Neutrino Mixing and Leptogenesis in μ−τ\mu-\tau Symmetry

We study the consequences of the $Z_2$-symmetry behind the $\mu$--$\tau$ universality in neutrino mass matrix. We then implement this symmetry in the type-I seesaw mechanism and show how it can accommodate all sorts of lepton mass hierarchies and generate enough lepton asymmetry to interpret the observed baryon asymmetry in the universe. We also show how a specific form of a high-scale perturbation is kept when translated via the seesaw into the low scale domain, where it can accommodate the neutrino mixing data. We finally present a realization of the high scale perturbed texture through addition of matter and extra exact symmetries.Comment: 29 pages, 1 figure, 3 tables. Complete re-analysis. Version to appear in PR

Pure electroweak mechanism for the electric dipole moment of neutron in the Kobayashi-Maskawa model

The pure electroweak three-loop mechanism for the induced electric and chromoelectric dipole moments of quarks is studied in the Kobayashi-Maskawa model with three and four generations. In the standard three generation case, this mechanism is found to produce a negligible contribution to the electric dipole moment of neutron. In the presence of the fourth heavy generation, however, pure electroweak corrections are important and might be several times larger than the corresponding QCD contribution for the masses of heaviest quarks $\sim$ 500-600 GeV. The resulting electric dipole moment of neutron naturally arises at the level of $10^{-29} \,e\cdot cm$. The effects of the fourth generation physics are parametrized at standard electroweak scale by the presence of the effective charged right-handed currents.Comment: 6 pages, LATeX file, 4 figures available upon reques

Carcinome parathyroidien

Parathyroid cancer is uncommon and its etiology is largely unknown. It is difficult to diagnose. The preoperative syndrome is unusually severe primary hyperparathyroidism. Intraoperatively, many characteristics of the tumor may be highly suggestive. Confirmation requires pathological analysis of the operative specimens and the diagnosis is strengthened in the presence of associated Shantz and Castelman criteria. Specific immunohistochemical techniques have been shown to be contributive. The diagnosis can be further supported by the clinical course of local recurrence or metastatic spread.Treatment of this tumor is primarly surgical. In some cases, postoperative radiotherapy may improve locoregional control of the tumor. The disease control can be monitored by regula assay of serum calcium and the parathormone. We report a case of parathyroid carcinoma, with special emphasis on the diagnostic modalities of this tumor, its treatmentand its prognosis.Keywords: Hypercalcemia, Primary Hyperparathyroidism, Parathyroid carcinoma, Surgery

Iatrogenic colorectal Kaposi sarcoma complicating a refractory ulcerative colitis in a human immunodeficiency negative-virus patient

Kaposi sarcoma is a mesenchymal tumor associated to a human herpes virus-8. It often occurs in human immunodeficiency virus-positive subjects. Colorectal localization is rare. We report the case of a colorectal Kaposi sarcoma complicating a refractory ulcerative colitis treated with surgery after the failure of immunomodulator therapy in a human immunodeficiency virus-negative heterosexual man.Key words: Kaposi’s Sarcoma, ulcerative colitis, Human Herpes Virus-8, Infliximab, immunosuppressio

Supersymmetric radiative corrections at large tan beta

In the minimal supersymmetric extension of the Standard Model (MSSM), fermion masses and Yukawa couplings receive radiative corrections at one loop from diagrams involving the supersymmetric particles. The corrections to the relation between down-type fermion masses and Yukawa couplings are enhanced by tan beta, which makes them potentially very significant at large tan beta. These corrections affect a wide range of processes in the MSSM, including neutral and charged Higgs phenomenology, rare B meson decays, and renormalization of the CKM matrix. We give a pedagogical review of the sources and phenomenological effects of these corrections.Comment: 10 pages, 1 figure, to appear in the proceedings of 30 Years of Supersymmetry, Minneapolis, Minnesota, October 13-27, 2000; references adde

