A higher dimensional explanation of the excess of Higgs-like events at CERN LEP

Searches for the SM Higgs boson by the four LEP experiments have found a 2.3 sigma excess at 98 GeV and a smaller 1.7 sigma at around 115 GeV. We interpret these excesses as evidence for a Higgs boson coupled to a higher dimensional singlet scalar. The fit implies a relatively low dimensional mixing scale mu_{lhd} < 50 GeV, which explains the low confidence level found for the background fit in the range s^{1/2} > 100 GeV. The data show a slight preference for a five-dimensional over a six-dimensional field. This Higgs boson cannot be seen at the LHC, but can be studied at the ILC.Comment: 9 page

A simple SU(5) model with unification near the Planck scale

We study unification in the SU(5) model with an extra Dirac multiplet in the ${\bf 24}$ representation. After spontaneous symmetry breaking we have at low energies a singlet, a colorless triplet and a neutral color-octet. All other particles can be taken at the unification scale. This combination leads to a unification very near the Planck scale. The triplet is light, its neutral component is a dark matter candidate. The model is in agreement with a recently derived anomaly condition, that implies that the number of (Weyl)-fermions has to be a multiple of 16.Comment: 6 page

Resonance in Strong WW Rescattering in Massive SU(2) Gauge Theory

We investigate the effects of WW rescattering through strong anomalous four-vector boson couplings. In the I=1, J=1 channel, we find a resonance with a mass of approximately 200 GeV and a width of less than 12 GeV. In an application to pion physics we find a small correction to the KSRF relation.Comment: 21 pages, extended discussion, some minor change

A flat space-time model of the Universe

We propose a model of the Universe based on Minkowski flat space-time metric. In this model the space-time does not evolve. Instead the matter evolves such that all the mass parameters increase with time. We construct a model based on unimodular gravity to show how this can be accomplished within the framework of flat space-time. We show that the model predicts the Hubble law if the masses increase with time. Furthermore we show that it fits the high z supernova data in a manner almost identical to the standard Big Bang model. Furthermore we show that at early times the Universe is dominated by radiative energy density. The phenomenon of recombination also arises in our model and hence predicts the existence of CMBR. However a major difference with the standard Big Bang is that the radiative temperature and energy density does not evolve in our model. Furthermore we argue that the basic motivation for inflation is absent in our model.Comment: 11 pages, no figures, changes in presentatio

Gravitational anomaly and fundamental forces

I present an argument, based on the topology of the universe, why there are three generations of fermions. The argument implies a preferred gauge group of SU(5), but with SO(10) representations of the fermions. The breaking pattern SU(5) to SU(3)xSU(2)xU(1) is preferred over the pattern SU(5) to SU(4)xU(1). On the basis of the argument one expects an asymmetry in the early universe microwave data, which might have been detected already.Comment: Contribution to the 2nd School and Workshop on Quantum Gravity and Quantum Geometry. Corfu, september 13-20 2009. 10 page

Natural Z′Z' model with an inverse seesaw and leptonic dark matter

We consider a model for a Z'-boson coupled only to baryon minus lepton number and hypercharge. Besides the usual right-handed neutrinos, we add a pair of fermions with a fractional lepton charge, which we therefore call leptinos. One of the leptinos is taken to be odd under an additional Z_2 charge, the other even. This allows for a natural (inverse) seesaw mechanism for neutrino masses. The odd leptino is a candidate for dark matter, but has to be resonantly annihilated by the Z'-boson or the Higgs-boson responsible for giving mass to the former. Considering collider and cosmological bounds on the model, we find that the Z'-boson and/or the extra Higgs-boson can be seen at the LHC. With more pairs of leptinos leptogenesis is possible.Comment: 29 pages, 9 figures. RGE section moved to appendix and other minor corrections applied to matched published versio

Non--decoupling, triviality and the ρ\rho parameter

The dependence of the $\rho$ parameter on the mass of the Higgs scalar and the top quark is computed non--perturbatively using the $1/N_F$ expansion in the standard model. We find an explicit expression for the $\rho$ parameter that requires the presence of a physical cutoff. This should come as no surprise since the theory is presumably trivial. By taking this cutoff into account, we find that the $\rho$ parameter can take values only within a limited range and has finite ambiguities that are suppressed by inverse powers of the cutoff scale, the so called ``scaling--violations". We find that large deviations from the perturbative results are possible, but only when the cutoff effects are also large.Comment: 16pp, Figures NOT included, harvmac, minor modifications incl. wording, refs., UCLA/92/TEP/23,OHSTPY-HEP-T-92-00

Bounding CKM Mixing with a Fourth Family

CKM mixing between third family quarks and a possible fourth family is constrained by global fits to the precision electroweak data. The dominant constraint is from nondecoupling oblique corrections rather than the Zbb vertex correction used in previous analyses. The possibility of large mixing suggested by some recent analyses of FCNC processes is excluded, but 3-4 mixing of the same order as the Cabbibo mixing of the first two families is allowed.Comment: 16 pages, 3 figures: added references, minor revision

The process gg -> WW as a background to the Higgs signal at the LHC

The production of W pairs from the one-loop gluon fusion process is studied. Formulas are presented for the helicity amplitudes keeping the top mass finite, but all other quark masses zero. The correlations among the leptons coming from the W bosons are kept. The contribution of this background to the Higgs boson search in the WW decay mode at the LHC is estimated by applying the cuts foreseen in experimental searches using the PYTHIA Monte Carlo program. Kinematic distributions for the final state leptons are compared to those of the Higgs boson signal and of the q qbar -> WW background. After applying final cuts, the gg background is found to be large, at the level of 35% of the q qbar background.The characteristics of the gg background are very similar to those of the signal. Therefore, an experimental normalization of this background component appears to be very difficult and the uncertainty must largely be determined by theory. As a result, the significance of a Higgs signal in the gg -> H -> WW mode at the LHC is reduced.Comment: 24 pages, 4 figure