2,181 research outputs found
Rapid analytical determination of glutaraldehyde concentrations
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
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
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
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 and
The two Higgs doublet model emerges as a minimal scenario in which to
address, at the same time, the excess at 750 GeV and the lepton
flavour violating decay into of the 125 GeV Higgs boson.
The price to pay is additional matter to enhance the 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
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
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 is constructed, which leads to the dominant -block in
the neutrino mass matrix, thus predicting normal hierarchy. This symmetry makes
it possible to reproduce current data and predicts
and strongly suppressed neutrinoless
-decay. Moreover, it implies a relation between lepton and quark mixing
angles: . The Cabibbo mixing can
also be reproduced and . 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
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
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 and the Dirac-type Yukawa couplings to be
known, we find the triplet Yukawa coupling matrix , 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 , there is a dual
solution , where is the VEV of the triplet Higgs.
Thus, unlike in pure type I (II) seesaw, there is no unique allowed structure
for the matrix . For lepton generations the number of solutions is
. We develop an exact analytic method of solving the seesaw non-linear
matrix equation for .Comment: 4 pages, revtex, small clarifications added, title changed to match
published versio
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