3,923 research outputs found
Models of flavour with discrete symmetries
We briefly review some recent developments in theoretical models of fermion
masses, mixings and CP violation with discrete non-Abelian symmetries. Then, we
explain the main ideas of a recently proposed Minimal S_3 Invariant Extension
of the Standard Model and its application to a unified analysis of masses,
mixings and CP violation in the leptonic and quark sectors as well as the
explicit computation of the V_PMNS and V_CKM mixing matrices.Comment: Latex, 17 pages, no figure
Neutrino masses and mixings in a Minimal S_3-invariant Extension of the Standard Model
The mass matrices of the charged leptons and neutrinos, that had been derived
in the framework of a Minimal S_3-invariant Extension of the Standard Model,
are here reparametrized in terms of their eigenvalues. The neutrino mixing
matrix, V_PMNS, is then computed and exact, explicit analytical expressions for
the neutrino mixing angles as functions of the masses of the neutrinos and
charged leptons are obtained. The reactor, theta_13, and the atmosferic,
theta_23, mixing angles are found to be functions only of the masses of the
charged leptons. The numerical values of theta_13{th} and theta_23{th} computed
from our theoretical expressions are found to be in excellent agreement with
the latest experimental determinations. The solar mixing angle, theta_12{th},
is found to be a function of both, the charged lepton and neutrino masses, as
well as of a Majorana phase phi_nu. A comparison of our theoretical expression
for the solar angle theta_12{th} with the latest experimental value
theta_12{exp} ~ 34 deg allowed us to fix the scale and origin of the neutrino
mass spectrum and obtain the mass values |m_nu1|=0.0507 eV, |m_nu2|=0.0499 eV
and |m_nu3|=0.0193 eV, in very good agreement with the observations of neutrino
oscillations, the bounds extracted from neutrinoless double beta decay and the
precision cosmological measurements of the CMB.Comment: To appear in the Proceedings of the XXIX Symposium on Nuclear
Physics, Cocoyoc, Mex., January 2006. Some typographical errors on formulae
correcte
On quark-lepton complementarity
Recent measurements of the neutrino solar mixing angle and the Cabibbo angle
satisfy the empirical relation theta_{sol} + theta_{C} ~ 45^{o}. This relation
suggests the existence of a correlation between the mixing matrices of leptons
and quarks, the so called quark-lepton complementarity. Here, we examine the
possibility that this correlation originates in the strong hierarchy in the
mass spectra of quarks and charged leptons, and the seesaw mechanism that gives
mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in
which the mass matrices of all fermions have a similar Fritzsch texture, we
calculate the mixing matrices V_{CKM} and U_{MNSP} as functions of quark and
lepton masses and only two free parameters, in very good agreement with the
latest experimental values on masses and mixings. Three essential ingredients
to explain the quark-lepton complementarity relation are identified: the strong
hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw
mechanism and the assumption of maximal CP violation in the lepton sector.Comment: 6 pages, to appear in "Particles and fields: Xth Mexican Workshop on
Particles and Fields" (Morelia, Mich. Mexico, November 6-12, 2005), Eds. A.
Bashir and L. Villasenor, AIP Conference proceedings (2006
Coulomb correlations of a few body system of spatially separated charges
A Hartree-Fock and Hartree-Fock-Bogoliubov study of a few body system of
spatially separated charge carriers was carried out. Using these variational
states, we compute an approximation to the correlation energy of a finite
system of electron-hole pairs. This energy is shown as a function of the
Coulomb coupling and the interplane distance. We discuss how the correlation
energy can be used to theoretically determine the formation of indirect
excitons in semiconductors which is relevant for collective phenomena such as
Bose-Einstein condensation (BEC).Comment: Conference EDISON16 (2009), 4 page
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