Martin Hirsch

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0. Introduction. Let M be a finite dimensional Riemann manifold without boundary. Kupka [5], Sacker [9], and others have studied perturbations of a flow or diffeomorphism of M leaving invariant a compact submanifold. Anosov [2] considers perturbations of a nonsingular flow, which of course leaves invariant each leaf of the foliation by trajectories. In both(More)
We prove a general low-energy theorem establishing a generic relation between the neutrino Majorana mass and the superpartner sneutrino B-L-violating ”Majorana”-like mass term. The theorem states that, if one of these two quantities is non-zero the other one is also non-zero and, vice versa, if one of them vanishes the other vanishes, too. The theorem is a(More)
We point out that, if R-parity is broken spontaneously, the neutralino can decay to the final state majoron plus neutrino, which from the experimental point of view is indistinguishable from the standard missing momentum signal of supersymmetry. We identify the regions of parameter space where this decay mode is dominant and show that they are independent(More)
Left-right symmetric models provide a natural framework for neutrinoless double beta (0νββ) decay. In the analysis of 0νββ decay in left-right symmetric models, however, it is usually assumed that all neutrinos are light. On the other hand, heavy right-handed neutrinos appear quite naturally in left-right symmetric models and should therefore not be(More)
Measuring a nonzero value for the cross section of any lepton number violating (LNV) process would put a strong lower limit on the washout factor for the effective lepton number density in the early Universe at times close to the electroweak phase transition and thus would lead to important constraints on any high-scale model for the generation of the(More)
Neutrinoless double beta decay (0νββ) violates lepton number by two units, a positive observation therefore necessarily implies physics beyond the standard model. Here, three possible contributions to 0νββ decay are briefly reviewed: (a) The mass mechanism and its connection to neutrino oscillations; (b) Left-right symmetric models and the lower limit on(More)
The smallness of the observed neutrino masses might have a radiative origin. Here we revisit a specific two-loop model of neutrino mass, independently proposed by Babu and Zee. We point out that current constraints from neutrino data can be used to derive strict lower limits on the branching ratio of flavour changing charged lepton decays, such as μ → eγ.(More)
In models where the breaking of lepton number is spontaneous a massless Goldstone boson, the Majoron (J), appears. We calculate the theoretically allowed range for the branching ratios of Majoron emitting charged lepton decays, such as Br(μ → eJ) and Br(μ → eJγ), in a supersymmetric model with spontaneous breaking of R-parity. Br(μ → eJ) is maximal in the(More)