2 research outputs found
Extended QCD(2) from dimensional projection of QCD(4)
We study an extended QCD model in (1+1) dimensions obtained from QCD in 4D by
compactifying two spatial dimensions and projecting onto the zero-mode
subspace. We work out this model in the large limit and using light cone
gauge but keeping the equal-time quantization. This system is found to induce a
dynamical mass for transverse gluons -- adjoint scalars in QCD(2), and to
undergo a chiral symmetry breaking with the full quark propagators yielding
non-tachyonic, dynamical quark masses, even in the chiral limit. We study
quark-antiquark bound states which can be classified in this model by their
properties under Lorentz transformations inherited from 4D. The scalar and
pseudoscalar sectors of the theory are examined and in the chiral limit a
massless ground state for pseudoscalars is revealed with a wave function
generalizing the so called 't Hooft pion solution.Comment: JHEP class, 16 pages, 3 figures. Change in the title, some
improvements in section 2, minors changes and comments added in introduction
and conclusions. References added. Version appearing in JHE
Heavy Quark Expansion and Preasymptotic Corrections to Decay Widths in the 't Hooft Model
We address nonperturbative power corrections to inclusive decay widths of
heavy flavor hadrons in the context of the 't Hooft model (two-dimensional QCD
at N_c->oo), with the emphasis on the spectator-dependent effects sensitive to
the flavor of the spectator. The summation of exclusive widths is performed
analytically using the `t Hooft equation. We show that the 1/m_Q expansion of
both the Weak Annihilation and Pauli Interference widths coincides with the OPE
predictions, to the computed orders. Violation of local duality in the
inclusive widths is quantified, and the new example is identified where the OPE
prediction and the actual effect are completely saturated by a single final
state. The qualitative aspects of quark hadronization emerging from the
analysis in the 't Hooft model are discussed. Certain aspects of summation of
spectator-independent hadronic weak decay widths are given in more detail,
which were not spelled out previously. We also give some useful details of the
1/m_Q expansion in the 't~Hooft model.Comment: 54 pages, 8 figures in the text. Version to be published in Phys.
Rev. D. A number of typos are corrected and relevant references added.
Clarifications in Conclusions, Appendices 2.1 and 3 are adde