arXiv subjects

Jose Bernabeu

Publications and source records attributed to Jose Bernabeu.

At least 19 recordsLinked to original sources

arXiv2024

Terrestrial Very-Long-Baseline Atom Interferometry: Summary of the Second Workshop

This summary of the second Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) Workshop provides a comprehensive overview of our meeting held in London in April 2024, building on the initial discussions during the inaugural workshop held at CERN in March 2023. Like the summary of the first workshop, this document records a critical milestone for the international atom interferometry community. It documents our concerted efforts to evaluate progress, address emerging challenges, and refine strategic directions for future large-scale atom interferometry projects. Our commitment to collaboration is manifested by the integration of diverse expertise and the coordination of international resources, all aimed at advancing the frontiers of atom interferometry physics and technology, as set out in a Memorandum of Understanding signed by over 50 institutions.

hep-ex↗

arXiv2023

No space-time singularity in black-hole physics

Massive stellar gravitational collapse is not an endless process. The Standard Model of particle physics predicts the existence of a repulsive interaction, two-neutrino mediated, with a coherent weak charge of macroscopic matter proportional to the number of constituents. After gravity, this is the second longest range -- microns -- force and, below nanometers, its magnitude overcomes the attractive gravitation. The layer distribution of pressure inside a compact neutronized uniform sphere, independent of its size, is compared for the two interactions with opposite pressure gradient. Taking as reference the mean square radius, the volume evolution of the pressure, for fixed mass and weak charge, leads to an equilibrium scenario with a characteristic black-hole radius $R_B = 1.58$ nm. This size scale should be universal, independent of the mass, as long as the mass is nearly proportional to the weak charge.

physics.gen-ph↗

arXiv2023

Terrestrial Very-Long-Baseline Atom Interferometry: Workshop Summary

This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.

hep-ex↗

arXiv2022

$B^0-\bar B^0$ entanglement for an ideal experiment on the direct CP violation $ϕ_3/γ$ phase

$B^0$--$\bar B^0$ Entanglement offers a conceptual alternative to the single charged B-decay asymmetry for the measurement of the direct CP violating $γ/ϕ_3$ phase. With $f=J/ΨK_L,J/ΨK_S$ and $g=(ππ)^0,(ρ_Lρ_L)^0$ the 16 time-ordered double decay rate Intensities to $(f, g)$ depend on the relative phase between the the $f$- and $g$-decay amplitudes given by $γ$ at tree-level. Several constraining consistencies appear. An intrinsic accuracy of the method at the level of $\pm 1^\circ$ could be achievable at Belle-II with an improved determination of the penguin amplitude to $g$-channels from existing facilities.

hep-ph↗

arXiv2022

Can Future Observation of the Living Partner Post-tag the Past Decayed State in Entangled Neutral K-Mesons ?

Entangled neutral K-mesons allow the study of their correlated dynamics at interference and decoherence times not accessible in any other system. We find novel quantum phenomena associated to a correlation-in-time between the two partners: the past state of the first decayed kaon, when it was entangled before its decay, is post-tagged by the result and the time of the future observation of the second decay channel. This surprising "from future to past" effect is fully observable and leads to the unique experimental tag of the KS-state, an unsolved problem since the discovery of CP violation.

quant-ph↗

arXiv2022

Cold Atoms in Space: Community Workshop Summary and Proposed Road-Map

We summarize the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with ESA and national space and research funding agencies.

astro-ph.IM↗

arXiv2020

The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.

