Energy Independent Solution to the Solar Neutrino Anomaly including the SNO data

The global data on solar neutrino rates and spectrum, including the SNO charged current rate, can be explained by LMA, LOW or the energy independent solution -- corresponding to near-maximal mixing. All the three favour a mild upward renormalisation of the Cl rate. A mild downward shift of the $B$ neutrino flux is favoured by the energy independent and to a lesser extent the LOW solution, but not by LMA. Comparison with the ratio of SK elastic and SNO charged current scattering rates favours the LMA over the other two solutions, but by no more than $1.5\sigma$.Comment: 18 pages, latex, 3 figure

Constraints on SUSY Lepton Flavour Violation by rare processes

We study the constraints on flavour violating terms in low energy SUSY coming from several processes as li -> lj gamma, li -> lj lj lj and mu -> e in Nuclei. We show that a combined analysis of the processes allows us to extract additional information with respect to an individual analysis of all the processes. In particular, it makes possible to put bounds on sectors previously unconstrained by li -> lj gamma. We perform the analysis both in the mass eigenstate and in the mass insertion approximations clarifying the limit of applicability of these approximations.Comment: 23 pages, 15 figures. Typos corrected, several references and equations added. Results and conclusions completely unchanged. Accepted version for publication in JHE

The floor in the interplanetary magnetic field: Estimation on the basis of relative duration of ICME observations in solar wind during 1976-2000

To measure the floor in interplanetary magnetic field and estimate the time- invariant open magnetic flux of Sun, it is necessary to know a part of magnetic field of Sun carried away by CMEs. In contrast with previous papers, we did not use global solar parameters: we identified different large-scale types of solar wind for 1976-2000 interval, obtained a fraction of interplanetary CMEs (ICMEs) and calculated magnitude of interplanetary magnetic field B averaged over 2 Carrington rotations. The floor of magnetic field is estimated as B value at solar cycle minimum when the ICMEs were not observed and it was calculated to be 4,65 \pm 6,0 nT. Obtained value is in a good agreement with previous results.Comment: 10 pages, 2 figures, submitted in GR

Trimaximal neutrino mixing from modular A 4 invariance with residual symmetries

We construct phenomenologically viable models of lepton masses and mixing based on modular A 4 invariance broken to residual symmetries Z 3T or Z 3ST and Z 2S respectively in the charged lepton and neutrino sectors. In these models the neutrino mixing matrix is of trimaximal mixing form. In addition to successfully describing the charged lepton masses, neutrino mass-squared differences and the atmospheric and reactor neutrino mixing angles \u3b8 23 and \u3b8 13 , these models predict the values of the lightest neutrino mass (i.e., the absolute neutrino mass scale), of the Dirac and Majorana CP violation (CPV) phases, as well as the existence of specific correlations between i) the values of the solar neutrino mixing angle \u3b8 12 and the angle \u3b8 13 (which determines \u3b8 12 ), ii) the values of the Dirac CPV phase \u3b4 and of the angles \u3b8 23 and \u3b8 13 , iii) the sum of the neutrino masses and \u3b8 23 , iv) the neutrinoless double beta decay effective Majorana mass and \u3b8 23 , and v) between the two Majorana phases

Determining the Dirac CP Violation Phase in the Neutrino Mixing Matrix from Sum Rules

Using the fact that the neutrino mixing matrix $U = U^\dagger_{e}U_{\nu}$, where $U_{e}$ and $U_{\nu}$ result from the diagonalisation of the charged lepton and neutrino mass matrices, we analyse the sum rules which the Dirac phase $\delta$ present in $U$ satisfies when $U_{\nu}$ has a form dictated by, or associated with, discrete symmetries and $U_e$ has a ``minimal'' form (in terms of angles and phases it contains) that can provide the requisite corrections to $U_{\nu}$, so that reactor, atmospheric and solar neutrino mixing angles $\theta_{13}$, $\theta_{23}$ and $\theta_{12}$ have values compatible with the current data. The following symmetry forms are considered: i) tri-bimaximal (TBM), ii) bimaximal (BM) (or corresponding to the conservation of the lepton charge $L' = L_e - L_\mu - L_{\tau}$ (LC)), iii) golden ratio type A (GRA), iv) golden ratio type B (GRB), and v) hexagonal (HG). We investigate the predictions for $\delta$ in the cases of TBM, BM (LC), GRA, GRB and HG forms using the exact and the leading order sum rules for $\cos\delta$ proposed in the literature, taking into account also the uncertainties in the measured values of $\sin^2\theta_{12}$, $\sin^2\theta_{23}$ and $\sin^2\theta_{13}$. This allows us, in particular, to assess the accuracy of the predictions for $\cos\delta$ based on the leading order sum rules and its dependence on the values of the indicated neutrino mixing parameters when the latter are varied in their respective 3$\sigma$ experimentally allowed ranges

