摘要:

The idea of extra dimensions has always played an important ro⁁le in string theory. However, until recently, most of the interest has been on small extra dimensions. With the introduction of braneworlds, this view has been turned around, and many investigations have been made of incorporating large extra dimensions into string theory. Here I provide a brief survey of how such large dimensions may arise from string theory, and additionally discuss some experimental signatures for extra dimensions. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543496

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We perform a one‐loop test of the holographic interpretation of the Karch‐Randall model, whereby a massive graviton appears on an AdS4brane in an AdS5bulk. Within the AdS/CFT framework, we examine the quantum corrections to the graviton propagator on the brane, and demonstrate that they induce a graviton mass in exact agreement with the Karch‐Randall result. Interestingly enough, at one loop order, the spin 0, spin 1/2 and spin 1 loops contribute to the dynamically generated (mass)2in the same 1 : 3 : 12 ratio as enters the Weyl anomaly and the 1/r3corrections to the Newtonian gravitational potential. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543497

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

It is shown how small Dirac and Majorana masses for neutrinos arise in five dimensional models with warped geometry. The atmospheric and solar neutrino anomalies can be satisfactorily resolved. Rare processes, such as proton decay, neutrinoless double beta decay and flavor violation, may provide valuable information on the higher dimensional theory. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543498

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

What lies beyond the standardSU(3)c×SU(2) ×U(1) model has occupied theorists for almost three decades now. Experimental evidence supporting the presence of new physics has been steadily mounting, especially in recent years. After a brief review I discuss a number of topics including supersymmetric GUTs with intimate connection to inflation and leptogenesis (and with crucial input from neutrino oscillations), extra dimensions, warped geometry, cosmological constant problem, andD‐brane inflation. Supersymmetry and extra dimensions should continue to play an important role in the search for a more fundamental theory. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543499

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Precision distance‐redshift observations can map out the recent expansion history of the universe, including the present acceleration and the transition to matter dominated deceleration. The proposed Supernova/Acceleration Probe (SNAP) will carry out observations determining the components and equations of state of the energy density, providing insights into the cosmological model, the nature of the accelerating dark energy, and potentially clues to fundamental high energy physics theories and gravitation. This includes the ability to distinguish between various dynamical scalar field models for the dark energy, as well as higher dimension and alternate gravity theories. A new, advantageous parametrization for the study of dark energy to high redshift is also presented. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543500

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The possibility to explain the CMB measurement of the baryon asymmetry with leptogenesis results in a stringent bound on neutrino masses such thatm12 + m22 + m32 < 0.30eV. We discuss the implications of such a bound for future experiments on the absolute neutrino mass scale. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543501

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Neutrinos play prominent roles in both particle physics and cosmology. In this talk, I will cover two broad topics. The first will be possible origins for neutrino masses and mixings and the implications of this physics for cosmology. Some non‐cosmological digressions on the flavour problem in general will be made. The second topic will be Big Bang Nucleosynthesis (BBN) and bounds on active‐sterile neutrino mixing. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543502

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A recent revival of interest in synchronised oscillations due to neutrino‐neutrino forward scattering in dense gases has led to two interesting applications with notable outcomes: (i) cosmological bounds on neutrino‐antineutrino asymmetries are improved owing to flavour equilibration prior to the onset of big bang nucleosynthesis, and (ii) a neutron‐rich environment required forr‐process nucleosynthesis is shown to be always maintained in a supernova hot bubble irrespective of flavour oscillations, contrary to results from previous studies. I present in this talk a pedagogical review of these works. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1543503

出版商:AIP    

年代:1903

数据来源: AIP