244 research outputs found
Muon Capture Constraints on Sterile Neutrino Properties
We show that ordinary and radiative muon capture impose stringent constraints
on sterile neutrino properties. In particular, we consider a sterile neutrino
with a mass between 40 to that has a large mixing with the muon
neutrino and decays predominantly into a photon and light neutrinos due to a
large transition magnetic moment. Such a model was suggested as a possible
resolution to the puzzle presented by the results of the LSND, KARMEN, and
MiniBooNE experiments. We find that the scenario with the radiative decay to
massless neutrinos is ruled out by measurements of the radiative muon capture
rates at TRIUMF in the relevant mass range by a factor of a few in the squared
mixing angle. These constraints are complementary to those imposed by the
process of electromagnetic upscattering and de-excitation of beam neutrinos
inside the neutrino detectors induced by a large transition magnetic moment.
The latter provide stringent constraints on the size of the transitional
magnetic moment between muon, electron neutrinos and . We also show that
further extension of the model with another massive neutrino in the final state
of the radiative decay may be used to bypass the constraints derived in this
work.Comment: 5 pages, 5 figures, revtex4-1. v2: updated to consider anisotropic
sterile neutrino decay and a way of relaxing the RMC constraints by
introducing another massive sterile neutrino; improved estimate of decay
probability in targe
ULTRASOUND AND ORGANIC ACIDS INVESTIGATIONS ON MINERALIZED BIOLOGICAL STRUCTURES. FIFTH COMMUNICATION. DEMINERALIZATION OF BIO-STRUCTURES (BONES AND SHELLS) WITH COMPLEXON III SOLUTION IN ULTRASOUND ENVIRONMENT
No abstract
FURTHER ON THE PROBLEM OF QUANTITATIVE DETERMINATION OF CHOLESTEROL IN CONCREMENTS : Communication II
No abstract
Proton Zemach radius from measurements of the hyperfine splitting of hydrogen and muonic hydrogen
While measurements of the hyperfine structure of hydrogen-like atoms are
traditionally regarded as test of bound-state QED, we assume that theoretical
QED predictions are accurate and discuss the information about the
electromagnetic structure of protons that could be extracted from the
experimental values of the ground state hyperfine splitting in hydrogen and
muonic hydrogen. Using recent theoretical results on the proton polarizability
effects and the experimental hydrogen hyperfine splitting we obtain for the
Zemach radius of the proton the value 1.040(16) fm. We compare it to the
various theoretical estimates the uncertainty of which is shown to be larger
that 0.016 fm. This point of view gives quite convincing arguments in support
of projects to measure the hyperfine splitting of muonic hydrogen.Comment: Submitted to Phys. Rev.
ON ТНЕ QUANTIТAТIVE DEТERMINATION OF CONCREMENTS
In our previous report the results were presented of comparative studies of methods for quantitative determination of calcium, magnesium, oxalate and phosphate ions in model solutions of concrements. The experimental data obtained indicate that the following methods may bе considered the most appropriate:1. Complexometric determination of Са2+ with 0,002 М solution of complexon III with fluorexon - thymolphthalein as indicator.2. Simultaneous complexometric determination of Са2-+ аnd Mg2 + а separate determination of Са2+ and detection of the amount of Mg2+ through the existing difference. 3. Plumbometric determination of C2O42 - with 0,1 М solution of Рb(NО3)2.4. Direct complexometric determination of РO43 - with 0,01 M solution of MgSO4. The purpose of the prelimiпary work was to evaluate contemporary methods for the determination of Ca2+, Mg2+, С2O42 - and РO43 - first оn model solutions аnd then on native concrements. In the present work some results are reported of the quantitative study of concrements of renal or vesical origin. The materials are obtained at the Surgical Clinic and the Propedeutic Iпternal Clinic at the Higher Medical Institute in Varna. Data presented are compaired with data obtained bу means of other methods
On the Positronium g-factor
In this letter, we recall the main facts concerning the g-factor of
positronium and we show how the value of the g-factor of the positronium is
important. Taking it better into consideration may provide a solution to the
reported discrepancy between QED theory and experiments concerning the
hyperfine splitting of the fundamental level of the positronium. We also give
the only experimental value that existing experiments can provide,
at .Comment: Submitted to EPJ
ON ТНЕ QUANTIТAТIVE DEТERMINATION OF CONCREMENTS
The chemical composition of concrements has been of clinical interest for long. For that reason methods for its determination have already been devised. А method for the qualitative examination of concrements is proposed bу Halman. These methods are old in many respects and do not meet the present capacities of chemical analysis. А method for quantitative determination has been proposed also bу Schpet and Кeiser, but this method is neither contemporary.The interest shown in internal and urological practice toward the quantitative composition of concrements stimulated us to elaborate а method for quantitative analysis, primarily of renal and vesical concrements. We directed our attention mainly toward modern methods. Our definite experimental work consisted of the following: 1) comparative study of known methods on model solutions prepared bу us; 2) application of selected methods for definite analysis of concrements. We chose mainly complexometric methods which imvosed а necessity to specify the conditions for determination of Са +, Mg2+, C2O42-, РO43- in model solutions, resembling concrement solutions. The results are reported in the present work
Precision Spectroscopy of Molecular Hydrogen Ions: Towards Frequency Metrology of Particle Masses
We describe the current status of high-precision ab initio calculations of
the spectra of molecular hydrogen ions (H_2^+ and HD^+) and of two experiments
for vibrational spectroscopy. The perspectives for a comparison between theory
and experiment at a level of 1 ppb are considered.Comment: 26 pages, 13 figures, 1 table, to appear in "Precision Physics of
Simple Atomic Systems", Lecture Notes in Physics, Springer, 200
Jacobi Identity for Vertex Algebras in Higher Dimensions
Vertex algebras in higher dimensions provide an algebraic framework for
investigating axiomatic quantum field theory with global conformal invariance.
We develop further the theory of such vertex algebras by introducing formal
calculus techniques and investigating the notion of polylocal fields. We derive
a Jacobi identity which together with the vacuum axiom can be taken as an
equivalent definition of vertex algebra.Comment: 35 pages, references adde
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