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SUMMARY:SPACE seminar: Giuseppe Filiberto Vitale\; Sara Rufrano Aliberti
DTSTART:20260707T100000Z
DTEND:20260707T110000Z
DTSTAMP:20260803T015300Z
UID:indico-event-18194@indico.global
DESCRIPTION:Speaker 1: Giuseppe Filiberto Vitale (University of Salerno)\n
 Title 1:  Microscopic Primordial Black Holes as Macroscopic Dark Matter f
 rom Large Extra Dimensions\nAbstract 1: We study the coupled cosmological 
 evolution of primordial black holes (PBHs) and radiation in the Arkani-Ham
 ed-Dimopoulos-Dvali (ADD) framework with $n$ large extra dimensions and a 
 fundamental gravity scale $M_\\star$ at the TeV scale. For PBHs with horiz
 on radius smaller than the compactification scale\,  the higher-dimension
 al geometry implies a larger horizon size at fixed mass and therefore a su
 ppressed Hawking temperature. As a result\, radiation accretion can overco
 me evaporation in the early Universe and drive a "runaway'' phase of rapid
  mass growth. By numerically solving the coupled mass and energy-density e
 volution equations\, we show that for $n \\geq 2$ initially microscopic PB
 Hs with initial mass $M_i \\gtrsim 10^{12}\\\,$g can grow by many orders o
 f magnitude and potentially reach macroscopic\, even solar-mass\, scales b
 y matter-radiation equality. We determine the critical initial abundance $
 \\beta_{\\rm crit}$ required for PBHs to account for the observed dark mat
 ter density and find that extra dimensions dramatically lower this thresho
 ld\, allowing viable scenarios with $\\beta_{\\rm crit}\\sim 10^{-44}$. Th
 is identifies a previously unexplored region of parameter space in which t
 he dark matter abundance is achieved through dynamical mass growth rather 
 than large initial collapse fractions.\nReferences 1:\n\nG.F. Vitale\, G. 
 Lambiase\, T.K. Poddar and L. Visinelli\, arXiv:2604.14871 [astro-ph.CO]\n
 N. Arkani-Hamed\, S. Dimopoulos\, and G.R. Dvali\, Phys. Lett. B 429\, 263
  (1998)\, arXiv:hep-ph/9803315 \nA. Friedlander\, K.J. Mack\, S. Schon\, N
 . Song\, and A.C. Vincent\, Phys. Rev. D 105\, 103508 (2022)\, arXiv:2201.
 11761 [hep-ph]\nB. Nayak and L.P. Singh\, Pramana 76\, 173 (2011)\, arXiv:
 0905.3243 [gr-qc] \n\n -------------------------------------------------
 ------------------------\nSpeaker 2: Sara Rufrano Aliberti (SSM)\nTitle 2:
  Radiation-Reaction Correction to Scattering Binary Dynamics at Next-to-L
 eading Post-Newtonian Order\nAbstract 2: Radiation-reaction force encodes
  dissipative effects in a binary system emitting gravitational waves. With
 in the post-Newtonian framework\, radiation-reaction terms enter the equat
 ions of motion starting at 2.5PN order and affect the system’s dynamics 
 accordingly. These effects can be incorporated as corrections to the quasi
 -Keplerian orbital parameters in the center-of-mass frame. This presentati
 on focuses on the Lagrange method of variation of constants\, which we use
 d to determine the radiation-reaction corrections to the quasi-hyperbolic 
 orbit at 3.5PN order.\nReferences 2:\n\nD. Bini\, A. Geralico\, S. Rufrano
  Aliberti\, “Radiation-reaction correction to scattering binary dynamics
  at the Next-to-Leading Post-Newtonian Order”\, Phys. Rev. D 112\, 10400
 5 (2025)\nB. R. Iyer and C. M. Will\, “Post-Newtonian gravitational radi
 ation reaction for two-body systems: Nonspinning bodies”\, Phys. Rev. D 
 52\, 6882 (1995)\nT. Damour\, “Gravitational Radiation Reaction in the B
 inary Pulsar and the Quadrupole-Formula Controversy”\, Phys. Rev. Lett. 
 51\, 1019 (1983)\nD. Bini\, T. Damour\, A. Geralico\, “Radiated momentum
  and radiation reaction in gravitational two-body scattering including tim
 e-asymmetric effects“\, Phys. Rev. D 107\, 024012 (2023)\n\n------------
 -------------------------------------------------------------\nZoom link:
  click here\n\nhttps://indico.global/event/18194/
LOCATION:Aula 4 (San Marcellino)
URL:https://indico.global/event/18194/
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