Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Estimating the Final Spin of Binary Black Holes Merger in STU
  Supergravity   In this paper, we adopt the so-called Buonanno-Kidder-Lehner (BKL) recipe to
estimate the final spin of a rotating binary black hole merger in STU
supergravity. According to the BKL recipe, the final spin can be viewed as the
sum of the individual spins plus the orbital angular momentum of the binary
system which could be approximated as the angular momentum of a test particle
orbiting at the innermost stable circular orbit around the final black hole.
Unlike previous works, we consider the contribution of the orbital angular
momentum of the binary system to the final spin by requiring the test particle
to preserve the scaling symmetry in the Lagrangian of supergravity. We find
some subtle differences between two cases corresponding to whether the symmetry
is taken into account or not. In the equal initial spin configuration, when the
initial black holes are non-spinning, the final spin of the merger is always
larger than that in the case in which the symmetry is not imposed although the
general behaviors are similar. The difference increases firstly and then
decreases as the initial mass ratio approaches unity. Besides, as the initial
spins exceed a threshold, the final spin is always smaller than that in the
case where the scaling symmetry is not considered. The difference decreases
constantly as the equal initial mass limit is approached. All these features
exist in the merger of a binary STU black hole with different charge
configurations. We also study the final spin's difference between different
charge configurations and different initial spin configurations.

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The categories of this paper are: acc-phys
3
The categories of this paper are: physics
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: plasm-ph