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Yao, D. L., Alvarez-Ruso, L., & Vicente Vacas, M. J. (2019). Neutral-current weak pion production off the nucleon in covariant chiral perturbation theory. Phys. Lett. B, 794, 109–113.
Abstract: Neutral current single pion production induced by neutrinos and antineutrinos on nucleon targets has been investigated in manifestly relativistic baryon chiral perturbation theory with explicit Delta(1232) degrees of freedom up to O(p(3)). At low energies, where chiral perturbation theory is applicable, the total cross sections for the different reaction channels exhibit a sizable non-resonant contribution, which is not present in event generators of broad use in neutrino oscillation and cross section experiments such as GENIE and NuWro.
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Bonilla, C., & Valle, J. W. F. (2016). Naturally light neutrinos in Diracon model. Phys. Lett. B, 762, 162–165.
Abstract: We propose a simple model for Dirac neutrinos where the smallness of neutrino mass follows from a parameter kappa whose absence enhances the symmetry of the theory. Symmetry breaking is performed in a two-doublet Higgs sector supplemented by a gauge singlet scalar, realizing an accidental global U(1) symmetry. Its spontaneous breaking at the few TeV scale leads to a physical Nambu -Goldstone – boson the Diracon, denoted D – which is restricted by astrophysics and induces invisible Higgs decays such as h -> DD. The scheme provides a rich, yet very simple scenario for symmetry breaking studies at colliders such as the LHC.
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Molina, R., & Oset, E. (2020). Molecular picture for the X-0(2866) as a D*(K)over-bar* J(P)=0(+) state and related 1(+), 2(+) states. Phys. Lett. B, 811, 135870–7pp.
Abstract: We recall the predictions made ten years ago about a bound state of J(P) = 0(+) in I = 0 of the D*(K) over bar* system, which is manifestly exotic, and we associate it to the X-0(2866) state reported in the recent LHCb experiment. Fine tuning the parameters to reproduce exactly the mass and width of the X-0(2866) state, we report two more states stemming from the same interaction, one with 1(+) and the other with 2(+). For reasons of parity, the 1(+) state cannot be observed in D (K) over bar decay, and we suggest to observe it in the D*(K) over bar spectrum. On the other hand, the 2(+) state can be observed in D (K) over bar decay but the present experiment has too small statistics in the region of its mass to make any claim. We note that measurements of the D*(K) over bar spectrum and of the D (K) over bar with more statistics should bring important information concerning the nature of the X-0(2866) and related ones that could be observed.
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Chen, M. C., Li, X. Q., Liu, X. G., Medina, O., & Ratz, M. (2024). Modular invariant holomorphic observables. Phys. Lett. B, 852, 138600–13pp.
Abstract: In modular invariant models of flavor, observables must be modular invariant. The observables discussed so far in the literature are functions of the modulus tau and its conjugate, (tau) over bar. We point out that certain combinations of observables depend only on tau , i.e. are meromorphic, and in some cases even holomorphic functions of tau. These functions, which we dub “invariants” in this Letter, are highly constrained, renormalization group invariant, and allow us to derive many of the models' features without the need for extensive parameter scans. We illustrate the robustness of these invariants in two existing models in the literature based on modular symmetries, Gamma(3) and Gamma(5). We find that, in some cases, the invariants give rise to robust relations among physical observables that are independent of tau. Furthermore, there are instances where additional symmetries exist among the invariants. These symmetries are relevant phenomenologically and may provide a dynamical way to realize symmetries of mass matrices.
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Gariazzo, S., Giunti, C., Laveder, M., & Li, Y. F. (2018). Model-independent (nu)over-bar(e) short-baseline oscillations from reactor spectral ratios. Phys. Lett. B, 782, 13–21.
Abstract: We consider the ratio of the spectra measured in the DANSS neutrino experiment at 12.7 and 10.7 m from a nuclear reactor. These data give a new model-independent indication in favor of short-baseline (nu) over bar (e) oscillations which reinforce the model-independent indication found in the late 2016 in the NEOS experiment. The combined analysis of the NEOS and DANSS spectral ratios in the framework of 3+1 active-sterile neutrino mixing favor short-baseline (nu) over bar (e) oscillations with a statistical significance of 3.7 sigma. The two mixing parameters sin(2)2 nu ee and Delta m(41)(2) are constrained at 2 sigma a narrow-Delta m(41)(2) island at Delta m(41)(2) similar or equal to 1.3 eV(2), with sin(2)2 nu(ee)= 0.049 +/- 0.023(2 sigma). We discuss the implications of the model-independent NEOS+DANSS analysis for the reactor and Gallium anomalies. The NEOS+DANSS model-independent determination of short-baseline (nu) over bar (e) oscillations allows us to analyze the reactor rates without assumptions on the values of the main reactor antineutrino fluxes and the data of the Gallium source experiments with free detector efficiencies. The corrections to the reactor neutrino fluxes and the Gallium detector efficiencies are obtained from the fit of the data. In particular, we confirm the indication in favor of the need for a recalculation of the (235)Ureactor antineutrino flux found in previous studies assuming the absence of neutrino oscillations.
