Chiral transition and deconfinement in N_f = 2 QCD

The transition is studied by means of a disorder parameter detecting condensation of magnetic monopoles in the vacuum. The deconfining transition is found to coincide with the chiral transition and the susceptibility \rho, related to the disorder parameter, is consistent with a first order phase transition.Comment: 3 pages, 2 figures. Poster presented at Lattice2004(topology), Fermilab, June 21-26, 200

Improving the topological charge density operator on the lattice

We analyze the properties of a class of improved lattice topological charge density operators, constructed by a smearing-like procedure. By optimizing the choice of the parameters introduced in their definition, we find operators having (i) a much better statistical behavior as estimators of the topological charge density on the lattice, i.e. much less noisy; (ii) a multiplicative renormalization much closer to one; (iii) a large suppression of the perturbative tail in the corresponding lattice topological susceptibility.Comment: 4 pages, to be published in the Proceedings of Lattice 95, uuencoded postscript fil

Order, Disorder and Confinement

Studying the order of the chiral transition for $N_f=2$ is of fundamental importance to understand the mechanism of color confinement. We present results of a numerical investigation on the order of the transition by use of a novel strategy in finite size scaling analysis. The specific heat and a number of susceptibilities are compared with the possible critical behaviours. A second order transition in the O(4) and O(2) universality classes are excluded. Substantial evidence emerges for a first order transition. Results are in agreement with those found by studying the scaling properties of a disorder parameter related to the dual superconductivity mechanism of color confinement.Comment: 7 pages, 11 figures. Talk given at the International Workshop on Quantum Chromodynamics: QCD@Work 2005, Conversano, Italy, 16-20 June 200

The chiral transition in two-flavor QCD

QCD with N_f=2 is a specially interesting system to investigate the chiral transition. The order of the transition has still not been established. We report the results of an in-depth numerical investigation performed with staggered fermions on lattices with L_t=4 and L_s=12,16,20,24,32 and quark masses am_q ranging from 0.01335 to 0.307036. Using finite-size techniques we compare the scaling behavior of a number of thermodynamical susceptibilities with the expectations of O(4) and O(2) universality classes. Clear disagreement is observed. Indications of a first order transition are found.Comment: 6 pages, 4 figures, PoS style. Talk presented at Lattice 2005 (Nonzero temperature and density), Dublin, Ireland, July 25-3

QCD, monopoles on the Lattice and gauge invariance

The number and the location of the monopoles observed on the lattice in QCD configurations happens to depend strongly on the choice of the gauge used to expose them, in contrast to the physical expectation that monopoles be gauge invariant objects. It is proved by use of the non abelian Bianchi identities (NABI) that monopoles are indeed gauge invariant, but the method used to detect them depends, in a controllable way, on the choice of the abelian projection. Numerical checks are presented.Comment: 3 pages, 1 figure. Presented at the Conference QUARK CONFINEMENT AND THE HADRON SPECTRUM IX, Madrid Aug.30-Sept.3 201

Deconfining transition in two-flavor QCD

The order and the nature of the finite-temperature phase transition of QCD with two flavors of dynamical quarks is investigated. An analysis of the critical exponent of the specific heat is performed through finite-size and finite-mass scaling of various susceptibilities. Dual superconductivity of QCD vacuum is investigated using a disorder parameter, namely the v.e.v. of a monopole creation operator. Hybrid R simulations were run at lattice spatial sizes of $12^3$, $16^3$, $20^3$ and $32^3$ and temporal size $N_t=4$, with quark masses in the range $am_q = 0.3 - 0.01$.Comment: Lattice2003(topology), 3 page

Functional implications of minor mandibular asymmetry: clinical and digital research on a sample of healthy patients

OBJECTIVE.The aim of the study is to evaluate the influence that the mandibular asymmetry could have towards the other components of the Stomathognatic system and to further related structures from a functional point of view. MATERIALS and METHODS. A sample of 18 young asymmetric patients, in healthy status, was investigated with clinical evaluation and questionnaires and digital devices such as Electromiography, Stabilometry, T-scan and Formetric. Descriptive and quantitative statistical analysis were performed. RESULTS. ASIM electromyography index was significant only in a short percentage of the sample. Hypertonia of temporalis muscle in the same side of mandibular deviation and the cross-activation of the contralateral masseter were present. The data of the stabilometric platform showed that only 33% of patients had a load discrepancy between right and left side. All patients presented similar and limited postural anomalies during the Formetric examination. No significant results emerged from statistics . CONCLUSIONS. From the emerging data, mandibular asymmetry does not seem to be considered a potential risk factor for the development of functional anomalies both in the stomatognatic system and in the postural one. The only issue that should be considered is the condylar retrusion of the mandibular shortest side that is a possible destabilizing factor of the TMJ condyle-disc coordination

Functional implications of minor mandibular asymmetry: clinical and digital research on a sample of healthy patients

OBJECTIVE.The aim of the study is to evaluate the influence that the mandibular asymmetry could have towards the other components of the Stomathognatic system and to further related structures from a functional point of view. MATERIALS and METHODS. A sample of 18 young asymmetric patients, in healthy status, was investigated with clinical evaluation and questionnaires and digital devices such as Electromiography, Stabilometry, T-scan and Formetric. Descriptive and quantitative statistical analysis were performed. RESULTS. ASIM electromyography index was significant only in a short percentage of the sample. Hypertonia of temporalis muscle in the same side of mandibular deviation and the cross-activation of the contralateral masseter were present. The data of the stabilometric platform showed that only 33% of patients had a load discrepancy between right and left side. All patients presented similar and limited postural anomalies during the Formetric examination. No significant results emerged from statistics . CONCLUSIONS. From the emerging data, mandibular asymmetry does not seem to be considered a potential risk factor for the development of functional anomalies both in the stomatognatic system and in the postural one. The only issue that should be considered is the condylar retrusion of the mandibular shortest side that is a possible destabilizing factor of the TMJ condyle-disc coordination

A test of first order scaling in Nf=2 QCD

We complete our analysis of Nf=2 QCD based on the lattice staggered fermion formulation. Using a series of Monte Carlo simulations at fixed (amq*Ls^yh) one is able to test the universality class with given critical exponent yh. This strategy has been used to test the O(4) universality class and it has been presented at the previous Lattice conferences. No agreement was found with simulations in the mass range amq=[0.01335,0.15] using lattices with Ls=16 up to 32 and Lt=4. With the same strategy, we now investigate the possibility of a first order transition using a new set of Monte Carlo data corresponding to yh=3 in the same mass and volume range as the one used for O(4). A substantial agreement is observed both in the specific heat scaling and in the scaling of the chiral condensate, while the chiral susceptibilities still presents visible deviation from scaling in the mass range explored.Comment: 5 pages, 6 figures, Presented at the XXV International Symposium on Lattice Field Theory, July 30 - August 4 2007, Regensburg, German

Two flavor QCD and confinement - II

This paper is part of a program of investigation of the chiral transition in Nf=2 QCD, started in Phys.Rev.D72:114510,2005. Progress is reported on the understanding of some possible systematic errors. A direct test of first order scaling is presented.Comment: 7 pages, 6 figure