Higgs potential in a minimal S3 invariant extension of the standard model

金沢大学大学院自然科学研究科物理学金沢大学理学部Minimal S3 invariant Higgs potential with real soft S 3 breaking masses is investigated. It is required that without having a problem with triviality, all physical Higgs bosons, except one neutral one, become heavy ≳ 10 TeV in order to sufficiently suppress flavor-changing neutral currents. There exist three nonequivalent soft mass terms that can be characterized according to their discrete symmetries, and the one that breaks S3 completely. The S2′ invariant vacuum expectation values (VEVs) of the Higgs fields are the most economic VEVs in the sense that the freedom of VEVs can be completely absorbed into the Yukawa couplings so that it is possible to derive, without referring to the details of the VEVs, the most general form for the fermion mass matrices in minimal S3 extension of the standard model. We find that except for the completely broken case of the soft terms, the S2′ invariant VEVs are unique VEVs that satisfy the requirement of heavy Higgs bosons. It is found that they also correspond to a local minimum in the completely broken case. ©2004 The American Physical Society

Peripheral Blood as a Preferable Source of Stem Cells for Salvage Transplantation in Patients with Graft Failure after Cord Blood Transplantation: A Retrospective Analysis of the Registry Data of the Japanese Society for Hematopoietic Cell Transplantation

To compare the different stem cell sources used in salvage transplantation for graft failure (GF) after cord blood transplantation (CBT), we retrospectively analyzed data of 220 patients who developed GF after undergoing CBT between January 2001 and December 2007 and underwent a second hematopoietic stem cell transplantation (HSCT) within 3 months. The donor sources for salvage HSCT were cord blood (n = 180), peripheral blood stem cells (PBSCs; n = 24), and bone marrow (BM; n = 16). The cumulative incidence of neutrophil engraftment on day 30 after the second HSCT was 39% with CB, 71% with PBSCs, and 75% with BM. Multivariate analysis revealed that PBSC and BM grafts were associated with a significantly higher engraftment rate than CB (hazard ratio [HR], 7.77; P < .001 and HR, 2.81; P = .016, respectively). Although the incidence of grade II-IV acute graft-versus-host disease was significantly higher in the PBSC group than in the CB group (HR, 2.83; P = .011), the incidence of 1-year nonrelapse mortality was lower in the PBSC group than in the CB group (HR, 0.43; P = .019), and 1-year overall survival was superior in the PBSC group compared with the CB group (HR, 0.45; P = .036). Our results suggest that PBSC is the preferable source of stem cells in salvage HSCT for GF after CBT