Unification without low-energy supersymmetry

Without supersymmetry, the gauge couplings in the standard model with five Higgs doublets unify around 10^14 GeV. In this case, the trinified model, SU(3)_C x SU(3)_L x SU(3)_R x Z_3, with the minimal Higgs sector required for symmetry breaking, is the ideal grand-unified candidate. Small neutrino masses are generated via a radiative seesaw mechanism, without the need for intermediate scales, additional Higgs fields, or higher-dimensional operators. The proton lifetime is above the experimental limits, with the decay modes p -> \bar\nu K^+ and p -> mu^+ K^0 potentially observable. The split-SUSY version of the model, with one light Higgs doublet, is equally attractive.Comment: To appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 200

Sterile Neutrinos and Global Symmetries

We use an effective-field-theory approach to construct models with naturally light sterile neutrinos, due to either exact or accidental global symmetries. The most attractive models we find are based on gauge symmetries, either discrete or continuous. We give examples of simple models based on Z_N, U(1)', and SU(2)'.Comment: 8 pages. v2 (as in PRD): minor changes, typos corrected, two refs adde

Higgs at the Tevatron in Extended Supersymmetric Models

Supersymmetric models with an additional singlet field offer the Higgs boson the possibility to decay to two pseudoscalars, a. If the mass of these pseudoscalars is above the b bbar threshold, a -> b bbar is generically the dominant decay mode. The decay h -> a a -> b bbar b bbar may be seen above backgrounds at the Tevatron if the Higgs production cross section is enhanced relative to that of the standard model.Comment: 3 page

Dimension-Five Operators in Grand Unified Theories

Extensions of the standard model with low-energy supersymmetry generically allow baryon- and lepton-number violating operators of dimension four and five, yielding rapid proton decay. The dimension-four operators are usually forbidden by matter parity. We investigate to what extent the appearance of dimension-five operators at the Planck scale may be constrained by the different grand-unified gauge groups. Dimension-five operators are suppressed in models based on E_6 and SU(3)_C x SU(3)_L x SU(3)_R, where four matter fields do not form a gauge singlet. An intermediate scale offers the possibility to sufficiently suppress these dimension-five operators.Comment: 4 pages, v3: version to appear in PR

Higher-dimensional operators in SUSY SO(10) GUT models

SO(10) GUT models with only small Higgs fields use higher-dimensional operators to generate realistic fermion mass matrices. In particular, a Higgs field in the spinor representation, 16^d_H, acquires a weak scale vev. We include the weak vev of the corresponding field \bar{16}^u_H and investigate the effect on two successful models, one by Albright and Barr (AB) and another by Babu, Pati and Wilczek (BPW). We find that the BPW model is a particular case within a class of models with identical fermion masses and mixings. In contrast, we expect corrections to the parameters of AB-type models.Comment: 3 page

Operator Analysis for Proton Decay in SUSY SO(10) GUT Models

Non-renormalizable operators both account for the failure of down quark and charged lepton Yukawa couplings to unify and reduce the proton decay rate via dimension-five operators in minimal SUSY SU(5) GUT. We extend the analysis to SUSY SO(10) GUT models.Comment: Higgs sector clarified, two Refs adde

Naturalness and the Neutrino Matrix

The observed pattern of neutrino mass splittings and mixing angles indicates that their family structure is significantly different from that of the charged fermions. We investigate the implications of these data for the fermion mass matrices in grand unified theories with a type-I seesaw mechanism. We show that, with simple assumptions, naturalness leads to a strongly hierarchical Majorana mass matrix for heavy right-handed neutrinos and a partially cascade form for the Dirac neutrino matrix. We consider various model building scenarios which could alter this conclusion, and discuss their consequences for the construction of a natural model. We find that including partially lopsided matrices can aid us in generating a satisfying model.Comment: Discussion about neutrinoless double beta decay expanded; typos corrected; references added and update

Trinification, the Hierarchy Problem and Inverse Seesaw Neutrino Masses

In minimal trinification models light neutrino masses can be generated via a radiative see-saw mechanism, where the masses of the right-handed neutrinos originate from loops involving Higgs and fermion fields at the unification scale. This mechanism is absent in models aiming at solving or ameliorating the hierarchy problem, such as low-energy supersymmetry, since the large seesaw-scale disappears. In this case, neutrino masses need to be generated via a TeV-scale mechanism. In this paper, we investigate an inverse seesaw mechanism and discuss some phenomenological consequences.Comment: 10 pages, 11 figure

Proton Decay in a Consistent Supersymmetric SU(5) GUT Model

It is widely believed that minimal supersymmetric SU(5) GUTs have been excluded by the SuperKamiokande bound for the proton decay rate. In the minimal model, however, the theoretical prediction assumes unification of Yukawa couplings, Y_d=Y_e, which is known to be badly violated. We analyze the implications of this fact for the proton decay rate. In a consistent SU(5) model with higher dimensional operators, where SU(5) relations among Yukawa couplings hold, the proton decay rate can be several orders of magnitude smaller than the present experimental bound

Vorläufiges Wallnöfer-Werkverzeichnis (WallWV)

Eine chronologisch-systematische Aufstellung sämtlicher Werke des Komponisten Adolf Wallnöfer (1854-1946) unter Angabe ihrer Quellen und Drucklegungsdaten zusammengestellt nach Recherchen im Wallnöfer-Familiennachlass in München, der Städtischen Musikbibliothek München und der Österreichischen Nationalbibliothek in Wien (ÖNB