A luminosity monitor for the A4 parity violation experiment at MAMI

A water Cherenkov luminosity monitor system with associated electronics has been developed for the A4 parity violation experiment at MAMI. The detector system measures the luminosity of the hydrogen target hit by the MAMI electron beam and monitors the stability of the liquid hydrogen target. Both is required for the precise study of the count rate asymmetries in the scattering of longitudinally polarized electrons on unpolarized protons. Any helicity correlated fluctuation of the target density leads to false asymmetries. The performance of the luminosity monitor, investigated in about 2000 hours with electron beam, and the results of its application in the A4 experiment are presented.Comment: 22 pages, 12 figures, submitted to NIM

Faktor-faktor yang Berhubungan dengan Kepatuhan Odha (Orang dengan Hiv/aids) dalam Menjalani Terapi Antiretroviral di RSU. Dr. Pirngadi Medan Tahun 2012

Antiretroviral therapy was a therapy that taken by people living with HIV/AIDS (PLWHA) to increase their life quality. Although it hasn't been able to cure disease but antiretroviral therapy could suppress viral load and increase CD4 of PLWHA. More of people living with HIV/AIDS who received ARV, hope their life quality be better if ARV was used obediently. Adherence was a patient's behavior to comply with the provisions given by health workers that include discipline and obedience. To assure adherence, it was critical for patient to receive and understand information about ARV, the ability/ willingness of long-term treatment, the drug-resistance, the side effects, the range of medicines and the time to initiate of therapy. This research aimed to know the associated factors of PLWHA's adherence at RSU. dr. Pirngadi Medan in 2012. The design of this research was a cross sectional analytic with sample of 59 respondents and obtained by Accidental Sampling. The data analysis were used univariate and bivariate with Chi square test. By the univariate analysis known that respondents had a good knowledge (52.5%), good perception (76.3%), better health services (71.2%). Furthermore social support included in the medium category (57.6%) and adherence of PLHIV was high (57.6%). By the results of bivariate known that there was no associated between knowledge of ARV on adherence (p = 0.648) and there was no associated between perception on adherence (p = 0.231). In addition it was known that there was a associated between social support on adherence (p = 0.047) and there was a associated between health service to the perception patient undergoing ARV (p = 0.040). Health services and all levels of society were expected to continue to provide full support to them so as instill obedience and discipline to patient during undergo treatment and care with antiretroviral therapy

On the gauge boson's properties in a candidate technicolor theory

The technicolor scenario replaces the Higgs sector of the standard model with a strongly interacting sector. One candidate for a realization of such a sector is two-technicolor Yang-Mills theory coupled to two degenerate flavors of adjoint, massless techniquarks. Using lattice gauge theory the properties of the technigluons in this scenario are investigated as a function of the techniquark mass towards the massless limit. For that purpose the minimal Landau gauge two-point and three-point correlation functions are determined, including a detailed systematic error analysis. The results are, within the relatively large systematic uncertainties, compatible with a behavior very similar to QCD at finite techniquark mass. However, the limit of massless techniquarks exhibits features which could be compatible with a (quasi-)conformal behavior.Comment: 27 pages, 17 figures, 1 table; v2: persistent notational error corrected, some minor modification

More on Gribov copies and propagators in Landau-gauge Yang-Mills theory

Fixing a gauge in the non-perturbative domain of Yang-Mills theory is a non-trivial problem due to the presence of Gribov copies. In particular, there are different gauges in the non-perturbative regime which all correspond to the same definition of a gauge in the perturbative domain. Gauge-dependent correlation functions may differ in these gauges. Two such gauges are the minimal and absolute Landau gauge, both corresponding to the perturbative Landau gauge. These, and their numerical implementation, are described and presented in detail. Other choices will also be discussed. This investigation is performed, using numerical lattice gauge theory calculations, by comparing the propagators of gluons and ghosts for the minimal Landau gauge and the absolute Landau gauge in SU(2) Yang-Mills theory. It is found that the propagators are different in the far infrared and even at energy scales of the order of half a GeV. In particular, also the finite-volume effects are modified. This is observed in two and three dimensions. Some remarks on the four-dimensional case are provided as well.Comment: 23 pages, 16 figures, 6 tables; various changes throughout most of the paper; extended discussion on different possibilities to define the Landau gauge and connection to existing scenarios; in v3: Minor changes, error in eq. (3) & (4) corrected, version to appear in PR