Leptonic Dirac CP Violation Predictions from Residual Discrete Symmetries

Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton) flavour symmetry, corresponding to a non-Abelian discrete symmetry group Gf, and that Gf is broken to specific residual symmetries Ge and G\u3bd of the charged lepton and neutrino mass terms, we derive sum rules for the cosine of the Dirac phase \u3b4 of the neutrino mixing matrix U. The residual symmetries considered are: i) Ge=Z2 and G\u3bd=Zn, n>2 or Zn 7Zm, n, m 652; ii) Ge=Zn, n>2 or Zn 7Zm, n, m 652 and G\u3bd=Z2; iii) Ge=Z2 and G\u3bd=Z2; iv) Ge is fully broken and G\u3bd=Zn, n>2 or Zn 7Zm, n, m 652; and v) Ge=Zn, n>2 or Zn 7Zm, n, m 652 and G\u3bd is fully broken. For given Ge and G\u3bd, the sum rules for cos \u3b4 thus derived are exact, within the approach employed, and are valid, in particular, for any Gf containing Ge and G\u3bd as subgroups. We identify the cases when the value of cos \u3b4 cannot be determined, or cannot be uniquely determined, without making additional assumptions on unconstrained parameters. In a large class of cases considered the value of cos \u3b4 can be unambiguously predicted once the flavour symmetry Gf is fixed. We present predictions for cos \u3b4 in these cases for the flavour symmetry groups Gf=S4, A4, T' and A5, requiring that the measured values of the 3-neutrino mixing parameters sin2\u3b812, sin2\u3b813 and sin2\u3b823, taking into account their respective 3\u3c3 uncertainties, are successfully reproduced. \ua9 2015 The Authors

The See-Saw Mechanism, Neutrino Yukawa Couplings, LFV Decays l_i to l_j + gamma and Leptogenesis

The LFV charged lepton decays mu to e + gamma, tau to e + gamma and tau to mu + gamma and thermal leptogenesis are analysed in the MSSM with see-saw mechanism of neutrino mass generation and soft SUSY breaking with universal boundary conditions. The case of hierarchical heavy Majorana neutrino mass spectrum, M_1 10^9 GeV. Considering the natural range of values of the heaviest right-handed Majorana neutrino mass, M_3 > 5*10^{13} GeV, and assuming that the soft SUSY breaking universal gaugino and/or scalar masses have values in the range of few 100 GeV, we derive the combined constraints, which the existing stringent upper limit on the mu to e + gamma decay rate and the requirement of successful thermal leptogenesis impose on the neutrino Yukawa couplings, heavy Majorana neutrino masses and SUSY parameters. Results for the three possible types of light neutrino mass spectrum -- normal and inverted hierarchical and quasi-degenerate -- are obtained.Comment: 25 pages, 9 figures; typos corrected, few clarifying comments and one figure added; version submitted for publicatio

Predicting the values of the leptonic CP violation phases in theories with discrete flavour symmetries

Using the fact that the neutrino mixing matrix $U = U^\dagger_{e}U_{\nu}$, where $U_{e}$ and $U_{\nu}$ result from the diagonalisation of the charged lepton and neutrino mass matrices, we consider a number of forms of $U_{\nu}$ associated with a variety of discrete symmetries: i) bimaximal (BM) and ii) tri-bimaximal (TBM) forms, the forms corresponding iii) to the conservation of the lepton charge $L' = L_e - L_\mu - L_{\tau}$ (LC), iv) to golden ratio type A (GRA) mixing, v) golden ratio type B (GRB) mixing, and vi) to hexagonal (HG) mixing. Employing the minimal form of $U_e$, in terms of angles and phases it contains, that can provide the requisite corrections to $U_{\nu}$ so that reactor, atmospheric and solar neutrino mixing angles $\theta_{13}$, $\theta_{23}$ and $\theta_{12}$ have values compatible with the current data, including a possible sizable deviation of $\theta_{23}$ from $\pi/4$, we discuss the possibility to obtain predictions for the CP violation phases in the neutrino mixing matrix. Considering the ``standard ordering'' of the the 12 and the 23 rotations in $U_e$ and following the approach developed in \cite{Marzocca:2013cr} we derive predictions for the Dirac phase $\delta$ and the rephasing invariant $J_{\rm CP}$ in the cases of GRA, GRB and HG forms of $U_{\nu}$ (results for the TBM and BM (LC) forms were obtained in \cite{Marzocca:2013cr}). We show also that under rather general conditions within the scheme considered the values of the Majorana phases in the PMNS matrix can be predicted for each of the forms of $U_{\nu}$ discussed. We give examples of these predictions and of their implications for neutrinoless double beta decay. In the GRA, GRB and HG cases, as in the TBM one, relatively large CP violation effects in neutrino oscillations are predicted ($|J_{CP}| \sim (0.031 - 0.034)$). Distinguishing between the TBM, BM (LC), GRA, GRB and HG forms of $U_{\nu}$ requires a measurement of $\cos\delta$ or a relatively high precision measurement of $J_{\rm CP}$