Novel Type ofCPTViolation for Correlated Einstein-Podolsky-Rosen States of Neutral Mesons

Abstract

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 EPR correlation imposed by Bose statistics. The latter is parametrized by a complex parameter controlling the amount of contamination by the "wrong" symmetry state. The physical consequences are studied, and novel observables of CPT-violation in φ factories are proposed.PACS numbers: 11.30.Er; 13.25.Es; 03.65.UdThe CPT theorem is one of the most profound results of quantum field theory [1]. It is a consequence of Lorentz invariance, locality, as well as quantum mechanics (specifically unitary evolution of a system). One implication of CPT invariance is the equality of the masses between particles and antiparticles. In this respect, the best experimental tests of the CPT symmetry so far have been in the neutral Kaon system, where the equality of particle -antiparticle masses has been confirmed to better than one part in 10 17 [2]. However, this is not the end of the story, given that CPT violation may manifest itself in many subtle ways, thus motivating further experimental searches in various directions.The possibility of a violation of CPT invariance has been considered in a number of theoretical contexts that go beyond conventional local quantum field theory. In several models of quantum gravity (QG), for example, the axioms of quantum field theory, as well as conventional quantum mechanical behaviour, may not be maintained [3] in the presence of special field configurations, such as wormholes, microscopic (Planck size) black holes, and other topologically non-trivial solitonic objects, such as geons [4]. Such configurations are collectively referred to as space time foam, a terminology coined by J.A. Wheeler [5], who first conceived the idea that the structure of quantum space-time at Planckian scales (10 −35 m) may actually be fuzzy, characterised by a "foamy" nature. Given that such "objects" cannot be accessible to low-energy observers, it has been argued that a mixed state description must be employed (QG-induced decoherence) [3,6], "tracing" over them in the context of an effective field theory. In the case of microscopic black holes, for example, the decoherence arises due to the loss of information across microscopic event horizons, leading to complications in defining proper asymptotic statevectors and thus a Heisenberg scattering matrix. As a corollary of this, it has been argued [7] that, in general, CPT invariance in its strong form must be abandoned in quantum gravity. Since in such models the breakdown of the CPT symmetry happens at a fundamental level, it would imply that a proper CPT operator is ill defined. This in turn would lead to possible deviations from standard quantum mechanical evolution of states [8], which may not be necessarily associated with the mass difference between particle and antipar...

The fundamental symmetries in the neutral kaon system—a pedagogical choice

“…Some examples are: (i) the quantum-mechanical result for the correlation among two distant particles in an entangled state, rather than a weaker correlation limited by the assumption of Local Realism [110][111][112], (ii) the perturbation expansion of the Schrödinger equation [113,114] leading to the two dimensional spinor representation with the exponential decay law, (iii) the unitarity relations [115], (iv) the complementarity of CP parity and strangeness [116][117][118], (v) that the K 0 and the K 0 from φ decay are exact CPT conjugates [84], (vi) the conservation of the purity of states of isolated particles, manifested by the long time coherence of the kaon matter wave [65,66]. On the last subject, data from the CPLEAR Collaboration in combination with earlier data from the CERN-HEIDELBERG Collaboration achieve a sensitivity of ≈ 10 −21 GeV.…”

“…The authors of [84] point out that ω = 0 for the kaons in φ → K 0 K 0 represents a novel kind of CPT violation.…”

Probing violations of CPT with $B_d$ mesons

“…The CPT breaking associated to ill-defined particle-antiparticle states modifies the EPR correlation and produces the ω-effect [25][26][27]. Treating it perturbatively, i.e.…”

Quantum Gravity, CPT symmetry and entangled states

“…with A(X, Y ) the appropriate Φ decay amplitude [10], where one of the Kaon products decays to the final state X at t 1 and the other to the final state Y at time t 2 (with t = 0 the moment of the Φ decay). It must be noticed that in Kaon factories there is a particularly good channel, the one with bi-pion states π + π − as final decay products, which enhances the sensitivity to the ω-effect by three orders of magnitude.…”