physics.ins-det↗

arXiv2020

Symmetries and their breaking in the fundamental laws of physics

Symmetries in the Physical Laws of Nature lead to observable effects. Beyond regularities and conserved magnitudes, the last decades in Particle Physics have seen the identification of symmetries, and their well defined breaking, as the guiding principle for the elementary constituents of matter and their interactions. Flavour SU(3) symmetry of hadrons led to the Quark Model and the antisymmetry requirement under exchange of identical fermions led to the colour degree of freedom, the charge for the interactions of quarks and gluons in the SU(3) local gauge symmetry. Parity Violation in weak interactions led to consider the Chiral Fields with definite transformation properties under the weak isospin gauge group of the ElectroWeak SU(2)xU(1) Symmetry, which predicted novel weak neutral current interactions. CP-Violation led to three families of quarks opening the field of Flavour Physics. Time-Reversal-Violation has been observed with Entangled neutral mesons, compatible with CPT-invariance. The cancellation of gauge anomalies leads to Quark-Lepton Symmetry. Neutrinos were postulated to save energy and angular momentum conservation in beta decay. The discovery of neutrino oscillations led to a new era about their origin of mass, mixing, discrete symmetries and the global lepton-number violation. Leptogenesis may be the source of the matter-antimatter asymmetry in the Universe. The discovery of quarks and leptons and the mediators of their interactions, with observables in spectacular agreement with this Standard Theory, is the triumph of Symmetries. Gauge symmetry is exact only when the particles are massless. One needs a subtle breaking of the symmetry, providing the Origin of Mass, without affecting the interactions: the Brout-Englert-Higgs Mechanism which produces the Higgs Boson as a remnant. Open present problems are addressed with the search of New Physics Beyond-the-Standard-Model.

hep-ph↗

arXiv2020

Absolute neutrino mass and the Dirac/Majorana distinction from the weak interaction of aggregate matter

The 2$ν$-mediated force has a range of microns, well beyond the atomic scale. The effective potential is built from the t-channel absorptive part of the scattering amplitude and depends on neutrino properties on-shell. We demonstrate that neutral aggregate matter has a weak charge and calculate the matrix of six coherent charges for its interaction with definite-mass neutrinos. Near the range of the potential the neutrino pair is non-relativistic, leading to observable absolute mass and Dirac/Majorana distinction via different r-dependence and violation of the weak equivalence principle.

hep-ph↗

arXiv2019

Genuine and Matter-induced Components of the CPV Asymmetry for Neutrino Oscillations

These results represent the solution for the historical problem of the contamination by matter effects on the CPV Asymmetry for neutrino oscillations. Vacuum is CPT-symmetric and matter is T-symmetric, the goal is accomplished by using this guiding principle. Independent of the theoretical framework for the dynamics of the active neutrino flavors, we prove the Disentanglement Theorem A(CP)=A(CP, T)+A(CP, CPT) for the experimental CPV Asymmetry, with A(CP, T) genuine T-odd and A(CP, CPT) fake CPT-odd. For the effective Hamiltonian written as the sum of free mass propagation plus the matter potential for electron-neutrinos, the two components have definite parities under the baseline L, the matter potential "a", the imaginary part $\sinδ$ of the PMNS mixing matrix and the hierarchy "h"=$\pm 1$ in the neutrino mass ordering: A(CP, T) is odd in L and $\sinδ$ plus even in a and h; A(CP, CPT) is even in L and $\sinδ$ plus odd in a and almost odd in h. For present terrestrial accelerator sources of muon-neutrinos and antineutrinos, the two components of the appearance CPV asymmetry A(CP) can be disentangled by either baseline dependence (HKK) or energy dependence (DUNE). At the DUNE baseline, the higher energy region above the first oscillation node provides a dominant matter-induced A(CP, CPT) component and the sign of the experimental asymmetry A(CP) gives the hierarchy in the neutrino mass ordering. On the contrary, there is a "magic energy" E around the second oscillation maximum in which the fake A(CP, CPT) component has a first-rank zero whereas the genuine A(CP, T) component has a maximum proportional to sinδ. With a modest energy resolution $ΔE \sim 200$ MeV an effective zero remains in the matter-induced A(CP, CPT).

hep-ph↗

arXiv2019

AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space

We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity. This paper is based on a submission (v1) in response to the Call for White Papers for the Voyage 2050 long-term plan in the ESA Science Programme. ESA limited the number of White Paper authors to 30. However, in this version (v2) we have welcomed as supporting authors participants in the Workshop on Atomic Experiments for Dark Matter and Gravity Exploration held at CERN: ({\tt https://indico.cern.ch/event/830432/}), as well as other interested scientists, and have incorporated additional material.

