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We study high speed collision and reconnection of cosmic strings in the type-II regime (scalar-to-gauge mass ratios larger than one) of the Abelian Higgs model. New phenomena such as multiple reconnections and clustering of small scale structure have been observed and reported in a previous paper, as well as the fact that the previously observed loop that mediates the second intercommutation is only a loop for sufficiently large beta = m_scalar^2/m_gauge^2. Here we give a more detailed account of our study, involving 3D numerical simulations with beta in the range 1 to 64, the largest value simulated to date, as well as 2D simulations of vortex-antivortex (v-av) collisions to understand the possible relation to the new 3D phenomena. Our simulations give further support to the idea that Abelian Higgs strings never pass through each other, unless this is the result of a double reconnection; and that the critical velocity (v_c) for double reconnection goes down with increasing mass ratio, but energy conservation suggests a lower bound around 0.77c. We discuss the qualitative change in the intermediate state observed for large mass ratios. We relate it to a similar change in the outcome of 2D v-av collisions in the form of radiating bound states. In the deep type-II regime the angular dependence of v_c for double reconnection does not seem to conform to semi-analytic predictions based on the Nambu-Goto approximation. We model the high angle collisions reasonably well by incorporating the effect of core interactions, and the torque they produce on the approaching strings, into the Nambu-Goto description of the collision. An interesting, counterintuitive aspect is that the effective collision angle is smaller because of the torque. Our results suggest differences in network evolution and radiation output with respect to the predictions based on Nambu-Goto or beta = 1 Abelian Higgs dynamics.
We discuss dual formulations of vortex strings (magnetic flux tubes) in the four-dimensional ${cal N} =1$ supersymmetric Abelian Higgs model with the Fayet--Iliopoulos term in the superspace formalism. The Lagrangian of the model is dualized into a L
We study field theoretical models for cosmic strings with flat directions in curved space-time. More precisely, we consider minimal models with semilocal, axionic and tachyonic strings, respectively. In flat space-time, the string solutions of these
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The Higgs could couple to a topological 4-form sector which yields a complex vacuum structure. In general such couplings could lead to direct CP violation in the Higgs sector. In many of the Higgs vacua electroweak symmetry is unbroken. In just as ma
We summarize previous results on the most general Proca theory in 4 dimensions containing only first-order derivatives in the vector field (second-order at most in the associated Stuckelberg scalar) and having only three propagating degrees of freedo