De Romeri, V., Martin Lozano, V., & Sanchez Garcia, G. (2024). Neutrino window to scalar leptoquarks: From low energy to colliders. Phys. Rev. D, 109(5), 055014–21pp.
Abstract: Leptoquarks are theorized particles of either scalar or vector nature that couple simultaneously to quarks and leptons. Motivated by recent measurements of coherent elastic neutrino -nucleus scattering, we consider the impact of scalar leptoquarks coupling to neutrinos on a few complementary processes, from low energy to colliders. In particular, we set competitive constraints on the typical mass and coupling of scalar leptoquarks by analyzing recent COHERENT data. We compare these constraints with bounds from atomic parity violation experiments, deep inelastic neutrino -nucleon scattering and collider data. Our results highlight a strong complementarity between different facilities and demonstrate the power of coherent elastic neutrino -nucleus scattering experiments to probe leptoquark masses in the sub-TeV range. Finally, we also present prospects for improving current bounds with future upgrades of the COHERENT detectors and the planned European Spallation Source.
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Sanchis-Lozano, M. A., & Sanz, V. (2024). Observable imprints of primordial gravitational waves on the temperature anisotropies of the cosmic microwave background. Phys. Rev. D, 109(6), 063529–11pp.
Abstract: We examine the contribution of tensor modes, in addition to the dominant scalar ones, on the temperature anisotropies of the cosmic microwave background (CMB). To this end, we analyze in detail the temperature two -point angular correlation function C(Theta) from the Planck 2018 dataset, focusing on large angles (Theta greater than or similar to 120 degrees) corresponding to small l multipoles. A hierarchical set of infrared cutoffs are naturally introduced to the scalar and tensor power spectra of the CMB by invoking an extra Kaluza-Klein spatial dimension compactifying at about the grand unified theory scale between the Planck epoch and the start of inflation. We associate this set of lower scalar and tensor cutoffs with the parity of the multipole expansion of the C(Theta) function. By fitting the Planck 2018 data we compute the multipole coefficients, thereby reproducing the well-known odd -parity preference in angular correlations seen by all three satellite missions: Cosmic Background Explorer, WMAP, and Planck. Our fits improve significantly once tensor modes are included in the analysis, hence providing a hint of the imprints of primordial gravitational waves on the temperature correlations observed in the CMB today. To conclude, we suggest a relationship between, on the one hand, the lack of (positive) large -angle correlations and the odd -parity dominance in the CMB and, on the other hand, the effect of primordial gravitational waves on the CMB temperature anisotropies.
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Liang, W. H., Ban, T., & Oset, E. (2024). B0 → K(*)0X, B- K(*) -X, Bs-η(η1;φ)X from the X(3872) molecular perspective. Phys. Rev. D, 109(5), 054030–9pp.
Abstract: We study the decays B over bar 0 – over bar K0X, B- – K-X, B over bar 0s – eta(eta 1)X, B over bar 0 – over bar K*0X, B- – K*-X, B over bar 0s – phi X, with X equivalent to X(3872), from the perspective of the X(3872) being a molecular state made from the interaction of the D*+D-; D*0 over bar D0, and c:c: components. We consider both the external and internal emission decay mechanisms and find an explanation for the over bar K0X and K-X production rates, based on the mass difference of the charged and neutral D*D over bar components. We also find that the internal and external emission mechanisms add constructively in the B over bar 0 – over bar K0X, B- – K-X reactions, while they add destructively in the case of widths of the present measurements and allows us to make predictions for the unmeasured modes of B over bar 0s – eta(eta 1)X(3872) and B- – K*-X(3872). The future measurement of these decay modes will help us get a better perspective on the nature of the X(3872) and the mechanisms present in production reactions of that state. B over bar 0 – over bar K*0X, B- – K*-X reactions. This feature explains the decay
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Abreu, L. M., Song, J., Brandao, P. C. S., & Oset, E. (2024). A note on the tensor and vector exchange contributions to K (K)over-bar → K (K)over-bar, D(D)over-bar → D(D)over-bar and π+π- → π+π- reactions. Eur. Phys. J. A, 60(3), 76–10pp.
Abstract: In this note we study the tensor and vector exchange contributions to the elastic reactions involving the pseudoscalars mesons pi(+) pi(-), K+ K- and D+D-. In the case of the tensor-exchange contributions we assume that an intermediate tensor f(2)(1270) is dynamically generated from the interaction of two virtual rho mesons, with the use of a pole approximation. The calculation of the two-loop amplitude is facilitated since the triangle loops can be factorized and computed separately. The results show very small contributions coming from the tensor-exchange mechanisms when compared with those from the vector-exchange processes. We compare our results for pi pi and K (K) over bar scattering with those obtained in other works where the f2(1270) is considered as an ordinary q (q) over bar meson. Our picture provides a smaller contribution but of similar order of magnitude for pion scattering and stabilizes the results in the case of K (K) over bar, allowing us to make estimates for D (D) over bar scattering.
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Maso-Ferrando, A., Sanchis-Gual, N., Font, J. A., & Olmo, G. J. (2024). Numerical evolutions of boson stars in Palatini f(R) gravity. Phys. Rev. D, 109(4), 044042–14pp.
Abstract: We investigate the time evolution of spherically symmetric boson stars in Palatini f(R) gravity through numerical relativity computations. Employing a novel approach that establishes a correspondence between modified gravity with scalar matter and general relativity with modified scalar matter, we are able to use the techniques of numerical relativity to simulate these systems. Specifically, we focus on the quadratic theory f(R) = R + xi R2 and compare the obtained solutions with those in general relativity, exploring both positive and negative values of the coupling parameter xi. Our findings reveal that boson stars in Palatini f(R) gravity exhibit both stable and unstable evolutions. The latter give rise to three distinct scenarios: migration toward a stable configuration, complete dispersion, and gravitational collapse leading to the formation of a baby universe structure.
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