Truly Minimal Left-Right Model of Quark and Lepton Masses

We propose a left-right model of quarks and leptons based on the gauge group $SU(3)_C \times SU(2)_L \times SU(2)_R \times U(1)_{B-L}$, where the scalar sector consists of only two doublets: (1,2,1,1) and (1,1,2,1). As a result, any fermion mass, whether it be Majorana or Dirac, must come from dimension-five operators. This allows us to have a common view of quark and lepton masses, including the smallness of Majorana neutrino masses as the consequence of a double seesaw mechanism.Comment: Version to appear in PRL, title changed by journal to "Left-right model of quark and lepton masses without a scalar bidoublet

Inverse Seesaw Neutrino Mass from Lepton Triplets in the U(1)_Sigma Model

The inverse seesaw mechanism of neutrino mass, i.e. m_nu = (m_D^2/m_N^2)epsilon_L where epsilon_L is small, is discussed in the context of the U(1)_Sigma model. This is a gauge extension of the Standard Model of particle interactions with lepton triplets (Sigma^+,Sigma^),Sigma^-) as (Type III) seesaw anchors for obtaining small Majorana neutrino masses.Comment: 7 pages, no figur

El doctor Sardà i Salvany i la Renaixença

El doctor Sardà i Salvany i la Renaixenç

Portada

Foto de portada: Guta Hedewig i Cesc Casadesús a la segona cita: Pas, Pont de Baumadestral, 29 d 'agost. Llauró 12 Cites. Foto: Ernest Gutiérrez

Algunas consideraciones sobre la iglesia de Santa Caterina de Barcelona

Una nova lectura de les informacions que posseïem del convent de Santa Caterina de Barcelona, l'aportació de noves dades i un estudi comparatiu amb les fàbriques mendicants contemporànies permeten proposar l'existència d'una fàbrica d'arcs diafragmàtics, precedent a l'església gòtica, que, sense grans canvis, perdurà fins al segle XIX. Fet que significa haver de modificar la datació de l'església gòtica, tot avançant-la fins al segle XIV, fruit d'una campanya de millores que substituiria l'església aixecada al segle XIII.A new interpretation of the data used so far, the addition of other unpublished information and a comparative study with other buildings are elements wich enable us to propose the existence of a structure prior to the church of the Dominican friary of Barcelona, Santa Caterina. This initial church, built in the second half of the 13th century, following the pattern of others erectet by the mendicant orders, was to be replaced in the 14th century by structure in full Gothic style, wich lasted in much the same form, with few major changes, down to the 19th century