scholarly journals Black hole with a scalar field as a particle accelerator

2017 ◽  
Vol 26 (10) ◽  
pp. 1750108 ◽  
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Center Of Mass ◽  
High Energy ◽  
Particle Accelerator ◽  
Particle Collision ◽  
Axially Symmetric ◽  
Speed Of Light ◽  
Test Particles ◽  
Energy Formula

We consider stationary axially symmetric black holes with the background scalar field and test particles that can interact with this field directly. Then, particle collision near a black hole can lead to the unbounded energy [Formula: see text] in the center of mass frame (contrary to some recent claims in literature). This happens always if one of the particles is neutral whereas another one has nonzero scalar charge. Kinematically, two cases occur here. (i) A neutral particle approaches the horizon with the speed of light while the velocity of the charged one remains separated from it (this is direct analogue of the situation with collision of geodesic particles.). (ii) Both particles approach the horizon with the speed almost equal to that of light but with different rates. As a result, in both cases the relative velocity also approaches the speed of light, so that [Formula: see text] becomes unbounded. We consider also a case when the metric coefficient [Formula: see text] near a black hole. Then, overlap between the geometric factor and the presence of the scalar field opens additional scenarios in which unbounded energy [Formula: see text] is possible as well. We give a full list of possible scenarios of high-energy collisions for the situations considered.

scholarly journals Spinning dilaton black hole in 2 + 1 dimensions as a particle accelerator

2017 ◽  
Vol 32 (13) ◽  
pp. 1750074 ◽  
Author(s):  
Sharmanthie Fernando
Keyword(s):  
Black Hole ◽  
String Theory ◽  
Center Of Mass ◽  
Low Energy ◽  
Particle Accelerator ◽  
Particle Collision ◽  
Dilaton Black Hole

In this paper, we have studied particle collision around a spinning dilaton black hole in 2 + 1 dimensions. This black hole is a solution to the low-energy string theory in 2 + 1 dimensions. Time-like geodesics are presented in detail and the center-of-mass (CM) energy of two-particle collision at the horizon of a spinning black hole is considered. We noticed that there is a possibility of the two masses to create infinite CM energy.

scholarly journals High-energy collision of particles in the magnetic field far from black holes

2014 ◽  
Vol 29 (29) ◽  
pp. 1450151
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Center Of Mass ◽  
High Energy ◽  
Axially Symmetric ◽  
High Energy Collision ◽  
Mass Frame ◽  
Symmetric Black Hole ◽  
Rotating Star ◽  
The Magnetic Field

We consider collision of two particles in the axially symmetric black hole metric in the magnetic field. If the value of the angular momentum |L| of one particles grows unbound (but its Killing energy remains fixed) one can achieve unbound energy in the center-of-mass frame E c.m. In the absence of the magnetic field, collision of this kind is known to happen in the ergoregion. However, if the magnetic field strength B is also large, with the ratio |L|/B being finite, large E c.m. can be achieved even far from a black hole, in the almost flat region. Such an effect also occurs in the metric of a rotating star.

scholarly journals Particles collision near Kerr–Sen Dilaton-Axion black hole

2019 ◽  
Vol 35 (07) ◽  
pp. 2050033 ◽  
Author(s):  
Ujjal Debnath
Keyword(s):  
Black Hole ◽  
Effective Potential ◽  
Circular Orbit ◽  
Center Of Mass ◽  
Particle Accelerator ◽  
Cauchy Horizon ◽  
Mass Energy ◽  
Axially Symmetric ◽  
Neutral Particles ◽  
Center Of Mass Energy

Here, we consider axially symmetric, stationary, rotating and charged Kerr–Sen Dilaton-Axion black hole as particle accelerator. We find the effective potential and discuss the circular orbit of a particle. We investigate the center of mass energy of two colliding neutral particles with different rest masses falling from rest at infinity to near the non-extremal horizons (event horizon and Cauchy horizon) and extremal horizon of the Kerr–Sen Dilaton-Axion black hole. Analogous to the Compton process, we discuss the collision of a particle and a massless photon. Finally, we find the center of mass energy due to the collision of two photons in the background of Kerr–Sen Dilaton-Axion black hole.

