+-------+-------------------+
| tau   | R Documentation   |
+-------+-------------------+

Tau Particle Decay Modes
------------------------

Description
~~~~~~~~~~~

The ``tau`` data frame has 60 rows and 2 columns.

The tau particle is a heavy electron-like particle discovered in the
1970's by Martin Perl at the Stanford Linear Accelerator Center. Soon
after its production the tau particle decays into various collections of
more stable particles. About 86% of the time the decay involves just one
charged particle. This rate has been measured independently 13 times.

The one-charged-particle event is made up of four major modes of decay
as well as a collection of other events. The four main types of decay
are denoted rho, pi, e and mu. These rates have been measured
independently 6, 7, 14 and 19 times respectively. Due to physical
constraints each experiment can only estimate the composite
one-charged-particle decay rate or the rate of one of the major modes of
decay.

Each experiment consists of a major research project involving many
years work. One of the goals of the experiments was to estimate the rate
of decay due to events other than the four main modes of decay. These
are uncertain events and so cannot themselves be observed directly.

Usage
~~~~~

::

    tau

Format
~~~~~~

This data frame contains the following columns:

``rate``
    The decay rate expressed as a percentage.

``decay``
    The type of decay measured in the experiment. It is a factor with
    levels ``1``, ``rho``, ``pi``, ``e`` and ``mu``.

Source
~~~~~~

The data were obtained from

Efron, B. (1992) Jackknife-after-bootstrap standard errors and influence
functions (with Discussion). *Journal of the Royal Statistical Society,
B*, **54**, 83â€“127.

References
~~~~~~~~~~

Davison, A.C. and Hinkley, D.V. (1997) *Bootstrap Methods and Their
Application*. Cambridge University Press.

Hayes, K.G., Perl, M.L. and Efron, B. (1989) Application of the
bootstrap statistical method to the tau-decay-mode problem. *Physical
Review, D*, **39**, 274-279.
