Bombacigno, F., Moretti, F., Boudet, S., & Olmo, G. J. (2023). Landau damping for gravitational waves in parity-violating theories. J. Cosmol. Astropart. Phys., 02(2), 009–29pp.
Abstract: We discuss how tensor polarizations of gravitational waves can suffer Landau damping in the presence of velocity birefringence, when parity symmetry is explicitly broken. In particular, we analyze the role of the Nieh-Yan and Chern-Simons terms in modified theories of gravity, showing how the gravitational perturbation in collisionless media can be characterized by a subluminal phase velocity, circumventing the well-known results of General Relativity and allowing for the appearance of the kinematic damping. We investigate in detail the connection between the thermodynamic properties of the medium, such as temperature and mass of the particles interacting with the gravitational wave, and the parameters ruling the parity violating terms of the models. In this respect, we outline how the dispersion relations can give rise in each model to different regions of the wavenumber space, where the phase velocity is subluminal, superluminal or does not exist. Quantitative estimates on the considered models indicate that the phenomenon of Landau damping is not detectable given the sensitivity of present-day instruments.
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Feruglio, F., Gherardi, V., Romanino, A., & Titov, A. (2021). Modular invariant dynamics and fermion mass hierarchies around tau = i. J. High Energy Phys., 05(5), 242–26pp.
Abstract: We discuss fermion mass hierarchies within modular invariant flavour models. We analyse the neighbourhood of the self-dual point tau = i, where modular invariant theories possess a residual Z(4) invariance. In this region the breaking of Z(4) can be fully described by the spurion epsilon approximate to tau – i, that flips its sign under Z(4). Degeneracies or vanishing eigenvalues of fermion mass matrices, forced by the Z(4) symmetry at tau = i, are removed by slightly deviating from the self-dual point. Relevant mass ratios are controlled by powers of vertical bar epsilon vertical bar. We present examples where this mechanism is a key ingredient to successfully implement an hierarchical spectrum in the lepton sector, even in the presence of a non-minimal Kahler potential.
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Arbelaez, C., Carcamo Hernandez, A. E., Cepedello, R., Hirsch, M., & Kovalenko, S. (2019). Radiative type-I seesaw neutrino masses. Phys. Rev. D, 100(11), 115021–7pp.
Abstract: We discuss a radiative type-I seesaw. In these models, the radiative generation of Dirac neutrino masses allows to explain the smallness of the observed neutrino mass scale for rather light right-handed neutrino masses in a type-1 seesaw. We first present the general idea in a model-independent way. This allows us to estimate the typical scale of right-handed neutrino mass as a function of the number of loops. We then present two example models, at the one- and two-loop level, which we use to discuss neutrino masses and lepton-flavor-violating constraints in more detail. For the two-loop example, right-handed neutrino masses must lie below 100 GeV, thus making this class of models testable in heavy neutral lepton searches.
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Albaladejo, M., & Nieves, J. (2022). Compositeness of S-wave weakly-bound states from next-to-leading order Weinberg's relations. Eur. Phys. J. C, 82(8), 724–12pp.
Abstract: We discuss a model-independent estimator of the likelihood of the compositeness of a shallow S-wave bound or virtual state. The approach is based on an extension of Weinberg's relations in Weinberg (Phys Rev 137:B672, 1965) and it relies only on the proximity of the energy of the state to the two-hadron threshold to which it significantly couples. The scheme only makes use of the experimental scattering length and the effective range low energy parameters, and it is shown to be fully consistent for predominantly molecular hadrons. As explicit applications, we analyse the case of the deuteron, the S-1(0) nucleon virtual state and the exotic D-so(*)(2317)(+/-) , and find strong support to the molecular interpretation in all cases. Results are less conclusive for the D* (s0)(2317)+/-, since the binding energy of this state would be significantly higher than that of the deuteron, and the approach employed here is at the limit of its applicability. We also qualitatively address the case of the recently discovered T + cc state, within the isospin limit to avoid the complexity of the very close thresholds (DD)-D-0*+ and D + D*(0), which could mask the ingredients of the approach proposed in this work.
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Cordero-Carrion, I., Hirsch, M., & Vicente, A. (2020). General parametrization of Majorana neutrino mass models. Phys. Rev. D, 101(7), 075032–25pp.
Abstract: We discuss a general formula which allows to automatically reproduce experimental data for Majorana neutrino mass models, while keeping the complete set of the remaining model parameters free for general scans, as necessary in order to provide reliable predictions for observables outside the neutrino sector. We provide a proof of this master parametrization and show how to apply it for several well-known neutrino mass models from the literature. We also discuss a list of special cases, in which the Yukawa couplings have to fulfill some particular additional conditions.
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ANTARES Collaboration(Reeb, N. et al), Alves, S., Carretero, V., Colomer, M., Hernandez-Rey, J. J., Khan-Chowdhury, N. R., et al. (2023). Studying bioluminescence flashes with the ANTARES deep-sea neutrino telescope. Limnol. Oceanogr. Meth., 21(11), 734–760.
