Escape of superheavy and highly energetic particles produced by particle collisions near maximally charged black holes

Nemoto, Hiroya; Miyamoto, Umpei; Harada, Tomohiro; Kokubu, Takafumi

doi:10.1103/physrevd.87.127502

Cited by 27 publications

(28 citation statements)

References 21 publications

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“…It was shown in [6] (and confirmed by another methods in [7]) that for the Reissner-Nordström black hole the upper limit on the energy of debris of collision does not exist. There also some indications in the favour of unbounded E for geodesics at high inclinations to the equatorial plane of motion [8].…”

Section: Introductionmentioning

confidence: 95%

Unbounded energies of debris from head-on particle collisions near black holes

Заславский

2015

Mod. Phys. Lett. A

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If two particles move toward a black hole and collide near the horizon, the energy E c.m. in the centre of mass can grow unbounded. This is a so-called Bañados-SilkWest (BSW) effect. One of problems creating obstacles to the possibility of its observation consists in that individual energy E of a fragment at infinity remains finite because of redshift. We show that in the case of head-on collision, debris may have unbounded energy E. An essential ingredient of this scenario is a particle moving away from a black hole in the near-horizon region. It can appear due to precedent collision that implies multiple scattering.

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Section: Introductionmentioning

confidence: 95%

Unbounded energies of debris from head-on particle collisions near black holes

Заславский

2015

Mod. Phys. Lett. A

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“…Since the elementary charge is just one order of magnitude short of the Planck mass, they would actually have to be extremely relativistic. This issue was previously noted in [22], and it led the authors to introduce macroscopic objects acting as critical particles, which would make ε ∼ 1 possible (note ε > 1 due to (37)).…”

Section: Energy Feeding Problemmentioning

confidence: 98%

“…Thus, the Schnittman variant again fares better. The problem is actually related to other two caveats for microscopic particles spotted earlier [15,22]. As the energy of (nearly) critical particles is proportional to their charge, the (nearly) critical microscopic particles need to be highly relativistic (i.e.…”

Section: Introduction and Conclusionmentioning

confidence: 99%

Extraction of energy from an extremal rotating electrovacuum black hole: Particle collisions along the axis of symmetry

2019

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High-energy collisions can occur for radially moving charged test particles in the extremal Reissner-Nordström spacetime if one of the particles is fine-tuned and the collision point is taken close to the horizon. This is an analogy of the Bañados-Silk-West (BSW) effect, first described for extremal Kerr black holes. However, it differs significantly in terms of energy extraction: unlike for the original BSW process, no unconditional upper bounds on mass and energy of an escaping test particle produced in the collision were found for the charged version. We show that these results can be replicated for the motion of charged test particles along the axis of a general extremal rotating electrovacuum black hole, also including the Schnittman-type process with reflected fine-tuned particles. This brings the possibility of high-energy extraction closer to astrophysical black holes, which can be fast spinning and have a small "Wald charge" due to interaction with external magnetic fields. Nevertheless, we find numerous caveats that can make the energy extraction unfeasible despite the lack of unconditional kinematic bounds. CONTENTS

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“…All particles are considered in the test approximation, so self-gravitation is neglected. There exists another mechanism of the energy extraction related to the electrically charged particles [26], [27] but we did not discuss it here. How to take into account the effect of self-gravitaiton for particle collision under discussion remains unresolved very interesting problem.…”

Section: Quarks-2016mentioning

confidence: 99%

High energy particle collisions near black holes

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2016

EPJ Web Conf.

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Abstract. If two geodesic particles collide near a rotating black hole, their energy in the centre of mass frame E c.m. can become unbound under certain conditions (the so-called BSW effect). The special role is played here by so-called critical geodesics when one of particles has fine-tuned energy and angular momentum. The nature of geodesics reveals itself also in fate of the debris after collisions. One of particles moving to a remote observer is necessarily near-critical. We discuss, when such a collision can give rise not only unboud E c.m. but also unbound Killing energy E (so-called super-Penrose process).Investigation of high energy collisions of particles near black holes comes back to works [1] - [3]. In recent years, an interest to this issue revived after the observation made by Bañados, Silk and West (the BSW effect, after the names of its authors) that particle collision near the Kerr black hole can lead, under certain additional conditions, to the unbounded growth of the energy in their centre of mass E c.m. [4]. Later on, in a large series of works, this observation was generalized and extended to other objects and scenarios. The energy that appears in the BSW effect is relevant for an observer who is present just near the point of collision in the vicinity of the black hole horizon. Meanwhile, what is especially physically important is the Killing energy E of debris after such a collision measured by an observer at infinity. Strong redshift "eats" significant part of E c.m. , so it was not quite clear in advance, to what extent the energy E may be high. If E exceeds the initial energy of particles, we are faced with the energy extraction from a black hole. This is a so-called collisional Penrose process (the Penrose process that occurs due to particle collisions). Thus there are two related but different issues: (i) investigation of the effect of unbounded E c.m. , (ii) study of properties of E and the question about the maximum possible efficiency of the collisional Penrose process.Consider the generic axially symmetric metric. It can be written asHere, the metric coefficients do not depend on t and φ. On the horizon N = 0. Alternatively, one can use coordinates θ and r, similar to Boyer-Lindquist ones for the Kerr metric, instead of l and z. In (1) we assume that the metric coefficients are even functions of z, so the equatorial plane θ = π 2 (z = 0) is a symmetry one.In the space-time under discussion there are two conserved quantities u 0 ≡ −E and u φ ≡ L where u μ = dx μ dτ is the four-velocity of a test particle, τ is the proper time and x μ = (t, φ, l, z) are coordinates..The aforementioned conserved quantities have the physical meaning of the energy per unit mass (or frequency for a lightlike particle) and azimuthal component of the angular momentum,

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Escape of superheavy and highly energetic particles produced by particle collisions near maximally charged black holes

Cited by 27 publications

References 21 publications

Unbounded energies of debris from head-on particle collisions near black holes

Unbounded energies of debris from head-on particle collisions near black holes

Extraction of energy from an extremal rotating electrovacuum black hole: Particle collisions along the axis of symmetry

High energy particle collisions near black holes

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