Investigació
http://hdl.handle.net/10550/53
2015-04-26T09:45:46ZCognitive variables in science problem solving: a review of research
http://hdl.handle.net/10550/43424
Cognitive variables in science problem solving: a review of research
Solaz Portolés, Joan Josep; Sanjosé López, Vicente
This paper provides an overview of research into cognitive variables that are involved in problem solving and how these variables affect the performance of problem solvers. The variables discussed are grouped together in: prior knowledge, formal reasoning ability and neo-Piagetian variables, long-term memory and working memory, knowledge base, and metacognitive variables.
2007-01-01T00:00:00ZA Wilson-Yukawa Model with undoubled chiral fermions in 2D
http://hdl.handle.net/10550/43376
A Wilson-Yukawa Model with undoubled chiral fermions in 2D
Hernández Gamazo, Pilar; Boucaud, Ph.
We consider the fermion spectrum in the strong coupling vortex phase of a lattice fermion-scalar model with a global U(1)L×U(1)R, in 2D, in the context of a recently proposed two-cutoff lattice formulation. The fermion doublers are made massive by a strong Wilson-Yukawa coupling, but in contrast with the standard formulation of these models, in which the light fermion spectrum was found to be massive and vectorlike, we find massless undoubled fermions with chiral quantum numbers at finite lattice spacing. When the global symmetry is gauged, this model is expected to give rise to a chiral gauge theory.
1998-01-01T00:00:00ZThe minimal 3+2 neutrino model versus oscillation anomalies
http://hdl.handle.net/10550/43375
The minimal 3+2 neutrino model versus oscillation anomalies
Donini, Andrea; Hernández Gamazo, Pilar; López Pavón, Jacobo; Maltoni, Michele; Schwetz, Thomas
We study the constraints imposed by neutrino oscillation experiments on the minimal extension of the Standard Model that can explain neutrino masses, which requires the addition of just two singlet Weyl fermions. The most general renormalizable couplings of this model imply generically four massive neutrino mass eigenstates while one remains massless: it is therefore a minimal 3+2 model. The possibility to account for the confirmed solar, atmospheric and long-baseline oscillations, together with the LSND/MiniBooNE and reactor anomalies is addressed. We find that the minimal model can fit oscillation data including the anomalies better than the standard 3ν model and similarly to the 3+2 phenomenological models, even though the number of free parameters is much smaller than in the latter. Accounting for the anomalies in the minimal model favours a normal hierarchy of the light states and requires a large reactor angle, in agreement with recent measurements. Our analysis of the model employs a new parametrization of seesaw models that extends the Casas-Ibarra one to regimes where higher order corrections in the light-heavy mixings are significant.
2012-01-01T00:00:00ZProbing the chiral regime of N(f)=2 QCD with mixed actions
http://hdl.handle.net/10550/43374
Probing the chiral regime of N(f)=2 QCD with mixed actions
Bernardoni, Fabio; Garron, Nicolas; Hernández Gamazo, Pilar; Necco, Silvia; Pena Ruano, Carlos
We report on our first experiences with a mixed action setup with overlap valence quarks and non-perturbatively O(a) improved Wilson sea quarks. For the latter we employ CLS Nf=2 configurations with light sea quark masses at small lattice spacings. Exact chiral symmetry allows to consider very light valence quarks and explore the matching to (partially quenched) Chiral Perturbation Theory (ChPT) in a mixed epsilon/p-regime. We compute the topological susceptibility and the low-lying spectrum of the massless Neuberger-Dirac operator for three values of the sea quark mass, and compare the sea quark mass dependence to NLO ChPT in the mixed regime. This provides two different determinations of the chiral condensate, as well as information about some NLO low-energy couplings. Our results allow to test the consistency of the mixed-regime approach to ChPT, as well as of the mixed action framework.
2011-01-01T00:00:00Z