Using a holographic dual model of QCD, we compute the pion electromagnetic form factor F π(Q 2) in the spacelike momentum transfer region, as well as pion couplings to vector mesons g ρ(n)ππ. Spontaneous and explicit chiral symmetry breaking are intrinsic features of this particular holographic model. We consider variants with both ''hard-wall'' and ''soft-wall'' infrared cutoffs, and find that the F π(Q 2) data tend to lie closer to the hard-wall model predictions, although both are too shallow for large Q 2. By allowing the parameters of the soft-wall model (originally fixed by observables such as m ρ) to vary, one finds fits that tend to agree better with F π(Q 2). We also compute the pion charge radius r π 2 for a variety of parameter choices, and use the values of f (n) ρ, g ρ(n)ππ and m (n) ρ to observe the saturation of F π(0) by ρ poles.
- Gauge-gravity correspondence
ASJC Scopus subject areas
- Nuclear and High Energy Physics