2,181 research outputs found

    Rapid analytical determination of glutaraldehyde concentrations

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    Technique utilizes the iodimetric procedure which adds unknown excess of bisulfite to glutaraldehyde /GA/ then titrates unreacted bisulfite with standard iodine isotope to determine GA concentrations. Technique may interest microscopists, food researchers, biochemical or medical laboratories, and drug manufacturers

    The bearable compositeness of leptons

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    Partial compositeness as a theory of flavor in the lepton sector is assessed. We begin presenting the first systematic analysis of neutrino mass generation in this context, and identifying the distinctive mass textures. We then update the bounds from charged lepton flavor and CP violating observables. We put forward a U(1)3 × CP symmetry of the composite sector, in order to allow the new physics to be not far above the TeV scale. This hypothesis effectively suppresses the new contributions to the electron EDM and μ → eγ, by far the most constraining observables, and results in a novel pattern of flavor violation and neutrino masses. The CP violation in the elementary-composite mixing is shown to induce a CKM phase of the correct size, as well as order-one phases in the PMNS matrix. We compare with the alternative possibility of introducing multiple scales of compositeness for leptons, that also allow to evade flavor and CP constraints. Finally, we examine violations of lepton flavor universality in B-meson semi-leptonic decays. The neutral-current anomalies can be accommodated, predicting strong correlations among different lepton flavors, with a few channels close to the experimental sensitivity

    Fermion masses in SUSY SO(10) with type II seesaw: a non-minimal predictive scenario

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    A predictive framework for fermion masses and mixing is given by the supersymmetric SO(10) model with one 10, one bar126, one 126 and one 210 Higgs representations, and type II seesaw dominating the neutrino mass matrix. We investigate the origin of the tension between this model and lepton mixing data and refine previous numerical analyses. We discuss an extension of the minimal model that includes one 120 Higgs chiral superfield representation. This exhausts the possible renormalizable contributions to the Yukawa sector. In spite of the increase in the number of parameters the predictivity of the minimal setting is not spoiled. We argue that the contributions to fermion masses due to the doublet components of 120 can be naturally small compared to those of 10 and 126, thus acting as a perturbation in the fermion mass generation. The antisymmetric nature of the 120 Yukawa coupling affects at leading order the determination of the mixing angles and it allows to remove the inconsistencies between predictions and data on the neutrino parameters. An improvement in the experimental bound on |Ue3| can tell this scenario from the minimal model.Comment: 11 pages, 3 figures; Note and references added on new KamLAND dat

    Extending higher dimensional quasi-cocycles

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    Let G be a group admitting a non-elementary acylindrical action on a Gromov hyperbolic space (for example, a non-elementary relatively hyperbolic group, or the mapping class group of a closed hyperbolic surface, or Out(F_n) for n>1). We prove that, in degree 3, the bounded cohomology of G with real coefficients is infinite-dimensional. Our proof is based on an extension to higher degrees of a recent result by Hull and Osin. Namely, we prove that, if H is a hyperbolically embedded subgroup of G and V is any G-module, then any n-quasi cocycle on H with values in V may be extended to G. Also, we show that our extensions detect the geometry of the embedding of hyperbolically embedded subgroups, in a suitable sense.Comment: Minor revisions. This version has been accepted for publication by the Journal of Topolog

    Two Higgs doublets to explain the excesses pp→γγ(750 GeV)pp\rightarrow \gamma\gamma(750\ {\rm GeV}) and h→τ±μ∓h \to \tau^\pm \mu^\mp

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    The two Higgs doublet model emerges as a minimal scenario in which to address, at the same time, the γγ\gamma\gamma excess at 750 GeV and the lepton flavour violating decay into τ±μ∓\tau^\pm \mu^\mp of the 125 GeV Higgs boson. The price to pay is additional matter to enhance the γγ\gamma\gamma rate, and a peculiar pattern for the lepton Yukawa couplings. We add TeV scale vector-like fermions and find parameter space consistent with both excesses, as well as with Higgs and electroweak precision observables.Comment: 15 pages, 1 figure; v2: discussion of tau-->mu gamma added, leading to an additional constraint. v3: references added, figure 1 recovered and figure 2 adde

    Neutron therapy of cancer

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    Reports relate applications of neutrons to the problem of cancer therapy. The biochemical and biophysical aspects of fast-neutron therapy, neutron-capture and neutron-conversion therapy with intermediate-range neutrons are presented. Also included is a computer program for neutron-gamma radiobiology

    Large neutrino mixing and normal mass hierarchy: a discrete understanding

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    We discuss the possibility of flavor symmetries to explain the pattern of charged lepton and neutrino masses and mixing angles. We emphasize what are the obstacles for the generation of an almost maximal atmospheric mixing and what are the minimal ingredients to obtain it. A model based on the discrete symmetry S3S_3 is constructed, which leads to the dominant μτ\mu\tau-block in the neutrino mass matrix, thus predicting normal hierarchy. This symmetry makes it possible to reproduce current data and predicts 0.01≲θ13≲0.030.01\lesssim\theta_{13}\lesssim 0.03 and strongly suppressed neutrinoless 2β2\beta-decay. Moreover, it implies a relation between lepton and quark mixing angles: θ23q≈2(π/4−θ23)\theta_{23}^q \approx 2(\pi/4-\theta_{23}). The Cabibbo mixing can also be reproduced and θ13q∼θ12qθ23q\theta_{13}^q\sim \theta_{12}^q\theta_{23}^q. S3S_3 is thus a candidate to describe all the basic features of Standard Model fermion masses and mixing.Comment: 9 pages, revtex, 1 eps figure; clarifications and comments added in sections III.A.1. and III.C.; typos corrected; several references adde

    European development banks and the political cycle

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    This paper investigates whether the lending activity of European development banks is affected by opportunistic political behavior, by looking at the change in loans extended by these entities in election years. The empirical analysis leverages on a unique manually collected dataset that includes all the development banks headquartered in Europe, for the period 2002\u20132015. A comparison with the rest of the European banking system reveals that while the political view of development banks cannot be supported as a general rule, it finds empirical evidence in flawed democracies, where large development banks actually tend to increase their lending activity in election years

    Duality in Left-Right Symmetric Seesaw Mechanism

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    We consider type I+II seesaw mechanism, where the exchanges of both right-handed neutrinos and isotriplet Higgs bosons contribute to the neutrino mass. Working in the left-right symmetric framework and assuming the mass matrix of light neutrinos mνm_\nu and the Dirac-type Yukawa couplings to be known, we find the triplet Yukawa coupling matrix ff, which carries the information about the masses and mixing of the right-handed neutrinos. We show that in this case there exists a duality: for any solution ff, there is a dual solution f^=mν/vL−f\hat{f}=m_\nu/v_L-f, where vLv_L is the VEV of the triplet Higgs. Thus, unlike in pure type I (II) seesaw, there is no unique allowed structure for the matrix ff. For nn lepton generations the number of solutions is 2n2^n. We develop an exact analytic method of solving the seesaw non-linear matrix equation for ff.Comment: 4 pages, revtex, small clarifications added, title changed to match published versio
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