Twist-3 distribution amplitude of the pion in QCD sum rules

Abstract

We apply the background field method to calculate the moments of the pion two-particles twist-3 distribution amplitude (DA) φ p (ξ) in QCD sum rules. In this paper,we do not use the equation of motion for the quarks inside the pion since they are not on shell and introduce a new parameter m p 0 to be determined. We get the parameter m p 0 ≈ 1.30GeV in this approach. If assuming the expansion of φ p (ξ) in the series in Gegenbauer polynomials C 1/2 n (ξ), one can obtain its approximate expression which can be determined by its first few moments.

Consistency of the light-front quark model with chiral symmetry in the pseudoscalar meson analysis

“…Twists a [5,6,10,11] but consistent with the chiral quark model predictions [9]. Again, the differences between our LFQM and QCD sum-rule may be attributed to different treatment of constituent quark masses as we discussed about the results shown in Fig.…”

“…The twist-2 DA of a pseudoscalar meson has been analyzed in our previous work of LFQM [7]. Essentially, there are two independent twist-3 two-particle DAs of a pseudoscalar meson, namely, φ [4][5][6][8][9][10][11] corresponding to pseudoscalar and tensor channels of a meson (M ), respectively. In this work, we shall study φ …”

“…These nonperturbative quantities are defined as vacuum-to-hadron matrix elements of particular nonlocal quark or quark-gluon operators and thus encode important information on bound states in strong interaction physics. It has motivated many studies using various nonperturbative models [4][5][6][7][8][9][10][11] and led to develop distinct phenomenological models over the past two decades. Among them, the light-front quark model (LFQM) appears to be one of the most efficient and effective tools in hadron physics as it takes advantage of the distinguished features of the light-front dynamics (LFD) [12].…”

Two-particle twist-3 distribution amplitudes of the pion and kaon in the light-front quark model

“…In particular, the shape of the pion DA has been extensively discussed due to the nature of the pion as the massless Nambu-Goldstone boson [5,6]. Finding the fundamental nonperturbative information of QCD motivated many theoretical studies to calculate meson DAs using nonperturbative methods such as the QCD sum rule [3,[7][8][9][10][11][12][13][14][15], the chiral-quark model from the instanton vacuum [16][17][18], the Nambu-JonaLasinio (NJL) model [19,20], the Dyson-Schwinger equation (DSE) approach [21,22], and the light-front quark model (LFQM) [23,24]. Among them, the LFQM appears to be one of the most effective and efficient tools in studying hadron physics as it takes advantage of the distinguished features of the light-front dynamics (LFD) [25].…”

Revisiting the pion leading-twist distribution amplitude within the QCD background field theory

“…The QCD sum rules within the background field theory has already been adopted to study the meson properties, cf.Refs. [33][34][35][36][37][38].…”