1,429 research outputs found

    Universality Class of Confining Strings

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    A recently proposed model of confining strings has a non-local world-sheet action induced by a space-time Kalb-Ramond tensor field. Here we show that, in the large-D approximation, an infinite set of ghost- and tachyon-free truncations of the derivative expansion of this action all lead to c=1 models. Their infrared limit describes smooth strings with world-sheets of Hausdorff dimension D_H=2 and long-range orientational order, as expected for QCD strings.Comment: 11 pages, harvma

    Thermal Pions at Finite Isospin Chemical Potential

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    The density corrections, in terms of the isospin chemical potential μI\mu_I, to the mass of the pions are studied in the framework of the SU(2) low energy effective chiral lagrangian. The pion decay constant fπ(T,μI)f_{\pi}(T, \mu_{I}) is also analized. As a function of temperature for μI=0\mu_I =0, the mass remains quite stable, starting to grow for very high values of TT, confirming previous results. However, there are interesting corrections to the mass when both effects (temperature and chemical potential) are simultaneously present. At zero temperature the π±\pi ^{\pm} should condensate when μI=mπ\mu_{I} = \mp m_{\pi}. This is not longer valid anymore at finite TT. The mass of the π0\pi_0 acquires also a non trivial dependence on μI\mu_I due to the finite temperature.Comment: 13 pages, 5 figure

    A Vector Non-abelian Chern-Simons Duality

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    Abelian Chern-Simons gauge theory is known to possess a `SS-self-dual' action where its coupling constant kk is inverted {\it i.e.} k1kk \leftrightarrow {1 \over k}. Here a vector non-abelian duality is found in the pure non-abelian Chern-Simons action at the classical level. The dimensional reduction of the dual Chern-Simons action to two-dimensions constitutes a dual Wess-Zumino-Witten action already given in the literature.Comment: 14+1 pages, LaTeX file, no figures, version to appear in Phys. Rev

    Anomalies in orbifold field theories

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    We study the constraints on models with extra dimensions arising from local anomaly cancellation. We consider a five-dimensional field theory with a U(1) gauge field and a charged fermion, compactified on the orbifold S^1/(Z_2 x Z_2'). We show that, even if the orbifold projections remove both fermionic zero modes, there are gauge anomalies localized at the fixed points. Anomalies naively cancel after integration over the fifth dimension, but gauge invariance is broken, spoiling the consistency of the theory. We discuss the implications for realistic supersymmetric models with a single Higgs hypermultiplet in the bulk, and possible cancellation mechanisms in non-minimal models.Comment: 10 pages, 2 figures, LaTex; v2: final version to be published in Phys. Lett.

    On Charge Quantization and Abelian Gauge Horizontal Symmetries

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    Under the assumption that there exists a local gauge horizontal symmetry GHG_H wich allows only for a top quark mass at tree level, we look for the constraints that charge quatization and the family structure of the standard model imposes on that symmetry.Comment: 13 pages, LaTeX, Acepted in Physics Letters

    Efficacy, safety and patient reported outcomes (PROS) in adult patients with atopic dermatitis treated with dupilumab at week-52 in usual clinical practice

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    P15 Background: Dupilumab, an anti-interleikin-4-receptor-a monoclonal antibody, is a new treatment for atopic dermatitis in adults. Objective: To evaluate – at week 52 – patient reported outcomes, satisfaction, efficacy and safety, with dupilumab in adult patients with moderate-to-severe atopic dermatitis refractory to the usual treatments previously performed under conditions of usual clinical practice. Methods: Twelve patients were enrolled. Patients from our hospital, under routine clinical practice, were treated with subcutaneous dupilumab 300 mg every 2 weeks. The outcomes were evaluated at baseline, week 4, 8, 12, 16, 28 , 40 and week 52. The variables evaluated were: itch, difficulty to sleep, previous stressful life events, severity (SCORAD), anxiety and depression symptoms (HADS), quality of life (DLQI, EQ5D3L), satisfaction, adherence to the treatment, efficacy and safety. Results: At week 52 significant improvement was observed in severity, itch, difficulty to sleep, anxiety and depression symptoms, and quality of life. Satisfaction with dupilumab compared to previous treatments was significantly higher in all aspects assessed. No significant dupilumab-induced laboratory abnormalities were noted, and adverse events were mild and transient. Conclusions: Dupilumab used under routine clinical practice for 52 weeks improved atopic dermatitis signs and symptoms, with a good safety profile and patient satisfaction

    Anomalies, Anomalous U(1)'s and generalized Chern-Simons terms

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    A detailed analysis of anomalous U(1)'s and their effective couplings is performed both in field theory and string theory. It is motivated by the possible relevance of such couplings in particle physics, as well as a potential signal distinguishing string theory from other UV options. The most general anomaly related effective action is analyzed and parameterized. It contains Stuckelberg, axionic and Chern-Simons-like couplings. It is shown that such couplings are generically non-trivial in orientifold string vacua and are not in general fixed by anomalies. A similar analysis in quantum field theories provides similar couplings. The trilinear gauge boson couplings are also calculated and their phenomenological relevance is advocated. We do not find qualitative differences between string and field theory in this sector.Comment: 52 pages, 2 eps figures, LaTeX, feynmf & youngtab packages (v2 - Minor corrections, references added

    Tilted axis rotation, candidates for chiral bands, and wobbling motion in 138Nd

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    High-spin states in 138Nd were investigated using the reaction 94Zr(48Ca,4n), detecting coincident γ rays with the gasp spectrometer. A rich level scheme was constructed including four bands of negative parity at low spins, eight bands of dipole transitions, and eight bands of quadrupole transitions at medium spins. The cranked shell model and the tilted-axis cranking model are used to assign configurations to the observed bands, where zero pairing is assumed. For selected configurations the case of finite pairing is also considered. A consistent notation for configuration assignment that applies for both zero and finite pairing is introduced. The observed bands are interpreted as rotation around the short and long principal axes (quadrupole bands), as well as around a tilted axis (dipole bands). The dipole bands have an intermediate character, between magnetic and collective electric rotation. A pair of dipole bands is identified as candidates for chiral partners. The possible existence of the wobbling mode at low deformation and medium spins is discussed. The consistent interpretation of the multitude of observed bands strongly supports the existence of stable triaxial deformation at medium spins in 138Nd. ©2012 American Physical Societ

    Anomalies, Fayet-Iliopoulos terms and the consistency of orbifold field theories

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    We study the consistency of orbifold field theories and clarify to what extent the condition of having an anomaly-free spectrum of zero-modes is sufficient to guarantee it. Preservation of gauge invariance at the quantum level is possible, although at the price, in general, of introducing operators that break the 5d local parity. These operators are, however, perfectly consistent with the orbifold projection. We also clarify the relation between localized Fayet-Iliopoulos (FI) terms and anomalies. These terms can be consistently added, breaking neither local supersymmetry nor the gauge symmetry. In the framework of supergravity the localized FI term arises as the boundary completion of a bulk interaction term: given the bulk Lagrangian the FI is fixed by gauge invariance.Comment: 31 pages, 1 figure. v2: some typos corrected, references adde
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