4,390 research outputs found

    Hidden local symmetry and color confinement

    Full text link
    The hidden local symmetry is a successful model to describe the properties of the vector mesons in QCD. We point out that if we identify this hidden gauge theory as the magnetic picture of QCD, a linearized version of the model simultaneously describes color confinement and chiral symmetry breaking. We demonstrate that such a structure can be seen in the Seiberg dual picture of a softly broken supersymmetric QCD. The model possesses exact chiral symmetry and reduces to QCD when mass parameters are taken to be large. Working in the regime of the small mass parameters, we show that there is a vacuum where chiral symmetry is spontaneously broken and simultaneously the magnetic gauge group is Higgsed. If the vacuum we find persists in the limit of large mass parameters, one can identify the rho meson as the massive magnetic gauge boson, that is an essential ingredient for color confinement.Comment: 20 pages, 3 figure

    Neutralino spin measurement with ATLAS detector at LHC

    Get PDF
    Minimal Supergravity (mSUGRA) [1] Supersimmetry breaking mechanism is a leading candidate for yielding new physics beyond the Standard Model (SM). Within mSUGRA framework masses, mixings and decays of all SUSY and Higgs particles are determined in terms of four input parameters and a sign: the common mass m 0 of scalar particles at the grand unification scale, the common fermion mass m 1/2, the common trilinear coupling A 0, the ratio of the Higgs vacuum expectation values tan β and the sign of the supersymmetric Higgs mass parameter μ. Once a signal of a physics beyond the Standard Model is seen at LHC, it will be fundamental to measure properties of new particles, like spin, in order to prove that they are indeed supersymmetric partners. The present work [2] is based on the spin analysis method proposed in [3] and allows the discrimination of different hypotheses for spin assignments. Some studies [4, 5] show that this method can also be used for the discrimination of SUSY from an Universal Extra Dimensions model which can mimick low energy SUSY at hadron colliders. In this report two selected points inside stau-coannihilation and bulk regions of the allowed mSUGRA parameter space are considered. Fast simulation [6] of the ATLAS detector was performed in order to investigate the feasibility of supersymmetric particles’ spin measurement

    Short-term effects of air pollution on cardiovascular hospitalizations in the pisan longitudinal study

    Get PDF
    Air pollution effects on cardiovascular hospitalizations in small urban/suburban areas have been scantly investigated. Such effects were assessed among the participants in the analytical epidemiological survey carried out in Pisa and Cascina, Tuscany, Italy (2009-2011). Cardiovascular hospitalizations from 1585 subjects were followed up (2011-2015). Daily mean pollutant concentrations were estimated through random forests at 1 km (particulate matter: PM10, 2011-2015; PM2.5, 2013-2015) and 200 m (PM10, PM2.5, NO2, O3, 2013-2015) resolutions. Exposure effects were estimated using the case-crossover design and conditional logistic regression (odds ratio-OR-and 95% confidence interval-CI-for 10 ÎĽg/m3 increase; lag 0-6). During the period 2011-2015 (137 hospitalizations), a significant effect at lag 0 was observed for PM10 (OR = 1.137, CI: 1.023-1.264) at 1 km resolution. During the period 2013-2015 (69 hospitalizations), significant effects at lag 0 were observed for PM10 (OR = 1.268, CI: 1.085-1.483) and PM2.5 (OR = 1.273, CI: 1.053-1.540) at 1 km resolution, as well as for PM10 (OR = 1.365, CI: 1.103-1.690), PM2.5 (OR = 1.264, CI: 1.006-1.589) and NO2 (OR = 1.477, CI: 1.058-2.061) at 200 m resolution; significant effects were observed up to lag 2. Larger ORs were observed in males and in subjects reporting pre-existent cardiovascular/respiratory diseases. Combining analytical and routine epidemiological data with high-resolution pollutant estimates provides new insights on acute cardiovascular effects in the general population and in potentially susceptible subgroups living in small urban/suburban areas

    Study of second lightest neutralino spin measurement with ATLAS detector at LHC

    Get PDF
    One of the goals of the ATLAS experiment at the CERN Large Hadron Collider is to search for evidence of Supersymmetry (SUSY) signals. If SUSY would be discovered, it will be fundamental to measure the spin of the new particles in order to prove that they are indeed supersymmetric partners. Left-handed squark cascade decay to second lightest neutralino which further decays to slepton can represent a good opportunity for SUSY particles' spin measurement. Assuming the neutralino spin to be 1/2, the invariant mass distributions of some detectable final products of the reactions have to be charge asymmetric. In the present work the detectability of this charge asymmetry is analysed in the stau-coannihilation region and in the bulk region of the minimal Supergravity parameter space allowed by the latest experimental constraints. The criteria used to isolate the decay chain of interest and to reject the background, coming from both Standard Model and different SUSY decay channels, are described as obtained by suitable optimizations on Monte Carlo samples produced with the ATLAS fast simulation. The estimates of the residual contributions to background and of the applied cut efficiencies are presented. Results on charge asymmetry are then shown and discussed

