Journal of High Energy Physics

, 2010:66 | Cite as

Particle collisions on stringy black hole background

  • Shao-Wen Wei
  • Yu-Xiao Liu
  • Hai-Tao Li
  • Feng-Wei Chen


The collision of two particles in the background of a Sen black hole is studied. With the equations of motion of the particles, the center-of-mass energy is investigated when the collision takes place at the horizon of a Sen black hole. For an extremal Sen black hole, we find that the center-of-mass energy will be arbitrarily high with two conditions: (1) spin a ≠ 0 and (2) one of the colliding particles has the critical angular momentum l c = 2. For a nonextremal Sen black hole, we show that, in order to obtain an unlimited center-of-mass energy, one of the colliding particles should have the critical angular momentum l c = 2r +/a (r + is the radius of the outer horizon for a nonextremal black hole). However, a particle with the angular momentum l = l c could not approach the black hole from outside of the horizon through free fall, which implies that the collision with arbitrarily high center-of-mass energy could not take place. Thus, there is an upper bound of the center-of-mass energy for the nonextremal black hole. We also obtain the maximal center-of-mass energy for a near-extremal black hole and the result implies that the Planck-scale energy is hard to be approached. Furthermore, we also consider the back-reaction effects. The result shows that, neglecting the gravitational radiation, it has a weak effect on the center-of-mass energy. However, we argue that the maximum allowed center-of-mass energy will be greatly reduced to below the Planck-scale when the gravitational radiation is included.


Black Holes Classical Theories of Gravity 


  1. [1]
    M. Bañados, J. Silk and S.M. West, Kerr Black Holes as Particle Accelerators to Arbitrarily High Energy, Phys. Rev. Lett. 103 (2009) 111102 [arXiv:0909.0169] [SPIRES].CrossRefADSGoogle Scholar
  2. [2]
    E. Berti, V. Cardoso, L. Gualtieri, F. Pretorius and U. Sperhake, Comment on “Kerr Black Holes as Particle Accelerators to Arbitrarily High Energy”, Phys. Rev. Lett. 103 (2009) 239001 [arXiv:0911.2243] [SPIRES].CrossRefADSGoogle Scholar
  3. [3]
    T. Jacobson and T.P. Sotiriou, Spinning Black Holes as Particle Accelerators, Phys. Rev. Lett. 104 (2010) 021101 [arXiv:0911.3363] [SPIRES].CrossRefADSGoogle Scholar
  4. [4]
    K.S. Thorne, Disk accretion onto a black hole. 2. Evolution of the hole, Astrophys. J. 191 (1974) 507 [SPIRES].CrossRefADSGoogle Scholar
  5. [5]
    K. Lake, Particle Accelerators inside Spinning Black Holes, Phys. Rev. Lett. 104 (2010) 211102 [Erratum ibid. 104 (2010) 259903] [arXiv:1001.5463] [SPIRES].CrossRefADSGoogle Scholar
  6. [6]
    A.A. Grib and Y.V. Pavlov, On Particle Collisions in the Gravitational Field of Black Hole, arXiv:1001.0756 [SPIRES].
  7. [7]
    A.A. Grib and Y.V. Pavlov, On the collisions between particles in the vicinity of rotating black holes, JETP Lett. 92 (2010) 125. CrossRefADSGoogle Scholar
  8. [8]
    A.A. Grib and Y.V. Pavlov, On particle collisions near Kerr’s black holes, arXiv:1007.3222 [SPIRES].
  9. [9]
    O.B. Zaslavskii, Acceleration of particles as universal property of rotating black holes, Phys. Rev. D 82 (2010) 083004 [arXiv:1007.3678] [SPIRES].ADSMathSciNetGoogle Scholar
  10. [10]
    S.-W. Wei, Y.-X. Liu, H. Guo and C.-E. Fu, Charged Spinning Black Holes as Particle Accelerators, Phys. Rev. D 82 (2010) 103005 [arXiv:1006.1056] [SPIRES].ADSGoogle Scholar
  11. [11]
    A.A. Grib and Y.V. Pavlov, On particles collisions near rotating black holes, arXiv:1010.2052 [SPIRES].
  12. [12]
    A. Sen, Rotating charged black hole solution in heterotic string theory, Phys. Rev. Lett. 69 (1992) 1006 [hep-th/9204046] [SPIRES].CrossRefMATHADSMathSciNetGoogle Scholar
  13. [13]
    P.A. Blaga and C. Blaga, Bounded radial geodesics around a Kerr-Sen black hole, Class. Quant. Grav. 18 (2001) 3893 [SPIRES].CrossRefMATHADSMathSciNetGoogle Scholar
  14. [14]
    K. Hioki and U. Miyamoto, Hidden symmetries, null geodesics and photon capture in the Sen black hole, Phys. Rev. D 78 (2008) 044007 [arXiv:0805.3146] [SPIRES].ADSMathSciNetGoogle Scholar
  15. [15]
    T. Houri, D. Kubiznak, C.M. Warnick and Y. Yasui, Generalized hidden symmetries and the Kerr-Sen black hole, JHEP 07 (2010) 055 [arXiv:1004.1032] [SPIRES].CrossRefADSMathSciNetGoogle Scholar

Copyright information

© SISSA, Trieste, Italy 2010

Authors and Affiliations

  • Shao-Wen Wei
    • 1
  • Yu-Xiao Liu
    • 1
  • Hai-Tao Li
    • 1
  • Feng-Wei Chen
    • 1
  1. 1.Institute of Theoretical PhysicsLanzhou UniversityLanzhouP. R. China

Personalised recommendations