Search results for "PT symmetry"
showing 10 items of 40 documents
A search for neutrino–antineutrino mass inequality by means of sterile neutrino oscillometry
2015
The investigation of the oscillation pattern induced by the sterile neutrinos might determine the oscillation parameters, and at the same time, allow to probe CPT symmetry in the leptonic sector through neutrino-antineutrino mass inequality. We propose to use a large scintillation detector like JUNO or LENA to detect electron neutrinos and electron antineutrinos from MCi electron capture or beta decay sources. Our calculations indicate that such an experiment is realistic and could be performed in parallel to the current research plans for JUNO and RENO. Requiring at least 5$\sigma$ confidence level and assuming the values of the oscillation parameters indicated by the current global fit, w…
Final report on the CERN muon storage ring including the anomalous magnetic moment and the electric dipole moment of the muon, and a direct test of r…
1978
Abstract A comprehensive description of the muon storage ring and its operation is given, and the final results of the experiment are presented and discussed. The anomalous magnetic moments of positive and negative muons are found to be aμ+ = 1165911(11) × 10−9 and aμ− = 1165937(12) × 10−9 giving an average value for muons of aμ = 1165924(8.5) × 10−9. The electric dipole moments were also measured with the results Dμ+= (8.6 ± 4.5) × 10−9e · cm and Dμ− = (0.8 ± 4.3) × 10−19e · cm. Under the assumption of the CPT theorem these yield a weighted average of Dμ = (3.7 ± 3.4) × 10−19e · cm. Finally the time transformation of special relativity is shown to be valid to (0.8 ± 0.7) × 10−3 at γ ≅ 29.3…
Measurements of relativistic time dilatation for positive and negative muons in a circular orbit
1977
The lifetimes of both positive and negative relativistic (γ = 29.33) muons have been measured in the CERN Muon Storage Ring with the results τ+ = 64.419 (58) µs, τ− = 64.368 (29) µs The value for positive muons is in accordance with special relativity and the measured lifetime at rest: the Einstein time dilation factor agrees with experiment with a fractional error of 2×10−3 at 95% confidence. Assuming special relativity, the mean proper lifetime for μ− is found to be τ0− = 2.1948(10) µs the most accurate value reported to date. The agreement of this value with previously measured values of τ0+ confirms CPT invariance for the weak interaction in muon decay.
CP Violation in Correlated Production and Decay of Unstable Particles
2011
We study resonant CP-violating Einstein--Podolsky--Rosen correlations that may take place in the production and decay of unstable scalar particles at high-energy colliders. We show that as a consequence of unitarity and CPT invariance of the S-matrix, in 2 --> 2 scatterings mediated by mixed scalar particles, at least three linearly independent decay matrices associated with the unstable scalar states are needed to obtain non-zero CP-odd observables that are also odd under C-conjugation. Instead, for the correlated production and decay of two unstable particle systems in 2 --> 4 processes, we find that only two independent decay matrices are sufficient to induce a net non-vanishing CP…
A measurement of the phases of the CP-violating amplitudes in K0→2π decays and a test of CPT invariance
1990
Abstract The phases of the CP-violating amplitudes in K0→π+π− and K0→2π0 decays, φ+−=46.9°±2.2° and φ00=47.1°±2.8°, have been measured in the same experiment, and a direct comparison gives the phase difference φ00−φ+−=0.2°±2.9°. This result leads to an upper limit on possible CPT violation in the K0 mass matrix, of |(m K 0 −m K 0 )/m K 0 | −18 at the 95% confidence level and is the most stringent test of the equality of particle and antiparticle masses.
Search for Lorentz and CPT violation using sidereal time dependence of neutrino flavor transitions over a short baseline
2017
A class of extensions of the Standard Model allows Lorentz and CPT violations, which can be identified by the observation of sidereal modulations in the neutrino interaction rate. A search for such modulations was performed using the T2K on-axis near detector. Two complementary methods were used in this study, both of which resulted in no evidence of a signal. Limits on associated Lorentz and CPT-violating terms from the Standard Model extension have been derived by taking into account their correlations in this model for the first time. These results imply such symmetry violations are suppressed by a factor of more than 1020 at the GeV scale.
Tests ofCPTsymmetry inB0−B¯0mixing and inB0→cc¯K0decays
2016
Using the eight time dependences for the decays Upsilon(4S)-> B0 B0bar -> fj fk with the dacay into a flavor-specific state fj = ell+- X before or after the decay into a CP eigenstate fk = c cbar KS,KL, as measured by the BABAR experiment, we determine the three CPT-sensitive parameters Re(z) and Im(z) in B0-B0bar mixing and |Abar/A| in B0 -> c cbar K0 decays. We find Im(z) = 0.010 +- 0.030 +- 0.013, Re(z) = -0.065 +- 0.028 +- 0.014, and |Abar/A| = 0.999 +- 0.023 +- 0.017, in agreement with CPT symmetry.
Precision mass measurements of antiprotons in a Penning trap
1992
Utilizing electron cooling, the TRAP collaboration has lowered the energy at which antiprotons can be stored and studied by more than 10 orders of magnitude, starting with 6 MeV particles from LEAR. We have held cryogenic antiprotons a few degrees above absolute zero for two months and the storage lifetime so established, more than 3.4 months is the longest directly measured limit for antiprotons. Measuring their cyclotron frequencies in a precision cylindrical Penning trap, we have shown that the inertial masses of the antiprotons and protons are the same to a fractional accuracy of 4 parts in 108, a 1000-fold improvement over the previous comparisons. This is the most stringent test of CP…
Novel type of CPT violation for correlated Einstein-Podolsky-Rosen states of neutral mesons.
2004
We discuss modifications to the concept of an "antiparticle," induced by a breakdown of the CPT symmetry at a fundamental level, realized within an extended class of quantum gravity models. The resulting loss of particle-antiparticle identity in the neutral-meson system induces a breaking of the Einstein-Podolsky-Rosen correlation imposed by Bose statistics. This is parametrized by a complex parameter associated with the contamination by the "wrong symmetry" state. The physical consequences are studied, and novel observables of CPT violation in phi factories are proposed.
High-precision comparison of the antiproton-to-proton charge-to-mass ratio
2015
Invariance under the charge, parity, time-reversal (CPT) transformation$^{1}$ is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry—that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime—although it is model dependent$^{2}$. A number of high-precision CPT and Lorentz invariance tests—using a co-magnetometer, a torsion pendulum and a maser, among others—have been performed$^{3}$, but only a few direct high-precision CPT tests …