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Ikeno, N., Toledo, G., & Oset, E. (2023). Model independent analysis of femtoscopic correlation functions: An application to the D∗s0(2317). Phys. Lett. B, 847, 138281–6pp.
Abstract: We face the inverse problem of obtaining the interaction between coupled channels from the correlation functions of these channels. We apply the method to the interaction of the (DK+)-K-0, (D+K0), and D-s(+)eta channels, from where the D-s0(& lowast;)(2317) state emerges. We use synthetic data extracted from an interaction model based on the local hidden gauge approach and find that the inverse problem can determine the existence of a bound state of the system with a precision of about 20 MeV. At the same time, we can determine the isospin nature of the bound state and its compositeness in terms of the channels. Furthermore, we evaluate the scattering length and effective range of all three channels, as well as the couplings of the bound state found to all the components. Lastly, the size parameter of the source function, R, which in principle should be a magnitude provided by the experimental teams, can be obtained from a fit to the data with relatively high accuracy. These findings show the value of the correlation function to learn about the meson-meson interaction for systems which are difficult to access in other present facilities.
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Botella, F. J., Branco, G. C., & Rebelo, M. N. (2010). Minimal flavour violation and multi-Higgs models. Phys. Lett. B, 687(2-3), 194–200.
Abstract: We propose an extension of the hypothesis of Minimal Flavour Violation (MFV) to general multi-Higgs models without the assumption of Natural Flavour Conservation (NFC) in the Higgs sector. We study in detail under what conditions the neutral Higgs couplings are only functions of V-CKM and propose a MFV expansion for the neutral Higgs couplings to fermions.
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de Medeiros Varzielas, I., King, S. F., Luhn, C., & Neder, T. (2017). Minima of multi-Higgs potentials with triplets of Delta(3n(2)) and Delta(6n(2)). Phys. Lett. B, 775, 303–310.
Abstract: We analyse the minima of scalar potentials for multi-Higgs models where the scalars are arranged as either one triplet or two triplets of the discrete symmetries A(4), S-4, Delta (27), Delta (54), as well as Delta (3n(2)) and Delta(6n2) with n > 3. The results should be useful for both multi-Higgs models involving electroweak doublets and multi-flavon models involving electroweak singlets, where in both cases the fields transform as triplets under some non-Abelian discrete symmetry.
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Bayar, M., & Oset, E. (2022). Method to observe the J(P)=2(+) partner of the X-0(2866) in the B+ -> D+ D- K+ reaction. Phys. Lett. B, 833, 137364–6pp.
Abstract: We propose a method based on the moments of the D- K+ mass distribution in the B+ -> D+ D- K+ decay to disentangle the contribution of the 2(+) state, partner of X-0(2900) in the (D) over bar *K* picture for this resonance. Some of these moments show the interference patterns of the X-1(2900) and X-0(2900) with the 2(+) state, which provide a clearer signal of the 2(+) resonance than the 2(+) signal alone. The construction of these magnitudes from present data is easy to implement, and based on these data we show that clear signals for that resonance should be seen even with the present statistics.
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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Measurements of the Lambda(0)(b) -> J/psi Lambda decay amplitudes and the Lambda(0)(b) polarisation in pp collisions at root s=7 TeV. Phys. Lett. B, 724(1-3), 27–35.
Abstract: An angular analysis of Lambda(0)(b) -> J/psi Lambda decays is performed using a data sample corresponding to 1.0 fb(-1) collected in pp collisions at root s = 7 TeV with the LHCb detector at the LHC. A parity violating asymmetry parameter characterising the Lambda(0)(b) -> J/psi Lambda decay of 0.05 +/- 0.17 +/- 0.07 and a Lambda(0)(b) transverse production polarisation of 0.06 +/- 0.07 +/- 0.02 are measured, where the first uncertainty is statistical and the second systematic.
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