Dynamics of monopoles and flux tubes in two-flavor dynamical QCD

We investigate the confining properties of the QCD vacuum with N_f=2 flavors of dynamical quarks, and compare the results with the properties of the quenched theory. We use non-perturbatively O(a) improved Wilson fermions to keep cut-off effects small. We focus on color magnetic monopoles. Among the quantities we study are the monopole density and the monopole screening length, the static potential and the profile of the color electric flux tube. We furthermore derive the low-energy effective monopole action. Marked differences between the quenched and dynamical vacuum are found. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(03-162) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Thermodynamics and heavy quark potential in N_f=2 dynamical QCD

We study N_f = 2 lattice QCD with nonperturbatively improved Wilson fermions at finite temperature on 16"3.8 lattices. We determine the transition temperature at m_#pi#/m_#rho# #propor to# 0.8 and lattice spacing as small as a #propor to# 0.12fm. The string breaking at T < T_c is also studied. We find that the static potential can be fitted by a simple expression involving string model potential at finite temperature. (orig.)Available from TIB Hannover: RA 2999(02-135) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Baryonic flux in quenched and two-flavor dynamical QCD

We study the distribution of color electric flux of the three-quark system in quenched and full QCD (with N_f=2 flavors of dynamical quarks) at zero and finite temperature. To reduce ultra-violet fluctuations, the calculations are done in the Abelian projected theory fixed to the maximally Abelian gauge. In the confined phase we find clear evidence for a Y-shape flux tube surrounded and formed by the solenoidal monopole current, in accordance with the dual superconductor picture of confinement. In the deconfined, high temperature phase monopoles cease to condense, and the distribution of the color electric field becomes Coulomb-like. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(04-004) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Profiles of the broken string in two-flavor QCD below and above the finite temperature transition

We study the Abelian flux tube profile of mesonic and the baryonic configurations of static quarks below and above the finite-temperature transition in N_f = 2 full QCD. To reduce effects of ultra-violet fluctuations we measure Abelian distributions of the action density, the color-electric field and the monopole current after fixing to the maximally Abelian gauge. Changing the distance R between quarks for fixed T/T_c < 1, one can see a clear signal of string breaking for large R. The electric field becomes Coulomb-like and the circulating monopole current disappears. We study also the temperature dependence of the flux profile for fixed R #approx# 0.7 fm. The disappearance of the squeezed flux is observed clearly above T_c. Similar behaviors are observed both in the mesonic and the baryonic systems. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(04-005) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Structure of the baryonic flux tube in N_f=2 lattice QCD at finite temperature

We study the flux tube profile in the baryonic system in full QCD at finite temperature of N_t=8 lattice. We fix the maximally Abelian gauge and measure the monopole and the photon parts of the Abelian action density, the color electric field and the monopole current on both sides of the finite temperature transition. We demonstrate the disappearance of the flux tube in the high temperature phase. (orig.)Available from TIB Hannover: RA 2999(03-144) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Finite temperature QCD with two flavors of dynamical quarks on 24"3 x 10 lattice

We present results obtained in QCD with two flavors of non-perturbatively improved Wilson fermions at finite temperature on 16"3 x 8 and 24"3 x 10 lattices. We determine the transition temperature in the range of quark masses 0.6 < m_#pi#/m_#rho# < 0.8 at lattice spacing a#approx#0.1 fm and extrapolate the transition temperature to the continuum and to the chiral limits. (orig.)SIGLEAvailable from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman