117998143
Static quark free energies at finite temperature
We determine the static quark free energies around the transition temperature using 2+1 flavors of staggered fermions. Simulations are carried out on N_t=4,6,8 and 10 lattices using physical quark masses. The free energies extracted from Polyakov-loop correlators are extrapolated to the continuum limit.
118751094
Lattice SU(3) thermodynamics and the onset of perturbative behaviour
We present the equation of state (pressure, trace anomaly, energy density and entropy density) of the SU(3) gauge theory from lattice field theory in an unprecedented precision and temperature range. We control both finite size and cut-off effects. The studied temperature window ($0.7... 1000 T_c$) stretches from the glueball dominated system into the perturbative regime, which allows us to discuss the range of validity of these approaches. From the critical couplings on fine lattices we get $T_c/\Lambdamsbar=1.26(7)$ and use this ratio to express the perturbative free energy in $T_c$ units. We also determine the preferred renormalization scale of the Hard Thermal Loop scheme and we fit the unknown $g^6$ order perturbative coefficient at extreme high temperatures $T>100T_c$. We furthermore quantify the nonperturbative contribution to the trace anomaly using two simple functional forms.
18088920
Dynamical overlap fermions, results with HMC algorithm
We present results of a hybrid Monte-Carlo algorithm for dynamical, n f = 2 , four-dimensional QCD with overlap fermions. The fermionic force requires careful treatment, when changing topological sectors. The pion mass dependence of the topological susceptibility is studied on 6 4 and 12 ⋅ 6 3 lattices. The results are transformed into physical units.
15253180
Pentaquark hadrons from lattice QCD
We study spin 1/2 isoscalar and isovector candidates in both parity channels for the recently discovered ?+ (1540) pentaquark particle in quenched lattice QCD. Our analysis takes into account all possible uncertainties, such as statistical, finite size and quenching errors when performing the chiral and continuum extrapolations and we have indications that our signal is separated from scattering states. The lowest mass that we find in the IP = 0? channel is in complete agreement with the experimental value of the ?+ mass. On the other hand, the lowest mass state in the opposite parity IP = 0+ channel is much higher. Our findings suggests that the parity of the ?+ is negative.
17575686
The equation of state in lattice QCD: with physical quark masses towards the continuum limit
The equation of state of QCD at vanishing chemical potential as a function of temperature is determined for two sets of lattice spacings. Coarser lattices with temporal extension of Nt=4 and finer lattices of Nt=6 are used. Symanzik improved gauge and stout-link improved staggered fermionic actions are applied. The results are given for physical quark masses both for the light quarks and for the strange quark. Pressure, energy density, entropy density, quark number susceptibilities and the speed of sound are presented.
123195956
QCD equation of state from the lattice
We calculate the QCD equation of state with 2+1 staggered lattice flavors and a physical pion mass. We present precision data on the trace anomaly and pressure based on simulations at Nt = 6,8 and 10. These results are confirmed by Nt = 12 simulations at three temperatures. Detailed results can be found in [arXiv:1007.2580v2].
117344060
On the Motivic Stable Pairs Invariants of K3 Surfaces
For a K3 surface S and a class β ∈ Pic(S), we study motivic invariants of stable pairs moduli spaces associated to 3-fold thickenings of S. We conjecture suitable deformation and divisibility invariances for the Betti realization. Our conjectures, together with earlier calculations of Kawai-Yoshioka, imply a full determination of the theory in terms of the Hodge numbers of the Hilbert schemes of points of S. The work may be viewed as the third in a sequence of formulas starting with Yau-Zaslow and Katz-Klemm-Vafa (each recovering the former). Numerical data suggest the motivic invariants are linked to the Mathieu M24 moonshine phenomena.