Lepton Flavor Violation in SUSY GUT Model with Non-universal Sfermion Masses

We analyze lepton flavor violating $\tau \to \mu \gamma$ and $\mu \to e \gamma$ processes in SUSY GUT model in which sfermions have special mass spectrum. It is assumed that only third generation sfermions which are contained in ${\bf 10}(Q, U^c, E^c)$ of SU(5) can have a different mass from the others. This mass spectrum is led from $E_6$ GUT model with horizontal symmetries. It is shown that branching ratios of $\tau \to \mu \gamma$ and $\mu \to e \gamma$ depend strongly on a right-handed stau mass. The weak scale stability requires the light stau, so large decay rates can be expected in this scenario. When stau is around 150 GeV and $\tan \beta \sim 10$, the branching ratios can be larger than $Br(\tau \to \mu \gamma) \simeq 10^{-8}$ and $Br(\mu \to e \gamma) \simeq 5\times 10^{-12}$, which are within reach of future experiments. In addition, this model has an interesting feature that the final state charged lepton tends to have the right-handed chirality.Comment: 17 pages, 12 figures, v3 a reference adde

Revisiting Minimal Lepton Flavour Violation in the Light of Leptonic CP Violation

The Minimal Lepton Flavour Violation (MLFV) framework is discussed after the recent indication for CP violation in the leptonic sector. Among the three distinct versions of MLFV, the one with degenerate right-handed neutrinos will be disfavoured, if this indication is confirmed. The predictions for leptonic radiative rare decays and muon conversion in nuclei are analysed, identifying strategies to disentangle the different MLFV scenarios. The claim that the present anomalies in the semi-leptonic $B$-meson decays can be explained within the MLFV context is critically re-examined concluding that such an explanation is not compatible with the present bounds from purely leptonic processes.Comment: 36 pages, 4 figures. V2: References added; version accepted for publication on JHE

Three-Neutrino Mixing and Combined Vacuum Oscillations and MSW Transitions of Solar Neutrinos

Assuming three flavour neutrino mixing takes place in vacuum, we investigate the possibility that the solar nu_e take part in MSW transitions in the Sun due to Delta m^2_{31} from 10^{-7} eV^2 to 10^{-4} eV^2, followed by long wave length vacuum oscillations on the way to the Earth, triggered by Delta m^2_{21} (or Delta m^2_{32}) from 10^{-12} eV^2 to 10^{-10} eV^2, Delta m^2_{31} and Delta m^2_{21} (Delta m^2_{32}) being the corresponding neutrino mass squared differences. The solar nu_e survival probability is shown to be described in this case by a simple analytic expression. Depending on whether the vacuum oscillations are due to Delta m^2_{21} or Delta m^2_{32} there are two very different types of interplay between the MSW transitions and the vacuum oscillations of the solar nu_e. Performing an analysis of the most recently published solar neutrino data we have found several qualitatively new solutions of the solar neutrino problem of the hybrid MSW transitions + vacuum oscillations type. The solutions differ in the way the pp, 7Be and 8B neutrino fluxes are affected by the transitions in the Sun and the oscillations in vacuum. The specific features of the new solutions are discussed.Comment: 37 pages Latex, 16 Postscript Figure

Radiative Emission of Neutrino Pairs in Atoms and Light Sterile Neutrinos

The process of Radiative Emission of Neutrino Pair (RENP) in atoms is sensitive to the absolute neutrino mass scale, the type of spectrum neutrino masses obey and the nature - Dirac or Majorana - of massive neutrinos. We analyse the possibility to test the hypothesis of existence of neutrinos with masses at the eV scale coupled to the electron in the weak charged lepton current in an RENP experiment. The presence of eV scale neutrinos in the neutrino mixing is associated with the existence of sterile neutrinos which mix with the active flavour neutrinos. At present there are a number of hints for active-sterile neutrino oscillations driven by $\Delta m^2 \sim 1~{\rm eV^2}$. We perform a detailed analysis of the RENP phenomenology within the "3 + 1" scheme with one sterile neutrino.Comment: LATEX file, 19 pages, the effects of the 3-4 mixing taken into account, one table and four figures added, version to be published in Phys. Lett.

