scholarly journals High Energy Rho Meson Leptoproduction §

2014 ◽  
Vol 1 (1) ◽  
pp. 33-35
Author(s):  
Adrien Besse ◽  
Lech Szymanowski ◽  
Samuel Wallon
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
Good Description ◽  
High Energy ◽  
Energy Limit ◽  
Rho Meson ◽  
Forward Limit ◽  
Helicity Amplitudes ◽  
Impact Parameter Space ◽  
The Impact

We investigate the longitudinal and transverse polarized cross-sections of the leptoproduction of the ρ meson in the high energy limit. Our model is based on the computation of the impact factor γ*(λγ)→ ρ (λρ) using the twist expansion in the forward limit which is expressed in the impact parameter space. This treatment involves in the final stage the twist 2 and twist 3 distribution amplitudes (DAs) of the ρ meson and the dipole scattering amplitude. Taking models that exist for the DAs and for the dipole cross-section. We get a phenomenological model for the helicity amplitudes. We compare our predictions with HERA data and get a fairly good description for large enough virtualities of the photon. PACS number(s): 13.60.Le, 12.39.St, 12.38.Bx.

scholarly journals Some Recent Results on High-Energy Proton Interactions

Particles ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 57-69 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
High Energy ◽  
Unitarity Condition ◽  
Total Cross Sections ◽  
Energy Proton ◽  
Elastic Scattering Amplitude ◽  
Energy Behavior ◽  
Impact Parameter Space ◽  
The Impact

Recent experimental results about the energy behavior of the total cross sections, the share of elastic and inelastic contributions to them, the peculiar shape of the differential cross section and our guesses about the behavior of real and imaginary parts of the elastic scattering amplitude are discussed. The unitarity condition relates elastic and inelastic processes. Therefore it is used in the impact-parameter space to get some information about the shape of the interaction region of colliding protons by exploiting new experimental data. The obtained results are described.

scholarly journals Loops and trees in generic EFTs

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Nathaniel Craig ◽  
Minyuan Jiang ◽  
Ying-Ying Li ◽  
Dave Sutherland
Keyword(s):  
Standard Model ◽  
High Energy ◽  
Tree Level ◽  
Energy Limit ◽  
High Energy Limit ◽  
Functional Methods ◽  
Weakly Coupled ◽  
The Standard Model ◽  
Helicity Amplitudes ◽  
The Impact

Abstract We consider aspects of tree and one-loop behavior in a generic 4d EFT of massless scalars, fermions, and vectors, with a particular eye to the high-energy limit of the Standard Model EFT at operator dimensions 6 and 8. First, we classify the possible Lorentz structures of operators and the subset of these that can arise at tree-level in a weakly coupled UV completion, extending the tree/loop classification through dimension 8 using functional methods. Second, we investigate how operators contribute to tree and one-loop helicity amplitudes, exploring the impact of non-renormalization theorems through dimension 8. We further observe that many dimension 6 contributions to helicity amplitudes, including rational parts, vanish exactly at one-loop level. This suggests the impact of helicity selection rules extends beyond one loop in non-supersymmetric EFTs.

scholarly journals High energy scattering of Dirac particles on smooth potentials

2016 ◽  
Vol 31 (23) ◽  
pp. 1650126 ◽  
Author(s):  
Nguyen Suan Han ◽  
Le Anh Dung ◽  
Nguyen Nhu Xuan ◽  
Vu Toan Thang
Keyword(s):  
Dirac Equation ◽  
Cross Sections ◽  
Differential Cross ◽  
Scattering Amplitude ◽  
High Energy ◽  
Type Representation ◽  
Dirac Particles ◽  
Energy Scattering ◽  
Two Component ◽  
High Energy Scattering

The derivation of the Glauber type representation for the high energy scattering amplitude of particles of spin 1/2 is given within the framework of the Dirac equation in the Foldy–Wouthuysen (FW) representation and two-component formalism. The differential cross-sections on the Yukawa and Gaussian potentials are also considered and discussed.

scholarly journals SMALL-X QCD EFFECTS IN PARTICLE COLLISIONS AT HIGH ENERGIES

2002 ◽  
Vol 17 (23) ◽  
pp. 3185-3203
Author(s):  
TANCREDI CARLI
Keyword(s):  
Perturbative Qcd ◽  
Cross Sections ◽  
High Energy ◽  
Particle Collisions ◽  
Energy Limit ◽  
High Energy Limit ◽  
High Energies ◽  
Small X ◽  
Theoretical Developments

Recent theoretical developments to calculate cross sections of hadronic objects in the high energy limit are summarised and experimental attempts to establish the need for new QCD effects connected with a resummation of small hadron momentum fractions x are reviewed. The relation between small-x parton dynamics and the phenomenon of diffraction is briefly out-lined. In addition, a search for a novel, non-perturbative QCD effect, the production of QCD instanton induced events, is presented.

