scholarly journals Determining the Kl3 form factors directly at zero momentum transfer

2010 ◽  
Author(s):  
James Zanotti ◽  
Peter A. Boyle ◽  
Andreas Juttner ◽  
J. M. Flynn ◽  
Chris Kelly ◽  
...  
Keyword(s):  
Momentum Transfer ◽  
Form Factors ◽  
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 D meson semileptonic form factors at zero momentum transfer in 2+1+1 flavor lattice QCD

2016 ◽  
Author(s):  
Thomas Primer ◽  
Doug Toussaint ◽  
Claude Bernard ◽  
Javad Komijani ◽  
Carleton DeTar ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Momentum Transfer ◽  
D Meson ◽  
Form Factors ◽  
Zero Momentum

PROTON-NUCLEUS ELASTIC SCATTERING AT ~1 GeV AND THE NN AMPLITUDE

2007 ◽  
Vol 16 (06) ◽  
pp. 1741-1755 ◽  
Author(s):  
Z. A. KHAN ◽  
MINITA SINGH
Keyword(s):  
Elastic Scattering ◽  
Momentum Transfer ◽  
Form Factors ◽  
Matter Density ◽  
Additional Information ◽  
Density Distributions ◽  
Transfer Region ◽  
Realistic Form ◽  
Basic Input

Working within the framework of Coulomb modified correlation expansion of the Glauber amplitude, we analyse the elastic scattering of ~1 GeV protons on 4 He , 12 C , 16 O and 40 Ca nuclei. Emphasis has been put on the use of different parametrizations of the basic (input) NN amplitude, which provide equivalently good accounts of the elastic NN scattering observables up to the available momentum transfer region. Using realistic form factors for target nuclei, it is found that the proton-nucleus collisions could provide a test to know which is the better choice of the NN amplitude. The analysis also considers the possibility of extracting some additional information about the matter density distributions.

scholarly journals On the zero-crossing of the three-gluon Green’s function from lattice simulations

2018 ◽  
Vol 175 ◽  
pp. 12012 ◽  
Author(s):  
Andreas Athenodorou ◽  
Philippe Boucaud ◽  
Feliciano de Soto ◽  
José Rodríguez-Quintero ◽  
Savvas Zafeiropoulos
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Large Volume ◽  
Form Factors ◽  
Tree Level ◽  
Zero Crossing ◽  
Zero Momentum ◽  
Made In

We report on some efforts recently made in order to gain a better understanding of some IR properties of the 3-point gluon Green’s function by exploiting results from large-volume quenched lattice simulations. These lattice results have been obtained by using both tree-level Symanzik and the standard Wilson action, in the aim of assessing the possible impact of effects presumably resulting from a particular choice for the discretization of the action. The main resulting feature is the existence of a negative log-aritmic divergence at zero-momentum, which pulls the 3-gluon form factors down at low momenta and, consequently, yields a zero-crossing at a given deep IR momentum. The results can be correctly explained by analyzing the relevant Dyson-Schwinger equations and appropriate truncation schemes.

ON THE STRUCTURE OF π AND K MESONS

1987 ◽  
Vol 02 (06) ◽  
pp. 1829-1838 ◽  
Author(s):  
S.N. BANERJEE ◽  
R.K. DAS ◽  
A.K. SARKER
Keyword(s):  
Differential Cross Section ◽  
Statistical Model ◽  
Momentum Transfer ◽  
Cross Section ◽  
Differential Cross ◽  
Form Factors ◽  
Scattering Data ◽  
Elastic Differential Cross Section ◽  
K Mesons ◽  
Characteristic Features

We have investigated the form factors of the π and K mesons within the framework of the statistical model. Our results reveal several well-spaced minima and maxima for different values of Q2, the square of the momentum transfer. The characteristic features of the elastic differential cross section, dσ/dt, for π±P and K±P scattering data are well reproduced, as a consequence.

scholarly journals PION FORM FACTORS AT INTERMEDIATE MOMENTUM TRANSFER IN A COVARIANT APPROACH

1996 ◽  
Vol 11 (04) ◽  
pp. 655-675 ◽  
Author(s):  
ADAM SZCZEPANIAK ◽  
ANTHONY G. WILLIAMS
Keyword(s):  
Wave Function ◽  
Form Factor ◽  
Momentum Transfer ◽  
Transition Form Factor ◽  
Form Factors ◽  
Transition Form ◽  
Gauge Invariant ◽  
Pion Wave Function ◽  
Covariant Gauge ◽  
Text Component

We study the pion electromagnetic and γ*+π0→γ transition form factors at intermediate momentum transfer. We calculate soft, nonperturbative corrections to the leading perturbative amplitudes which arise from the [Formula: see text] component of the pion wave function. We work in Minkowski space and use a Lorentz-covariant, gauge-invariant generalized perturbative integral representation for the [Formula: see text] amplitudes. For the transition form factor we find relative insensitivity to the detailed nonperturbative structure of the wave function for |q2|≳10 GeV 2, whereas considerable sensitivity is found for the electromagnetic form factor.

scholarly journals Rare Λb → nl+l− decays in the relativistic quark–diquark picture

2017 ◽  
Vol 32 (24) ◽  
pp. 1750125 ◽  
Author(s):  
R. N. Faustov ◽  
V. O. Galkin
Keyword(s):  
Momentum Transfer ◽  
Branching Fraction ◽  
Branching Fractions ◽  
Form Factors ◽  
Relativistic Effects

The form factors of the rare [Formula: see text] decays are calculated in the framework of the relativistic quark–diquark picture of baryons with the consistent account of the relativistic effects. Their momentum transfer squared dependence is determined explicitly in the whole accessible kinematical range. The decay branching fractions, forward–backward asymmetries and the fractions of longitudinally polarized dileptons are determined. The branching fraction of the rare [Formula: see text] decay are found to be [Formula: see text] and thus could be measured at the LHC. Prediction for the branching fraction of the rare radiative [Formula: see text] decay is also given.

Sign in / Sign up

Export Citation Format

Share Document