Recent work by Jenkins and Sakellariadou claims that cusps on cosmic strings lead to black hole production.
To derive this conclusion they use the hoop conjecture in the rest frame of the string loop, rather than in the rest frame of the proposed black hole.
Most of the energy they include is the bulk motion of the string near the cusp.
We redo the analysis taking this into account and find that cusps on cosmic strings with realistic energy scale do not produce black holes, unless the cusp parameters are extremely fine-tuned.
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Similar
R. R. Caldwell and Paul Casper, “Formation of black holes from collapsed cosmic string loops,” Phys. Rev. D53
1996
Cited alongside, same era.
J. J. Blanco-Pillado and Ken D. Olum, “The Form of cosmic string cusps,” Phys. Rev. D59
1999
Cited alongside, same era.
R. N. Hansen, M. Christensen, and A. L. Larsen, “Cosmic string loops collapsing to black holes,” Int. J. Mod. Phys. A15