119771181
Double beta decay, supersymmetry and lepton number violation
Neutrinoless double beta (0νββ) decay violates lepton number and is therefore a sensitive probe of physics beyond the standard model. Limits from 0νββ decay are usually expressed in terms of limits on the Majorana neutrino mass, the best experiment now giving 〈mν〉 ≤ 0.5 eV. However, in supersymmetric extensions of the SM there can be other sources of lepton number violation than the neutrino mass, the best-known example being RP-violation. 0νββ decay provides the most stringent limits on certain Rp MSSM parameters, ruling out first generation squarks as a possible explanation of the recent HERA high Q2-events. Furthermore, current low-energy constraints on and future collider phenomenology of (B − L) violating sneutrino masses are discussed. As has been proven recently such a (B − L) violating sneutrino mass is a necessary ingredient of any supersymmetric model with finite Majorana neutrino masses.
35525710
Phenomenology of neutrinoless double beta decay
Neutrinoless double beta decay ( 0 ν β β ) violates lepton number by two units, a positive observation therefore necessarily implies physics beyond the standard model. Here, three possible contributions to 0 ν β β decay are briefly reviewed: (a) The mass mechanism and its connection to neutrino oscillations; (b) Left-right symmetric models and the lower limit on the right-handed W boson mass; and (c) R-parity violating supersymmetry. In addition, the recently published “extended black box” theorem is briefly discussed. Combined with data from oscillation experiments this theorem provides proof that the 0 ν β β decay amplitude must receive a non-zero contribution from the mass mechanism, if neutrinos are indeed Majorana particles.
53701384
Enhancing $l_i 3 l_j$ with the $Z^0$-penguin
Lepton flavor violation (LFV) has been observed in neutrino oscillations. For charged lepton FV decays only upper limits are known, but sizable branching ratios are expected in many neutrino mass models. High scale models, such as the classical supersymmetric seesaw, usually predict that decays $l_i \to 3 l_j$ are roughly a factor $\alpha$ maller than the corresponding decays $l_i \to l_j \gamma$. Here we demonstrate that the $Z^0$-penguin diagram can give an enhancement for decays $l_i \to 3 l_j$ in many extensions of the MSSM. We first discuss why the $Z^0$-penguin is not dominant in the MSSM with seesaw and show that much larger contributions from the $Z^0$-penguin are expected in general. We then demonstrate the effect numerically in two example models, namely, the supersymmetric inverse seesaw and R-parity violating supersymmetry.
11803420
Majoron emission in muon and tau decays revisited
9 pages, 4 figures.-- ISI article identifier:000264762400078.-- ArXiv pre-print avaible at: http://arxiv.org/abs/0902.0525
53865432
Hefty MSSM-like light Higgs in extended gauge models
A bstractIt is well known that in the MSSM the lightest neutral Higgs h0 must be, at the tree level, lighter than the Z boson and that the loop corrections shift this stringent upper bound up to about 130 GeV. Extending the MSSM gauge group in a suitable way, the new Higgs sector dynamics can push the tree-level mass of h0 well above the tree-level MSSM limit if it couples to the new gauge sector. This effect is further pronounced at the loop level and h0 masses in the 140GeV ballpark can be reached easily. We exemplify this for a sample setting with a low-scale U(1)R × U(1)B−L gauge symmetry in which neutrino masses can be implemented via the inverse seesaw mechanism.
119290526
Probing a supersymmetric model for neutrino masses at ultrahigh energy neutrino telescopes
Abstract A bilinear R-parity breaking SUSY model for neutrino mass and mixing predicts the lightest superparticle to decay mainly into a pair of tau leptons or b quarks along with a neutrino for relatively light SUSY spectra. This leads to a distinctive triple bang signature of SUSY events at ultrahigh energy neutrino telescopes like IceCube or Antares. While the expected signal size is only marginal at IceCube, it will be promising for a future multi-km 3 size neutrino telescope.
118354862
Maximizing Kepler science return per telemetered pixel: Searching the habitable zones of the brightest stars 1
In today's mailing, Hogg et al. propose image modeling techniques to maintain 10-ppm-level precision photometry in Kepler data with only two working reaction wheels. While these results are relevant to many scientific goals for the repurposed mission, all modeling efforts so far have used a toy model of the Kepler telescope. Because the two-wheel performance of Kepler remains to be determined, we advocate for the consideration of an alternate strategy for a >1 year program that maximizes the science return from the "low-torque" fields across the ecliptic plane. Assuming we can reach the precision of the original Kepler mission, we expect to detect 800 new planet candidates in the first year of such a mission. Our proposed strategy has benefits for transit timing variation and transit duration variation studies, especially when considered in concert with the future TESS mission. We also expect to help address the first key science goal of Kepler: the frequency of planets in the habitable zone as a function of spectral type.