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Bevan, A. J. et al, Martinez-Vidal, F., Pich, A., Azzolini, V., Bernabeu, J., Lopez-March, N., et al. (2014). The Physics of the B Factories. Eur. Phys. J. C, 74(11), 3026–916pp.
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Bernabeu, J., & Navarro-Salas, J. (2019). A Non-Local Action for Electrodynamics: Duality Symmetry and the Aharonov-Bohm Effect, Revisited. Symmetry-Basel, 11(10), 1191–13pp.
Abstract: A non-local action functional for electrodynamics depending on the electric and magnetic fields, instead of potentials, has been proposed in the literature. In this work we elaborate and improve this proposal. We also use this formalism to confront the electric-magnetic duality symmetry of the electromagnetic field and the Aharonov-Bohm effect, two subtle aspects of electrodynamics that we examine in a novel way. We show how the former can be derived from the simple harmonic oscillator character of vacuum electrodynamics, while also demonstrating how the magnetic version of the latter naturally arises in an explicitly non-local manner.
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BABAR Collaboration(Lees, J. P. et al), Bernabeu, J., Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2012). Observation of Time-Reversal Violation in the B-0 Meson System. Phys. Rev. Lett., 109(21), 211801–8pp.
Abstract: Although CP violation in the B meson system has been well established by the B factories, there has been no direct observation of time-reversal violation. The decays of entangled neutral B mesons into definite flavor states (B-0 or (B) over bar (0)), and J/psi K-L(0) or c (c) over barK(S)(0) final states (referred to as B+ or B-), allow comparisons between the probabilities of four pairs of T-conjugated transitions, for example, (B) over bar (0) -> B- and B- -> (B) over bar (0), as a function of the time difference between the two B decays. Using 468 X 10(6) B (B) over bar pairs produced in Y(4S) decays collected by the BABAR detector at SLAC, we measure T-violating parameters in the time evolution of neutral B mesons, yielding Delta S-T(+) = -137 +/- 0.14(stat) +/- 0.06(syst) and Delta S-T(-) = 1.17 +/- 0.18(stat) +/- 0.11(syst). These nonzero results represent the first direct observation of T violation through the exchange of initial and final states in transitions that can only be connected by a T-symmetry transformation.
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Helling, C. et al, Bernabeu, J., Lacasta, C., & Solaz, C. (2020). Strip sensor performance in prototype modules built for ATLAS ITk. Nucl. Instrum. Methods Phys. Res. A, 978, 164402–6pp.
Abstract: ATLAS experiment is preparing an upgrade of its detector for High-Luminosity LHC (HL-LHC) operation. The upgrade involves installation of the new all-silicon Inner Tracker (ITk). In the context of the ITk preparations, more than 80 strip modules were built with prototype barrel sensors. They were tested with electrical readout on a per-channel basis. In general, an excellent performance was observed, consistent with previous ASIC-level and sensor-level tests. However, the lessons learned included two phenomena important for the future phases of the project. First was the need to store and test the modules in a dry environment due to humidity sensitivity of the sensors. The second was an observation of high noise regions for 2 modules. The high noise regions were tested further in several ways, including monitoring the performance as a function of time and bias voltage. Additionally, direct sensor-level tests were performed on the affected channels. The inter-strip resistance and bias resistance tests showed low values, indicating a temporary loss of the inter-strip isolation. A subsequent recovery of the noise performance was observed. We present the test details, an analysis of how the inter-strip isolation affects the module noise, and the relationship with sensor-level quality control tests.
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Bernabeu, J., Botella, F. J., Nebot, M., & Segarra, A. (2022). B-0 – (B)over-bar(0) entanglement for an ideal experiment for the direct CP violation phi(3)/gamma phase. Phys. Rev. D, 106(5), 054026–7pp.
Abstract: B-0-(B) over bar0 entanglement offers a conceptual alternative to the single charged B-decay asymmetry for the measurement of the direct CP-violating gamma/phi(3) phase. With f = J/Psi(L); J/Psi K-S and g = (pi pi)(0); (rho(L)rho(L))(0), the 16 time-ordered double-decay rate intensities to (f, g) depend on the relative phase between the f- and g-decay amplitudes given by gamma at tree level. Several constraining consistencies appear. An intrinsic accuracy of the method at the level of +/- 1 degrees could be achievable at Belle-II with an improved determination of the penguin amplitude to g channels from existing facilities.
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