681,570 research outputs found

    Using Charge Asymmetries to Measure Single Top Quark Production at the LHC

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    Electroweak production of single top quarks is an as-yet-unverified prediction of the Standard model, potentially sensitive to new physics. Two of the single top quark productions channels have significant charge asymmetries at the LHC, while the much larger background from ttˉt\bar{t} is nearly charge-symmetric. This can be used to reduce systematic uncertainties and make precision measurements of single top quark production.Comment: 4 pages, 1 figur

    Trailing Edge Unification via an Intermediate Pati-Salam Group

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    We demonstrate to two-loop order that an intermediate symmetrically embedded Pati-Salam SU(2)L×SU(2)R×SU(4)SU(2)_L \times SU(2)_R \times SU(4) level of symmetry is all that is necessary to accommodate empirical values of α(Mz),αs(Mz)\alpha(M_z), \alpha_s(M_z) and sin2θw(Mz)\sin^2\theta_w(M_z) within a grand unification context but with a high (10^{14} GeV) intermediate mass scale and with a concomitant higher GUT scale.Comment: 7 pages, 4 embedded eps figur

    Study of the double non linear quantum resonances in diatomic molecules

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    We study the quantum dynamics of diatomic molecule driven by a circularly polarized resonant electric field. We look for a quantum effect due to classical chaos appearing due to the overlapping of nonlinear resonances associated to the vibrational and rotational motion. We solve the Schr\"odinger equation associated with the wave function expanded in term of proper stationary states, n>lm>|n>\otimes|lm> (vibrational\otimesangular momentum states). Looking for quantum-classic correspondence, we consider the Liouville dynamics in the two dimensional phase space defined by the coherent -like state of vibrational states, and it is found some similarities when the quantum dynamics is pictured in terms of number and phase operators.Comment: 15 pages, 4 figure

    Wavelet-based cross-correlation analysis of structure scaling in turbulent clouds

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    We propose a statistical tool to compare the scaling behaviour of turbulence in pairs of molecular cloud maps. Using artificial maps with well defined spatial properties, we calibrate the method and test its limitations to ultimately apply it to a set of observed maps. We develop the wavelet-based weighted cross-correlation (WWCC) method to study the relative contribution of structures of different sizes and their degree of correlation in two maps as a function of spatial scale, and the mutual displacement of structures in the molecular cloud maps. We test the WWCC for circular structures having a single prominent scale and fractal structures showing a self-similar behavior without prominent scales. Observational noise and a finite map size limit the scales where the cross-correlation coefficients and displacement vectors can be reliably measured. For fractal maps containing many structures on all scales, the limitation from the observational noise is negligible for signal-to-noise ratios >5. (abbrev). Application of the WWCC to the observed line maps of the giant molecular cloud G333 allows to add specific scale information to the results obtained earlier using the principle component analysis. It confirms the chemical and excitation similarity of 13^{13}CO and C18^{18}O on all scales, but shows a deviation of HCN at scales of up to 7' (~7 pc). This can be interpreted as a chemical transition scale. The largest structures also show a systematic offset along the filament, probably due to a large-scale density gradient. The WWCC can compare correlated structures in different maps of molecular clouds identifying scales that represent structural changes such as chemical and phase transitions and prominent or enhanced dimensions.Comment: 26 pages, 41 figures, accepted to A&
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