Projects / Programmes
Search for microscopic black hole signatures with ultra-high energy cosmic rays
| Code |
Science |
Field |
Subfield |
| 1.02.06 |
Natural sciences and mathematics |
Physics |
Experimental physics of elementary particles |
| Code |
Science |
Field |
| P210 |
Natural sciences and mathematics |
Elementary particle physics, quantum field theory |
| Code |
Science |
Field |
| 1.03 |
Natural Sciences |
Physical sciences |
cosmic rays, microscopic black holes, extreme energies, hadronization
Researchers (9)
Organisations (2)
Abstract
Microscopic Black holes, Shower Simulations and UHECR at the Pierre Auger Observatory
Over the last couple of years, with the Large Hadron Collider (LHC) in the spotlight, the possibility of microscopic black-hole (MBH) production received significant media coverage. During this same time frame the Pierre Auger Observatory (PAO) in Argentina was collecting data on the extended air showers (EAS) produced by ultra-high-energy cosmic ray (UHECR) interactions in the Earth's atmosphere, corresponding to center of mass collision energies at least 10 times greater than those of the LHC. A thorough investigation of MBH creation in this context, taking advantage of both a direct access to the data accumulated at PAO with increasing statistics, and the latest progress in our understanding of MBH formation and evaporation processes as well as of the evolution of their decay products, is the main subject of this proposal. A theoretical and data-based analysis will be carried out, with the aim of quantifying the possibility that MBHs have been created and observed by PAO detectors. Alternatively, this research project could produce significant lower bounds on the mass of such MBHs and consequently also on the possible size of extra space-time dimensions.
This proposal aims to balance the current asymmetry between the improved statistics of PAO and the few and now outdated analyses of MBHs in UHECR physics by updating the theoretical calculations for BH forming collisions and the subsequent shower creation, and then performing a direct search and analysis of signatures in the UHECR data collected at the PAO. These studies will also be greatly aided by recent results from the search for MBHs at LHC.
The foundation of all studies on MBH creation is the hoop conjecture. This conjecture is based on the simple and solid physical principle that, in theories with gravitational interactions described by Einstein's general theory of relativity, a MBH will form when the mass inside a volume is greater than the mass of a BH the horizon of which could surround that volume. Accordingly, the actual collision of two particles is expected to create a MBH when the impact parameter is smaller than the radius of a Schwarzschild BH with mass bounded by the total collision energy. Actually, there have been several numerical analyses of the non-linear equations of General Relativity that provide strong support for the hoop conjecture. If the fundamental scale of gravity is of the order of TeV, as predicted by theories with large/warped extra dimensions, collisions with small impact parameters occurring at such (or higher) center of mass energies, may satisfy the premise of this conjecture and thus give rise to MBHs.
We plan to estimate the differences in the EAS development from black-hole decay arising from the use of different models in all stages of the simulation. We will also provide quantitative predictions on the extent to which the onset of a MBH intermediate stage can modify the properties of cosmic EASs in terms of final detectable particles. Possible consequences of limits and uncertainties on theoretical quantities, like the MBH production cross-section or the MBH minimal mass, can be studied by comparing theoretical predictions with PAO data. We plan to conduct specific analyses on the shower data sets, in particular the fluorescence detector data (for the characterization of the electromagnetic component of EAS) and the ground array data (for muon studies), to finally set limits on possible extra dimensions that could have allowed formation of MBHs by TeV scale gravitational interactions. In the course of this project we also aim to shed light on various anomalies that have been noticed in the data from PAO and that cannot be explained in the framework of the current standard theoretical picture of extremely high energy particle collisions that neglect gravitational effects.
Significance for science
The project with the goal to investigate production and decay of microscopic black holes (MBH) at the highest energies achievable in collisions between ultra-high energy cosmic rays (UHECR) and the Earth's atmosphere (several 10's of times higher than the projected final energies of the LHC collider) was at the forefront of the global physics endeavors in fundamental science. It is a fact that ultra high energy cosmic rays are the most energetic particles in nature, and that collisions at those energies may with present technologies never be achievable in man-made particle colliders. Experimental analysis of UHECR data collected by the Pierre Auger Observatory may be more difficult than that for data collected at accelerators, however at present we have this data (which well surpasses even the future LHC capabilities) on hand for detailed analysis and interpretation. A confirmation of the existence of experimental signatures of MBH creation and decay would be revolutionary and a possibility of tackling this problem is therefore extremely appealing. As an example, the consequences of MBH creation in particle collisions would be the existence of extra dimensional space-time where all the fundamental interactions (including gravity) take place and in which our 4-dmensional space-time is only a sub-space. Such a discovery would have a great impact on science in general, and in particular on particle physics, astro(particle) physics and cosmology. Furthermore, the project was strongly integrated in the global research endeavor at the forefront of physics, with competent partners from the USA, Brazil and EU countries, including Slovenia. The collaboration with our partners from Germany, France, Portugal, Brazil and Slovenia, who are among the largest contributors to the P. Auger project was predominantly experimental, and the collaboration with the US and Swiss partners was mostly of theoretical nature.
Significance for the country
Direct impact of the project on the economy and society was executed through the transfer of knowledge and state-of-the-art technologies, developed for use at the Pierre Auger Observatory (PAO), to Slovenia for public service use, a task in which we have been actively pursuing since our initial involvement with PAO. As a direct spin-off of the basic research at PAO (characterization of the atmosphere as the main detector media using Lidar technology, timing of the ground detector array using GPS signals) the Laboratory for Astroparticle Physics of the University of Nova Gorica (together with its Center for Atmospheric Research and the Slovenian Environmental Agency) constructed the first lidar observatory site in Slovenia at Otlica, which among others successfully tracked and characterized Icelandic volcanic ash in 2010 Eyjafjallajökull eruption. We independently developed a Raman lidar system for the remote profiling of water vapor concentrations in the atmosphere, and in collaboration with the Slovenian companies Optotech and Fotona we have also developed a mobile lidar for aerosol tracking and identification. We are also investigating the impact of ionospheric perturbations on GPS and the posibilities of their mitigation, which may be of considerable importance in the times of the coming solar maximum. All these devices provide not only scientific results but also results with a broader impact on society. These activities were expanded and intensfied in the scope of this project and will lead to scientific and other contributions of Slovenia to the construction of the Cherenkov Telescope Array observatory (CTA). As an indirect impact of the project on society we highlight the active and competitive participation of Slovenian researchers and students in these leading-edge global research activities; success of this and other such projects will help ensure the recognition of Slovenia as a high technology oriented country, which would further stimulate and promote international scientific, economical and financial cooperation. The project also facilitatated the transfer of knowledge at the leading edge of current global research activities and state-of-the art technology into Slovenia, and in particular, provided a deeper insight into the description of fundamental interactions that govern our world, including gravity. Project results brought indirect benefits on many levels of social activities, including on a cultural level and a technological level, as a profound understanding of nature inevitably leads to the development of tools beneficial to the society and the humankind as a whole.
Most important scientific results
Annual report
2013,
2014,
2015,
final report
Most important socioeconomically and culturally relevant results
Annual report
2013,
2014,
2015,
final report
