An S3S_3 Model for Lepton Mass Matrices with Nearly Minimal Texture

We propose a simple extension of the electroweak standard model based on the discrete $S_3$ symmetry that is capable of realizing a nearly minimal Fritzsch-type texture for the Dirac mass matrices of both charged leptons and neutrinos. This is achieved with the aid of additional $Z_5$ and $Z_3$ symmetries, one of which can be embedded in $U(1)_{B-L}$. Five complex scalar singlet fields are introduced in addition to the SM with right-handed neutrinos. Although more general, the modified texture of the model retains the successful features of the minimal texture without fine-tuning; namely, it accommodates the masses and mixing of the leptonic sector and relates the emergence of large leptonic mixing angles with the seesaw mechanism. For large deviations of the minimal texture, both quasidegenerate spectrum or inverted hierarchy are allowed for neutrino masses.Comment: 11pp, 2 figures. v2: vev alignment addressed, additional analysis performed; to appear in PR

FCNC in the minimal 3-3-1 model revisited

We show that in the minimal 3-3-1 model the flavor changing neutral currents (FCNCs) do not impose necessarily strong constraints on the mass of the $Z^\prime$ of the model if we also consider the neutral scalar contributions to such processes, like the neutral mesons mass difference and rare semileptonic decays. We first obtain numerical values for all the mixing matrices of the model i.e., the unitary matrices that rotate the left- and right-handed quarks in each charge sector which give the correct mass of all the quarks and the CKM mixing matrix. Then, we find that there is a range of parameters in which the neutral scalar contributions to these processes may interfere with those of the $Z^\prime$, implying this vector boson may be lighter than it has been thought.Comment: Extended version including the effect of a pseudoscalar. 37 pags. and 12 figures. New references added. Version matches the published versio

The Quest for an Intermediate-Scale Accidental Axion and Further ALPs

The recent detection of the cosmic microwave background polarimeter experiment BICEP2 of tensor fluctuations in the B-mode power spectrum basically excludes all plausible axion models where its decay constant is above $10^{13}$ GeV. Moreover, there are strong theoretical, astrophysical, and cosmological motivations for models involving, in addition to the axion, also axion-like particles (ALPs), with decay constants in the intermediate scale range, between $10^9$ GeV and $10^{13}$ GeV. Here, we present a general analysis of models with an axion and further ALPs and derive bounds on the relative size of the axion and ALP photon (and electron) coupling. We discuss what we can learn from measurements of the axion and ALP photon couplings about the fundamental parameters of the underlying ultraviolet completion of the theory. For the latter we consider extensions of the Standard Model in which the axion and the ALP(s) appear as pseudo Nambu-Goldstone bosons from the breaking of global chiral $U(1)$ (Peccei-Quinn (PQ)) symmetries, occuring accidentally as low energy remnants from exact discrete symmetries. In such models, the axion and the further ALP are protected from disastrous explicit symmetry breaking effects due to Planck-scale suppressed operators. The scenarios considered exploit heavy right handed neutrinos getting their mass via PQ symmetry breaking and thus explain the small mass of the active neutrinos via a seesaw relation between the electroweak and an intermediate PQ symmetry breaking scale. We show some models that can accommodate simultaneously an axion dark matter candidate, an ALP explaining the anomalous transparency of the universe for $\gamma$-rays, and an ALP explaining the recently reported 3.55 keV gamma line from galaxies and clusters of galaxies, if the respective decay constants are of intermediate scale.Comment: 43pp, 4 figures. v2: version accepted for publication in JHE

Hours of work and retirement behavior

Using a novel dataset from the 2006 Portuguese Labor Force Survey this paper examines the impact of a voluntary reduction in hours of work, before retirement, on the moment of exit from the labor force. If, as often suggested, flexibility in hours of work is a useful measure to postpone retirement, then a reduction in working hours should be associated with retirement at later ages. Results prove otherwise suggesting that reducing hours of work before retirement is associated with early exits from the labor force. A reduction in hours of work seems to signal the worker’s wish to retire sooner rather than to announce the desire of remaining in the labor market.aging, retirement, working hours, older workers.

Hours of Work and Retirement Behavior

Using a novel dataset from the 2006 Portuguese Labor Force Survey this paper examines the impact of a voluntary reduction in hours of work, before retirement, on the moment of exit from the labor force. If, as often suggested, flexibility in hours of work is a useful measure to postpone retirement, then a reduction in working hours should be associated with retirement at later ages. Results prove otherwise suggesting that reducing hours of work before retirement is associated with early exits from the labor force. A reduction in hours of work seems to signal the worker's wish to retire sooner rather than to announce the desire of remaining in the labor market. This result may enclose the need for some alternative policy strategies regarding working hours.aging, retirement, working hours, older workers

Age and opportunities for promotion

Using a panel of new firms and their employees, this paper studies the promotion opportunities for older workers within the same firm. Survival analysis suggests that younger employees experience shorter times to promotion than older workers and, therefore, the latter face a smaller likelihood of promotion. Although men are promoted more often than women, empirical results show that women have shorter survival times to promotion than men. Also, previous promotions are stronger determinants of subsequent ones and this finding provides support to the evidence on promotion “fast-tracks”.aging, older workers, employment relationships, promotion

Looking at the photoproduction of massive gauge bosons at the LHeC

In this contribution we report on the investigation of the photoproduction of W and Z bosons in the planned electron-proton/nucleus collider, the LHeC. The production cross sections and the number of events are provided and theoretical uncertainties are discussed. We also analyze the sensitivity of the LHeC experiment to physics beyond Standard Model by studying the role played by anomalous WWgamma coupling in the presented process.Comment: Contribution to the proceedings of the XXI International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2013), Marseille, 22-26 April 201