Related papers: Higher-Dimensional QCD without the Strong CP Probl…
The QCD phase diagram is studied in the presence of an isospin asymmetry using continuum extrapolated staggered quarks with physical masses. In particular, we investigate the phase boundary between the normal and the pion condensation…
We show on the basis of an effective theory of QCD that a wide variety of observables in the hadron world is governed by the chiral symmetry together with an interplay between the axial anomaly and the explicit symmetry breaking due to the…
QCD perturbation theory using quark and gluon propagators that have an extra term at zero four-momentum is equivalent to standard PQCD in the presence of massless quark and gluon pairs in the perturbative vacuum. We verify at low orders in…
We present a new mechanism for solving the strong CP problem using a Z2 discrete symmetry and an anomalous U(1) symmetry. A Z2 symmetry is used so that two gauge groups have the same theta angle. An anomalous U(1) symmetry makes the…
We suggest a new solution to the strong CP problem. The solution is based on the proper use of the boundary conditions for the QCD generating functional integral. We expand the perturbative boundary conditions to both perturbative and…
A broad experimental program is targeting the QCD axion band predicted by single-axion solutions to the strong CP problem. Multi-axion theories provide a well-motivated departure from this canonical picture, since additional states…
Although the axion is the most compelling solution to the strong CP problem, the ad hoc introduced global Peccei-Quinn symmetry suffers from a severe fine-tuning problem known as the quality problem. In this Letter, we show that the…
Four-dimensional chiral gauge theory can be formulated as the boundary theory on a five-dimensional manifold in a manner that may be realized on a finite lattice. There are interesting features of these theories which defy a purely…
We study the stability of the highest symmetric solution (Wigner-solution) of Dyson-Schwinger equations in chiral limit and at zero temperature. Our results confirm that if the chemical potential is not very large, the QCD vacuum is in the…
I first sketch recent developments concerning the phase diagram of strongly interacting matter as a function of temperature and baryon density, obtained using a model for two-flavor QCD in which the interaction between quarks is modelled on…
We consider QCD axion models where the Peccei-Quinn symmetry is badly broken by a larger amount in the past than in the present, in order to avoid the axion isocurvature problem. Specifically we study supersymmetric axion models where the…
Using a general Ginzburg-Landau effective Lagrangian, we study the topological structure and low-lying collective modes of dense QCD having both chiral and diquark condensates, for two and three massless flavors. As we found earlier, the…
Formalism for a unified description of distinct superfluid phases of a deconfined QCD matter at finite density together with the phase of spontaneously broken chiral symmetry is presented. Dispersion laws of the quasiquark excitations in…
The strong CP problem is a compelling motivation for physics beyond the Standard Model. The most popular solutions invoke a global Peccei-Quinn symmetry, but are challenged by quantum gravitational corrections which are thought to be…
We argue that instantons play a crucial role in triggering the spontaneous breaking of chiral symmetry in the physics of the three light quarks in quantum chromodynamics. However, instantons may also play an essential role in our…
We use a variational procedure to study finite density QCD in an approximation in which the interaction between quarks is modelled by that induced by instantons. We find that uniform states with conventional chiral symmetry breaking have…
We study lattice QCD with two flavors of dynamical domain wall quarks. With renormalization group motivated actions, we find chiral symmetry can be preserved to a high degree at lattice cut off of a^{-1} \sim 2 GeV even for fifth dimension…
We show that the quark (not nucleon) based chiral linear $\sigma$ model which receives strong support as a mean field theory for the strong interactions can actually be made asymptotically free by coupling to gluons. It has the further…
In this talk we discuss the microscopic limit of QCD at nonzero chemical potential. In this domain, where the QCD partition function is under complete analytical control, we uncover an entirely new link between the spectral density of the…
The QCD sum rule approach is employed in order to study chiral properties of positive- and negative-parity nucleon resonances. It is pointed out that nucleons with an ``exotic'' chiral property, which can be represented by local five-quark…