Imaging Dynamical Chiral-Symmetry Breaking: Pion Wave Function on the Light Front

Chang, Lei; Cloët, Ian C.; Cobos-Martínez, J. J.; Roberts, Craig D.; Schmidt, S.; Tandy, P. C.

doi:10.1103/physrevlett.110.132001

Cited by 266 publications

(323 citation statements)

References 27 publications

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“…(A1) is compatible with the DSE treatment of more sophisticated interactions, and hence preserves the known connection between the momentum-dependence of an interaction and that of observables, such as meson electromagnetic form factors [see Eq. (46)] and the large-x behaviour of parton distribution amplitudes and functions [16,78]. We can thus be certain that our treatment of both infrared and ultraviolet phenomena is valid.…”

Section: Gap Equationmentioning

confidence: 96%

Features and flaws of a contact interaction treatment of the kaon

et al. 2013

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Elastic and semileptonic transition form factors for the kaon and pion are calculated using the leading-order in a global-symmetry-preserving truncation of the Dyson-Schwinger equations and a momentum-independent form for the associated kernels in the gap and Bethe-Salpeter equations. The computed form factors are compared both with those obtained using the same truncation but an interaction that preserves the one-loop renormalisation-group behaviour of QCD and with data. The comparisons show that: in connection with observables revealed by probes with |Q 2 | M 2 , where M ≈ 0.4 GeV is an infrared value of the dressed-quark mass, results obtained using a symmetry-preserving regularisation of the contact-interaction are not realistically distinguishable from those produced by more sophisticated kernels; and available data on kaon form factors do not extend into the domain whereupon one could distinguish between the interactions. The situation is different if one includes the domain Q 2 > M 2 . Thereupon, a fully consistent treatment of the contact interaction produces form factors that are typically harder than those obtained with QCD renormalisation-group-improved kernels. Amongst other things also described are a Ward identity for the inhomogeneous scalar vertex, similarity between the charge distribution of a dressed-u-quark in the K + and that of the dressed-u-quark in the π + , and reflections upon the point whereat one might begin to see perturbative behaviour in the pion form factor. Interpolations of the form factors are provided, which should assist in working to chart the interaction between light-quarks by explicating the impact on hadron properties of differing assumptions about the behaviour of the Bethe-Salpeter kernel.

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Section: Gap Equationmentioning

confidence: 96%

Features and flaws of a contact interaction treatment of the kaon

et al. 2013

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“…This has, e.g. recently enabled unification [24] of the topdown approach to determining the quark-antiquark scattering kernel directly from analyses of gauge-sector dynamics [28,29] with the bottom-up approach, which uses a sophisticated, nonperturbative, symmetry-preserving truncation of matter-sector bound-state equations in order to construct a solution to the same problem via a comparison with empirical data [30][31][32][33].…”

mentioning

confidence: 99%

Scale-setting, flavor dependence, and chiral symmetry restoration

2017

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We determine the flavour dependence of the renormalisation-group-invariant running interaction through judicious use of both unquenched Dyson-Schwinger equation and lattice results for QCD's gauge-sector two-point functions. An important step is the introduction of a physical scale setting procedure that enables a realistic expression of the effect of different numbers of active quark flavours on the interaction. Using this running interaction in concert with a well constrained class of dressed-gluon-quark vertices, we estimate the critical number of active lighter-quarks above which dynamical chiral symmetry breaking becomes impossible: n cr f ≈ 9; and hence in whose neighbourhood QCD is plausibly a conformal theory.Keywords: dynamical chiral symmetry breaking, Dyson-Schwinger equations, gluon-quark vertex, non-Abelian gauge-sector dynamics, numerical simulations of lattice-regularised QCD 1. Introduction. The last decade has seen the gauge sector of QCD provide important clues to some of the many puzzles encountered in the quest to understand the infrared (IR) dynamics of strongly-coupled theories. Of particular interest is the feature that the gluon propagator saturates at infrared momenta, i.e. ∆(k 2 0) = 1/m 2 g , m g 0.5 GeV [1-6], which entails that the long-range propagation characteristics of gluons are dramatically affected by their self-interactions. A similar feature is expressed in the dressed-quark propagator [7][8][9]; and, hence, it is now known that the Schwinger functions of both these elementary coloured excitations violate reflection positivity, a sufficient condition for confinement [10][11][12][13][14][15][16][17][18][19][20][21]. A consistent picture is thus beginning to emerge: strong dynamics generates IR cutoffs in QCD so that long-wavelength (λ 2/m g ∼ 1 fm) coloured-modes decouple and their role in hadron physics is superseded by interactions between light-hadrons [22][23][24][25].

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“…Using the light-front boosts for the transition from frame cm (12) to frame CM(12-3) (and further from frame CM to the Breit frame) implies several Melosh rotations which change the wave functions of initial and final states. Fortunately the Melosh rotation of all spins does not violate the Pauli exclusion principle for the full 3q wave function (see, e.g., a discussion in [10]), though the calculation technique (fraction parentage coefficients, etc.)…”

Section: High Q 2 Quark Configurations and Melosh Transformationsmentioning

confidence: 99%

“…with κ =1 was recently reconstructed [12] starting from the Bethe-Salpeter wave function projected onto the light front (there are also approximations with κ =1 -2). The nucleon pole-like w.f.…”

Section: Nucleon and Roper Resonance Wave Functions At Light Frontmentioning

confidence: 99%

Electroproduction of lightest nucleon resonances up to Q2=12 GeV2 in quark models at light front

et al. 2017

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Abstract. The lightest nucleon resonances are described at light front as mixed states of the 3q cluster ("quark core") possessing a definite value of the inner orbital momentum L = 0,1 and a hadron molecular state, N+σ or Λ+K. Helicity amplitudes of the resonance electroproduction off the proton are calculated at large Q 2 up to 12 GeV 2 and compared to the last CLAS data. At this basis we have estimated the probability of quark core in lightest nucleon resonances and predicted the high Q 2 behaviour of the resonance electrocoupling.

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Imaging Dynamical Chiral-Symmetry Breaking: Pion Wave Function on the Light Front

Cited by 266 publications

References 27 publications

Features and flaws of a contact interaction treatment of the kaon

Features and flaws of a contact interaction treatment of the kaon

Scale-setting, flavor dependence, and chiral symmetry restoration

Electroproduction of lightest nucleon resonances up to Q2=12 GeV2 in quark models at light front

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Imaging Dynamical Chiral-Symmetry Breaking: Pion Wave Function on the Light Front

Cited by 266 publications

References 27 publications

Features and flaws of a contact interaction treatment of the kaon

Features and flaws of a contact interaction treatment of the kaon

Scale-setting, flavor dependence, and chiral symmetry restoration

Electroproduction of lightest nucleon resonances up to Q*2=12 GeV*2 in quark models at light front

Contact Info

Product

Resources

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Electroproduction of lightest nucleon resonances up to Q2=12 GeV2 in quark models at light front