Limit on Nuclear Time-Reversal-Invariance Violation from the Neutron Electric Dipole Moment

1972 ◽  
Vol 5 (5) ◽  
pp. 1228-1231 ◽  
Author(s):  
D. J. Broadhurst
1999 ◽  
Vol 08 (06) ◽  
pp. 513-526 ◽  
Author(s):  
WILLEM T. H. VAN OERS

Time-reversal-invariance non-conservation has for the first time been unequivocally demonstrated in a direct measurement at CPLEAR. One then can ask the question: What about tests of time-reversal-invariance in systems other than the kaon system? Tests of time-reversal-invariance can be distinguished as belonging to two classes: the first one deals with parity violating (P-odd)/time-reversal-invariance-odd (T-odd) interactions, while the second one deals with P-even/T-odd interactions (assuming CPT conservation this implies C-conjugation non-conservation). Limits on a P-odd/T-odd interaction follow from measurements of the electric dipole moment of the neutron (with a present upper limit of 6 × 10-26 e.cm [95% C.L.]). It provides a limit on a P-odd/T-odd pion-nucleon coupling constant which is less than 10-4 times the weak interaction strength. Experimental limits on a P-even/T-odd interaction are much less stringent. Following the standard approach of describing the nucleon-nucleon interaction in terms of meson exchanges it can be shown that only charged rho-meson exchange and A 1-meson exchange can lead to a P-even/T-odd interaction. The better constraints stem from measurements of the electric dipole moment of the neutron and from measurements of charge-symmetry breaking in neutron-proton elastic scattering. The latter experiments were executed at TRIUMF (497 and 347 MeV) and at IUCF (183 MeV). Weak decay experiments may provide limits which will possibly be comparable. All other experiments, like gamma decay experiments, detailed balance experiments, polarization–analyzing power difference determinations, and five-fold correlation experiments with polarized incident nucleons and aligned nuclear targets, have been shown to be at least an order of magnitude less sensitive. The question then emerges: is there room for further experimentation?


2021 ◽  
Vol 103 (5) ◽  
Author(s):  
C. Alexandrou ◽  
A. Athenodorou ◽  
K. Hadjiyiannakou ◽  
A. Todaro

2008 ◽  
Vol 23 (25) ◽  
pp. 2085-2091 ◽  
Author(s):  
EZEQUIEL ÁLVAREZ ◽  
ALEJANDRO SZYNKMAN

In this letter we reinterpret and reanalyze the available data of the B-meson factories showing the existence of direct experimental evidence of time reversal invariance violation in B-mesons. This reinterpretation consists of using the available observables to define a new observable which, in a model-independent way and without assuming CPT invariance, compares a transition between a B0 and a here-defined Bα-state, with its time reversed transition. The observable then offers a direct way to probe time reversal invariance and it is therefore independent of any conclusion obtained from current experimental information on CP violation and CPT invariance. As far as we are concerned, this is the first direct evidence of time reversal invariance violation in B-mesons and also the first one obtained from decaying particles whose mean lifetime difference is negligible.


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