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Alves, J. M., Botella, F. J., Branco, G. C., & Nebot, M. (2020). Extending trinity to the scalar sector through discrete flavoured symmetries. Eur. Phys. J. C, 80(8), 710–14pp.
Abstract: We conjecture the existence of a relation between elementary scalars and fermions, making it plausible the existence of three Higgs doublets. We introduce a Trinity Principle (TP) which, given the fact that there are no massless quarks, requires the existence of a minimum of three Higgs doublets. The TP states that each row of the mass matrix of a quark of a given charge should receive the contribution from one and only one scalar doublet and furthermore a given scalar doublet should contribute to one and only one row of the mass matrix of a quark of a given charge. This principle is analogous to the Natural Flavour Conservation (NFC) of Glashow and Weinberg with the key distinction that NFC required the introduction of a flavour blind symmetry, while the TP requires a flavoured symmetry, to be implemented in a natural way. We provide two examples which satisfy the Trinity Principle based on Z(3) and Z(2) x Z(2)' flavoured symmetries, and show that they are the minimal multi-Higgs extensions of the Standard Model where CP can be imposed as a symmetry of the full Lagrangian and broken by the vacuum, without requiring soft-breaking terms. We show that the vacuum phases are sufficient to generate a complex CKM matrix, in agreement with experiment. The above mentioned flavoured symmetries lead to a strong reduction in the number of parameters in the Yukawa interactions, enabling a control of the Scalar Flavour Changing Neutral Couplings (SFCNC). We analyse some of the other physical implications of the two models, including an estimate of the enhancement of the Baryon Asymmetry of the Universe provided by the new sources of CP violation, and a discussion of the strength of their tree-level SFCNC.
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Fuster, J., Irles, A., Melini, D., Uwer, P., & Vos, M. (2017). Extracting the top-quark running mass using t$(t)over-bar-$+1-jet events produced at the Large Hadron Collider. Eur. Phys. J. C, 77(11), 794–9pp.
Abstract: We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top- quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a tit of the theoretical results presented here to the LHC data.
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Motohashi, H., & Starobinsky, A. A. (2017). f (R) constant-roll inflation. Eur. Phys. J. C, 77(8), 538–8pp.
Abstract: The previously introduced class of two-parametric phenomenological inflationary models in general relativity in which the slow-roll assumption is replaced by the more general, constant-roll condition is generalized to the case of f (R) gravity. A simple constant-roll condition is defined in the original Jordan frame, and exact expressions for a scalaron potential in the Einstein frame, for a function f (R) (in the parametric form) and for inflationary dynamics are obtained. The region of the model parameters permitted by the latest observational constraints on the scalar spectral index and the tensor-to-scalar ratio of primordial metric perturbations generated during inflation is determined.
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Liang, W. H., Xie, J. J., & Oset, E. (2016). f(0)(500), f(0)(980), and a(0)(980) production in the chi(c1) -> eta pi(+)pi(-) reaction. Eur. Phys. J. C, 76(12), 700–7pp.
Abstract: We study the chi(c1) -> eta pi(+)pi(-) decay, paying attention to the production of f(0)(500), f(0)(980), and a(0)(980) from the final state interaction of pairs of mesons that can lead to these three mesons in the final state, which is implemented using the chiral unitary approach. Very clean and strong signals are obtained for the a(0)(980) excitation in the eta pi invariant mass distribution and for the f(0)(500) in the pi(+)pi(-) mass distribution. A smaller, but also clear signal for the f(0)(980) excitation is obtained. The results are contrasted with experimental data and the agreement found is good, providing yet one more test in support of the picture where these resonances are dynamically generated from the meson-meson interaction.
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Torres-Sanchez, P., Steiger, H. T. J., Mastinu, P., Wyss, J. L., Kayser, L., Silvestrin, L., et al. (2024). Fast neutron production at the LNL Tandem from the 7Li(14N,xn)X reaction. Eur. Phys. J. C, 84(4), 372–11pp.
Abstract: Fast neutron beams (E-n>1 MeV) are of relevance for many scientific and industrial applications. This paper explores fast neutron production using a TANDEM accelerator at the Legnaro National Laboratories, via an energetic ion beam (90 MeV N-14) onto a lithium target. The high energy models for nuclear collision of FLUKA foresee large neutron yields for reactions of this kind. The experiment aimed at validating the expected neutron yields from FLUKA simulations, using two separate and independent set-ups: one based on the multi-foil activation technique, and the other on the time of flight technique, by using liquid scintillator detectors. The results of the experiment show clear agreement of the measured spectra with the FLUKA simulations, both in the shape and the magnitude of the neutron flux at the mea-sured positions. The neutron spectrum is centered around the 8 MeV range with mild tails, and a maximum neutron energy spanning up to 50 MeV. These advantageous results provide a starting point in the development of fast neutron beams based on high energy ion beams from medium-sized accelerator facilities
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