The impact of high ligation on results of endovenous laser treatment for varicose veins of lower limbs: comparative study

Catedra chirurgie generală, USMF ”Nicolae Testemițanu”, Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Tratamentul endovenos cu laser (TEVL) reprezintă actualmente una dintre cele mai frecvent utilizate tehnici curative adresate varicelor membrelor inferioare. Necesitatea asocierii crosectomiei în cazurile respective continuă a fi un aspect controversat. Scopul studiului: Ilucidarea impactului crosectomiei asupra rezultatelor clinice la un an după TEVL. Material şi metode: A fost realizată analiza comparativă între 2 loturi convenţionale de pacienţi cu maladie varicoasă în sistemul venei safena magna, trataţi cu laser endovenos: cu crosectomie asociată (lotul “CE”; n=20) şi fără crosectomie (lotul ”non-CE”; n=20). TEVL a fost aplicat utilizînd dioda laser cu lungimea de undă de 940 nm, energia termică fiind emisă endoluminal în regim continuu, prin intermediul unei fibre “bare-tip” de 600 mkm. Accesul endovenos s-a realizat percutan ecoghidat sau prin mini-incizie în 1/3 distală a coapsei sau 1/3 proximală a gambei (”non-CE”); ori prin propulsarea retrogradă a fibrei după crosectomie prin incizie în plica inghinală (“CE”). Rezultate: Coraportul în funcţie de gen a constituit – 4/1 (F/B) pentru ambele loturi; vârsta medie a bolnavilor fiind 44,2 ani (“CE”) vs. 38,3 ani (”non-CE”). Repartizarea cazurilor în funcţie de clasa clinică (C) a clasificării CEAP: C2-C3 – 45% şi C4-C6 – 55% în lotul “CE” şi C2-C3 – 60%, C4-C6 – 40% în lotul ”non-CE”. Valoarea medie a indicelui LEED (linear endovenous energy density) a constituit 71,6±4,86 J/cm (“CE”) vs. 60,73±5,39 J/cm (”non-CE”). Totodată, recurenţa clinică a fost înregistrată doar la 1 (5%) bolnav (”non-CE”), fiind cauzată de dezvoltarea refluxului prin vena safenă accesorie anterioară a coapsei competentă preoperator. Concluzii: Datele studiului reflectă absenţa unei diferenţe semnificative între rezultatele clinice la un an după TEVL cu şi fără crosectomie. Pînă la obţinerea evidenţei ştiințifice certe asocierea de rutină a crosectomiei la TEVL al maladiei varicoase nu pare a fi justificată.Introduction: Endovenous laser treatment (EVLT) is currently one of the most commonly used minimally invasive technique addressed to varicose veins of lower limb. The necessity to add high ligation in these cases continues to be a controversial issue. The aim of study: To highlight the impact of high ligation on clinical outcomes one year after EVLT. Material and methods: We conducted a comparative analysis between two conventional groups of patients with varicose veins, refers to great saphenous vein system, treated with endovenous laser: associated with high ligation (group “HL”; n=20) and without high ligation (group “non-HL” n=20). EVLT was applied using diode laser with a wavelength of 940 nm, thermal energy being emitted endoluminally on a continuous basis through a 600 mkm bare-tip fiber. Endovenous access was achieved by percutaneous echo-guided puncture or through a small incision in the distal thigh or proximal calf (“non-HL”); or by retrograde passing of the fibre after high ligation, performed through an incision in the groin fold (“HL”). Results: The female/male ratio was 4:1 for both groups; while the average age of patients was 44.2 years (“HL”) vs. 38.3 years (“non-HL”). The distribution of cases according to clinical class (C) of the CEAP classification: C2-C3 – 45%, C4-C6 – 55% in the “HL” group and C2-C3 – 60%, C4-C6 – 40% in the “non-HL” group. The mean linear endovenous energy density (LEED) accounted 71.6±4.86 J/cm (“HL”) vs. 60.73±5.39 J/cm (“non-HL”). However, clinical recurrence was registered only in 1 (5%) patient (“non-HL”), and was caused by development of pathological reflux in previously competent anterior accessory saphenous vein of the thigh. Conclusions: Our study data reflects the absence of significant differences in clinical outcomes at one year after EVLT performed with and without high ligation. Until accumulation of reliable scientific evidence routine association of EVLT with high ligation for treating varicose veins does not seems to be justified

Day-night asymmetry of high and low energy solar neutrino events in Super-Kamiokande and in the Sudbury Neutrino Observatory

In the context of solar neutrino oscillations among active states, we briefly discuss the current likelihood of Mikheyev-Smirnov-Wolfenstein (MSW) solutions to the solar neutrino problem, which appear to be currently favored at large mixing, where small Earth regeneration effects might still be observable in Super-Kamiokande (SK) and in the Sudbury Neutrino Observatory (SNO). We point out that, since such effects are larger at high (low) solar neutrino energies for high (low) values of the mass square difference \delta m^2, it may be useful to split the night-day rate asymmetry in two separate energy ranges. We show that the difference \Delta of the night-day asymmetry at high and low energy may help to discriminate the two large-mixing solutions at low and high \delta m^2 through a sign test, both in SK and in SNO, provided that the sensitivity to \Delta can reach the (sub)percent level.Comment: 6 pages (RevTeX) + 4 figures (PostScript). Final version, to appear in Phys. Rev.

