scholarly journals Cosmological Consequences of an Unstable Heavy Neutrino

1987 ◽  
Vol 117 ◽  
pp. 493-493
Author(s):  
T. Padmanabhan ◽  
M. M. Vasanthi
Keyword(s):  
Decay Mode ◽  
Decay Product ◽  
The Other ◽  
Light Neutrino ◽  
Heavy Neutrino ◽  
Scalar Boson ◽  
Kinematic Constraints ◽  
Cosmological Scenario ◽  
Large Factor ◽  
Conventional Picture

In a recent paper Simpson has reported evidence for a heavy neutrino of about 17.1 kev mass. Cosmological bounds on stable neutrino species imply that this neutrino [νH] must be unstable. The most likely decay mode νH→νL+f where νL is a light neutrino and f is a scalar boson leads to a cosmological scenario which is quite different from the conventional picture. In this scenario universe becomes matter dominated at a redshift of z ∼ 107 and becomes radiation dominated [by the decay product νL of νH] at z ∼ 310. The kinematic constraints on the lifetime of νH do not lead to any contradictions. On the other hand, growth of baryonic perturbations is severely limited in this model due to two reasons: (i) virtually no growth can take place in the radiation dominated region z ≤ 310. (ii) Decay of νH is likely to disrupt and smoothen out past growth by a large factor. It is doubtful whether a simple way out of this difficulty exists.

Educational Opportunity in the Army of Occupation

1920 ◽  
Vol 13 (2) ◽  
pp. 45-52
Author(s):  
Eugene R. Smith ◽  
Harry D. Gaylord ◽  
Geo. Gailey Chambers ◽  
William E. Breckenridge ◽  
J. T. Rorer
Keyword(s):  
Educational Opportunity ◽  
Colleges And Universities ◽  
The Other ◽  
Student Body ◽  
Educational Work ◽  
Professional Schools ◽  
American University ◽  
Large Factor ◽  
French And English ◽  
Commander In Chief

The educational work of the A. E. F. was firmly established by General Orders 9 and 30, issued by the Commander in Chief. Among other things in these orders, General Pershing authorized three types of educational assignment for the men: first, at universities or colleges; second, at divisional schools; third, at post schools. Only the work for illiterates at post schools was to be compulsory, but the elective opportunities attracted far more applicatioils than could be granted. Thousands of men took advantage of the remarkable privilege to study at the French and English universities and professional schools, while on the army payroll, and free of any personal expense. These in the main were men who had been in American colleges and universities, or who were fully prepared for university work when they left home. Shortly after they began their work at Cambridge, Oxford, Edinburgh, Paris, Grenoble, or any of the other established seats of learning, another call was issued announcing the opening of the American University at Beaune. Cote d'Or. Here was an educational miracle; a Harvard and Chicago combined, thirteen colleges completely organized almost over night and surprisingly well equipped, with a wonderful faculty of about one thousand, and a student body of more than eight thousand. During the three months that it was in session, it gave an intellectual impetus to thousands of young men and undoubtedly was a large factor subsequently in bringing many of these students back to home colleges and universities.

The Mabaruma Phase: A Return to the More Probable Interpretation

1966 ◽  
Vol 31 (4) ◽  
pp. 558-566 ◽  
Author(s):  
Donald W. Lathrap
Keyword(s):  
The Other ◽  
British Guiana ◽  
Large Factor ◽  
Probable Interpretation

In a recent publication Evans and Meggers have accused me of reinterpreting their work in an erroneous manner on two separate occasions (Evans and Meggers 1964). In one instance (Lathrap 1963a), I suggested that the Machalilla complex of Coastal Ecuador might be a member of the same ceramic tradition which also gave rise to Early Tutishcainyo and Late Tutishcainyo in the central Ucayali Basin in Peru. In the other case (Lathrap 1964), I offered what appeared to me to be a more reasonable seriation of the excavated levels of the Mabaruma phase of northwestern British Guiana and suggested that the age of the Mabaruma phase had been underestimated by a large factor.

scholarly journals The hadronic $$\tau $$ decay $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau $$ and the axial vector mixing angle

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
K. Hayasaka ◽  
Z. Huang ◽  
E. Kou
Keyword(s):  
Decay Rate ◽  
Decay Mode ◽  
Axial Vector ◽  
Sensitivity Study ◽  
The Other ◽  
Mixing Angle ◽  
Belle Ii ◽  
First Time ◽  
Hadronic Tau

