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Peinado, E., Reig, M., Srivastava, R., & Valle, J. W. F. (2020). Dirac neutrinos from Peccei-Quinn symmetry: A fresh look at the axion. Mod. Phys. Lett. A, 35(21), 2050176–9pp.
Abstract: We show that a very simple solution to the strong CP problem naturally leads to Dirac neutrinos. Small effective neutrino masses emerge from a type-I Dirac seesaw mechanism. Neutrino mass limits probe the axion parameters in regions currently inaccessible to conventional searches.
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Baamara, Y., Gessner, M., & Sinatra, A. (2023). Quantum-enhanced multiparameter estimation and compressed sensing of a field. SciPost Phys., 14(3), 050–18pp.
Abstract: We show that a significant quantum gain corresponding to squeezed or over-squeezed spin states can be obtained in multiparameter estimation by measuring the Hadamard coefficients of a 1D or 2D signal. The physical platform we consider consists of twolevel atoms in an optical lattice in a squeezed-Mott configuration, or more generally by correlated spins distributed in spatially separated modes. Our protocol requires the possibility to locally flip the spins, but relies on collective measurements. We give examples of applications to scalar or vector field mapping and compressed sensing.
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Reig, M. (2019). On the high-scale instanton interference effect: axion models without domain wall problem. J. High Energy Phys., 08(8), 167–13pp.
Abstract: We show that a new chiral, confining interaction can be used to break Peccei-Quinn symmetry dynamically and solve the domain wall problem, simultaneously. The resulting theory is an invisible QCD axion model without domain walls. No dangerous heavy relics appear.
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Bruschini, R., & Gonzalez, R. (2019). A plausible explanation of Upsilon(10860). Phys. Lett. B, 791, 409–413.
Abstract: We show that a good description of the Upsilon(10860) properties, in particular the mass, the e(+) e(-) leptonic widths and the pi(+) pi(-) Upsilon(ns) (n = 1, 2, 3) production rates, can be obtained under the assumption that Upsilon(10860) is a mixing of the conventional Upsilon(5s) quark model state with the lowest P-wave hybrid state.
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Delhom, A., Miralles, V., & Peñuelas, A. (2020). Effective interactions in Ricci-Based Gravity below the non-metricity scale. Eur. Phys. J. C, 80(4), 340–14pp.
Abstract: We show how minimally-coupled matter fields of arbitrary spin, when coupled to Ricci-based gravity theories, develop non-trivial effective interactions that can be treated perturbatively only below a characteristic high-energy scale . We then use this interactions to set bounds on the high-energy scale that controls departures of Ricci-Based Gravity theories from General Relativity. Particularly, for Eddington-inspired Born-Infeld gravity we obtain the strong bound vertical bar kappa vertical bar<10(-26)m(5)kg(-1)s(-2).
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Huang, F., Sanz, V., Shu, J., & Xue, X. (2021). LIGO as a probe of dark sectors. Phys. Rev. D, 104(10), 095001–9pp.
Abstract: We show how current LIGO data is able to probe interesting theories beyond the Standard Model, particularly dark sectors where a dark Higgs boson triggers symmetry breaking via a first-order phase transition. We use publicly available LIGO O2 data to illustrate how these sectors, even if disconnected from the Standard Model, can be probed by gravitational wave detectors. We link the LIGO measurements with the model content and mass scale of the dark sector, finding that current O2 data are testing a broad set of scenarios that can be mapped into many different types of dark-sector models where the breaking of SU(N) theories with Nf fermions is triggered by a dark Higgs boson at scales ? similar or equal to 108-109 GeV with reasonable parameters for the scalar potential.
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Caputo, A., Esposito, A., & Polosa, A. D. (2019). Sub-MeV dark matter and the Goldstone modes of superfluid helium. Phys. Rev. D, 100(11), 116007–6pp.