scholarly journals High energy particle collisions and geometry of horizon

2016 ◽  
Vol 25 (10) ◽  
pp. 1650095 ◽  
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Black Hole ◽  
Center Of Mass ◽  
Naked Singularity ◽  
High Energy ◽  
Fine Tuning ◽  
High Energy Particle ◽  
Axially Symmetric ◽  
Particle Collisions ◽  
Material Source ◽  
Mass Frame

We consider collision of two geodesic particles near the lightlike surface (black hole horizon or naked singularity) of such an axially symmetric rotating or static metric that the coefficient [Formula: see text] on this surface. It is shown that the energy in the center of mass frame [Formula: see text] is indefinitely large even without fine-tuning of particles’ parameters. Kinematically, this is the collision between two rapid particles that approach the horizon almost with the speed of light but at different angles (or they align along the normal to the horizon too slowly). The latter is the reason why the relative velocity tends to that of light, hence to high [Formula: see text]. Our approach is model-independent. It relies on general properties of geometry and is insensitive to the details of material source that supports the geometries of the type under consideration. For several particular models (the stringy black hole, the Brans–Dicke analogue of the Schwarzschild metric and the Janis–Newman–Winicour one) we recover the results found in literature previously.

Acoustic black hole in 2 + 1 dimensions as a particle accelerator

2019 ◽  
Vol 35 (08) ◽  
pp. 2050042
Author(s):  
Sharmanthie Fernando
Keyword(s):  
Black Hole ◽  
Fluid Flow ◽  
Center Of Mass ◽  
Particle Accelerator ◽  
Fine Tuning ◽  
Particle Collision ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Infinite Center

In this paper, we have studied particle collision around a rotating acoustic black hole in 2 + 1 dimensions. This black hole is analog to a fluid flow in a draining bath tub with a sink. Center of mass energy for two-particle collision at the horizon of the rotating acoustic black hole is considered. There is a possibility of the two-mass collision to create infinite center of mass energy for certain fine tuning of the parameters of the theory.

Single production of vector-like top partner in the Wb channel at eγ collision in the LHT model

2019 ◽  
Vol 34 (18) ◽  
pp. 1950093
Author(s):  
Guang Yang ◽  
Bingfang Yang ◽  
Biaofeng Hou ◽  
Hengheng Bi
Keyword(s):  
Search Strategy ◽  
Center Of Mass ◽  
High Energy ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Energy Formula ◽  
Single Production ◽  
Detector Simulation ◽  
Higgs Data ◽  
Integrated Luminosity

In the framework of the littlest Higgs Model with T-parity (LHT), we investigate the single production of vector-like top partner [Formula: see text] decaying to [Formula: see text] in the leptonic channel at the high energy [Formula: see text] collision. We utilize the polarized electron beam and photon beam to enhance the signal and propose a search strategy by performing a detector simulation. On the basis of the current limits from the precision electroweak data and Higgs data, we find that the top partner mass can be excluded up to 1350 (1380) GeV with integrated luminosity of 1000 fb[Formula: see text] and 1400 (1470) GeV with integrated luminosity of 3000 fb[Formula: see text] for the [Formula: see text] TeV (2.4 TeV) at the [Formula: see text] level. If the center-of-mass energy can be improved to 3.0 TeV, the limits on the top partner mass will reach 1450 (1550) GeV with integrated luminosities of 1000 (3000) fb[Formula: see text].

scholarly journals DISCUSSION ON SOME CHARACTERISTICS OF CHARGED BRANE-WORLD BLACK HOLES