AbstractWe propose to measure the $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau \ $$ τ - → K 1 - ν τ → ( K - ω ) ν τ → ( K - π + π - π 0 ) ν τ decay in order to determine the $$K_1$$ K 1 axial vector mixing angle $$\theta _{K_1}$$ θ K 1 . We derive, for the first time, the differential decay rate formula for this decay mode. Using the obtained result, we perform a sensitivity study for the Belle (II) experiment. We will show that the $$K^-\pi ^+\pi ^-\pi ^0$$ K - π + π - π 0 spectrum of the $$\tau ^-\rightarrow K_1^-\nu _\tau \rightarrow (K^-\omega ) \nu _\tau \rightarrow (K^- \pi ^+\pi ^-\pi ^0)\nu _\tau \ $$ τ - → K 1 - ν τ → ( K - ω ) ν τ → ( K - π + π - π 0 ) ν τ decay can discriminate the two solutions $$\theta _{K_1}=\sim 30^{\circ }$$ θ K 1 = ∼ 30 ∘ or $$\sim 60^{\circ }$$ ∼ 60 ∘ observed in the other measurements.

scholarly journals FREED LEPTOGENESIS

2011 ◽  
Vol 26 (39) ◽  
pp. 2983-2996 ◽  
Author(s):  
DMITRY V. ZHURIDOV
Keyword(s):  
Dark Matter ◽  
Lower Bound ◽  
Standard Model ◽  
Upper Bound ◽  
Light Neutrino ◽  
Heavy Neutrino ◽  
Neutrino Masses ◽  
Cp Asymmetry ◽  
The Standard Model

Economical extensions of the Standard Model (SM), in which famous Davidson–Ibarra bound on the CP asymmetry relevant for leptogenesis may be significantly relaxed by the loop effects, comparing to predictions of the SM extended only by heavy right-handed neutrinos with hierarchical masses, are discussed. This leads to decreasing of the lower bound on the heavy neutrino masses and increasing of the upper bound on the light neutrino masses, which is testable. In addition, the considered theory may help to solve the dark matter problem.

THE BAR INSTABILITY REVISITED IN COSMOLOGICAL SCENARIO

1998 ◽  
Vol 13 (25) ◽  
pp. 2035-2038
Author(s):  
ANNA CURIR
Keyword(s):  
Spiral Galaxies ◽  
The Other ◽  
Density Waves ◽  
Stationary Density ◽  
Tidal Interactions ◽  
Cosmological Scenario ◽  
Hydrodynamical Simulations

About two-thirds of spiral galaxies are classified as barred: only one-third is very strongly barred (SB) and the other is classified as "intermediate" SB galaxies, i.e. galaxies with a faint bar. Bars are quasi-stationary density waves originated by swing amplification mechanisms. We use smooth-particle-hydrodynamical simulations to give insights into the role triaxiality of the halo on triggering the bar instability and to investigate how tidal interactions act on the bar evolution. We argue that the triaxiality of the primordial halo and the weight of the halo have a fundamental role in monitoring the incidence of the bar instability in spiral galaxies.

An Extension of Screw Theory

1981 ◽  
Vol 103 (4) ◽  
pp. 725-735 ◽  
Author(s):  
M. S. Ohwovoriole ◽  
B. Roth
Keyword(s):  
Mathematical Modelling ◽  
Direct Contact ◽  
Theoretical Study ◽  
Screw Theory ◽  
The Other ◽  
Assembly Process ◽  
Kinematic Constraints ◽  
Total Freedom

It is shown that, if one considers the “total freedom” of instantaneous motion, three distinct types of screw systems arise. Of these only the ones which maintain the kinematic constraints—the so-called reciprocal screw systems—have been studied before. This paper introduces and studies the two new types, which we name “repelling” and “contrary” screws. We present a detailed theoretical study of the repelling screw systems, these as well as the other screw systems are useful in the mathematical modelling of the parts assembly process and the study of direct contact mechanisms.

scholarly journals Universal Path-Following of Wheeled Mobile Robots: A Closed-Form Bounded Velocity Solution

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7642
Author(s):  
Reza Oftadeh ◽  
Reza Ghabcheloo ◽  
Jouni Mattila
Keyword(s):  
Mobile Robots ◽  
Closed Form ◽  
Nonholonomic Constraints ◽  
Path Following ◽  
The Other ◽  
Wheeled Mobile Robots ◽  
Kinematic Constraints ◽  
Second Stage ◽  
Simulation Results ◽  
Asymptotic Path

