Eikonal approximation for high-energy inclusive processes

1975 ◽  
Vol 23 (1) ◽  
pp. 320-327
Author(s):  
B. M. Barbashov ◽  
V. V. Nesterenko
Keyword(s):  
Eikonal Approximation ◽  
High Energy ◽  
Inclusive Processes

scholarly journals SELECTED TOPICS IN HIGH ENERGY SEMI-EXCLUSIVE ELECTRO-NUCLEAR REACTIONS

2001 ◽  
Vol 10 (06) ◽  
pp. 405-457 ◽  
Author(s):  
MISAK M. SARGSIAN
Keyword(s):  
Present Status ◽  
Short Range ◽  
Nuclear Reactions ◽  
Eikonal Approximation ◽  
High Energy ◽  
Glauber Theory ◽  
Nucleon Recoil ◽  
High Energy Scattering ◽  
Nuclear Targets ◽  
Short Range Correlations

We review the present status of the theory of high energy reactions with semi-exclusive nucleon electro-production from nuclear targets. We demonstrate how the increase of transferred energies in these reactions opens a completely new window for study of the microscopic nuclear structure at small distances. The simplifications in theoretical descriptions associated with the increase in the energies are discussed. The theoretical framework for calculation of high energy nuclear reactions based on the effective Feynman diagram rules is described in detail. The result of this approach is the generalized eikonal approximation (GEA), which is reduced to the Glauber approximation when nucleon recoil is neglected. The method of GEA is demonstrated in the calculation of high energy electro-disintegration of the deuteron and A=3 targets. Subsequently, we generalize the obtained formulae for A>3 nuclei. The relation of GEA to the Glauber theory is analyzed. Then, based on the GEA framework we discuss some of the phenomena which can be studied in exclusive reactions: nuclear transparency and short-range correlations in nuclei. We illustrate how light-cone dynamics of high-energy scattering emerge naturally in high energy electro-nuclear reactions.

Hot electron in a polar crystal. I. The eikonal approximation

1976 ◽  
Vol 54 (20) ◽  
pp. 2093-2100
Author(s):  
B. Hede ◽  
T. McMullen
Keyword(s):  
Energy Loss ◽  
Fast Electron ◽  
Quantum Interference ◽  
Eikonal Approximation ◽  
High Energy ◽  
Function Technique ◽  
Hot Electron ◽  
Polar Crystal ◽  
The Individual ◽  
High Energy Scattering

A quantum theory of the rates of momentum and energy loss by a fast electron to the optic modes of a polar crystal as a function of time elapsed since injection of the fast electron is developed. A nonequilibrium Green function technique is used to formulate the problem, and permits inclusion of quantum interference between the individual phonon processes. An approximation, which has been called the eikonal approximation in high energy scattering and is valid when the fractional electron energy loss in a single phonon collision is small, enables us to sum the resulting diagrams. The relationship of this method to a Boltzmann equation approach is discussed.

Smallx EVOLUTION OF MULTI-POINT CORRELATORS OF WILSON LINES

2011 ◽  
Vol 04 ◽  
pp. 20-25
Author(s):  
JAMAL JALILIAN-MARIAN
Keyword(s):  
Evolution Equation ◽  
Evolution Equations ◽  
Scattering Amplitude ◽  
High Energy ◽  
Point Function ◽  
Forward Scattering Amplitude ◽  
Angular Correlations ◽  
Small X ◽  
Dipole Scattering ◽  
Inclusive Processes

At high energy (small x) n-point coorelators of Wilson lines appear in calculation of physical observables. The energy dependence of these observables is determined by the solution of the evolution equations these correlators satisfy. The most common correlator is the two-point function, the imaginary part of the forward scattering amplitude of a quark anti-quark dipole scattering on a target. This appears in structure functions in DIS as well as single inclusive hadron production in proton-nucleus collisions. Higher point correlators of Wilson lines appear in less inclusive processes, such as two-hadron angular and rapidity correlations and satisfy the Balitski-JIMWLK evolution equation. Here we derive the evolution equation satisfied by the six point correlator of Wilson lines which appears in di-hadron angular correlations in proton-nucleus collisions at high energy.

