Hinarejos, M., Perez, A., & Bañuls, M. C. (2012). Wigner function for a particle in an infinite lattice. New J. Phys., 14, 103009–19pp.
Abstract: We study the Wigner function for a quantum system with a discrete, infinite-dimensional Hilbert space, such as a spinless particle moving on a one-dimensional infinite lattice. We discuss the peculiarities of this scenario and of the associated phase-space construction, propose a meaningful definition of the Wigner function in this case and characterize the set of pure states for which it is non-negative. We propose a measure of non-classicality for states in this system, which is consistent with the continuum limit. The prescriptions introduced here are illustrated by applying them to localized and Gaussian states and to their superpositions.
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Dai, L. R., Yu, Q. X., & Oset, E. (2019). Triangle singularity in tau(-) -> nu(tau)pi(-) f(0)(980) (a(0)(980)) decays. Phys. Rev. D, 99(1), 016021–13pp.
Abstract: We study the triangle mechanism for the decay tau(-) -> nu(tau)pi(-) f(0)(980) with the f(0)(980) decaying into pi(+) pi(-). The mechanism for this process is initiated by tau(-) -> nu K-tau*(0) K- followed by the K*(0) decay into pi K--(+), then the K- K+ produce the f(0)(980) through a triangle loop containing K* K+ K- which develops a singularity around 1420 MeV in the pi f(0)(980) invariant mass. We find a narrow peak in the pi(+) pi(-) invariant mass distribution, which originates from the f(0)(980) amplitude. Similarly, we also study the triangle mechanism for the decay tau -> nu pi(-) a(0)(980), with the a(0)(980) decaying into pi(0)eta.The formalism leads to final branching ratios for pi(-) f(0)(980) and pi(-) a(0)(980) of the order of 4 x 10(-4) and 7 x 10(-5), respectively, which are within present measurable range. Experimental verification of these predictions will shed light on the nature of the scalar mesons and on the origin of the “a(1)(1420)” peak observed in other reactions.
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Braaten, E., Bruschini, R., He, L. P., Ingles, K., & Jiang, J. (2023). Evolution of charm-meson ratios in an expanding hadron gas. Phys. Rev. D, 107(7), 076006–6pp.
Abstract: We study the time evolution of the numbers of charm mesons after the kinetic freeze-out of the hadron gas produced by a central heavy-ion collision. The pi D* -> pi D* reaction rates have t-channel singularities that give contributions inversely proportional to the thermal width of the D. The ratio of the D0 and D+ production rates can differ significantly from those predicted using the measured D* branching fractions.
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Cheng, L., Eberhardt, O., & Murphy, C. W. (2019). Novel theoretical constraints for color-octet scalar models. Chin. Phys. C, 43(9), 093101–11pp.
Abstract: We study the theoretical constraints on a model whose scalar sector contains one color octet and one or two color singlet SU(2)(L) doublets. To ensure unitarity of the theory, we constrain the parameters of the scalar potential for the first time at the next-to-leading order in perturbation theory. Moreover, we derive new conditions guaranteeing the stability of the potential. We employ the HEPfit package to extract viable parameter regions at the electroweak scale and test the stability of the renormalization group evolution up to the multi-TeV region. Furthermore, we set upper limits on the scalar mass splittings. All results are given for both cases with and without a second scalar color singlet.
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Dai, L. R., Roca, L., & Oset, E. (2020). Tau decay into tau(t) and a(1)(1260), b(1)(1235), and two K-1(1270). Eur. Phys. J. C, 80(7), 673–9pp.
Abstract: We study the tau -> nu(tau). A decay, with A an axialvector meson. We produce the a(1) (1260) and b(1) (1235) resonances in the Cabibbo favored mode and two K-1 (1270) states in the Cabibbo suppressed mode. We take advantage of previous chiral unitary approach results where these resonances appear dynamically from the vector and pseudoscalar meson interaction in s-wave. Actually two different poles were obtained associated to the K-1(1270) quantum numbers. We find that the unmeasured rates for b(1)(1235) production are similar to those of the a(1)(1260) and for the two K-1 states we suggest to separate the present information on the (K) over bar pi pi invariant masses into (K) over bar*pi and rho K modes, the channels to which these two resonances couple most strongly, predicting that thesemodes peak at different energies and have different widths. These measurements should shed light on the existence of these two K-1 states. In addition, we have gone one step further making a comparison with experimental results of three meson decay channels, letting the vector mesons of our approach decay into pseudoscalars, and we find an overall good agreement with experiment.
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