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Mangano, G., Miele, G., Pastor, S., Pisanti, O., & Sarikas, S. (2012). Updated BBN bounds on the cosmological lepton asymmetry for non-zero theta(13). Phys. Lett. B, 708(1-2), 1–5.
Abstract: We discuss the bounds on the cosmological lepton number from Big Bang Nucleosynthesis (BBN), in light of recent evidences for a large value of the neutrino mixing angle theta(13), sin(2) theta(13) greater than or similar to 0.01 at 2 sigma. The largest asymmetries for electron and mu, tau neutrinos compatible with He-4 and H-2 primordial yields are computed versus the neutrino mass hierarchy and mixing angles. The flavour oscillation dynamics is traced till the beginning of BBN and neutrino distributions after decoupling are numerically computed. The latter contains in general, non-thermal distortion due to the onset of flavour oscillations driven by solar squared mass difference in the temperature range where neutrino scatterings become inefficient to enforce thermodynamical equilibrium. Depending on the value of theta(13), this translates into a larger value for the effective number of neutrinos, N-eff. Upper bounds on this parameter are discussed for both neutrino mass hierarchies. Values for N-eff which are large enough to be detectable by the Planck experiment are found only for the (presently disfavoured) range sin(2) theta(13) <= 0.01.
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Celis, A., Fuentes-Martin, J., & Serodio, H. (2014). Effective aligned 2HDM with a DFSZ-like invisible axion. Phys. Lett. B, 737, 185–190.
Abstract: We discuss the possibility of having a non-minimal scalar sector at the weak scale within the framework of invisible axion models. To frame our discussion we consider an extension of the Dine-Fischler-Srednicki-Zhitnitsky invisible axion model with two additional Higgs doublets blind under the Peccei-Quinn symmetry. Due to mixing effects among the scalar fields, it is possible to obtain a rich scalar sector at the weak scale in certain decoupling limits of the theory. In particular, this framework provides an ultraviolet completion of the so-called aligned two-Higgs-doublet model and solves the strong CP problem. The axion properties and the smallness of active neutrino masses are also discussed.
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Albertus, C., Hernandez, E., & Nieves, J. (2011). Exclusive c -> s, d semileptonic decays of ground-state spin-1/2 doubly charmed baryons. Phys. Lett. B, 704(5), 499–509.
Abstract: We evaluate exclusive semileptonic decays of ground-state spin-1/2 doubly heavy charmed baryons driven by a c -> s, d transition at the quark level. Our results for the form factors are consistent with heavy quark spin symmetry constraints which are valid in the limit of an infinitely massive charm quark and near zero recoil. Only a few exclusive semileptonic decay channels have been theoretically analyzed before. For those cases we find that our results are in a reasonable agreement with previous calculations.
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Nieves, J., Ruiz Simo, I., & Vicente Vacas, M. J. (2013). Two particle-hole excitations in charged current quasielastic antineutrino-nucleus scattering. Phys. Lett. B, 721(1-3), 90–93.
Abstract: We evaluate the quasielastic and multinucleon contributions to the antineutrino-nucleus scattering cross section and compare our results with the recent MiniBooNE data. We use a local Fermi gas model that includes RPA correlations and gets the multinucleon part from a systematic many body expansion of the W boson selfenergy in the nuclear medium. The same model had been quite successful for the neutrino cross section and contains no new parameters. We have also analyzed the relevance of 2p2h events for the antineutrino energy reconstruction.
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Yamagata-Sekihara, J., & Oset, E. (2010). V P gamma radiative decay of resonances dynamically generated from the vector meson-vector meson interaction. Phys. Lett. B, 690(4), 376–381.
Abstract: We evaluate the radiative decay into a vector, a pseudoscalar and a photon of several resonances dynamically generated from the vector-vector interaction. The process proceeds via the decay of one of the vector components into a pseudoscalar and a photon, which have an invariant mass distribution very different from phase space as a consequence of the two vector structure of the resonances. Experimental work along these lines should provide useful information on the nature of these resonances.
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Jimenez, R., Pena-Garay, C., & Verde, L. (2011). Is it possible to explore Peccei-Quinn axions from frequency-dependence radiation dimming? Phys. Lett. B, 703(3), 232–236.
