The following effects in the nearly forward ("soft") region of the LHC are proposed to be investigated:• At small |t| the fine structure of the cone (Pomeron) should be scrutinized: a) a break of the cone near t ≈ −0.1 GeV 2 , due to the two-pion threshold, and required by t-channel unitarity, and b) possible small-period oscillations between t = 0 and the dip region.• In measuring the elastic pp scattering and total pp cross section at the LHC, the experimentalists are urged to treat the total cross section σ t , the ratio ρ of real to imaginary part of the forward scattering amplitude, the forward slope B and the luminosity L as free parameters, and to publish model-independent results on dN/dt.• Of extreme interest are the details of the expected diffraction minimum in the differential cross section. Its position, expected in the interval 0.4 < −t < 1 GeV 2 at the level of about 10 −2 mb· GeV −2 ÷10 −1 mb· GeV −2 , cannot be predicted unambiguously, and its depth, i.e. the ratio of dσ/dt at the minimum to that at the subsequent maximum (about −t = 5 GeV 2 , which is about 5) is of great importance.• The expected slow-down with increasing |t| of the shrinkage of the second cone (beyond the dip-bump), together with the transition from an exponential to a power decrease in −t, will be indicative of the transition from "soft" to "hard" physics. Explicit models are proposed to help in quantifying this transition.• In a number of papers a limiting behavior, or saturation of the black disc limit (BDL), was predicted. This controversial phenomenon shows that the BDL may not be the ultimate limit, instead a transition from shadow to antishadow scattering may by typical of the LHC energy scale. 7 The rapidity coverage could be extended further by simple Forward Shower Counters (FSCs) placed at 60 to 140 meters from IP5.
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 hypothesis including both the Pomeron and odderon as double poles, and ω and f mesons as single poles in the complex-J plane, generates a hollow in the inelasticity at low impact parameters. The hollowness effect, which generally may be sensitive to model details, does unequivocally take place both for pp and pp collisions within the applied Regge framework, indicating inapplicability of inelasticity-folding geometric approaches.
Abstract. By using the concept of duality between direct channel resonances and Regge exchanges we relate the small-and large-x behavior of the structure functions. We show that even a single resonance exhibits Bjorken scaling at large Q 2 .
An explicit model realizing parton-hadron duality and fitting the data is suggested. Complex nonlinear Regge trajectories are important ingredients of the model. The inclusion of ∆ and N * trajectories should account for all resonances in the direct channel. The exotic trajectory is responsible for the smooth background.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.