30,242 research outputs found
A novel and economical explanation for SM fermion masses and mixings
I propose the first multiscalar singlet extension of the Standard Model (SM),
that generates tree level top quark and exotic fermion masses as well as one
and three loop level masses for charged fermions lighter than the top quark and
for light active neutrinos, respectively, without invoking electrically charged
scalar fields. That model, which is based on the discrete
symmetry, successfully explains the observed SM fermion mass and mixing
pattern. The charged exotic fermions induce one loop level masses for charged
fermions lighter than the top quark. The charged scalar singlet
generates the observed charged fermion mass and quark mixing pattern.Comment: 4 pages. Section on the 750 GeV diphoton anomaly removed. Accepted
for publication as a Letter in the European Physical Journal
Study of the strong and in a non-relativistic quark model
We present results for the strong widths corresponding to the and decays. We apply our
model in Ref. Phys. Rev. D 72, 094022 (2005) where we previously studied the
corresponding transitions in the charmed sector. Our non-relativistic
constituent quark model uses wave functions that take advantage of the
constraints imposed by heavy quark symmetry. Partial conservation of axial
current hypothesis allows us to determine the strong vertices from an analysis
of the axial current matrix elements.Comment: 6 latex pages, 1 table, new references adde
Generalised Fractional Evolution Equations of Caputo Type
This paper is devoted to the study of generalised time-fractional evolution
equations involving Caputo type derivatives. Using analytical methods and
probabilistic arguments we obtain well-posedness results and stochastic
representations for the solutions. These results encompass known linear and
non-linear equations from classical fractional partial differential equations
such as the time-space-fractional diffusion equation, as well as their far
reaching extensions. \\ Meaning is given to a probabilistic generalisation of
Mittag-Leffler functions.Comment: To be published in 'Chaos, Solitons & Fractals
A predictive model with flavour symmetry
We propose a predictive model based on the gauge group supplemented by the discrete group, which successfully describes
the SM fermion mass and mixing pattern. The small active neutrino masses are
generated via inverse seesaw mechanism with three very light Majorana
neutrinos. The observed charged fermion mass hierarchy and quark mixing pattern
are originated from the breaking of the
discrete group at very high scale. The obtained values for the physical
observables for both quark and lepton sectors are in excellent agreement with
the experimental data. The model predicts a vanishing leptonic Dirac CP
violating phase as well as an effective Majorana neutrino mass parameter of
neutrinoless double beta decay, with values 2 and 48 meV
for the normal and the inverted neutrino mass hierarchies, respectively.Comment: 20 pages. Final version published in Nuclear Physics
Fermion mass and mixing pattern in a minimal T7 flavor 331 model
We present a model based on the
gauge symmetry having an extra
flavor group, which successfully describes the observed SM fermion mass and
mixing pattern. In this framework, the light active neutrino masses arise via
double seesaw mechanism and the observed charged fermion mass and quark mixing
hierarchy is a consequence of the symmetry
breaking at very high energy. In our minimal flavor 331 model, the
spectrum of neutrinos includes very light active neutrinos as well as heavy and
very heavy sterile neutrinos. The model has in total 16 effective free
parameters, which are fitted to reproduce the experimental values of the 18
physical observables in the quark and lepton sectors. The obtained physical
observables for both quark and lepton sectors are compatible with their
experimental values. The model predicts the effective Majorana neutrino mass
parameter of neutrinoless double beta decay to be 3 and
40 meV for the normal and the inverted neutrino spectrum, respectively.
Furthermore, our model features a vanishing leptonic Dirac CP violating phase.Comment: 18 pages. Final version. To be published in Journal of Physics G.
arXiv admin note: substantial text overlap with arXiv:1309.656
The role of hyperfine mixing in semileptonic decays of doubly-heavy baryons
We analyze the effects of hyperfine mixing in semileptonic decays
of doubly heavy baryons. We qualitatively confirm the results by W. Roberts and
M. Pervin in Int. J. Mod. Phys. A, 2009, {\bf 24}: 2401-2413, finding that
mixing has a great impact on those transitions. However, predictions without
mixing differ by a factor of 2 and this discrepancy translates to the mixed
case where large differences in decay widths are observed between the two
calculations.Comment: 3 latex pages. Talk given at The 5-th International Conference on
Quarks and Nuclear Physics (QNP09), Beijing, September 200
Coherent pion production off nuclei at T2K and MiniBooNE energies revisited
As a result of a new improved fit to old bubble chamber data of the dominant
axial C_5^A nucleon-to-Delta form factor, and due to the relevance of this form
factor for neutrino induced coherent pion production, we re-evaluate our model
predictions in Phys. Rev. D79, 013002 (2009) for different observables of the
latter reaction. Central values for the total cross sections increase by 20% to
30%, while differential cross sections do not change their shape appreciably.
Furthermore, we also compute the uncertainties on total, differential and flux
averaged cross sections induced by the errors in the determination of C_5^A.
Our new results turn out to be compatible within about 1 sigma with the former
ones. Finally, we stress the existing tension between the recent experimental
determination of the sigma(CC coh \pi^+)/sigma(NC coh \pi^0) ratio by the
SciBooNE Collaboration and the theoretical predictions.Comment: 6 latex pages, 1 table, 2 figures. Shortened versio
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