2009 ◽  
Vol 24 (04) ◽  
pp. 719-739 ◽  
Author(s):  
M. KALAM ◽  
F. RAHAMAN ◽  
A. GHOSH ◽  
B. RAYCHAUDHURI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Field ◽  
Scalar Field ◽  
Brane World ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Effective Potentials ◽  
Test Particles ◽  
Jacobi Formalism

Several physical natures of charged brane-world black holes are investigated. Firstly, the timelike and null geodesics of the charged brane-world black holes are presented. We also analyze all the possible motions by plotting the effective potentials for various parameters for circular and radial geodesics. Secondly, we investigate the motion of test particles in the gravitational field of the charged brane-world black holes using the Hamilton–Jacobi formalism. We consider charged and uncharged test particles and examine their behavior in both static and nonstatic cases. Thirdly, the thermodynamics of the charged brane-world black holes are studied. Finally, it is shown that there is no phenomenon of superradiance for an incident massless scalar field for such a black hole.

scholarly journals Geodesic motion near self-gravitating scalar field configurations

2019 ◽  
Vol 27 (3) ◽  
pp. 231-241
Author(s):  
Ivan M. Potashov ◽  
Julia V. Tchemarina ◽  
Alexander N. Tsirulev
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Circular Orbit ◽  
Naked Singularity ◽  
Schwarzschild Black Hole ◽  
Null Geodesics ◽  
Naked Singularities ◽  
Test Particles ◽  
Stable Circular Orbit ◽  
Innermost Stable Circular Orbit

We study the geodesics motion of neutral test particles in the static spherically symmetric spacetimes of black holes and naked singularities supported by a selfgravitating real scalar field. The scalar field is supposed to model dark matter surrounding some strongly gravitating object such as the centre of our Galaxy. The behaviour of timelike and null geodesics very close to the centre of such a configuration crucially depends on the type of spacetime. It turns out that a scalar field black hole, analogously to a Schwarzschild black hole, has the innermost stable circular orbit and the (unstable) photon sphere, but their radii are always less than the corresponding ones for the Schwarzschild black hole of the same mass; moreover, these radii can be arbitrarily small. In contrast, a scalar field naked singularity has neither the innermost stable circular orbit nor the photon sphere. Instead, such a configuration has a spherical shell of test particles surrounding its origin and remaining in quasistatic equilibrium all the time. We also show that the characteristic properties of null geodesics near the centres of a scalar field naked singularity and a scalar field black hole of the same mass are qualitatively different.

scholarly journals Particle acceleration and the origin of the very high energy emission around black holes and relativistic jets

2020 ◽  
Vol 14 (S342) ◽  
pp. 13-18
Author(s):  
Elisabete M. de Gouveia Dal Pino ◽  
Grzegorz Kowal ◽  
Luis Kadowaki ◽  
Tania E. Medina-Torrejón ◽  
Yosuke Mizuno ◽  
...  
Keyword(s):  
Black Hole ◽  
Particle Acceleration ◽  
Magnetic Reconnection ◽  
High Energy ◽  
Black Hole Binaries ◽  
Mhd Instabilities ◽  
Test Particles ◽  
Very High Energy ◽  
General Relativistic ◽  
Very High

AbstractParticle acceleration induced by fast magnetic reconnection may help to solve current puzzles related to the interpretation of the very high energy (VHE) and neutrino emissions from AGNs and compact sources in general. Our general relativistic-MHD simulations of accretion disk-corona systems reveal the growth of turbulence driven by MHD instabilities that lead to the development of fast magnetic reconnection in the corona. In addition, our simulations of relativistic MHD jets reveal the formation of several sites of fast reconnection induced by current-driven kink turbulence. The injection of thousands of test particles in these regions causes acceleration up to energies of several PeVs, thus demonstrating the ability of this process to accelerate particles and produce VHE and neutrino emission, specially in blazars. Finally, we discuss how reconnection can also explain the observed VHE luminosity-black hole mass correlation, involving hundreds of non-blazar sources like Perseus A, and black hole binaries.

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