MSSM-inspired multifield inflation

Despite the fact that experimentally with a high degree of statistical significance only a single Standard Model--like Higgs boson is discovered at the LHC, extended Higgs sectors with multiple scalar fields not excluded by combined fits of the data are more preferable theoretically for internally consistent realistic models of particle physics. We analyze the inflationary scenarios which could be induced by the two-Higgs doublet potential of the Minimal Supersymmetric Standard Model (MSSM) where five scalar fields have nonminimal couplings to gravity. Observables following from such MSSM-inspired multifield inflation are calculated and a number of consistent inflationary scenarios are constructed. Cosmological evolution with different initial conditions for the multifield system leads to consequences fully compatible with observational data on the spectral index and the tensor-to-scalar ratio. It is demonstrated that the strong coupling approximation is precise enough to describe such inflationary scenarios.Comment: 27 pages, 4 figures, 5 tables. Version to appear in JHEP. Additions made to the text of the Introduction dealing with the issues of conformity of this multifield model and models of N=1 supergravity (pages 2-3). Added new inflationary scenarios, which are an artifact of such analysis (pages 11-12, Tables 1-4). Additional comments on page 9 and page 13. New references adde

High Pressure studies of the magnetic phase transition in MnSi: revisited

New measurements of AC magnetic susceptibility and DC resistivity of a high quality single crystal MnSi were carried out at high pressure making use of helium as a pressure medium. The form of the AC magnetic susceptibility curves at the magnetic phase transition suddenly changes upon helium solidification. This implies strong sensitivity of magnetic properties of MnSi to non hydrostatic stresses and suggests that the early claims on the existence of a tricritical point at the phase transition line are probably a result of misinterpretation of the experimental data. At the same time resistivity behavior at the phase transition does not show such a significant influence of helium solidification. The sharp peak at the temperature derivative of resistivity, signifying the first order nature of the phase transition in MnSi successfully survived helium crystallization and continued the same way to the highest pressure.Comment: 4 pages, 6 figure