ASYMPTOTIC BEHAVIOR OF PHYSICAL AMPLITUDES IN A FINITE FIELD THEORY

1990 ◽  
Vol 05 (10) ◽  
pp. 1861-1880
Author(s):  
J.A. HELAYËL-NETO ◽  
S. RAJPOOT ◽  
A. WILLIAM SMITH
Keyword(s):  
Cross Section ◽  
Scattering Amplitude ◽  
High Energy ◽  
Energy Limit ◽  
Heavy Particles ◽  
Yang Mills ◽  
Physical Amplitude ◽  
Mass Terms ◽  
Scalar Scattering ◽  
The One

Using the N=4 super Yang-Mills theory softly broken by supersymmetric N=1 mass terms for the matter superfields, we compute the one-loop chiral+chiral→antichiral+antichiral scattering amplitude directly in superspace. By suitable choices of the mass parameters, one can endow the model with a hierarchy of light and heavy particles, and the decoupling of the heavy sector from the light-light physical amplitude is studied. We also analyze the high energy limit of the cross section for a two physical scalar scattering and find a (logs) behavior, which then respects the Froissart bound.

scholarly journals Forbidden transitions in excitation by proton impact in Li-like Al ions

2007 ◽  
Vol 25 (2) ◽  
pp. 277-282 ◽  
Author(s):  
V. Stancalie ◽  
V. Pais ◽  
M. Totolici ◽  
A. Mihailescu
Keyword(s):  
Cross Sections ◽  
Born Approximation ◽  
High Energy ◽  
Impact Excitation ◽  
Proton Impact ◽  
Collision Strength ◽  
Energy Behavior ◽  
Forbidden Transitions ◽  
Excitation Processes ◽  
The Impact

This paper presents cross-sections and collision strengths for proton-impact excitation of optically forbidden transitions in Al10+. These data, calculated in the impact-parameter formalism, covering the expected range of energies/temperature in laser-produced plasmas, are believed to represent the first such detailed treatment of this system. The cross-sections decrease with energy as E−1, while the collision strengths tend to finite limits as the energy of colliding proton becomes infinitely great. This high-energy limiting value has been evaluated combining results from the semi-classical treatment of ion-impact excitation processes and the Born approximation for high-energy behavior of the collision strength. The effective target size has been estimated from the calculated high-energy limit of the collision strength in the Born approximation.

scholarly journals Virtual next-to-leading corrections to the impact factors in the high-energy limit

1998 ◽  
Vol 57 (7) ◽  
pp. 4069-4079 ◽  
Author(s):  
Vittorio Del Duca ◽  
Carl R. Schmidt
Keyword(s):  
High Energy ◽  
Impact Factors ◽  
Energy Limit ◽  
High Energy Limit ◽  
The Impact

scholarly journals GAUGE/STRING-GRAVITY DUALITY AND FROISSART BOUND

2005 ◽  
Vol 20 (06) ◽  
pp. 1286-1294
Author(s):  
KYUNGSIK KANG
Keyword(s):  
Cross Sections ◽  
Particle Physics ◽  
Scattering Amplitude ◽  
Conformal Symmetry ◽  
High Energy ◽  
Total Cross Sections ◽  
Regge Behavior ◽  
Energy Behavior ◽  
Gravity Duality ◽  
String Gravity

The gauge/string-gravity duality correspondence opened renewed hope and possibility to address some of the fundamental and non-perturbative QCD problems of in particle physics, such as hadron spectrum and Regge behavior of the scattering amplitude at high energies. One of the most fundamental and long-standing problems is the high energy behavior of the total cross-sections. According to a series of exhaustive tests by the COMPETE group, (1) total cross sections have a universal Heisenberg behavior in energy corresponding to the maximal energy behavior allowed by the Froissart bound, i.e., A+B ln 2(s/s0) with B~0.32 mb and s0~34.41 GeV2 for all reactions, and (2). The factorization relation among σpp,even, σγp and σγγ is well satisfied by experiments. I discuss the recent interesting application of the gauge/string-gravity duality of AdS/CFT correspondence with a deformed background metric so as to break the conformal symmetry that lead to the Heisenberg behavior of rising total cross sections, and present some preliminary results on the high energy QCD from Planckian scattering in AdS and black-hole production.

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