Abstract: We develop a novel technique to exploit the extensive data sets provided by underwater neutrino telescopes to gain information on bioluminescence in the deep sea. The passive nature of the telescopes gives us the unique opportunity to infer information on bioluminescent organisms without actively interfering with them. We propose a statistical method that allows us to reconstruct the light emission of individual organisms, as well as their location and movement. A mathematical model is built to describe the measurement process of underwater neutrino telescopes and the signal generation of the biological organisms. The Metric Gaussian Variational Inference algorithm is used to reconstruct the model parameters using photon counts recorded by photomultiplier tubes. We apply this method to synthetic data sets and data collected by the ANTARES neutrino telescope. The telescope is located 40 km off the French coast and fixed to the sea floor at a depth of 2475 m. The runs with synthetic data reveal that we can model the emitted bioluminescent flashes of the organisms. Furthermore, we find that the spatial resolution of the localization of light sources highly depends on the configuration of the telescope. Precise measurements of the efficiencies of the detectors and the attenuation length of the water are crucial to reconstruct the light emission. Finally, the application to ANTARES data reveals the first localizations of bioluminescent organisms using neutrino telescope data.
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Ferreiro, A., Monin, S., & Torrenti, F. (2024). Physical scale adiabatic regularization in cosmological spacetimes. Phys. Rev. D, 109(4), 045015–16pp.
Abstract: We develop a new regularization method for the stress -energy tensor and the two -point function of free quantum scalar fields propagating in cosmological spacetimes. We proceed by extending the adiabatic regularization scheme with the introduction of two additional mass scales. By setting them to the order of the physical scale of the studied scenario, we obtain ultraviolet -regularized quantities that do not distort the power spectra amplitude at the infrared scales amplified by the expansion of the Universe. This is not ensured by the standard adiabatic approach. We also show how our proposed subtraction terms can be interpreted as a renormalization of coupling constants in the Einstein equations. We finally illustrate our proposed regularization method in two scenarios of cosmological interest: de Sitter inflation and geometric reheating.
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Toledo, G., Ikeno, N., & Oset, E. (2021). Theoretical study of the D-0 -> K-pi(+)eta reaction. Eur. Phys. J. C, 81(3), 268–11pp.
Abstract: We develop a model to study the D-0 -> K-pi(+)eta weak decay, starting with the color favored external emission and Cabibbo favored mode at the quark level. A less favored internal emission decay mode is also studied as a source of small corrections. Some pairs of quarks are allowed to hadronize producing two pseudoscalar mesons, which posteriorly are allowed to interact to finally provide the K-pi(+)eta state. The chiral unitary approach is used to take into account the final state interaction of pairs of mesons, which has as a consequence the production of the kappa (K-0*(700)) and the a(0)(980) resonances, well visible in the invariant mass distributions. We also introduce the (K) over bar*(0)eta production in a phenomenological way and show that the s-wave pseudoscalar interaction together with this vector excitation mode are sufficient to provide a fair reproduction of the experimental data. The model provides the relative weight of the a(0)(980) to the kappa excitation, and their strength is clearly visible in the low energy part of the K pi spectrum.
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Ikeno, N., Molina, R., & Oset, E. (2021). Triangle singularity mechanism for the pp -> pi(+)d fusion reaction. Phys. Rev. C, 104(1), 014614–16pp.
Abstract: We develop a model for the pp -> pi(+)d reaction based on the pp -> Delta(1232)N transition followed by Delta(1232) -> pi N' decay and posterior fusion of NN' to give the deuteron. We show that the triangle diagram depicting this process develops a triangle singularity leading to a large cross section of this reaction compared to ordinary fusion reactions. The results of the calculation also show that the process is largely dominated by the pp system in L = 2 and S = 0, which transfers J = 2 to the final pi(+)d system. This feature is shown to be well suited to provide L = 2, S = 1, and J(tot) = 3 for np in the np(I = 0) pi(-)pp reaction followed by the pp -> pi(+)d reaction, which has been proposed recently, as a means of describing the so far assumed dibaryon d* (2380) peak.
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Dai, L. R., & Oset, E. (2024). Dynamical generation of the scalar f0(500), f0(980), and K0*(700) resonances in the Ds+ → K+ π+ π- reaction. Phys. Rev. D, 109(5), 054008–9pp.
Abstract: We develop a model aimed at understanding the three mass distributions of pairs of mesons in the Cabibbo-suppressed D-s(+) – K+pi(+)pi(-) decay recently measured with high statistics by the BESIII collaboration. The largest contributions to the process come from the D-s(+) -> K+ rho(0) and D-s(+) -> K*(0)pi(+) decay modes, but the D-s(+) -> K-0*(1430)pi(+) and D-s(+) -> K+ f(0) (1370) modes also play a moderate role and all of them are introduced empirically. Instead, the contribution of the f(0)(500), f(0)(980) , and K-0*(700) resonances is introduced dynamically by looking at the decay modes at the quark level, hadronizing q (q) over bar over bar pairs to give two mesons, and allowing these mesons to interact, for which we follow the chiral unitary approach, to finally produce the K+ pi(+) pi(-) final state. While the general features of the mass distributions are fairly obtained, we pay special attention to the specific effects created by the light scalar resonances, which are visible in the low mass region of the pi(+) pi(-) (f(0)(500) and K+ pi(-) K+pi-(K-0*(700)) mass distributions and a narrow peak for pi(+) pi(-) distribution corresponding to f(0)(980) excitation. The contribution of these three resonances is generated by only one parameter. We see the agreement found in these regions as further support for the nature of the light scalar states as dynamically generated from the interaction of pseudoscalar mesons.
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