scholarly journals The eikonal model of reactions involving exotic nuclei; Roy Glauber's legacy in today's nuclear physics

2020 ◽  
Author(s):  
Pierre Capel
Keyword(s):  
Nuclear Physics ◽  
Eikonal Approximation ◽  
High Energy ◽  
Exotic Nuclei ◽  
Halo Nuclei ◽  
Eikonal Model ◽  
Energy Quantum

In this contribution, the eikonal approximation developed by Roy Glauber to describe high-energy quantum collisions is presented. This approximation has been—and still is—extensively used to analyse reaction measurements performed to study the structure of nuclei far from stability. This presentation focuses more particularly on the application of the eikonal approximation to the study of halo nuclei in modern nuclear physics. To emphasise Roy Glauber’s legacy in today’s nuclear physics, recent extensions of this model are reviewed.

scholarly journals PYTHIA and the preoccupied proton

2019 ◽  
Vol 206 ◽  
pp. 04001
Author(s):  
Thomas A. Trainor
Keyword(s):  
Eikonal Approximation ◽  
High Energy ◽  
Hadron Production ◽  
Binary Collision ◽  
Glauber Model ◽  
Multiple Target ◽  
Alternative Description ◽  
Ensemble Mean ◽  
Color Reconnection ◽  
Contradictory Data

The PYTHIA Monte Carlo (PMC) has been applied broadly to simulations of high-energy p-p and p- $ \bar p $ collisions. The PMC is based on several assumptions, such as that most hadrons result from jet production (multiple par-ton interactions or MPIs), that p-p centrality is relevant and that color reconnection (CR) strongly influences fragmentation to jets. An alternative description is provided by the two-component (soft + hard) model (TCM) of hadron production. TCM analysis of p-Pb ensemble-mean-pt data reveals centrality trends quite different from those estimated via a geometric Glauber model based on the eikonal approximation. Glauber estimates of binary-collision number are three times TCM estimates. Detailed study of p-Pb data conflicts with a basic Glauber assumption – that a projectile proton may interact simultaneously with multiple target nucleons. Instead, in both p-p and p-A collisions, a p-N collision once initiated is exclusive of other possible interactions (during that collision), and within the collision any pair of participant partons may interact –a p-N collision is thus “all or nothing.” In this presentation the PMC is challenged by an assortment of contradictory data, and evidence for p-N exclusivity is reviewed to make a case for the “preoccupied proton” of the title.

scholarly journals Forward particle production in proton-nucleus collisions at next-to-leading order

2018 ◽  
Vol 192 ◽  
pp. 00014
Author(s):  
D.N. Triantafyllopoulos
Keyword(s):  
Cross Section ◽  
Particle Production ◽  
Eikonal Approximation ◽  
High Energy ◽  
Fine Tuning ◽  
Color Glass ◽  
Leading Order ◽  
Energy Evolution ◽  
The Impact ◽  
Correct Size

We consider the next-to-leading order (NLO) calculation of single inclusive particle production at forward rapidities in proton-nucleus collisions and in the framework of the Color Glass Condensate (CGC). We focus on the quark channel and the corrections associated with the impact factor. In the first step of the evolution the kinematics of the emitted gluon is kept exactly (and not in the eikonal approximation), but such a treatment which includes NLO corrections is not explicitly separated from the high energy evolution. Thus, in this newly established “factorization scheme”, there is no “rapidity subtraction”. The latter suffers from fine tuning issues and eventually leads to an unphysical (negative) cross section. On the contrary, our reorganization of the perturbation theory leads by definition to a well-defined cross section and the numerical evaluation of the NLO correction is shown to have the correct size.

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