Relations between helicity amplitudes in high-energy elastic p-p scattering

1969 ◽  
Vol 1 (7) ◽  
pp. 369-374 ◽  
Author(s):  
H. A. Neal ◽  
Bing-lin Young
Keyword(s):  
High Energy ◽  
Helicity Amplitudes

Measurements of the spin rotation parameterR in high energy elastic scattering and helicity amplitudes at Serpukhov energies

1976 ◽  
Vol 26 (1) ◽  
pp. 13-24 ◽  
Author(s):  
J. Pierrard ◽  
C. Bruneton ◽  
J. Bystricky ◽  
G. Cozzika ◽  
J. Deregel ◽  
...  
Keyword(s):  
Elastic Scattering ◽  
High Energy ◽  
Spin Rotation ◽  
Helicity Amplitudes

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 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 Sum rules in the standard model effective field theory from helicity amplitudes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Jiayin Gu ◽  
Lian-Tao Wang
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Sum Rules ◽  
High Energy ◽  
Effective Field ◽  
Low Energy ◽  
Tree Level ◽  
The Standard Model ◽  
Helicity Amplitudes

Abstract The dispersion relation of an elastic 4-point amplitude in the forward direction leads to a sum rule that connects the low energy amplitude to the high energy observables. We perform a classification of these sum rules based on massless helicity amplitudes. With this classification, we are able to systematically write down the sum rules for the dimension-6 operators of the Standard Model Effective Field Theory (SMEFT), some of which are absent in previous literatures. These sum rules offer distinct insights on the relations between the operator coefficients in the EFT and the properties of the full theory that generates them. Their applicability goes beyond tree level, and in some cases can be used as a practical method of computing the one loop contributions to low energy observables. They also provide an interesting perspective for understanding the custodial symmetries of the SM Higgs and fermion sectors.

scholarly journals Phenomenological study of helicity amplitudes of high energy exclusive leptoproduction of theρmeson

2011 ◽  
Vol 84 (5) ◽  
Author(s):  
I. V. Anikin ◽  
A. Besse ◽  
D. Yu. Ivanov ◽  
B. Pire ◽  
L. Szymanowski ◽  
...  
Keyword(s):  
Phenomenological Study ◽  
High Energy ◽  
Helicity Amplitudes
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