Norepinephrine: more of a neurohormone than a vasopressor

Septic shock causes unpredictable cardiovascular responses through adrenoreceptor-mediated changes in cardiac function and vascular responsiveness. The use of norepinephrine should be regarded as neurohormonal augmentation therapy to defend decompensating haemodynamic function rather than as a rescue therapy to treat shock. Recent trials represent a perceptible change in clinical practice to preferentially use norepinephrine early in resuscitation to defend the mean arterial pressure and to use norepinephrine as a neurohormone rather than as a vasopressor

Viability of MSSM scenarios at very large tan(beta)

We investigate the MSSM with very large tan(beta) > 50, where the fermion masses are strongly affected by loop-induced couplings to the "wrong" Higgs, imposing perturbative Yukawa couplings and constraints from flavour physics. Performing a low-energy scan of the MSSM with flavour-blind soft terms, we find that the branching ratio of B->tau nu and the anomalous magnetic moment of the muon are the strongest constraints at very large tan(beta) and identify the viable regions in parameter space. Furthermore we determine the scale at which the perturbativity of the Yukawa sector breaks down, depending on the low-energy MSSM parameters. Next, we analyse the very large tan(beta) regime of General Gauge Mediation (GGM) with a low mediation scale. We investigate the requirements on the parameter space and discuss the implied flavour phenomenology. We point out that the possibility of a vanishing Bmu term at a mediation scale M = 100 TeV is challenged by the experimental data on B->tau nu and the anomalous magnetic moment of the muon.Comment: 29 pages, 7 figures. v2: discussion in sections 1 and 4 expanded, conclusions unchanged. Matches version published in JHE

Universal Texture of Quark and Lepton Mass Matrices and a Discrete Symmetry Z_3

Recent neutrino data have been favourable to a nearly bimaximal mixing, which suggests a simple form of the neutrino mass matrix. Stimulated by this matrix form, a possibility that all the mass matrices of quarks and leptons have the same form as in the neutrinos is investigated. The mass matrix form is constrained by a discrete symmetry Z_3 and a permutation symmetry S_2. The model, of course, leads to a nearly bimaximal mixing for the lepton sectors, while, for the quark sectors, it can lead to reasonable values of the CKM mixing matrix and masses.Comment: 24 pages, RevTEX, no figure, some references and comments were adde

Leptogenesis and neutrino parameters

We calculate the baryonic asymmetry of the universe in the baryogenesis-via-leptogenesis framework, assuming first a quark-lepton symmetry and then a charged-neutral lepton symmetry. We match the results with the experimentally favoured range. In the first case all the oscillation solutions to the solar neutrino problem, except the large mixing matter solution, can lead to the allowed range, but with fine tuning of the parameters. In the second case the general result is quite similar. Some related theoretical hints are discussed.Comment: RevTex, 21 pages with 8 figure

Neutrino Mass, Sneutrino Dark Matter and Signals of Lepton Flavor Violation in the MRSSM

We study the phenomenology of mixed-sneutrino dark matter in the Minimal R-Symmetric Supersymmetric Standard Model (MRSSM). Mixed sneutrinos fit naturally within the MRSSM, as the smallness (or absence) of neutrino Yukawa couplings singles out sneutrino A-terms as the only ones not automatically forbidden by R-symmetry. We perform a study of randomly generated sneutrino mass matrices and find that (i) the measured value of $\Omega_{DM}$ is well within the range of typical values obtained for the relic abundance of the lightest sneutrino, (ii) with small lepton-number-violating mass terms $m_{nn}^{2} {\tilde n} {\tilde n}$ for the right-handed sneutrinos, random matrices satisfying the $\Omega_{DM}$ constraint have a decent probability of satisfying direct detection constraints, and much of the remaining parameter space will be probed by upcoming experiments, (iii) the $m_{nn}^{2} {\tilde n} {\tilde n}$ terms radiatively generate appropriately small Majorana neutrino masses, with neutrino oscillation data favoring a mostly sterile lightest sneutrino with a dominantly mu/tau-flavored active component, and (iv) a sneutrino LSP with a significant mu component can lead to striking signals of e-mu flavor violation in dilepton invariant-mass distributions at the LHC.Comment: Revised collider analysis in Sec. 5 after fixing error in particle spectrum, References adde