Search results for " Neutrino"

The measurement of the pp chain solar neutrinos in Borexino

2019

Tau physics: theoretical perspective

2001

12 páginas, 10 figuras, 3 tablas.-- Comunicación presentada al 6º International Workshop on Tau Lepton Physics celebrado del 18 al 21 de Septiembre de 2000 en Victoria (Canada).-- arXiv:hep-ph/0012297v1

Improved global fit to Non-Standard neutrino Interactions using COHERENT energy and timing data

2020

We perform a global fit to neutrino oscillation and coherent neutrino-nucleus scattering data, using both timing and energy information from the COHERENT experiment. The results are used to set model-independent bounds on four-fermion effective operators inducing non-standard neutral-current neutrino interactions. We quantify the allowed ranges for their Wilson coefficients, as well as the status of the LMA-D solution, for a wide class of new physics models with arbitrary ratios between the strength of the operators involving up and down quarks. Our results are presented for the COHERENT experiment alone, as well as in combination with the global data from oscillation experiments. We also q…

Search for the exotic Θ+ resonance in the NOMAD experiment

2006

12 pages, 16 figures.-- PACS nrs.: 13.15.+g; 13.60.Le; 13.87.Fh; 14.40.Ev.-- ISI Article Identifier: 000243973100007.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ex/0612063.-- et al.

Neutrino Oscillations in the Dualized Standard Model

1998

A method developed from the Dualized Standard Model for calculating the quark CKM matrix and masses is applied to the parallel problem in neutrino oscillations. Taking the parameters determined from quarks and the masses of two neutrinos: $m_3^2 \sim 10^{-2} - 10^{-3} eV^2$ suggested by atmospheric neutrino data, and $m_2^2 \sim 10^{-10} eV^2$ suggested by the long wave-length oscillation (LWO) solution of the solar neutrino problem, one obtains from a parameter-free calculation all the mixing angles in reasonable agreement with existing experiment. However, the scheme is found not to accommodate comfortably the mass values $m_2^2 \sim 10^{-5} eV^2$ suggested by the MSW solution for solar n…

Confusing nonzero theta(13) with nonstandard interactions in the solar neutrino sector

2009

Solar and KamLAND data are in slight tension when interpreted in the standard two-flavor oscillations framework and this may be alleviated allowing for a non-zero value of the mixing angle theta_13. Here we show that, likewise, non-standard flavor-changing interactions (FCI), possibly intervening in the propagation of solar neutrinos, are equally able to alleviate this tension and therefore constitute a potential source of confusion in the determination of theta_13. By performing a full three-flavor analysis of solar and KamLAND data in presence of FCI we provide a quantitative description of the degeneracy existing between theta_13 and the vectorial coupling eps_e\tau^dV characterizing the…

An extended flipped SU(5) GUT model and the fermion mass hierarchy

1996

We present a viable flipped version of the SO(10) model consistent with the phenomenological requirements of having a non-trivial quark mixing matrix, natural doublet-triplet splitting, and a single pair of light electroweak Higgs doublet scalar bosons. In the presence of suitable non-renormalizable superpotential terms the model can reproduce the hierarchy observed in quark masses and mixings as well as an acceptable neutrino mass generated via the seesaw mechanism needed to explain dark matter and solar neutrino data.

Radiative neutrino mass in 331 scheme

2014

We propose a new radiative mechanism for neutrino mass generation based on the 3-3-1 electroweak gauge group. Lepton number is a symmetry of the Yukawa sector but spontaneously broken in the gauge sector. As a result light Majorana masses arise from neutral gauge boson exchange at the one-loop level. In addition to the isosinglet neutrinos which may be produced at the LHC through the extended gauge boson "portals", the model contains new isosinglet quarks which can also lie at the TeV scale and provide a plethora of collider phenomena.

Relating quarks and leptons with the T7 flavour group

2015

In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results lead to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.

Effective Field Theories for heavy probes in a hot QCD plasma and in the early universe

2016

International audience; There are many interesting problems in heavy-ion collisions and in cosmology that involve the interaction of a heavy particle with a medium. An example is the dissociation of heavy quarkonium seen in heavy-ion collisions. This was believed to be due to the screening of chromoelectric fields that prevents the heavy quarks from binding, however in the last years several perturbative and lattice computations have pointed out to the possibility that dissociation is due to the finite lifetime of a quarkonium state inside the medium. Regarding cosmology, the study of the behavior of heavy Majorana neutrinos in a hot medium is important to understand if this model can expla…