Analytical description of quasivacuum oscillations of solar neutrinos

We propose a simple prescription to calculate the solar neutrino survival probability P_{ee} in the quasivacuum oscillation (QVO) regime. Such prescription is obtained by matching perturbative and exact analytical results, which effectively take into account the density distribution in the Sun as provided by the standard solar model. The resulting analytical recipe for the calculation of P_{ee} is shown to reach its highest accuracy |\Delta P_{ee}| < 2.6 x 10^{-2} in the whole QVO range) when the familiar prescription of choosing the solar density scale parameter r_0 at the Mikheyev-Smirnov-Wolfenstein (MSW) resonance point is replaced by a new one, namely, when r_0 is chosen at the point of ``maximal violation of adiabaticity'' (MVA) along the neutrino trajectory in the Sun. The MVA prescription admits a smooth transition from the QVO regime to the MSW transition one. We discuss in detail the phase acquired by neutrinos in the Sun, and show that it might be of relevance for the studies of relatively short timescale variations of the fluxes of the solar \nu lines in the future real-time solar neutrino experiments. Finally, we elucidate the role of matter effects in the convective zone of the Sun.Comment: 25 pages (RevTeX) + 11 figures (postscript

Running neutrino masses and mixing in a SU(4) x SU(2)^2 x U(1)_X model

In this talk, we discuss the implications of the renormalization group equations for the neutrino masses and mixing angles in a supersymmetric string-inspired SU(4) x SU(2)_L x SU(2)_R x U(1)_X model with matter in fundamental and antisymmetric tensor representations only. The quark, charged lepton and neutrino Yukawa matrices are distinguished by different Clebsch-Gordan coefficients due to contracting over SU(4) and SU(2)_R indices. In order to permit for a more realistic, hierarchical light neutrino mass spectrum with bi-large mixing a second U(1)_X breaking singlet with fractional charge is introduced. By numerical investigation we find a region in the model parameter space where the neutrino mass-squared differences and mixing angles at low energy are consistent with experimental data.Comment: Talk presented at the Corfu Summer Institute, Corfu-Greece, September 4-14, 200

CP violation in the lepton sector and implications for leptogenesis

We review the current status of the data on neutrino masses and lepton mixing and the prospects for measuring the CP-violating phases in the lepton sector. The possible connection between low energy CP violation encoded in the Dirac and Majorana phases of the Pontecorvo-Maki-Nakagawa-Sakata mixing matrix and successful leptogenesis is emphasized in the context of seesaw extensions of the Standard Model with a flavor symmetry Gf (and CP symmetry)

The mu - e Conversion in Nuclei, mu --> e gamma, mu --> 3e Decays and TeV Scale See-Saw Scenarios of Neutrino Mass Generation

We perform a detailed analysis of lepton flavour violation (LFV) within minimal see-saw type extensions of the Standard Model (SM), which give a viable mechanism of neutrino mass generation and provide new particle content at the electroweak scale. We focus, mainly, on predictions and constraints set on each scenario from mu --> e gamma, mu --> 3e and mu - e conversion in the nuclei. In this class of models, the flavour structure of the Yukawa couplings between the additional scalar and fermion representations and the SM leptons is highly constrained by neutrino oscillation measurements. In particular, we show that in some regions of the parameters space of type I and type II see-saw models, the Dirac and Majorana phases of the neutrino mixing matrix, the ordering and hierarchy of the active neutrino mass spectrum as well as the value of the reactor mixing angle theta_{13} may considerably affect the size of the LFV observables. The interplay of the latter clearly allows to discriminate among the different low energy see-saw possibilities.Comment: Expressions for the factors |C_{me}|^2 and |C_{mu3e}|^2 in the mu-e conversion and mu-->3e decay rates, eqs. (36) and (49), respectively, corrected; results in subsections 2.2 and 2.3 quantitatively changed, qualitatively remain the same; figures 2, 3, 4 and 5 replace