Δt-dependent equal-sign dilepton asymmetry and CPTV effects in the symmetry of theB⁰–bar B⁰entangled state

Abstract

In this paper we discuss experimental consequences of a novel kind of CPT violation which would manifest itself in the symmetry of the entangled initial state of B 0 andB 0 through their loss of indistinguishability. The "wrong" symmetry component is proportional to ω. We focus our theoretical study on the ∆t-dependence of observables concerning equal-sign dilepton events for which the intensity vanishes at ∆t = 0 in absence of ω. We find that the charge asymmetry, A sl , acquires a ∆t-dependence linear in ω, whose relative importance appears on specific regions of time still unexplored. We also do a statistical analysis for the measurements here proposed and find a high sensitivity to this new CPT-violating effect in this charge asymmetry. We obtain the first limits on the ω-effect by re-analyzing existing data on the A sl asymmetry.

The signal of ill-defined CPT weakening entanglement in the $${B_d}$$ B d system

“…A deviation of the complex number ω from zero is found at 95% confidence level. This deviation comes essentially from Im (ω) and it represents a measurement of this parameter for the first time; the measurement of Re (ω) does not improve on the value obtained previously [21] from flavour specific decays.…”

“…Previous studies, like [21], exploited the use of two flavour specific decay channels to obtain bounds on Re (ω) (14) shows that, using flavour specific channels alone, there is no sensitivity to Im (ω): since R ± = 0, the terms in Im (ω) would be absent. 6 Fortunately enough, besides addressing the two different time orderings, in [2], one decay is flavour specific (labeled ± ), while the other is CP specific (decays into J/Ψ K S,L , labeled K S,L for short): sensitivity to both Re (ω) and Im (ω) is thus expected.…”

“…This last CPT violation does not invalidate the analysis followed in [8] and, in fact, genuine observables for CPT violation were found with their values obtained from experiment. However, the CPT breaking associated to "ill-defined" particle-antiparticle states modifies the EPR correlation, producing the aforementioned ω-effect [5,20,21]. Treating it in perturbation theory, in such a way that we still talk the language of B 0 d ,B 0 d , the perturbed two-particle state will contain a component of the "wrong" symmetry at the instant of their production by the decay of Υ (4S):…”

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.…”

“…For detailed discussions and results, we refer the interested reader to reference [28], from which we only mention here that one can indeed extract or bound both the real and imaginary parts of ω, as Fig. 3 shows: for the first time for Im (ω), and with less precision than analyses focusing only on flavour specific channels in the case of Re (ω) [27]. …”