This paper presents a nonlinear, universal, path-following controller for Wheeled Mobile Robots (WMRs). This approach, unlike previous algorithms, solves the path-following problem for all common categories of holonomic and nonholonomic WMRs, such as omnidirectional, unicycle, car-like, and all steerable wheels. This generality is the consequence of a two-stage solution that tackles separately the platform path-following and wheels’ kinematic constraints. In the first stage, for a mobile platform divested of the wheels’ constraints, we develop a general paradigm of a path-following controller that plans asymptotic paths from the WMR to the desired path and, accordingly, we derive a realization of the presented paradigm. The second stage accounts for the kinematic constraints imposed by the wheels. In this stage, we demonstrate that the designed controller simplifies the otherwise impenetrable wheels’ kinematic and nonholonomic constraints into explicit proportional functions between the velocity of the platform and that of the wheels. This result enables us to derive a closed-form trajectory generation scheme for the asymptotic path that constantly keeps the wheels’ steering and driving velocities within their corresponding, pre-specified bounds. Extensive experimental results on several types of WMRs, along with simulation results for the other types, are provided to demonstrate the performance and the efficacy of the method.

Radiation-Induced Degradation of Purine and Pyrimidine 2′-Deoxyribonucleosides in Aqueous KBr Solutions

1983 ◽  
Vol 38 (12) ◽  
pp. 1643-1651 ◽  
Author(s):  
J. Cadet ◽  
L. Voituriez ◽  
M. Berger ◽  
L. S. Myers
Keyword(s):  
Mass Spectrometry ◽  
Steady State ◽  
Degradation Products ◽  
Decay Product ◽  
The Other ◽  
Ionic Mechanism ◽  
Radiation Induced ◽  
Purine Ring ◽  
Induced Decomposition ◽  
C Nmr

Steady-state γ-radiolysis of 5 × 10-4 M pyrimidine and purine 2′-deoxyribonucleosides in aqueous solutions saturated with N2, N2O and O2, respectively, have been carried out in the presence of 0.1 M KBr. The main final degradation products have been isolated and characterised by various spectroscopic measurements including 1H and 13C NMR, UV, C.D. and mass spectrometry. The radiation-induced decomposition of thymidine is mostly accounted for by an ionic mechanism involving Br2, the decay product of Br2-·, as the reactive oxidising specie. On the other hand the degradation of the purine ring of 2′-deoxy-adenosine and 2′-deoxyguanosine may be accounted for by the action of Br2-·or Br3·2-

Experimental limits for heavy neutrino admixture deduced from 177Lu β decay and constraints on the life time of a radiative neutrino decay mode

1996 ◽  
Vol 48 (1-3) ◽  
pp. 201-203 ◽  
Author(s):  
S. Schönert ◽  
L. Oberauer ◽  
C. Hagner ◽  
F.v. Feilitzsch ◽  
K. Schreckenbach ◽  
...  
Keyword(s):  
Decay Mode ◽  
Life Time ◽  
Heavy Neutrino ◽  
Β Decay ◽  
Neutrino Decay

Stromatoporoids from the Famennian (Devonian) Wabamun Formation, Normandville oilfield, north–central Alberta, Canada

1988 ◽  
Vol 62 (03) ◽  
pp. 411-419 ◽  
Author(s):  
Colin W. Stearn
Keyword(s):  
Patch Reef ◽  
Abundant Species ◽  
The Other ◽  
North Central ◽  
Biotic Crisis

Stromatoporoids are the principal framebuilding organisms in the patch reef that is part of the reservoir of the Normandville field. The reef is 10 m thick and 1.5 km2in area and demonstrates that stromatoporoids retained their ability to build reefal edifices into Famennian time despite the biotic crisis at the close of Frasnian time. The fauna is dominated by labechiids but includes three non-labechiid species. The most abundant species isStylostroma sinense(Dong) butLabechia palliseriStearn is also common. Both these species are highly variable and are described in terms of multiple phases that occur in a single skeleton. The other species described areClathrostromacf.C. jukkenseYavorsky,Gerronostromasp. (a columnar species), andStromatoporasp. The fauna belongs in Famennian/Strunian assemblage 2 as defined by Stearn et al. (1988).

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