scholarly journals Exploratory studies for the position-space approach to hadronic light-by-light scattering in the muon g - 2

2018 ◽  
Vol 175 ◽  
pp. 06023 ◽  
Author(s):  
Nils Asmussen ◽  
Antoine Gérardin ◽  
Harvey B. Meyer ◽  
Andreas Nyffeler

The well-known discrepancy in the muon g − 2 between experiment and theory demands further theory investigations in view of the upcoming new experiments. One of the leading uncertainties lies in the hadronic light-by-light scattering contribution (HLbL), that we address with our position-space approach. We focus on exploratory studies of the pion-pole contribution in a simple model and the fermion loop without gluon exchanges in the continuum and in infinite volume. These studies provide us with useful information for our planned computation of HLbL in the muon g − 2 using full QCD.

2018 ◽  
Vol 179 ◽  
pp. 01017 ◽  
Author(s):  
Nils Asmussen ◽  
Antoine Gérardin ◽  
Jeremy Green ◽  
Oleksii Gryniuk ◽  
Georg von Hippel ◽  
...  

We briefly review several activities at Mainz related to hadronic light-by-light scattering (HLbL) using lattice QCD. First we present a position-space approach to the HLbL contribution in the muon g̅2, where we focus on exploratory studies of the pion-pole contribution in a simple model and the lepton loop in QED in the continuum and in infinite volume. The second part describes a lattice calculation of the double-virtual pion transition form factor Fπ0γ*γ* (q21; q21) in the spacelike region with photon virtualities up to 1.5 GeV2 which paves the way for a lattice calculation of the pion-pole contribution to HLbL. The third topic involves HLbL forward scattering amplitudes calculated in lattice QCD which can be described, using dispersion relations (HLbL sum rules), by γ*γ* → hadrons fusion cross sections and then compared with phenomenological models.


2016 ◽  
Author(s):  
Nils Asmussen ◽  
Jeremy Green ◽  
Harvey B. Meyer ◽  
Andreas Nyffeler

2020 ◽  
Author(s):  
Bai-Long Hoid ◽  
Martin Hoferichter ◽  
Bastian Kubis ◽  
Stefan Leupold ◽  
Sebastian Schneider

2018 ◽  
Vol 121 (11) ◽  
Author(s):  
Martin Hoferichter ◽  
Bai-Long Hoid ◽  
Bastian Kubis ◽  
Stefan Leupold ◽  
Sebastian P. Schneider

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.


1982 ◽  
Vol 60 (16) ◽  
pp. 2049-2056 ◽  
Author(s):  
Victor M. S. Gil ◽  
António J. C. Varandas

By using simple model potential energy functions for internal rotation of ethane derivatives (CH2X–CH2X and CHX2–CHX2), a comparison was made between the continuum and the rotational isomeric state models for obtaining conformation information (especially energy differences for the staggered conformers) from electric dipole moments. It is found that the results obtained by the two procedures may be appreciably different, depending on the features of the conformational energy function and on the temperature considered.


2018 ◽  
Vol 2018 (10) ◽  
Author(s):  
Martin Hoferichter ◽  
Bai-Long Hoid ◽  
Bastian Kubis ◽  
Stefan Leupold ◽  
Sebastian P. Schneider

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