It is a vast field of research, encompassing perturbative and non-perturbative dynamics, and ranging from purely theoretical developments to detailed phenomenological applications. It traces its origins to the proposal of Tullio Regge, almost sixty years ago, to study scattering phenomena in the complex angular momentum plane. In this very brief contribution, we look back to the early days of Regge theory, and follow a few of the many strands of its development, re…
We use Regge phenomenology to study the structure of the poles of the $N^*$ and $Δ^*$ spectrum. We employ the available pole extractions from partial wave analysis of meson scattering and photoproduction data. We assess the importance of the imaginary part of the poles (widths) to obtain a consistent determination of the parameters of the Regge trajectory. We compare the several pole extractions and show how Regge phenomenology can be used to gain insight in the internal structure of baryons. We find that the majority of the states in the parent Regge trajectories are compatible with a mostly …
The high-energy limit of $2\to 2$ scattering amplitudes offers an excellent setting to explore the universal features of gauge theories. At Leading Logarithmic (LL) accuracy the partonic amplitude is governed by Regge poles in the complex angular momentum plane. Beyond LL, Regge cuts in this plane begin to play an important role. Specifically, the real part of the amplitude at Next-to-Next-to-Leading Logarithmic (NNLL) accuracy presents for the first time both a Regge pole and a Regge cut. Analysing this tower of logarithms and computing it explicitly through four loops we are able to systemat…
The theoretical motivations that led Tullio Regge to investigate the analytical properties of the scattering amplitude of the collision process between two particles in terms of complex energy and complex angular momentum are briefly reviewed and set in the context of the S-matrix theory that was developed in the late Fifties and early Sixties of the last century, in an attempt to unravel the properties of the strong interaction.
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, on the other hand, introduces a clear role to the non-leading contributions for the asymptotic behavior of the total cross section. From these results, one introduces some simple parameterization 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 ar…
The procedure to improve the convergence in transverse momentum space of the NLL BFKL kernel using a w-shift is revisited. An accurate approximation to this shift only depending on transverse momenta is presented. This approximation is based on a Bessel function of the first kind with argument depending on the strong coupling and a double logarithm of the ratio of transverse scales. A comparison between different renormalization schemes is also included.
We study the high-energy small-angle {\it Regge} limit of the fermion-antifermion scattering in gauge theories and consider the part of the amplitude suppressed by a power of the scattering angle. For abelian gauge group all-order resummation of the double-logarithmic radiative corrections to the leading power-suppressed term is performed. We find that when the logarithm of the scattering angle is comparable to the inverse gauge coupling constant the asymptotic double-logarithmic enhancement overcomes the power suppression, a formally subleading term becomes dominant, and the small-angle expan…
We compute the three-loop leading-colour corrections to the Yang-Mills Regge trajectory and gluon impact factor. Conjecturing that, in analogy with $\mathcal{N}=4$ super Yang-Mills (SYM), in a suitable scheme $N_c$-subleading terms are absent from the three-loop Regge trajectory, we understand our result as the first computation of the pure gauge, or $n_f = 0$, part of the QCD three-loop Regge trajectory. The results are presented both for the bare and renormalised amplitudes and are consistent with predictions from infrared factorisation along with reproducing known results in planar $\mathca…
Regge behaviour of structure functions and solution of Dokshitzer-Gribov-Lipatov-Altarelli-Parisi Evolution equations in next-to-leading order at low-x
The proton-proton and proton-antiproton inelasticity profiles in the impact parameter display very interesting and sensitive features which cannot be deduced solely from the current large body of high-energy scattering data. In particular, phenomenological studies exhibit a link between the ratio of the real to imaginary parts of the elastic scattering amplitude at a finite momentum transfer, and the corresponding change of character of the inelastic processes from central to peripheral collisions. We describe how a theoretical model, accommodating the existing data, based on the Regge hypothe…
At small momentum transfer, the quark-gluon scattering cross section dσ/dt has a power-law divergence in the backward scattering region where the outgoing quark is nearly collinear to the incoming gluon. In this Regge limit |t|<< s, the leading behavior of the 2 2 amplitude can be described by the exchange of Glauber quarks. In Soft-Collinear Effective Theory (SCET) at leading power, Glauber quark exchange is given by five non-local Glauber quark operators, of which only one is generated at tree-level. We show that at leading power the QCD amplitude for quark-gluon backscattering at one-loop c…
Double-spin asymmetry in elastic proton-proton scattering as a probe for the Odderon
极化质子弹性散射中的双自旋不对称性A_{NN}的大小是利用先前确定的领先Regge极的自旋翻转耦合的结果来估计的（参见图1）。T.L.Trueman，Proceedings of the 16th International Spin Physics Symposium SPIN 2004，eds. F. Bradamante等人，World Scientific，2005.）所需的Regge削减估计使用吸收Regge模型。这个估计，然后用来确定在RHIC的实验的灵敏度的存在下的Odderon。
Recent results on the slope of the $pp$ diffraction cone measured by TOTEM at $7$ and $8$ GeV show an unexpected rapid rise in $s$, close to $B(s)\sim \ln^2$, rather than $\ln s$, typical of the Regge-pole predictions. We show that the new phenomenon can be accommodated by the inclusion of unitarity corrections to a simple Regge (pomeron) pole exchange. Interestingly, the odderon may also promote the acceleration of $B(s)$. The onset of the new regime may be indicative of the approach to the asymptotic dynamics of strong interactions. We analyse the new data together with other available forwa…