Yang-Mills Theory in lambda-Gauges

The gauge-independent phenomenon of color confinement in Yang-Mills theory manifests itself differently in different gauges. Therefore, the gauge dependence of quantities related to the infrared structure of the theory becomes important for understanding the confinement mechanism. Particularly useful are classes of gauges that are controlled by a single gauge parameter. We present results on propagators and the color-Coulomb potential for the so-called lambda-gauges, which interpolate between the (minimal) Landau gauge and the (minimal complete) Coulomb gauge. Results are reported for the SU(2) lattice gauge theory in three and four space-time dimensions. We investigate especially intermediate and low momenta. We find a continuous evolution of all quantities with the gauge parameter, except at zero four-momentum.Comment: 17 pages, 13 figures, 3 table

Color-superconductivity in the strong-coupling regime of Landau gauge QCD

The chirally unbroken and the superconducting 2SC and CFL phases are investigated in the chiral limit within a Dyson-Schwinger approach for the quark propagator in QCD. The hierarchy of Green's functions is truncated such that at vanishing density known results for the vacuum and at asymptotically high densities the corresponding weak-coupling expressions are recovered. The anomalous dimensions of the gap functions are analytically calculated. Based on the quark propagator the phase structure is studied, and results for the gap functions, occupation numbers, coherence lengths and pressure differences are given and compared with the corresponding expressions in the weak-coupling regime. At moderate chemical potentials the quasiparticle pairing gaps are several times larger than the extrapolated weak-coupling results.Comment: 14 pages, 9 figures; v2: one reference adde

Accessing directly the properties of fundamental scalars in the confinement and Higgs phase

The properties of elementary particles are encoded in their respective propagators and interaction vertices. For a SU(2) gauge theory coupled to a doublet of fundamental complex scalars these propagators are determined in both the Higgs phase and the confinement phase and compared to the Yang-Mills case, using lattice gauge theory. Since the propagators are gauge-dependent, this is done in the Landau limit of 't Hooft gauge, permitting to also determine the ghost propagator. It is found that neither the gauge boson nor the scalar differ qualitatively in the different cases. In particular, the gauge boson acquires a screening mass, and the scalar's screening mass is larger than the renormalized mass. Only the ghost propagator shows a significant change. Furthermore, indications are found that the consequences of the residual non-perturbative gauge freedom due to Gribov copies could be different in the confinement and the Higgs phase.Comment: 11 pages, 6 figures, 1 table; v2: one minor error corrected; v3: one appendix on systematic uncertainties added and some minor changes, version to appear in EPJ

Waves attractors in rotating fluids: a paradigm for ill-posed Cauchy problems

In the limit of low viscosity, we show that the amplitude of the modes of oscillation of a rotating fluid, namely inertial modes, concentrate along an attractor formed by a periodic orbit of characteristics of the underlying hyperbolic Poincar\'e equation. The dynamics of characteristics is used to elaborate a scenario for the asymptotic behaviour of the eigenmodes and eigenspectrum in the physically relevant r\'egime of very low viscosities which are out of reach numerically. This problem offers a canonical ill-posed Cauchy problem which has applications in other fields.Comment: 4 pages, 5 fi

Two infrared Yang-Mills solutions in stochastic quantization and in an effective action formalism

Three decades of work on the quantum field equations of pure Yang-Mills theory have distilled two families of solutions in Landau gauge. Both coincide for high (Euclidean) momentum with known perturbation theory, and both predict an infrared suppressed transverse gluon propagator, but whereas the solution known as "scaling" features an infrared power law for the gluon and ghost propagators, the "massive" solution rather describes the gluon as a vector boson that features a finite Debye screening mass. In this work we examine the gauge dependence of these solutions by adopting stochastic quantization. What we find, in four dimensions and in a rainbow approximation, is that stochastic quantization supports both solutions in Landau gauge but the scaling solution abruptly disappears when the parameter controlling the drift force is separated from zero (soft gauge-fixing), recovering only the perturbative propagators; the massive solution seems to survive the extension outside Landau gauge. These results are consistent with the scaling solution being related to the existence of a Gribov horizon, with the massive one being more general. We also examine the effective action in Faddeev-Popov quantization that generates the rainbow and we find, for a bare vertex approximation, that the the massive-type solutions minimise the quantum effective action.Comment: 13 pages, 7 figures. Change of title to reflect version accepted for publicatio