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| Identifier |
000388329 |
| Title |
Radiation in ultraplanckian particle collisions |
| Alternative Title |
Ακτινοβολία σε συγκρούσεις σωματιδίων Ν/ενέργειας μεγαλύτερης της ενέργειας του Planck |
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Author
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Κωνσταντίνου, Γιάννης
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Thesis advisor
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Τομαράς, Θεόδωρος
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Reviewer
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Πέτκου, Αναστάσιος
Τσάμης, Νικόλαος
Κοφινάς, Γεώργιος
Τούμπας, Νικόλαος
Κυρίτσης, Ηλίας
Παυλίδου, Βασιλική
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| Abstract |
We employ a perturbative scheme to study classical bremsstrahlung of a massless scalar field Φ and a massless vector field in gravity mediated ultra-relativistic collisions with impact parameter b of two massive point particles in the presence of d non-compact or toroidal extra dimensions. The spectral and angular distribution of the scalar and vector radiation are analyzed, while the total radiated energy is found to be it strongly enhanced by a d-dependent power of the Lorentz factor γ. The local radiation amplitude from the accelerated particles is shown to interfere destructively (in the first two leading ultra-relativistic orders) with the non-local amplitude in the frequency regime γ/b≤ω≤γ^2/b in all dimensions.
The same collision is studied for massless particles boosted to the speed of light in flat four-dimensions using essentially the same perturbative scheme. The corrections to the energy momentum tensor and to the metric are computed to second order and closed form formulas are provided. This includes the back-reaction on the metric after the collision. Including such corrections suggests that the tracelessness of the initial stress tensors of the colliding articles is preserved during and after the collision. The necessity for introducing an impact parameter in the perturbative treatment is highlighted and the breaking of the underlying perturbative approach at b=0 is motivated. In addition, the energy radiated in the form of gravitational bremsstrahlung radiation is discussed while an example from gravitational-waves collision is being studied.
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| Language |
English |
| Subject |
Black holes |
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Classical theories of gravity |
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Large extra dimensions |
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Κλασσικές θεωρίες βαρύτητας |
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Μαύρες Τρύπες |
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Μεγάλες επιπλέον διαστάσεις |
| Issue date |
2014-11-24 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
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Type of Work--Doctoral theses
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| Views |
770 |
Radiation in ultraplanckian particle collisions
