arXiv subjects

Hitoshi Murayama

Publications and source records attributed to Hitoshi Murayama.

292 records · Page 17Linked to original sources

arXiv1994

Probing Symmetry-Breaking Pattern Using Sfermion Masses

We study the mass spectrum of superparticles within supersymmetric grand unified models. For gaugino masses, it is pointed out that the GUT-relation in the $SU(5)$ model is applicable to a more general case where a grand-unified gauge group breaks down to the standard model gauge group by several steps. We also show that the mass spectrum of squarks and sleptons carries the information on the breaking pattern of the gauge symmetry. It is demonstrated in some $SO(10)$ models how the scalar mass spectrum distinguishes various $SO(10)$ breaking patterns from each other.

hep-ph↗

arXiv1993

Chaotic Inflation and Baryogenesis in Supergravity

We propose a Kähler potential in supergravity which successfully accommodates chaotic inflation. This model can have a large gravitino mass without giving a large mass to squarks and sleptons, and thus is free from both the gravitino problem and entropy crisis. In this model baryogenesis takes place naturally, identifying the inflaton with a right-handed sneutrino with its mass $M \simeq 10^{13}$GeV, which is consistent with the COBE data and the Mikheyev--Smirnov--Wolfenstein solution to the solar neutrino problem. The model can also accommodate the matter content appropriate for the mixed dark matter scenario.

hep-ph↗

arXiv1993

Leptogenesis in Supersymmetric Standard Model with Right-handed Neutrino

We show that the leptogenesis is automatic within the supersymmetric standard model if there exist right-handed neutrinos with mass less than $H_{\it inf}$, the expansion rate during the inflation. Its scalar component grows during the inflation due to the quantum fluctuation, oscillates coherently after the inflation, and its decay generates lepton asymmetry. The scenario is naturally embedded into $SO(10)$ GUT without any modifications. We also discuss the case with heavier right-handed neutrino.

hep-ph↗

arXiv1993

The Weinberg Angle Without Grand Unification

We assume that strong and electroweak interactions become strong at very high energies. With this assumption, we compute the low-energy gauge coupling constants $α_i (m_Z)$ as a function of the cutoff scale, taking the supersymmetric standard model with $3+2n$ families of quark and lepton multiplets. We find that only the five family case $(n=1)$ is consistent with the experimental values of the gauge coupling constants. This suggests the presence of a pair of families at $\sim 1$~TeV.

hep-ph↗