Signatures of microscopic black holes and extra dimensions at future neutrino telescopes

Abstract

In scenarios with large extra dimensions (LEDs), the fundamental Planck scale can be low enough that collisions between high-energy particles may produce microscopic black holes. High-energy cosmic neutrinos can carry energies much larger than a PeV, opening the door to a higher energy range than Earth-based colliders. Here, for the first time, we identify a number of unique signatures of microscopic black holes as they would appear in the next generation of large-scale neutrino observatories such as IceCube-Gen2 and the Pacific Ocean Neutrino Explorer. These signatures include new event topologies, energy distributions, and unusual ratios of hadronic-to-electronic energy deposition, visible through Cherenkov light echos due to delayed neutron recombination. We find that the next generation of neutrino telescopes can probe LEDs with a Planck scale up to 6 TeV, though the identification of unique topologies could push their reach even further. I. INTRODUCTIONAmong the diverse signatures of new physics above the TeV scale, the possibility of producing microscopic black holes in particle collisions remains one of the most alluring. In models with Large Extra Dimensions (LEDs), the large hierarchy between gravity and the electroweak scales can be at least partly explained by confining the Standard Model (SM) gauge interactions to a 3+1-dimensional brane, while allowing gravity to "leak" into one or more extra bulk dimensions [1][2][3][4][5][6]. This allows a true Planck scale M that can be much lower than the observed M P l ∼ 10 18 GeV. Such scenarios have been tested extensively in terms of gravitational force tests [7], supernova and neutron star cooling [8,9], and in collider experiments [10,11]. If only one LED exists, Solar System-scale modifications of Newtonian gravity [1] prohibit a TeV-scale Planck mass. However, two or more LEDs remain allowed by observation. Current constraints limit the scale M to be above about 3 -25 TeV [7][8][9][10][11][12], depending on the number of extra dimensions.A vastly-reduced Planck scale also allows for the creation of microscopic black holes (BHs) in the collision between two high-energy particles with centre of mass (CM) energy E CM M , a smoking gun signature of extra dimensions. The hoop conjecture [13] tells us that a black hole will form if the impact parameter b between two colliding particles is smaller than twice the horizon radius r H of a black hole with mass M • = E CM . This has mainly been studied in the context of high-energy colliders [14][15][16][17][18][19][20][21][22][23][24][25][26] by searching for the high-multiplicity signature from rapid Hawking evaporation [27]. The reach of collider experiments is limited by the finite CM collision energy. Cosmic accelerators thus provide an alluring alternative, as high-energy cosmic rays can reach much higher momenta. This has been known for some time, and extensive studies have been performed on the production of BHs in air showers [28][29][30][31][32][33][34][35], particularly if they are observed with energies a...

Hawking-radiation recoil of microscopic black holes

“…The only possible evidence could be from very short gamma-ray bursts as discussed in [17], unless the radiation process took place before the recombination era. The recoil effect on ordinary microscopic black holes in the context of extra spatial dimensions has been discussed in [18,19].…”

Primordial Black Hole Dark Matter in the Context of Extra Dimensions

“…While the instantaneous changes in flux due to these processes are described by Eqs. (40) and (41) separately, it is convenient to combine them into one term that accounts for the total effect.…”

“…We neglect the mass loss in the formation stage and assume the minimum black hole mass M min = M . For discussions see Ref [41]. and the reference therein.…”

Probing New Physics at Future Tau Neutrino Telescopes

“…Furthermore, the Ice-Cube events up to PeV energies have been used to constrain the neutrino cross section for the first time at a center-of-mass (COM) energy as high as ∼ 1 TeV for the neutrino-proton collision [31][32][33]. Besides verifying the SM predictions, UHE neutrino telescopes are also good facilities to probe certain new physics scenarios beyond the SM [34,35]: test of equivalence principle and Lorentz invariance [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54], unitarity [55][56][57], fifth forces [58], microscopic black holes [59][60][61][62][63][64][65][66][67][68][69][70], monopoles [71][72][73][74][75], neutrino transition magnetic moment [76,…”