Tests of quantum gravity and large extra dimensions models using high energy γ-ray observations

2004 ◽  
Vol 48 (5-6) ◽  
pp. 437-444 ◽  
Author(s):  
F.W Stecker
Keyword(s):  
Quantum Gravity ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
High Energy ◽  
Γ Ray

scholarly journals Physics Beyond The Standard Model: Experimental

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 92-103 ◽  
Author(s):  
R. L. Culbertson
Keyword(s):  
Standard Model ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
High Energy ◽  
Higgs Bosons ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Model Independent

The search for physics beyond the Standard Model includes Technicolor particles, Higgs Bosons, compositeness, many variations of Supersymmetry, large extra dimensions, model-independent searches for anomalies, and other topics. This article reports a subset of these ongoing searches at the high-energy colliders, Tevatron, HERA and LEP.

scholarly journals MIRROR WORLD VERSUS LARGE EXTRA DIMENSIONS

1999 ◽  
Vol 14 (33) ◽  
pp. 2321-2328 ◽  
Author(s):  
Z. K. SILAGADZE
Keyword(s):  
Quantum Gravity ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Branching Ratios ◽  
World Hypothesis ◽  
Mirror Matter

Recently proposed low scale quantum gravity scenario is expected to have a significant impact on the mirror world hypothesis. Some aspects of this influence is investigated here, assuming that the fundamental gravity scale is near a TeV. It is shown that future colliders will be capable of producing the mirror matter, but an experimental signature, which will distinguish such events from the background, is not clear. The "smoking gun" signals of the mirror world would be an observation of decays like [Formula: see text]. But unfortunately the expected branching ratios are very small. Finally, it is shown that a mirror supernova will be quite a spectacular event for our world too, because a considerable amount of ordinary energy is expected to be emitted in the first few seconds.

scholarly journals A PROBLEM IN VIRTUAL GRAVITON EXCHANGES IN FLAT LARGE EXTRA DIMENSIONS

2010 ◽  
Vol 25 (23) ◽  
pp. 4511-4523
Author(s):  
HARUKA NAMATAME
Keyword(s):  
Cross Sections ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
High Energy ◽  
Momentum Conservation ◽  
More Care ◽  
High Energy Collider ◽  
The Cross ◽  
Shell Production ◽  
Kaluza Klein

It is pointed out in a class of models with large extra dimensions that the cross-section of processes with virtual Kaluza–Klein graviton exchanges becomes either much smaller or much larger by many orders of magnitude than what is expected from that of the on-shell production of the Kaluza–Klein gravitons. We demonstrate how the problem arises using a toy model. The cause of this new problem lies in the fact that we do not have momentum conservation in the extra dimensions. To search for the signal of the large extra dimensions with high energy collider experiments, we need more care in interpreting the earlier results on the cross-sections of these processes.

scholarly journals BLACK HOLES IN THEORIES WITH LARGE EXTRA DIMENSIONS: A REVIEW

2004 ◽  
Vol 19 (29) ◽  
pp. 4899-4951 ◽  
Author(s):  
PANAGIOTA KANTI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Life Time ◽  
High Energy ◽  
High Energy Particle ◽  
Radiation Spectra ◽  
Black Hole Background

We start by reviewing the existing literature on the creation of black holes during high-energy particle collisions, both in the absence and in the presence of extra, compact, spacelike dimensions. Then, we discuss in detail the properties of the produced higher-dimensional black holes, namely the horizon radius, temperature and life-time, as well as the physics that governs the evaporation of these objects, through the emission of Hawking radiation. We first study the emission of visible Hawking radiation on the brane: we derive a master equation for the propagation of fields with arbitrary spin in the induced-on-the-brane black hole background, and we review all existing results in the literature for the emission of scalars, fermions and gauge bosons during the spin-down and Schwarzschild phases of the life of the black hole. Both analytical and numerical results for the graybody factors and radiation spectra are reviewed and exact results for the number and type of fields emitted on the brane as a function of the dimensionality of space–time are discussed. We finally study the emission of Hawking radiation in the bulk: graybody factors and radiation spectra are presented for the emission of scalar modes, and the ratio of the missing energy over the visible one is calculated for different values of the number of extra dimensions.

scholarly journals Higher curvature quantum gravity and large extra dimensions

2006 ◽  
Vol 633 (2-3) ◽  
pp. 368-374 ◽  
Author(s):  
Durmuş A. Demir ◽  
Şükrü H. Tanyıldızı
Keyword(s):  
Quantum Gravity ◽  
Extra Dimensions ◽  
Large Extra Dimensions

scholarly journals QUANTITATIVE CALCULATIONS FOR BLACK HOLE PRODUCTION AT THE LARGE HADRON COLLIDER

2009 ◽  
Vol 24 (06) ◽  
pp. 1105-1118
Author(s):  
NICOLAS BOCK ◽  
THOMAS J. HUMANIC
Keyword(s):  
Black Hole ◽  
Large Hadron Collider ◽  
Particle Tracking ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Hadron Collider ◽  
High Energy ◽  
The Other ◽  
Tracking Detector ◽  
Quantitative Calculations

The framework of large extra dimensions provides a way to explain why gravity is weaker than the other forces in nature. A consequence of this model is the possible production of D-dimensional black holes in high energy p–p collisions at the Large Hadron Collider. The present work uses the CATFISH black hole generator to study quantitatively how these events could be observed in the hadronic channel at midrapidity using a particle-tracking detector.

scholarly journals TESTING RELATIVITY AT HIGH ENERGIES USING SPACEBORNE DETECTORS

2007 ◽  
Vol 16 (12b) ◽  
pp. 2343-2355
Author(s):  
F. W. STECKER
Keyword(s):  
Cosmic Rays ◽  
Quantum Gravity ◽  
Background Radiation ◽  
Lorentz Invariance ◽  
Threshold Energy ◽  
High Energy ◽  
Ultrahigh Energy ◽  
Large Extra Dimension ◽  
Γ Ray ◽  
Ultrahigh Energy Cosmic Rays

The Gamma-Ray Large Area Space Telescope (GLAST), to be launched in the fall of 2007, will measure the spectra of distant extragalactic sources of high energy γ-rays, particularly active galactic nuclei and γ-ray bursts. GLAST can look for energy-dependent γ-ray propagation effects from such sources as a signal of Lorentz invariance violation (LIV). These sources should also exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions with low energy photons having a flux level as determined by various astronomical observations. Such annihilations result in electron–positron pair production above a threshold energy given by 2me in the center-of-momentum frame of the system, assuming Lorentz invariance. If Lorentz invariance is violated, this threshold can be significantly raised, changing the predicted absorption turnover in the observed spectrum of the sources. Stecker and Glashow have shown that the existence of such absorption features in the spectra of extragalactic sources puts constraints on LIV. Such constraints have important implications for some quantum gravity and large extra dimension models. Future spaceborne detectors dedicated to measuring γ-ray polarization can look for birefringence effects as a possible signal of loop quantum gravity. As shown by Coleman and Glashow, a much smaller amount of LIV has potential implications for possibly suppressing the "GZK cutoff" predicted to be caused by the interactions of cosmic rays having multijoule energies with photons of the 2.7 K cosmic background radiation in intergalactic space. Owing to the rarity of such ultrahigh energy cosmic rays, their spectra are best studied by a UV-sensitive satellite detector which looks down on a large volume of the Earth's atmosphere to study the nitrogen fluorescence tracks of giant air showers produced by these ultrahigh energy cosmic rays. We discuss here, in particular, a two-satellite mission called OWL, which would be suited for making such studies.

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