146,352 research outputs found
SiZer for time series: A new approach to the analysis of trends
Smoothing methods and SiZer are a useful statistical tool for discovering
statistically significant structure in data. Based on scale space ideas
originally developed in the computer vision literature, SiZer (SIgnificant ZERo
crossing of the derivatives) is a graphical device to assess which observed
features are `really there' and which are just spurious sampling artifacts. In
this paper, we develop SiZer like ideas in time series analysis to address the
important issue of significance of trends. This is not a straightforward
extension, since one data set does not contain the information needed to
distinguish `trend' from `dependence'. A new visualization is proposed, which
shows the statistician the range of trade-offs that are available. Simulation
and real data results illustrate the effectiveness of the method.Comment: Published at http://dx.doi.org/10.1214/07-EJS006 in the Electronic
Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Muon anomalous magnetic moment from effective supersymmetry
We present a detailed analysis on the possible maximal value of the muon
(g-2) (= 2 a_mu) within the context of effective SUSY models with R parity
conservation. First of all, the mixing among the second and the third family
sleptons can contribute at one loop level to the a_mu(SUSY) and tau -> mu gamma
simultaneously. One finds that the a_mu(SUSY) can be as large as (10-20)*10^-10
for any tan beta, imposing the upper limit on the tau -> mu gamma branching
ratio. Furthermore, the two-loop Barr-Zee type contributions to a_mu(SUSY) can
be significant for large tan beta, if a stop is light and mu and A_t are large
enough (O(1) TeV). In this case, it is possible to have a_mu(SUSY) upto
O(10)*10^-10 without conflicting with tau -> l gamma. We conclude that the
possible maximal value for a_mu(SUSY) is about 20*10^-10 for any tan beta.
Therefore the BNL experiment on the muon a_mu can exclude the effective SUSY
models only if the measured deviation is larger than \sim 30*10^-10.Comment: 10 pages, 3 figure
- …