    Supersymmetry Breaking on Gauged Non-Abelian Vortices

    Full text link
    There are a large number of systems characterized by a completely broken gauge symmetry, but with an unbroken global color-flavor diagonal symmetry, i.e., systems in the so-called color-flavor locked phase. If the gauge symmetry breaking supports vortices, the latter develop non-Abelian orientational zero-modes and become non-Abelian vortices, a subject of intense study in the last several years. In this paper we consider the effects of weakly gauging the full exact global flavor symmetry in such systems, deriving an effective description of the light excitations in the presence of a vortex. Surprising consequences are shown to follow. The fluctuations of the vortex orientational modes get diffused to bulk modes through tunneling processes. When our model is embedded in a supersymmetric theory, the vortex is still 1/2 BPS saturated, but the vortex effective action breaks supersymmetry spontaneously.Comment: Latex, 24 pages, 1 figur

    Ageing test of the ATLAS RPCs at X5-GIF

    Full text link
    An ageing test of three ATLAS production RPC stations is in course at X5-GIF, the CERN irradiation facility. The chamber efficiencies are monitored using cosmic rays triggered by a scintillator hodoscope. Higher statistics measurements are made when the X5 muon beam is available. We report here the measurements of the efficiency versus operating voltage at different source intensities, up to a maximum counting rate of about 700Hz/cm^2. We describe the performance of the chambers during the test up to an overall ageing of 4 ATLAS equivalent years corresponding to an integrated charge of 0.12C/cm^2, including a safety factor of 5.Comment: 4 pages. Presented at the VII Workshop on Resistive Plate Chambers and Related Detectors; Clermont-Ferrand October 20th-22nd, 200

    Selective formation, reactivity, redox and magnetic properties of MnIII and FeIII dinuclear complexes with shortened salen-type schiff base ligands

    Get PDF
    The reactivity of the shortened salen-type ligands H3salmp, H2salmen and H2sal(p-X)ben with variable para-substituent on the central aromatic ring (X = tBu, Me, H, F, Cl, CF3, NO2) towards the trivalent metal ions manganese(III) and iron(III) is presented. The selective formation of the dinuclear complexes [M2(m-salmp)2], M = Mn (1a), Fe (2a), [M2(m-salmen)2(m-OR)2)], R = Et, Me, H and M = Mn (3a\u2013c) or Fe (4a\u2013c), and (M2(m-sal[p-X]ben)2(m-OMe)2), X = tBu, Me, H, F, Cl, CF3, NO2 and M = Mn (5a\u2013g) or Fe (6a\u2013g), could be identified by reaction of the Schiff bases with metal salts and the base NEt3, and their characterization through elemental analysis, infrared spectroscopy, mass spectrometry and single-crystal X-ray diffraction of 2a.2AcOEt, 2a.2CH3CN and 3c.2DMF was performed. In the case of iron(III) and H3salmp, when using NaOH as a base instead of NEt3, the dinuclear complexes [Fe2(m-salmp)(m-OR)(salim)2], R = Me, H (2b\u2013c) could be isolated and spectroscopically characterized, including the crystal structure of 2b.1.5H2O, which showed that rupture of one salmp3\u2013 to two coordinated salim\u2013 ligands and release of one salH molecule occurred. The same hydrolytic tendency could be identified with sal(p-X)ben ligands in the case of iron(III) also by using NEt3 or upon standing in solution, while manganese(III) did not promote such a C\u2013N bond breakage. Cyclic voltammetry studies were performed for 3b, 4b, 5a and 6a, revealing that the iron(III) complexes can be irreversibly reduced to the mixed-valence FeIIFeIII and FeII2 dinuclear species, while the manganese(III) derivatives can be reversibly oxidized to either the mixed-valence MnIIIMnIV or to the MnIV2 dinuclear species. The super-exchange interaction between the metal centers, mediated by the bridging ligands, resulted in being antiferromagnetic (AFM) for the selected dinuclear compounds 3b, 4b, 5a, 5e, 5f, 6a and 6e. The coupling constants J (\u20132J \u15c1\ub7\u15c2 formalism) had values around \u201313 cm\u20131 for manganese(III) compounds, among the largest AFM coupling constants reported so far for dinuclear MnIII2 derivatives, while values between \u20133 and \u201310 cm\u20131 were obtained for iron(III) compounds

    Geometry and Dynamics of a Coupled 4D-2D Quantum Field Theory

    Get PDF
    Geometric and dynamical aspects of a coupled 4D-2D interacting quantum field theory - the gauged nonAbelian vortex - are investigated. The fluctuations of the internal 2D nonAbelian vortex zeromodes excite the massless 4D Yang-Mills modes and in general give rise to divergent energies. This means that the well-known 2D CP(N-1) zeromodes associated with a nonAbelian vortex become nonnormalizable. Moreover, all sorts of global, topological 4D effects such as the nonAbelian Aharonov-Bohm effect come into play. These topological global features and the dynamical properties associated with the fluctuation of the 2D vortex moduli modes are intimately correlated, as shown concretely here in a U(1) x SU(N) x SU(N) model with scalar fields in a bifundamental representation of the two SU(N) factor gauge groups.Comment: Latex, 39 pages, 5 figure

    Comments on orientifold projection in the conifold and SO x USp duality cascade

    Get PDF
    We study the O3-plane in the conifold. On the D3-brane world-volume we obtain SO x USp gauge theory that exhibits a duality cascade phenomenon. The orientifold projection is determined on the type IIB string side, and corresponds to that of O4-plane on the dual type IIA side. We show that SUGRA solutions of Klebanov-Tseytlin and Klebanov-Strassler survive under the projection. We also investigate the orientifold projection in the generalized conifolds, and verify desired features of the O4-projection in the type IIA picture.Comment: 1+27 pages, 9 figures, references added; version to appear in Phys. Rev.
    • …
    corecore