Speaker
Dr
Yury Valdau
(Forschungszentrum Jülich, Institut für Kernphysik)
Description
Time-reversal symmetry is one of the most fundamental symmetries
in nature. CP-violation phenomena, which can be regarded as
equivalent to T-violation provided that CPT is conserved, have been
observed in the $K0$ and $B$ systems. Currently all observed CP
phenomena appear to be consistent with the standard model (SM)
predictions. However, it is well known that in the SM this CP
violation is many orders of magnitude too small to account for the
apparent asymmetry between matter and anti-matter in the Universe.
The current upper limit for (parity-conserving) time-reversal
non-invariance was obtained through measuring the total cross
sections of a polarized neutron beam incident on a Holmium target.
However, the interpretation of such data at a fundamental level is
difficult due to the use of a complex nuclear targets. The
theoretical understanding of measurements with a polarized proton
beam and a deuterium target would certainly be much cleaner.
In order to improve the Holmium limit by an order of magnitude, the
parity-conserving time-reversal violating observable $A_{y,xz}$ in
proton-deuteron forward scattering would have to be measured with an
accuracy of $10^{-6}$. Such a measurement is planned as an internal
target transmission experiment, requiring the use of a polarized
proton beam and a tensor polarized deuterium target. In this
experiment the COSY ring would serve simultaneously as accelerator,
ideal forward spectrometer, and detector.
An openable storage cell and holding magnetic field system have
recently become available at the low beta section of the COSY ring
where the PAX studies are undertaken. Much more stable beam
conditions can be achieved here than elsewhere in the ring. Using the
large acceptance PAX detector system, in addition to performing a
measurement of $A_{y,xz}$, it is also possible to search for
violation of time-reversal invariance in differential observables.
The current status of the preparations for this experiment
will be presented.
Primary author
Dr
Yury Valdau
(Forschungszentrum Jülich, Institut für Kernphysik)
Co-authors
Dr
Dieter Eversheim
(Helmholtz-Institut für Strahlen- und Kernphysik, Nussallee 14-16, 53115 Bonn)
Dr
Frank Rathmann
(Forschungszentrum Jülich, Institut für Kernphysik)
Prof.
Hans Stroeher
(Forschungszentrum Jülich, Institut für Kernphysik)
Prof.
Reinhard Beck
(Helmholtz-Institut für Strahlen- und Kernphysik, Nussallee 14-16, 53115 Bonn)
