16,054 research outputs found

    Radiation damage effects on detectors and eletronic devices in harsh radiation environment

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    Radiation damage effects represent one of the limits for technologies to be used in harsh radiation environments as space, radiotherapy treatment, high-energy phisics colliders. Different technologies have known tolerances to different radiation fields and should be taken into account to avoid unexpected failures which may lead to unrecoverable damages to scientific missions or patient health

    On Hermitian separability of the next-to-leading order BFKL kernel for the adjoint representation of the gauge group in the planar N = 4 SYM

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    We analyze a modification of the BFKL kernel for the adjoint representation of the colour group in the maximally supersymmetric (N=4) Yang-Mills theory in the limit of a large number of colours, related to the modification of the eigenvalues of the kernel suggested by S. Bondarenko and A. Prygarin in order to reach the Hermitian separability of the eigenvalues. We restore the modified kernel in the momentum space. It turns out that the modification is related only to the real part of the kernel and that the correction to the kernel can not be presented by a single analytic function in the entire momentum region, which contradicts the known properties of the kernel

    Impact factors for Reggeon-gluon transition in N = 4 SYM with large number of colours

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    We calculate impact factors for Reggeon-gluon transition in supersymmetric Yang-Mills theory with four supercharges at large number of colours Nc. In the next-to-leading order impact factors are not uniquely defined and must accord with BFKL kernels and energy scales. We obtain the impact factor corresponding to the kernel and the energy evolution parameter, which is invariant under Moebius transformation in momentum space, and show that it is also Moebius invariant up to terms taken into account in the BDS ansatz.Comment: 13 page

    Discontinuites of BFKL amplitudes and the BDS ansatz

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    We perform an examination of discontinuities of multiple production amplitudes, which are required for further development of the BFKL approach. It turns out that the discontinuities of 2 →\to 2 + n amplitudes obtained in the BFKL approach contradict to the BDS ansatz for amplitudes with maximal helicity violation in N = 4 supersymmetric Yang-Mills theory with large number of colours starting with n = 2. Explicit expressions for the discontinuities of the 2 →\to 3 and 2 →\to 4 amplitudes in the invariant mass of pairs of produced gluons are obtained in the planar N=4 SYM in the next-to-leading logarithmic approximation. These expressions can be used for checking the conjectured duality between the light-like Wilson loops and the MHV amplitudes.Comment: 26 page

    Non-forward BFKL Pomeron at next-to-leading order

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    The kernel of the BFKL equation for non-zero momentum transfer is found at next-to-leading order. It is presented in various forms depending on the regularization of the infrared singularities in "virtual" and "real" parts of the kernel. The infrared safety of the total kernel is demonstrated and a form free from the singularities is suggested.Comment: 8 page

    QFT with Twisted Poincar\'e Invariance and the Moyal Product

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    We study the consequences of twisting the Poincare invariance in a quantum field theory. First, we construct a Fock space compatible with the twisting and the corresponding creation and annihilation operators. Then, we show that a covariant field linear in creation and annihilation operators does not exist. Relaxing the linearity condition, a covariant field can be determined. We show that it is related to the untwisted field by a unitary transformation and the resulting n-point functions coincide with the untwisted ones. We also show that invariance under the twisted symmetry can be realized using the covariant field with the usual product or by a non-covariant field with a Moyal product. The resulting S-matrix elements are shown to coincide with the untwisted ones up to a momenta dependent phase.Comment: 11 pages, references adde

    Contraction analysis of switched Filippov systems via regularization

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    We study incremental stability and convergence of switched (bimodal) Filippov systems via contraction analysis. In particular, by using results on regularization of switched dynamical systems, we derive sufficient conditions for convergence of any two trajectories of the Filippov system between each other within some region of interest. We then apply these conditions to the study of different classes of Filippov systems including piecewise smooth (PWS) systems, piecewise affine (PWA) systems and relay feedback systems. We show that contrary to previous approaches, our conditions allow the system to be studied in metrics other than the Euclidean norm. The theoretical results are illustrated by numerical simulations on a set of representative examples that confirm their effectiveness and ease of application.Comment: Preprint submitted to Automatic

    On the Decoupling of the Homogeneous and Inhomogeneous Parts in Inhomogeneous Quantum Groups

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    We show that, if there exists a realization of a Hopf algebra HH in a HH-module algebra AA, then one can split their cross-product into the tensor product algebra of AA itself with a subalgebra isomorphic to HH and commuting with AA. This result applies in particular to the algebra underlying inhomogeneous quantum groups like the Euclidean ones, which are obtained as cross-products of the quantum Euclidean spaces RqNR_q^N with the quantum groups of rotation Uqso(N)U_qso(N) of RqNR_q^N, for which it has no classical analog.Comment: Latex file, 27 pages. Final version to appear in J. Phys.
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