Nucleon pole contribution in thepp→ppK+K−reaction below theϕmeson threshold

2014 ◽  
Vol 90 (3) ◽  
Author(s):  
Qi-Fang Lü ◽  
Ju-Jun Xie ◽  
De-Min Li
Keyword(s):  
Pole Contribution ◽  
Nucleon Pole

Re-study of Nucleon Pole Contribution in J /ψ→ N N̄π Decay

2006 ◽  
Vol 46 (3) ◽  
pp. 507-513 ◽  
Author(s):  
Zong Yuan-Yuan ◽  
Shen Peng-Nian ◽  
Zou Bing-Song ◽  
Liu Ji-Feng ◽  
Liang Wei-Hong
Keyword(s):  
Pole Contribution ◽  
Nucleon Pole

scholarly journals PRODUCTION OF TWO PIONS INDUCED BY NEUTRINOS

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2309-2312 ◽  
Author(s):  
M. VALVERDE ◽  
J. NIEVES ◽  
E. HERNÁNDEZ ◽  
S. K. SINGH ◽  
M. J. VICENTE VACAS
Keyword(s):  
Roper Resonance ◽  
Nucleon Pole ◽  
Chiral Lagrangian

We study the threshold production of two pions induced by neutrinos in nucleon targets. The contribution of nucleon pole, pion and contact terms is calculated using a chiral Lagrangian. The contribution of the Roper resonance, neglected in earlier studies, has also been taken into account.

scholarly journals Pseudoscalar pole contribution to the hadronic light-by-light piece of aμ

2018 ◽  
Vol 192 ◽  
pp. 00027
Author(s):  
Adolfo Guevara ◽  
Pablo Roig ◽  
Juan José Sanz Cillero
Keyword(s):  
Form Factor ◽  
Chiral Symmetry ◽  
Chiral Symmetry Breaking ◽  
Form Factors ◽  
Effective Field ◽  
Pole Contribution ◽  
Symmetry Relations ◽  
The Impact ◽  
Best Fit ◽  
Momentum Region

We have studied the P → γ⋆ γ⋆ form factor in Resonance Chiral Theory, with P = π0; η, η', to compute the contribution of the pseudoscalar pole to the hadronic light-by-light piece of the anomalous magnetic moment of the muon. In this work we allow the leading U(3) chiral symmetry breaking terms, obtaining the most general expression for the form factor of order O(m2P). The parameters of the Effective Field Theory are obtained by means of short distance constraints on the form factor and matching with the expected behavior from QCD. Those parameters that cannot be fixed in this way are fitted to experimental determinations of the form factor within the spacelike momentum region of the virtual photon. Chiral symmetry relations among the transition form factors for π0, η and η' allow for a simultaneous fit to experimental data for the three mesons. This shows an inconsistency between the BaBar π0 data and the rest of the experimental inputs. Thus, we find a total pseudoscalar pole contribution of aP,HLbLη = (8:47 ± 0:16) · 10-10 for our best fit (neglecting the BaBar π0 data). Also, a preliminary rough estimate of the impact of NLO in 1=NC corrections and higher vector multiplets (asym) enlarges the uncertainty up to aP,HLbLη = (8:47 ± 0:16stat ± 0:09NC +0:5 -0:0asym).

scholarly journals Updated pseudoscalar contributions to the hadronic light-by-light of the muon (g − 2)

2016 ◽  
Vol 31 (31) ◽  
pp. 1630034 ◽  
Author(s):  
Pablo Sanchez-Puertas ◽  
Pere Masjuan
Keyword(s):  
Systematic Uncertainty ◽  
Form Factors ◽  
Data Driven ◽  
Rational Approach ◽  
Transition Form ◽  
Pole Contribution ◽  
Model Independent ◽  
First Time

In this work, we present our recent results on a new and alternative data-driven determination for the hadronic light-by-light pseudoscalar pole contribution to the muon (g − 2). Our approach is based on Canterbury approximants, a rational approach to describe the required transition form factors, which provides a systematic and model-independent framework beyond traditional large-[Formula: see text] approaches. As a result, we obtain a competitive determination with errors according to future (g − 2) experiments including, for the first time, a well-defined systematic uncertainty.

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
Keyword(s):  
Light Scattering ◽  
Simple Model ◽  
Pion Pole ◽  
Infinite Volume ◽  
Pole Contribution ◽  
Position Space ◽  
Fermion Loop ◽  
Scattering Contribution ◽  
Space Approach ◽  
The Continuum

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.

Sign in / Sign up

Export Citation Format

Share Document