Grand Unification without Higgs Bosons

We discuss how a model for the electroweak interactions without a Higgs could be embedded into a grand unified theory. The requirement of a non-trivial fixed point in the SU(2) sector of the weak interactions together with the requirement of the numerical unification of the gauge couplings leads to a prediction for the value of the SU(2) gauge coupling in the fixed point regime. The fixed point regime must be in the TeV region to solve the unitarity problem in the elastic scattering of W bosons. We find that the unification scale is at about 10^{14} GeV. Viable grand unified theories must thus conserve baryon number. We discuss how to build such a model without using Higgs bosons.Comment: 8 pages, to be published in the proceedings devoted to the Scientific and Human Legacy of Julius Wess, initiated by the JW2011 Workshop, August 27 - 28, 2011, Donji Milanovac, Serbi

Unitarity bounds on low scale quantum gravity

We study the unitarity of models with low scale quantum gravity both in four dimensions and in models with a large extra-dimensional volume. We find that models with low scale quantum gravity have problems with unitarity below the scale at which gravity becomes strong. An important consequence of our work is that their first signal at the Large Hadron Collider would not be of a gravitational nature such as graviton emission or small black holes, but rather linked to the mechanism which fixes the unitarity problem. We also study models with scalar fields with non minimal couplings to the Ricci scalar. We consider the strength of gravity in these models and study the consequences for inflation models with non-minimally coupled scalar fields. We show that a single scalar field with a large non-minimal coupling can lower the Planck mass in the TeV region. In that model, it is possible to lower the scale at which gravity becomes strong down to 14 TeV without violating unitarity below that scale.Comment: 15 page

One-particle inclusive CP asymmetries

One-particle inclusive CP asymmetries in the decays of the type B -> D(*) X are considered in the framework of a QCD based method to calculate the rates for one-particle inclusive decays.Comment: Latex, 13 pages, 6 figures (eps). Analytical and numerical results unchanged, extended discussion of model assumptions and systematic uncertainties. Version to be published in Phys. Rev. D 62, 0960xx. Additional transparencies are available via the WWW at http://www-ttp.physik.uni-karlsruhe.de/Slides

Non-locality in quantum field theory due to general relativity

We show that general relativity coupled to a quantum field theory generically leads to non-local effects in the matter sector. These non-local effects can be described by non-local higher dimensional operators which remarkably have an approximate shift symmetry. When applied to inflationary models, our results imply that small non-Gaussianities are a generic feature of models based on general relativity coupled to matter fields. However, these effects are too small to be observable in the cosmic microwave background

The Standard Model on Non-Commutative Space-Time

We consider the Standard Model on a non-commutative space and expand the action in the non-commutativity parameter theta. No new particles are introduced, the structure group is SU(3) x SU(2) x U(1). We derive the leading order action. At zeroth order the action coincides with the ordinary Standard Model. At leading order in theta we find new vertices which are absent in the Standard Model on commutative space-time. The most striking features are couplings between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the NCSM to the order considered.Comment: 28 pages, v3: typos corrected, new appendix on alternative kinetic terms for gauge bosons; v4: typos correcte

A Time Variation of Proton-Electron Mass Ratio and Grand Unification

Astrophysical observations indicate a time variation of the proton-electron mass ratio and of the fine-structure constant. We discuss this phenomenon in models of Grand Unification. In these models a time variation of the fine-structure constant and of the proton mass are expected, if either the unified coupling constant or the scale of unification changes, or both change. We discuss in particular the change of the proton mass. Experiments in Quantum Optics could be done to check these ideas.Comment: 5 page

The weak angle gamma from one-particle inclusive CP asymmetries in the B(s) system

We compute CP asymmetries of one-particle inclusive B(s) --> D(s) X decay rates. We find that the weak angle gamma could in principle be extracted from these asymmetries although they are very small. Taking the decay width difference into account, we find that the time integrated CP asymmetries are of the order A=1.4 10^(-4) sin(gamma). Some large uncertainties remain due to the lack of experimental data.Comment: 12 page

Three waves for quantum gravity

Using effective field theoretical methods, we show that besides the already observed gravitational waves, quantum gravity predicts two further massive classical fields leading to two new massive waves. We set a limit on the masses of these new modes using data from the E¨ot-Wash experiment. We point out that the existence of these new states is a model independent prediction of quantum gravity. We then explain how these new classical fields could impact astrophysical processes and in particular the binary inspirals of neutron stars or black holes. We calculate the emission rate of these new states in binary inspirals astrophysical processes

Spontaneous Symmetry Breaking through Mixing

We discuss a model, in which the negative mass square needed in the Higgs mechanism is generated by mixing with a heavy scalar. We have two scalar doublets in the standard model. Phenomenological properties of the heavy new scalar are discussed. The heavy scalar can be detected by the LHC.Comment: 4 page