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Abstract

We present a study of the pion structure in the context of the AdS/QCD soft-wall model. This approach provides the light-front wave function of the pion in terms of a set of parameters that we fit to available experimental information on the electromagnetic form factor and parton distribution of the pion. We discuss the corresponding predictions for the unpolarized transverse momentum dependent parton distribution of the pion. 1 Introduction AdS/QCD correspondence with soft-wall holographic models has been employed in a number of recent works to get new insights on hadronic physics [1-4]. Remarkably, light-front holographic QCD methods (see [5] and references therein for a complete review on the topic) have provided expressions for the light-front wave function (LFWF) of a meson valence Fock state [6,7]. This allows one to obtain direct information about many hadronic observables, which can be expressed in terms of overlaps of LFWFs. The outline of this work is as follows: In Sect. 2 we consider the expressions for the pion LFWF derived in [6,7]. We introduce the quark masses in a Lorentz invariant way and derive analytical expressions for the pion valence Parton Distribution Function (PDF) and electromagnetic Form Factor. We determine the free parameters of the LFWFs by fitting simultaneously the available experimental information on form factor and valence PDF. In Sect. 3, we discuss the corresponding predictions for the pion unpolarized valence Transverse Momentum Dependent parton distribution function (TMD). In the final section, we summarize the results. 2 The Pion LFWF The LFWFs in the soft-wall model of the AdS/QCD correspondence were originally derived in two different matching procedures [6,7].