2,373 research outputs found

    A variety of lepton number violating processes related to Majorana neutrino masses

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    A Majorana type of the neutrino mass matrix induces a class of lepton number violating processes. Cross sections of these reactions are given in terms of the neutrino mass matrix element, and a semi-realistic event rate is estimated. These processes provide mass and mixing parameters not directly accessible by the neutrino oscillation experiments. If these processes are discovered with a larger rate than given here, it would imply a new physics of the lepton number violation not directly related to the Majorana neutrino mass, such as R-parity violating operators in SUSY models.Comment: 15 pages, 1 figur

    Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

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    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide bandwidth (17.1-18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1-18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode

    Effective Autonomic Nerve Treatmentsin Female Patient with Migraine and Tension-Type Headache (TTH)

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    Authors have been involved in rehabilitation, sports medicine, and psychosomatic problems. Case presentation: The patient is 40-year-old female, who suffers from migraine and tension-type headache (TTH) for 10 years.Autonomic nerve exam showed decreased function of sympathetic and parasympathetic nerves with tachycardia as 103/min. We continued a series of autonomic nerve treatments, and then pulse was decreased to 90’s, 80’s, 70’s in 1,3,6 months. After treatments, she showed improved autonomic function and stress resilience. Discussion and Conclusion: The treatments suggest efficacy for recovery of autonomic nerve function. They may become useful reference for novel methods for future developmen

    Phase effects from the general neutrino Yukawa matrix on lepton flavor violation

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    We examine contributions from Majorana phases to lepton flavor violating processes in the framework of the minimal supersymmetric standard model with heavy right-handed neutrinos. All phases in the complex neutrino Yukawa matrix are taken into account in our study. We find that in the scenario with universal soft-breaking terms sizable phase effects can appear on the lepton flavor violating processes such as μeγ\mu \to e \gamma, τeγ\tau \to e \gamma, and τμγ\tau \to \mu \gamma. In particular, the branching ratio of μeγ\mu \to e \gamma can be considerably enhanced due to the Majorana phases, so that it can be much greater than that of τμγ\tau \to \mu \gamma.Comment: 14 pages, 4 eps figures, revtex

    Enhancement of lepton flavor violation in a model with bi-maximal mixing at the grand unification scale

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    We study phenomenological predictions in the scenario with the quasi-degenerate relation among neutrino Dirac masses, m_D1 simeq m_D2 < m_D3, assuming the bi-maximal mixing at the grand unification scale in supersymmetric standard models with right-handed neutrinos. A sufficient lepton number asymmetry can be produced for successful leptogenesis. The lepton flavor violating process mu to e gamma can be enhanced due to the Majorana phase, so that it can be detectable at forthcoming experiments. The processes tau to e gamma and tau to mu gamma are suppressed because of the structure of neutrino Dirac masses, and their branching ratios are smaller than that of mu to e gamma.Comment: 15 pages, 5 figure

    New Leptoquark Mechanism of Neutrinoless Double Beta Decay

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    A new mechanism for neutrinoless double beta (\znbb) decay based on leptoquark exchange is discussed. Due to the specific helicity structure of the effective four-fermion interaction this contribution is strongly enhanced compared to the well-known mass mechanism of \znbb decay. As a result the corresponding leptoquark parameters are severely constrained from non-observation of \znbb-decay. These constraints are more stringent than those derived from other experiments.Comment: LaTeX, 6 pages, 1 figur

    Sister chromatid telomere fusions, but not NHEJ-mediated inter-chromosomal telomere fusions, occur independently of DNA ligases 3 and 4

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    Telomeres shorten with each cell division and can ultimately become substrates for non-homologous end-joining repair, leading to large-scale genomic rearrangements of the kind frequently observed in human cancers. We have characterised over 1400 telomere fusion events at the single-molecule level, using a combination of high-throughput sequence analysis together with experimentally-induced telomeric double-stranded DNA breaks. We show that a single chromosomal dysfunctional telomere can fuse with diverse non-telomeric genomic loci, even in the presence of an otherwise stable genome, and that fusion predominates in coding regions. Fusion frequency was markedly increased in the absence of TP53 checkpoint control and significantly modulated by the cellular capacity for classical, versus alternative, non-homologous end joining (NHEJ). We observed a striking reduction in inter-chromosomal fusion events in cells lacking DNA ligase 4, in contrast to a remarkably consistent profile of intra-chromosomal fusion in the context of multiple genetic knockouts, including DNA ligase 3 and 4 double-knockouts. We reveal distinct mutational signatures associated with classical NHEJ-mediated inter-chromosomal, as opposed to alternative NHEJ-mediated intra-chromosomal telomere fusions and evidence an unanticipated sufficiency of DNA ligase 1 for these intra-chromosomal events. Our findings have implications for mechanisms driving cancer genome evolution
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