scholarly journals η−η′ mixing and the derivative of the topological susceptibility at zero momentum transfer

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
N. F. Nasrallah
Keyword(s):  
Momentum Transfer ◽  
Zero Momentum

AnalyticS-Matrix Approach to Zero-Momentum-Transfer Symmetry

1967 ◽  
Vol 161 (5) ◽  
pp. 1459-1463 ◽  
Author(s):  
N. F. Bali ◽  
James S. Ball ◽  
Geoffrey F. Chew ◽  
Alberto Pignotti
Keyword(s):  
Momentum Transfer ◽  
Matrix Approach ◽  
Zero Momentum

scholarly journals The vector form factor at zero momentum transfer on the lattice

2005 ◽  
Vol 705 (1-2) ◽  
pp. 339-362 ◽  
Author(s):  
D. Bećirević ◽  
G. Isidori ◽  
V. Lubicz ◽  
G. Martinelli ◽  
F. Mescia ◽  
...  
Keyword(s):  
Form Factor ◽  
Momentum Transfer ◽  
Vector Form Factor ◽  
Vector Form ◽  
Zero Momentum

scholarly journals Two-photon exchange in leptophilic dark matter scenarios

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Raghuveer Garani ◽  
Federico Gasparotto ◽  
Pierpaolo Mastrolia ◽  
Henrik J. Munch ◽  
Sergio Palomares-Ruiz ◽  
...  
Keyword(s):  
Dark Matter ◽  
Momentum Transfer ◽  
Direct Detection ◽  
Form Factors ◽  
Scalar Particle ◽  
Analytical Form ◽  
Photon Exchange ◽  
Two Photon ◽  
Zero Momentum ◽  
Pseudo Scalar

Abstract In leptophilic scenarios, dark matter interactions with nuclei, relevant for direct detection experiments and for the capture by celestial objects, could only occur via loop-induced processes. If the mediator is a scalar or pseudo-scalar particle, which only couples to leptons, the dominant contribution to dark matter-nucleus scattering would take place via two-photon exchange with a lepton triangle loop. The corresponding diagrams have been estimated in the literature under different approximations. Here, we present new analytical calculations for one-body two-loop and two-body one-loop interactions. The two-loop form factors are presented in closed analytical form in terms of generalized polylogarithms up to weight four. In both cases, we consider the exact dependence on all the involved scales, and study the dependence on the momentum transfer. We show that some previous approximations fail to correctly predict the scattering cross section by several orders of magnitude. Moreover, we quantitatively show that form factors in the range of momentum transfer relevant for local galactic dark matter, can be significantly smaller than their value at zero momentum transfer, which is the approach usually considered.

scholarly journals ELECTROMAGNETIC FORM-FACTOR OF THE π MESON WITH LIGHT-CONE QCD SUM RULES

2008 ◽  
Vol 23 (27n28) ◽  
pp. 4621-4636 ◽  
Author(s):  
ZHI-GANG WANG ◽  
ZHI-BIN WANG
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Momentum Transfer ◽  
Electromagnetic Form Factor ◽  
Light Cone ◽  
Sum Rules ◽  
Large Momentum ◽  
Normalization Condition ◽  
Qcd Sum Rules ◽  
Zero Momentum

In this paper, we calculate the electromagnetic form-factor of the π meson with the light-cone QCD sum rules. The numerical value [Formula: see text] is in excellent agreement with the experimental data (extrapolated to the limit of zero momentum transfer or the normalization condition Fπ(0) = 1). For large momentum transfers, the values from the two sum rules are all comparable with the experimental data and theoretical estimations.

scholarly journals Scale-invariant O(g4) Lipatov kernels at non-zero momentum transfer

1996 ◽  
Vol 468 (1-2) ◽  
pp. 219-240 ◽  
Author(s):  
Claudio Corianò ◽  
Rajesh R. Parwani ◽  
Alan R. White
Keyword(s):  
Momentum Transfer ◽  
Scale Invariant ◽  
Zero Momentum

The vector form factor at zero momentum transfer on the lattice

2005 ◽  
Vol 140 ◽  
pp. 387-389 ◽  
Author(s):  
D. Bećirević ◽  
G. Isidori ◽  
V. Lubicz ◽  
G. Martinelli ◽  
F. Mescia ◽  
...  
Keyword(s):  
Form Factor ◽  
Momentum Transfer ◽  
Vector Form Factor ◽  
Vector Form ◽  
Zero Momentum

EFFECTIVE LAGRANGIAN FOR THE TWO-COMPONENT APPROACH TO THE "PROTON SPIN" PUZZLE

1990 ◽  
Vol 05 (30) ◽  
pp. 2543-2553 ◽  
Author(s):  
J. SCHECHTER ◽  
V. SONI ◽  
A. SUBBARAMAN ◽  
H. WEIGEL
Keyword(s):  
Exact Solution ◽  
Matrix Element ◽  
Symmetry Breaking ◽  
Momentum Transfer ◽  
Proton Spin ◽  
Effective Lagrangian ◽  
Two Component ◽  
Component Approach ◽  
Entire Matrix ◽  
Zero Momentum

We display an effective chiral Lagrangian which illuminates the mechanism found by Shore and Veneziano for decomposing the proton matrix element of the axial singlet current into quark and gluonic pieces. The entire matrix element is shown to be proportional to the amplitude for SU(3) singlet exchange in baryon-baryon scattering at zero momentum transfer. An effect of SU(3) symmetry breaking relevant for analysis of the EMC experiment is discussed. In addition, an exact solution is presented for the pseudoscalar quark densities which enter into an alternative method of derivation.

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