DOI: 10.1140/epjc/s2003-01202
How well can we reconstruct the
system
near its threshold at future
e+e- linear colliders?
K. Ikematsu1, K. Fujii2, Z. Hioki3, Y. Sumino4 and T. Takahashi5
1 Department of Physics, Hiroshima University, Higashi Hiroshima 739-8526, Japan
2 IPNS, KEK, Tsukuba 305-0801, Japan
3 Institute of Theoretical Physics, University of Tokushima, Tokushima 770-8502, Japan
4 Department of Physics, Tohoku University, Sendai 980-8578, Japan
5 Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi Hiroshima 739-8530, Japan
ikematsu@post.kek.jp
fujiik@jlcuxf.kek.jp
hioki@ias.tokushima-u.ac.jp
sumino@tuhep.phys.tohoku.ac.jp
tohrut@hiroshima-u.ac.jp
(Received: 4 March 2003 / Published online: 23 May 2003)
Abstract
We developed a new method for the full kinematical reconstruction
of the
system near its threshold
at future linear
e+e- colliders.
In the core of the method lies likelihood fitting
which is designed to improve measurement accuracies
of the kinematical variables that specify the final states
resulting from
decays.
The improvement is demonstrated by applying this method
to a Monte Carlo
sample generated
with various experimental effects including beamstrahlung,
finite acceptance and resolution of the detector system, etc.
In most cases the fit takes a broad non-Gaussian distribution
of a given kinematical variable to a nearly Gaussian shape,
thereby justifying phenomenological analyses
based on simple Gaussian smearing of the parton-level momenta.
The standard deviations of the resultant distributions
of various kinematical variables are given in order to facilitate
such phenomenological analyses.
A possible application of the kinematical fitting method
and its expected impact are also discussed.
© Società Italiana di Fisica, Springer-Verlag 2003
