نتایج جستجو برای: electromagnetic form factor

تعداد نتایج: 1546779  

2009
C. Alexandrou G. Koutsou M. Vanderhaeghen J. W. Negele

We discuss the techniques to extract the electromagnetic ∆ form factors in Lattice QCD. We evaluate these form factors using dynamical fermions with smallest pion mass of about 350 MeV. We pay particular attention to the extraction of the electric quadrupole form factor that signals a deformation of the ∆. The magnetic moment of the ∆ is extrapolated using a chiral effective field theory. Using...

Journal: :Journal of Experimental and Theoretical Physics 2004

1996
C. D. Roberts

Kl3 and πe3 transition form factors are calculated as an application of DysonSchwinger equations. The role of nonanalytic contributions to the quark–W-boson vertex is elucidated. A one-parameter model for this vertex provides a uniformly good description of these transitions, including the value of the scalar form factor of the kaon at the Callan-Treiman point. The Kl3 form factors, f K ± , are...

2002
Johan Bijnens

We analyze the higher-twist effects and the SU(3)-flavour symmetry breaking in the correlation functions used to calculate form factors of pseudoscalar mesons in the QCD light-cone sum rule approach. It is shown that the Ward identities for these correlation functions yield relations between twist-4 twoand three-particle distribution amplitudes. In addition to the relations already obtained fro...

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