Abstract: We show how a relativistic effective field theory for the superfluid phase of 4 He can replace the standard methods used to compute the production rates of low-momentum excitations due to the interaction with an external probe. This is done by studying the scattering problem of a light dark matter particle in the superfluid and comparing to some existing results. We show that the rate of emission of two phonons, the Goldstone modes of the effective theory, gets strongly suppressed for sub-MeV dark matter particles due to a fine cancellation between two different tree-level diagrams in the limit of small exchanged momenta. This phenomenon is found to be a consequence of the particular choice of the potential felt by the dark matter particle in helium. The predicted rates can vary by orders of magnitude if this potential is changed. We prove that the dominant contribution to the total emission rate is provided by excitations in the phonon branch. Finally, we analyze the angular distributions for the emissions of one and two phonons and discuss how they can be used to measure the mass of the hypothetical dark matter particle hitting the helium target.
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Botella, F. J., Branco, G. C., Nebot, M., Rebelo, M. N., & Silva-Marcos, J. I. (2017). Vector-like quarks at the origin of light quark masses and mixing. Eur. Phys. J. C, 77(6), 408–14pp.
Abstract: We show how a novel fine-tuning problem present in the Standard Model can be solved through the introduction of a Z(6) flavour symmetry, together with three Q = -1/3 quarks, three Q = 2/3 quarks, as well as a complex singlet scalar. The Z(6) symmetry is extended to the additional fields and it is an exact symmetry of the Lagrangian, only softly broken in the scalar potential, in order to avoid the domain-wall problem. Specific examples are given and a phenomenological analysis of the main features of the model is presented. It is shown that even for vector-like quarks with masses accessible at the LHC, one can have realistic quark masses and mixing, while respecting the strict constraints on processes arising from flavour changing neutral currents. The vector-like quark decay channels are also described.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2017). Search for Invisible Decays of a Dark Photon Produced in e(+)e(-) Collisions at BABAR. Phys. Rev. Lett., 119(13), 131804–7pp.
Abstract: We search for single-photon events in 53 fb(-1) of e(+)e(-) collision data collected with the BABAR detector at the PEP-II B-Factory. We look for events with a single high-energy photon and a large missing momentum and energy, consistent with production of a spin-1 particle A' through the process e(+)e(-) -> gamma A'; A' -> invisible. Such particles, referred to as “dark photons,” are motivated by theories applying a U(1) gauge symmetry to dark matter. We find no evidence for such processes and set 90% confidence level upper limits on the coupling strength of A' to e(+)e(-) in the mass range m(A') <= 8 GeV. In particular, our limits exclude the values of the A' coupling suggested by the dark-photon interpretation of the muon (g – 2)(mu) anomaly, as well as a broad range of parameters for the dark-sector models.
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Brandao, P. C. S., Song, J., Abreu, L. M., & Oset, E. (2023). B+ decay to K+ ηη with (ηη) from the D bar-D(3720) bound state. Phys. Rev. D, 108(5), 054004–6pp.
Abstract: We search for a B decay mode where one can find a peak for a DD bound state predicted in effective theories and in lattice QCD calculations, which has also been claimed from some reactions that show an accumulated strength in D D over bar production at threshold. We find a good candidate in the B+-> K+eta eta reaction, by looking at the eta eta mass distribution. The reaction proceeds via a first step in which one has the B+-> D*+ D-0 reaction followed by D*(+) (s) decay to (DK+)-K-0 and a posterior fusion of D-0 over bar D-0 to eta eta, implemented through a triangle diagram that allows the D-0 over bar D-0 to be virtual and to produce the bound state. The choice of eta eta to see the peak is based on results of calculations that find the eta eta among the light pseudoscalar channels with stronger coupling to the D D over bar bound state. We find a neat peak around the predicted mass of that state in the eta eta mass distribution, with an integrated branching ratio for B+-> K+ (D D, bound); (D D, bound) -> eta eta of the order of 1.5 x 10(-4), a large number for hadronic B decays, which should motivate its experimental search.
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