arXiv subjects
Publications and source records attributed to Thomas Hambye.
It is known that realistic neutrino masses for neutrino oscillations may be obtained from R parity nonconserving supersymmetry. It is also known that such interactions would erase any preexisting lepton or baryon asymmetry of the Universe because of the inevitable intervention of the electroweak sphalerons. We now show how a crucial subset of these R parity nonconserving terms may in fact create its own successful leptogenesis.
The two-loop Higgs mass upper bounds are reanalyzed. Previous results for a cutoff scale $Λ\approx$ few TeV are found to be too stringent. For $Λ=10^{19}$ GeV we find $M_H < 180 \pm 4\pm 5$ GeV, the first error indicating the theoretical uncertainty, the second error reflecting the experimental uncertainty due to $ m_t = 175 \pm 6 $ GeV. We also summarize the lower bounds on $M_H$. We find that a SM Higgs mass in the range of 160 to 170 GeV will certainly allow for a perturbative and well-behaved SM up to the Planck-mass scale $Λ_{Pl}\simeq 10^{19}$ GeV, with no need for new physics to set in below this scale.
Matching conditions relate couplings to particle masses. We discuss the importance of one-loop matching conditions in Higgs and top-quark sector as well as the choice of the matching scale. We argue for matching scales $μ_{0,t} \simeq m_t$ and $μ_{0,H} \simeq max[ m_t, M_H ]$. Using these results, the two-loop Higgs mass upper bounds are reanalyzed. Previous results for $Λ\approx$ few TeV are found to be too stringent. For $Λ=10^{19}$ GeV we find $M_H < 180 \pm 4\pm 5$ GeV, the first error indicating the theoretical uncertainty, the second error reflecting the experimental uncertainty due to $m_t=175\pm6$ GeV.
Considering the standard model as an effective electroweak theory, in which we have no scalar mass term in the Higgs potential $(μ^2=0)$, we show that the spontaneous symmetry breaking of $SU(2)_L \times U(1)$ can be induced by top loops. The Higgs boson mass obtained is smaller than 300 GeV.