gr-qc↗

arXiv2019

Disentangling genuine from matter-induced CP violation in neutrino oscillations

We prove that, in any flavor transition, neutrino oscillation CP violating asymmetries in matter have two disentangled components: (a) a CPT-odd T-invariant term, non-vanishing iff there are interactions with matter; (b) a T-odd CPT-invariant term, non-vanishing iff there is genuine CP violation. As function of the baseline, these two terms are distinct L-even and L-odd observables, respectively. In the experimental region of terrestrial accelerator neutrinos, we calculate their approximate expressions from which we prove that, at medium baselines, the CPT-odd component is small and nearly $δ$-independent, so it can be subtracted from the experimental CP asymmetry as a theoretical background, provided the hierarchy is known. At long baselines, on the other hand, we find that (i) a Hierarchy-odd term in the CPT-odd component dominates the CP asymmetry for energies above the first oscillation node, and (ii) the CPT-odd term vanishes, independent of the CP phase $δ$, at E = 0.92 GeV(L/1300 km) near the second oscillation maximum, where the T-odd term is almost maximal and proportional to $\sinδ$. A measurement of the CP asymmetry in these energy regions would thus provide separate information on (i) the neutrino mass ordering, and (ii) direct evidence of genuine CP violation in the lepton sector.

hep-ph↗

arXiv2019

Do T asymmetries for neutrino oscillations in uniform matter have a CP-even component?

Observables of neutrino oscillations in matter have, in general, contributions from the effective matter potential. It contaminates the CP violation asymmetry adding a fake effect that has been recently disentangled from the genuine one by their different behavior under T and CPT. Is the genuine T-odd CPT-invariant component of the CP asymmetry coincident with the T asymmetry? Contrary to CP, matter effects in uniform matter cannot induce by themselves a non-vanishing T asymmetry; however, the question of the title remained open. We demonstrate that, in the presence of genuine CP violation, there is a new non-vanishing CP-even, and so CPT-odd, component in the T asymmetry in matter, which is of odd-parity in both the phase $δ$ of the flavor mixing and the matter parameter $a$. The two disentangled components, genuine $A^\mathrm{T;CP}_{αβ}$ and fake $A^\mathrm{T;CPT}_{αβ}$, could be experimentally separated by the measurement of the two T asymmetries in matter ($ν_α\leftrightarrow ν_β$) and ($\barν_α\leftrightarrow \barν_β$). For the ($ν_μ\leftrightarrow ν_e$) transitions, the energy dependence of the new $A^\mathrm{T;CPT}_{μe}$ component is like the matter-induced term $A^\mathrm{CP;CPT}_{μe}$ of the CP asymmetry which is odd under a change of the neutrino mass hierarchy. We have thus completed the physics involved in all observable asymmetries in matter by means of their disentanglement into the three independent components, genuine $A^\mathrm{CP;T}_{αβ}$ and fake $A^\mathrm{CP;CPT}_{αβ}$ and $A^\mathrm{T;CPT}_{αβ}$.

hep-ph↗

arXiv2018

Stimulated transitions in resonant atom Majorana mixing

Massive neutrinos demand to ask whether they are Dirac or Majorana particles. Majorana neutrinos are an irrefutable proof of physics beyond the Standard Model. Neutrinoless double electron capture is not a process but a virtual $ΔL = 2$ mixing between a parent $^AZ$ atom and a daughter $^A(Z-2)$ excited atom with two electron holes. As a mixing between two neutral atoms and the observable signal in terms of emitted two-hole X-rays, the strategy, experimental signature and background are different from neutrinoless double beta decay. The mixing is resonantly enhanced for almost degeneracy and, under these conditions, there is no irreducible background from the standard two-neutrino channel. We reconstruct the natural time history of a nominally stable parent atom since its production either by nature or in the laboratory. After the time periods of atom oscillations and the decay of the short-lived daughter atom, at observable times the relevant "stationary" states are the mixed metastable long-lived state and the non-orthogonal short-lived excited state, as well as the ground state of the daughter atom. We find that they have a natural population inversion which is most appropriate for exploiting the bosonic nature of the observed atomic transitions radiation. Among different observables of the atom Majorana mixing, we include the enhanced rate of stimulated X-ray emission from the long-lived metastable state by a high-intensity X-ray beam: a gain factor of 100 can be envisaged at current XFEL facilities. On the other hand, the historical population of the daughter atom ground state can be probed by exciting it with a current pulsed optical laser, showing the characteristic absorption lines: the whole population can be excited in a shorter time than typical pulse duration.

