Related papers: Instanton Effects in Three Flavor QCD
Now that lattice QCD simulations are able to include effects of light sea quarks, the prospects are good for constraining quark flavor phenomenology. This review talk for particle physics experimentalists begins with an introduction…
We present a lattice QCD determination of light quark masses with three sea-quark flavours ($N_f = 2+1$). Bare quark masses are known from PCAC relations in the framework of CLS lattice computations with a non-perturbatively improved…
We review highlights of recent results on the hadron spectrum and flavor physics from lattice QCD. We also discuss recent rapid progress on the muon anomalous magnetic moment.
Chiral quark model with a broken-U(3) flavor symmetry can be interpreted as the effective theory of the instanton-dominated non-perturbative QCD. This naturally suggests the possibility of a negative singlet/octet coupling ratio, which has…
I review the status of lattice-QCD calculations relevant to quark flavor physics. The recent availability of physical-mass ensembles with large physical volumes generated by a growing number of lattice collaborations is an exciting…
We report on an instanton-based analysis of the gluon Green functions in the Landau gauge for low momenta; in particular we use lattice results for $\alpha_s$ in the symmetric momentum subtraction scheme (${\rm MOM}$) for large-volume…
We investigate the phase structure of lattice QCD for general number of flavors $N_F$. Based on numerical results combined with the result of the perturbation theory we propose the following picture: When $N_F \ge 17$, there is only a…
The color-flavor transformation for the unitary group (Zirnbauer 1996) is extended to the special unitary group. The resulting partition function is represented as sum over disconnected sectors characterized by a U(1)-charge. Application to…
Evidence from lattice QCD calculations is presented showing that instantons and their associated zero modes play a major role in the physics of light hadrons and the propagation of light quarks in the QCD vacuum.
The instanton--antiinstanton pair induced asymptotics of perturbation theory expansion for QCD correlators is considered. It is argued that though the true asymptotics is dominated by renormalon, the instanton-induced contribution may…
We discuss the confining and chiral-symmetry breaking properties of QCD with a large number of flavors $N_f$. In a Monte Carlo simulation of QCD with $N_f =16$ staggered fermions, we find clear evidence of a first order bulk phase…
This is a progress report on 2+1 flavor simulation with the FP action on a lattice with spatial size L=1.2fm. Since m_{ud} is quite small in our simulation we are in the delta regime for the two light flavors where the low lying excitations…
Common lore suggests that $N$-color QCD with massive quarks has no useful order parameters which can be non-trivial at zero baryon density. However, such order parameters do exist when there are $n_f$ quark flavors with a common mass and…
Small instantons which increase the axion mass due to an appropriate modification of QCD at a UV scale $\Lambda_{\rm SI}$, can also enhance the effect of CP-violating operators to shift the axion potential minimum by an amount, $\theta_{\rm…
QCD(1+1) in the limit of a large number of flavours N_F and a large number of colours N_C is examined in the small N_F/N_C regime. Using perturbation theory in N_F/N_C, stringent results for the leading behaviour of the spectrum departing…
The influence of nonperturbative fields on instantons in quantum chromodynamics is studied. Effective action for instanton is derived in bilocal approximation and it is demonstrated that stochastic background gluon fields are responsible…
After a very brief overview recollecting the `classic' parts of QCD, that is its application to describe hard processes and static properties of hadrons, I survey recent work -- some very recent -- on QCD at non-zero temperature and…
To study continuum limit of lattice QCD with many light quark flavors, we investigate the zero temperature phase structures of multi-flavor QCD. Currently a series of exploratory simulations are being performed with the number of quark…
We present results of a simulation of 2 flavour QCD on a $16^3\times4$ lattice using p4-improved staggered fermions with bare quark mass $m/T=0.4$. Derivatives of the thermodynamic grand canonical partition function $Z(V,T,\mu_u,\mu_d)$…
We have measured the hadron spectrum in lattice QCD, using staggered fermions, for 0 (the quenched approximation), 2 and 4 light degenerate dynamical quarks. In addition to earlier results involving extrapolations in valence quark masses…