Abstract: We explore how the Peccei-Quinn (PQ) axion parameter space can be constrained by the frequency-dependence dimming of radiation from astrophysical objects. To do so we perform accurate calculations of photon-axion conversion in the presence of a variable magnetic field. We propose several tests where the PQ axion parameter space can be explored with current and future astronomical surveys: the observed spectra of isolated neutron stars, occultations of background objects by white dwarfs and neutron stars, the light-curves of eclipsing binaries containing a white dwarf. We find that the lack of dimming of the light-curve of a detached eclipsing white dwarf binary recently observed, leads to relevant constraints on the photon-axion conversion. Current surveys designed for Earth-like planet searches are well matched to strengthen and improve the constraints on the PQ axion using astrophysical objects radiation dimming.
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Maji, R., Park, W. I., & Shafi, Q. (2023). Gravitational waves from walls bounded by strings in SO(10) model of pseudo-Goldstone dark matter. Phys. Lett. B, 845, 138127–5pp.
Abstract: We explore the gravitational wave spectrum generated by string-wall structures in an SO (10) (Spin(10)) based scenario of pseudo-Goldstone boson dark matter (pGDM) particle. This dark matter candidate is a linear combination of the Standard Model (SM) singlets present in the 126 and 16 dimensional Higgs fields. The Higgs 126-plet vacuum expectation value (VEV) < 126(H)> leaves unbroken the Z(2) subgroup of Z(4), the center of SO (10). Among other things, this yields topologically stable cosmic strings with a string tension μsimilar to < 126(H)>(2). The subsequent (spontaneous) breaking of Z(2) at a significantly lower scale by the 16-plet VEV < 16(H)> leads to the appearance of domain walls bounded by the strings produced earlier. We display the gravitational wave spectrum for G μvalues varying between 10(-15) and 10(-9) (< 126(H)> similar to 10(11) – 10(14) GeV), and < 16(H)> similar to 0.1 – 10(2) TeV range (G denotes Newton's constant.) These predictions can be tested, as we show, by a variety of (proposed) experiments including LISA, ET, CE and others.
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Kang, S. K., Popov, O., Srivastava, R., Valle, J. W. F., & Vaquera-Araujo, C. A. (2019). Scotogenic dark matter stability from gauged matter parity. Phys. Lett. B, 798, 135013–10pp.
Abstract: We explore the idea that dark matter stability results from the presence of a matter-parity symmetry, arising naturally as a consequence of the spontaneous breaking of an extended SU(3) circle times SU(3)(L) circle times U(1)(X) circle times U(1)(N) electroweak gauge symmetry with fully gauged B-L. Using this framework we construct a theory for scotogenic dark matter and analyze its main features.
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Civiletti, M., Pallis, C., & Shafi, Q. (2014). Upper bound on the tensor-to-scalar ratio in GUT-scale supersymmetric hybrid inflation. Phys. Lett. B, 733, 276–282.
Abstract: We explore the upper bound on the tensor-to-scalar ratio r in supersymmetric (F-term) hybrid inflation models with the gauge symmetry breaking scale set equal to the value 2.86 . 10(16) GeV, as dictated by the unification of the MSSM gauge couplings. We employ a unique renormalizable superpotential and a quasi-canonical Kahler potential, and the scalar spectral index n(s) is required to lie within the two-sigma interval from the central value found by the Planck satellite. In a sizable region of the parameter space the potential along the inflationary trajectory is a monotonically increasing function of the inflaton, and for this case, r less than or similar to 2.9.10(-4), while the spectral index running, vertical bar dn(s)/d ln k vertical bar, can be as large as 0.01. Ignoring higher order terms which ensure the boundedness of the potential for large values of the inflaton, the upper bound on r is significantly larger, of order 0.01, for subplanckian values of the inflaton, and vertical bar dn(s)/dlnk vertical bar similar or equal to 0.006.
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Ferreiro, A., & Navarro-Salas, J. (2019). Running couplings from adiabatic regularization. Phys. Lett. B, 792, 81–85.
Abstract: We extend the adiabatic regularization method by introducing an arbitrary mass scale μin the construction of the subtraction terms. This allows us to obtain, in a very robust way, the running of the coupling constants by demanding mu-invariance of the effective semiclassical (Maxwell-Einstein) equations. In particular, we get the running of the electric charge of perturbative quantum electrodynamics. Furthermore, the method brings about a renormalization of the cosmological constant and the Newtonian gravitational constant. The running obtained for these dimensionful coupling constants has new relevant (non-logarithmic) contributions, not predicted by dimensional regularization.
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