hep-ph↗

arXiv2016

The signal of ill-defined CPT weakening entanglement in the $B_d$ system

In the presence of quantum gravity fluctuations (space-time foam), the CPT operator may be ill-defined. Its perturbative treatment leads to a modification of the Einstein-Podolsky-Rosen correlation of the neutral meson system by adding an Entanglement-weakening term of the wrong exchange symmetry, the $ω$-effect. In the current paper we identify how to probe the complex $ω$ in the entangled $B_d$-system using Flavour(f)-CP(g) eigenstate decay channels: the connection between the Intensities for the two time-ordered decays (f, g) and (g, f) is lost. Appropriate observables are constructed allowing independent experimental determinations of Re($ω$) and Im($ω$), disentangled from CPT violation in the evolution Hamiltonian Re($θ$) and Im($θ$). 2-$σ$ tensions for both Re($θ$) and Im($ω$) are shown to be uncorrelated.

hep-ph↗

arXiv2016

Genuine T, CP, CPT asymmetry parameters for the entangled $\boldsymbol{B_d}$ system

The precise connection between the theoretical T, CP, CPT asymmetries, in terms of transition probabilities between the filtered neutral meson $B_d$ states and the experimental asymmetries between the double decay rate intensities for Flavour-CP eigenstate decay products in a B-factory of entangled states, is established. This allows the identification of genuine Asymmetry Parameters in the time distribution of the asymmetries and their measurability by disentangling genuine and possible fake terms. We express the nine asymmetry parameters -- three different observables for each one of the three symmetries -- in terms of the ingredients of the Weisskopf-Wigner dynamical description of the entangled $B_d$-meson states and we obtain a global fit to their values from the BaBar collaboration experimental results. The possible fake terms are all compatible with zero and the information content of the nine asymmetry parameters is indeed different. The non-vanishing $Δ\mathscr S_c^{\rm T} =-0.687\pm 0.020 $ and $Δ\mathscr S_c^{\rm CP}=-0.680\pm 0.021$ are impressive separate direct evidence of Time-Reversal-violation and CP-violation in these transitions and compatible with Standard Model expectations. An intriguing 2$σ$ effect for the Re($θ$) parameter responsible of CPT-Violation appears which, interpreted as an upper limit, leads to $|M_{\bar B^0\bar B^0}-M_{B^0B^0}| < 4.0\times 10^{-5}$ eV at 95\% C.L. for the diagonal flavour terms of the mass matrix. It contributes to the CP-violating $Δ\mathscr C_c^{\rm CP}$ asymmetry parameter in an unorthodox manner -- in its $\cos(ΔM\,t)$ time dependence --, and it is accessible in facilities with non-entangled $B_d$'s, like the LHCb experiment.

hep-ph↗

arXiv2013

On the history of the PMNS Matrix... with today's perspective

The conceptual basis for understanding the interplay of neutrino mass and mixing for neutrino oscillations were paradoxically discussed in a period when the prevailing view was that of massless neutrinos. The name of Bruno Pontecorvo is associated to most of the components for this beautiful quantum phenomenon: muon-electron universality, different neutrino flavours, mismatch between weak interaction and mass eigenstates, neutrino oscillation phenomenology, including flavour and Majorana transitions.

hep-ph↗

arXiv2013

Novel T-Violation observable open to any pair of decay channels at meson factories

Quantum Entanglement between the two neutral mesons produced in meson factories has allowed the first indisputable direct observation of Time Reversal Violation in the time evolution of the neutral meson between the two decays. The exceptional meson transitions are directly connected to semileptonic and CP-eigenstate decay channels. The possibility of extending the observable asymmetries to more decay channels confronts the problem of the "orthogonality condition", which can be stated with this tongue-twister: Given a decay channel $f$, Which is the decay channel $f'$ such that the meson state not decaying to $f'$ is orthogonal to the meson state not decaying to $f$? In this paper we propose an alternative $T$-Violation Asymmetry at meson factories which allows its opening to any pair of decay channels. Instead of searching which is the pair of decay channels associated to the $T$-reverse meson transition, we build an asymmetry which tags the initial states of both the Reference and the $T$-reverse meson transitions. This observable filters the appropriate final states by means of two measurable survival probabilities. We discuss the methodology to be followed in the analysis of the new observable and the results expected in specific examples.

hep-ph↗