Constituent quarks, chiral symmetry, and chiral point of the constituent quark model

Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano

doi:10.1103/physrevd.74.054004

Cited by 15 publications

(15 citation statements)

References 41 publications

(47 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Of particular interest is the fact that, owing to DCSB, Nambu-Goldstone modes are the only pseudoscalar mesons to possess a nonzero leptonic decay constant in the chiral limit: the decay constants of their radial excitations vanish [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]:…”

Section: Introductionmentioning

confidence: 99%

Distribution amplitudes of radially-excitedπandKmesons

Chang

Gao

et al. 2016

Phys. Rev. D

View full text Add to dashboard Cite

A symmetry-preserving truncation of the two-body bound-state problem in relativistic quantum field theory is used to compute the leading-twist parton distribution amplitudes (PDAs) for the first radial excitations of the π-and K-mesons. In common with ground states in these channels, the PDAs are found to be dilated with respect to the relevant conformal-limit form and skewed toward the heavier valence-quark in asymmetric systems. In addition, the PDAs of radially-excited pseudoscalar mesons are not positive definite, owing to the fact that dynamical chiral symmetry breaking (DCSB) forces the leptonic decay constant of such states to vanish in the chiral limit. These results highlight that DCSB is expressed visibly in every pseudoscalar meson constituted from light-quarks. Hence, so long as its impact is empirically evident in the pseudoscalar members of a given spectrum level, it is unlikely that chiral symmetry is restored in any of the hadrons that populate this level.

show abstract

Section: Introductionmentioning

confidence: 99%

Distribution amplitudes of radially-excitedπandKmesons

Chang

Gao

et al. 2016

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…Relativistic quark models are based on a simplified picture of QCD: below the chiral symmetry breaking scale μ χ ≈ 1 GeV, quarks are treated as particles of fixed mass interacting via a relativistic potential and hadron wave functions and masses are found as solutions of threedimensional reductions of the Bethe-Salpeter equation. The structure of the confining potential is restricted by rigorous properties of QCD, such as heavy-quark symmetry for the heavy-quark sector [285,286] and spontaneously broken chiral symmetry for the light-quark sector [287]. The values of the constituent-quark masses and the parameters of the potential are fixed by requiring that the spectrum of observed hadron states is well reproduced [288,289].…”

Section: Comparison With Heavy-to-light Form Factors From Relativistimentioning

confidence: 99%

B, D and K decays

et al. 2008

View full text Add to dashboard Cite

With the advent of the LHC, we will be able to probe New Physics (NP) up to energy scales almost one order of magnitude larger than it has been possible with present accelerator facilities. While direct detection of new particles will be the main avenue to establish the presence of NP at the LHC, indirect searches will provide precious complementary information, since most probably it will not be possible to measure the full spectrum of new particles and their couplings through direct production. In particular, precision measurements and computations in the realm of flavor physics are expected to play a key role in constraining the unknown parameters of the Lagrangian of any NP model emerging from direct searches at the LHC.The aim of Working Group 2 was twofold: on the one hand, to provide a coherent up-to-date picture of the status of flavor physics before the start of the LHC; on the other hand, to initiate activities on the path towards integrating information on NP from high-p T and flavor data.This report is organized as follows: in Sect. 1, we give an overview of NP models, focusing on a few examples that have been discussed in some detail during the workshop, with a short description of the available computational tools for flavor observables in NP models. Section 2 contains a concise discussion of the main theoretical problem in flavor physics: the evaluation of the relevant hadronic matrix elements for weak decays. Section 3 contains a detailed discussion of NP effects in a set of flavor observables that we identified as "benchmark channels" for NP searches. The experimental prospects for flavor physics at future facilities are discussed in Sect. 4. Finally, Sect. 5 contains some assessEur. Phys. J. C (2008) 57: 309-492 311 ments on the work done at the workshop and the prospects for future developments.

show abstract

“…Since the light-quark mass parameter m appears in the framework of the BS equation, it should be understood as the effective quark mass which takes into account nonperturbative effects related to spontaneous chiral symmetry breaking in the soft region, i.e., the constituent quark mass. In [18,19], the constituent quark mass was calculated through the quark condensate in QCD with the result m ≃ 220 MeV at the chiral-symmetry breaking scale 1 GeV. The scale-dependence of the constituent mass of the light quark above 1 GeV was also reported in [18].…”

Section: Numerical Resultsmentioning

confidence: 96%

Heavy-to-light form factors: Sum rules on the light cone and beyond

2007

Self Cite

View full text Add to dashboard Cite

We report the first systematic analysis of the off-light-cone effects in sum rules for heavy-to-light form factors. These effects are investigated in a model based on scalar constituents, which allows a technically rather simple analysis but has the essential features of the analogous QCD calculation. The correlator relevant for the extraction of the heavy-to-light form factor is calculated in two different ways: first, by adopting the full Bethe-Salpeter amplitude of the light meson and, second, by performing the expansion of this amplitude near the light cone x 2 = 0. We demonstrate that the contributions to the correlator from the light-cone term x 2 = 0 and the off-light-cone terms x 2 = 0 have the same order in the 1/mQ expansion. The light-cone correlator, corresponding to x 2 = 0, is shown to systematically overestimate the full correlator, the difference being ∼ ΛQCD/δ, with δ the continuum subtraction parameter of order 1 GeV. Numerically, this difference is found to be 10 ÷ 20%.

show abstract

Constituent quarks, chiral symmetry, and chiral point of the constituent quark model

Cited by 15 publications

References 41 publications

Distribution amplitudes of radially-excitedπandKmesons

Distribution amplitudes of radially-excitedπandKmesons

B, D and K decays

Heavy-to-light form factors: Sum rules on the light cone and beyond

Contact Info

Product

Resources

About