|
|
NEXT Collaboration(Renner, J. et al), Benlloch-Rodriguez, J., Botas, A., Ferrario, P., Gomez-Cadenas, J. J., Alvarez, V., et al. (2017). Background rejection in NEXT using deep neural networks. J. Instrum., 12, T01004–21pp.
Abstract: We investigate the potential of using deep learning techniques to reject background events in searches for neutrinoless double beta decay with high pressure xenon time projection chambers capable of detailed track reconstruction. The differences in the topological signatures of background and signal events can be learned by deep neural networks via training over many thousands of events. These networks can then be used to classify further events as signal or background, providing an additional background rejection factor at an acceptable loss of efficiency. The networks trained in this study performed better than previous methods developed based on the use of the same topological signatures by a factor of 1.2 to 1.6, and there is potential for further improvement.
|
|
|
|
Bazeia, D., Losano, L., Olmo, G. J., & Rubiera-Garcia, D. (2017). Geodesically complete BTZ-type solutions of 2+1 Born-Infeld gravity. Class. Quantum Gravity, 34(4), 045006–21pp.
Abstract: We study Born-Infeld gravity coupled to a static, non-rotating electric field in 2 + 1 dimensions and find exact analytical solutions. Two families of such solutions represent geodesically complete, and hence nonsingular, spacetimes. Another family represents a point-like charge with a singularity at the center. Despite the absence of rotation, these solutions resemble the charged, rotating BTZ solution of general relativity but with a richer structure in terms of horizons. The nonsingular character of the first two families turn out to be attached to the emergence of a wormhole structure on their innermost region. This seems to be a generic prediction of extensions of general relativity formulated in metric-affine (or Palatini) spaces, where metric and connection are regarded as independent degrees of freedom.
|
|
|
|
IDS Collaboration(Lica, R. et al), & Morales, A. I. (2017). beta decay studies of n-rich Cs isotopes with the ISOLDE Decay Station. J. Phys. G, 44(5), 054002–14pp.
Abstract: Neutron-rich Ba isotopes are expected to exhibit octupolar correlations, reaching their maximum in isotopes around mass A = 146. The odd-A neutron-rich members of this isotopic chain show typical patterns related to non-axially symmetric shapes, which are however less marked compared to even-A ones, pointing to a major contribution from vibrations. In the present paper we present results from a recent study focused on Cs148-150 beta-decay performed at the ISOLDE Decay Station equipped with fast-timing detectors. A detailed analysis of the measured decay half-lives and decay scheme of Ba-149 is presented, giving a first insight in the structure of this neutron-rich nucleus.
|
|
|
|
Bellomo, N., Bellini, E., Hu, B., Jimenez, R., Pena-Garay, C., & Verde, L. (2017). Hiding neutrino mass in modified gravity cosmologies. J. Cosmol. Astropart. Phys., 02(2), 043–12pp.
Abstract: Cosmological observables show a dependence with the neutrino mass, which is partially degenerate with parameters of extended models of gravity. We study and explore this degeneracy in Horndeski generalized scalar-tensor theories of gravity. Using forecasted cosmic microwave background and galaxy power spectrum datasets, we find that a single parameter in the linear regime of the effective theory dominates the correlation with the total neutrino mass. For any given mass, a particular value of this parameter approximately cancels the power suppression due to the neutrino mass at a given redshift. The extent of the cancellation of this degeneracy depends on the cosmological large-scale structure data used at different redshifts. We constrain the parameters and functions of the effective gravity theory and determine the influence of gravity on the determination of the neutrino mass from present and future surveys.
|
|
|
|
Escudero, M., Hooper, D., & Witte, S. J. (2017). Updated collider and direct detection constraints on Dark Matter models for the Galactic Center gamma-ray excess. J. Cosmol. Astropart. Phys., 02(2), 038–21pp.
Abstract: Utilizing an exhaustive set of simplified models, we revisit dark matter scenarios potentially capable of generating the observed Galactic Center gamma-ray excess, updating constraints from the LUX and PandaX- II experiments, as well as from the LHC and other colliders. We identify a variety of pseudoscalar mediated models that remain consistent with all constraints. In contrast, dark matter candidates which annihilate through a spin-1 mediator are ruled out by direct detection constraints unless the mass of the mediator is near an annihilation resonance, or the mediator has a purely vector coupling to the dark matter and a purely axial coupling to Standard Model fermions. All scenarios in which the dark matter annihilates throught-channel processes are now ruled out by a combination of the constraints from LUX/ PandaX-II and the LHC.
|
|
