16,590 research outputs found
Radiation damage effects on detectors and eletronic devices in harsh radiation environment
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
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
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
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 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 3 and 2 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
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
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
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
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