Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userLarge theta_13 from finite quantum corrections in quasi-degenerate neutrino mass spectrum
100
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We study finite quantum corrections for several well known neutrino mixing matrices and find that it is hard to account for the large value of theta_13 recently reported by T2K and MINOS. To nicely reproduce all experimentally favored neutrino mixing angles and masses, we propose a new neutrino mixing pattern. We also demonstrate a simple realization by slightly extending the standard model to illustrate the quantum corrections.
rate research
Read More
Quasi-degenerate neutrino mass models (QDN) which can explain the current data on neutrino masses and mixings,are studied. In the first part, we study the effect of CP-phases on QDN mass matrix obeying $mu-tau$ symmetry in normal hierarchical (QD-NH) and inverted hierarchical (QD-IH) patterns.The numerical predictions are consistent with observed data on solar mixing angle, absolute neutrino mass parameter consistent with neutrinoless double beta decay mass parameter and sum of three absolute neutrino masses from cosmological bound.The neutrino mass matrix is parameterized using only two unknown parameters. The second part deals with the estimation of observed baryon asymmetry of the universe. The prediction is nearly consistent with observation with flavoured thermal leptogenesis scenario. QD-NH model appears to be more favourable than those of QD-IH models.The present analysis shows that the three absolute neutrino masses may exhibit quasi-degenerate pattern in nature. They are far from discrimination at the moment.
A parametrisation of the degenerate neutrino mass matrix obeying $mu -tau$ symmetry, is introduced for detailed numerical analysis. As a continuation of our earlier work on normal and inverted hierarchical models, the present parametrisation for degenerate models has the ability to lower the solar mixing angle below the tri-bimaximal value $tan^{2}theta_{12}=0.5$, while maintaining the condition of maximal atmospheric mixing angle and zero reactor angle. The combined data on the mass-squared differences derived from various oscillation experiments, and also from the bounds on absolute neutrino masses in $0 ubetabeta$ decay and cosmology, gives certain constraints on the validity of the degenerate models.
Nailing down the unknown neutrino mixing angle theta_13 is one of the most important goals in current lepton physics. In this context, we perform a global analysis of neutrino oscillation data, focusing on theta_13, and including recent results [Neutrino 2008, Proceedings of the XXIII International Conference on Neutrino Physics and Astrophysics, Christchurch, New Zealand, 2008 (unpublished)]. We discuss two converging hints of theta_13>0, each at the level of ~1sigma: an older one coming from atmospheric neutrino data, and a newer one coming from the combination of solar and long-baseline reactor neutrino data. Their combination provides the global estimate sin^2(theta_13) = 0.016 +- 0.010 (1sigma), implying a preference for theta_13>0 with non-negligible statistical significance (~90% C.L.). We discuss possible refinements of the experimental data analyses, which might sharpen such intriguing indication.
Including the effects of the ${cal{O}}(gtrsim 1 {rm GeV})$ masses of the charm quark, $tau$ lepton and target nucleon in DIS phenomenology is discussed with applications to CC neutrino DIS: Neutrino data for $F_2$ are revisited within the global analysis framework. A fully differential calculation refines the CC charm production process as a gate to extract ${s(x), {bar s} (x) }$. New results are presented for a heavy quark version of the CTEQ6 set of PDFs and for ($ u_{mu} to u_{tau}$ oscillation-signal) $tau$ neutrino cross sections.
We examine the prospects of probing nonstandard interactions (NSI) of neutrinos in the e-tau sector with upcoming long-baseline nu_mu -> nu_e oscillation experiments. First conjectured decades ago, neutrino NSI remain of great interest, especially in light of the recent 8B solar neutrino measurements by SNO, Super-Kamiokande, and Borexino. We observe that the recent discovery of large theta_13 implies that long-baseline experiments have considerable NSI sensitivity, thanks to the interference of the standard and new physics conversion amplitudes. In particular, in some parts of NSI parameter space, the upcoming NOvA experiment will be sensitive enough to see ~ 3sigma deviations from the SM-only hypothesis. On the flip side, NSI introduce important ambiguities in interpreting NOvA results as measurements of CP-violation, the mass hierarchy and the octant of theta_23. In particular, observed CP violation could be due to a phase coming from NSI, rather than the vacuum Hamiltonian. The proposed LBNE experiment, with its longer ~ 1300 km baseline, may break many of these interpretative degeneracies.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
