Comparison of exclusive decay rates forb→uandb→ctransitions

1987 ◽  
Vol 36 (1) ◽  
pp. 130-136 ◽  
Author(s):  
Shmuel Nussinov ◽  
Werner Wetzel
Keyword(s):  
Decay Rates ◽  
Exclusive Decay

scholarly journals SPLITTING OF MACROSCOPIC FUNDAMENTAL STRINGS IN FLAT SPACE AND HOLOGRAPHIC HADRON DECAYS

2007 ◽  
Vol 22 (15) ◽  
pp. 1057-1073 ◽  
Author(s):  
F. BIGAZZI ◽  
A. L. COTRONE ◽  
L. MARTUCCI ◽  
W. TROOST
Keyword(s):  
Gauge Theory ◽  
Flat Space ◽  
Heavy Quarks ◽  
Decay Rates ◽  
Fundamental String ◽  
Exclusive Decay ◽  
Large Spin

In this review we present the calculation of the splitting rate in flat space of a macroscopic fundamental string either intersecting at a generic angle a Dp-brane or lying on it. The result is then applied, in the context of the string/gauge theory correspondence, to the study of exclusive decay rates of large spin mesons into mesons. As examples, we discuss the cases of [Formula: see text] SYM with a small number of flavors, and of QCD-like theories in the quenched approximation. In the latter context, explicit analytic formulas are given for decay rates of mesons formed either by heavy quarks or by massless quarks.

Anomalous mass dependence of glueball exclusive decay rates

1983 ◽  
Vol 214 (1) ◽  
pp. 153-166 ◽  
Author(s):  
Bernard Pire ◽  
John P. Ralston
Keyword(s):  
Decay Rates ◽  
Mass Dependence ◽  
Exclusive Decay

scholarly journals A tale of invisibility: constraints on new physics in b → sνν

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Tobias Felkl ◽  
Sze Lok Li ◽  
Michael A. Schmidt
Keyword(s):  
Branching Ratio ◽  
Branching Ratios ◽  
New Physics ◽  
Effective Field ◽  
Decay Rates ◽  
Sterile Neutrinos ◽  
Increased Sensitivity ◽  
Belle Ii ◽  
Exclusive Decay ◽  
Inclusive Decay

Abstract The Belle II experiment will measure the rare decays B → Kνν and B → K∗νν with increased sensitivity which can hence be expected to serve as a very efficient probe of new physics. We calculate the relevant branching ratios in low-energy effective field theory (LEFT) including an arbitrary number of massive sterile neutrinos and discuss the expected sensitivity to the different operators. We also take into account the longitudinal polarisation fraction FL and the inclusive decay rate B → Xsνν. In our investigation we consider new physics dominantly contributing to one and two operators both for massless and massive (sterile) neutrinos. Our results show a powerful interplay of the exclusive decay rates B → Kνν and B → K∗νν, and a surprisingly large sensitivity of the inclusive decay mode to vector operators even under conservative assumptions about its uncertainty. Furthermore, the sensitivity of FL is competitive with the branching ratio of B → K∗νν in the search for new physics contributing to scalar operators and thus also complementary to B → Kνν and B → Xsνν.

Comparison of decay rates of faecal indicator organisms in recreational coastal water and sediment

2002 ◽  
Vol 2 (3) ◽  
pp. 131-138 ◽  
Author(s):  
D.L. Craig ◽  
H.J. Fallowfield ◽  
N.J. Cromar
Keyword(s):  
Water Column ◽  
Coastal Water ◽  
Decay Rates ◽  
Organic Carbon Content ◽  
Indicator Organisms ◽  
Filtration Method ◽  
E Coli ◽  
Water And Sediment ◽  
Increased Risk ◽  
High Organic Carbon Content

A laboratory based microcosm study utilising intact non-sterile sediment cores was undertaken to determine the survival of the faecal indicator organisms Escherichia coli, Enterococcus faecium and somatic coliphage in both recreational coastal water and sediment. Overlying water was inoculated with the test organisms and incubated at 10°C, 20°C or 30°C. E. coli, enterococcus and coliphage were enumerated from the water column and sediment by the membrane filtration method, Enterolert (IDEXX Laboratories) and the double-agar overlay methods respectively on days 0, 1, 2, 7, 14 and 28 following inoculation. It was demonstrated that for all organisms, greater decay (k; d-1) occurred in the water column compared to sediment. Sediment characteristics were found to influence decay, with lowest decay rates observed in sediment consisting of high organic carbon content and small particle size. Decay of E. coli was significantly greater in both the water column and sediment compared with enterococcus and coliphage under all conditions. Decay of enterococcus was found to closely resemble that of coliphage decay. Survival of all organisms was inversely related to temperature, with greatest decay at 30°C. However, increased temperature had a less significant impact on survival of enterococcus and coliphage compared with E. coli. The importance of this study for estimating risk from recreational exposure is great if some pathogenic microorganisms behave similarly to the organisms tested in this study. In particular if survival rates of pathogens are similar to enterococcus and coliphage, then their ability to accumulate in coastal sediment may lead to an increased risk of exposure if these organisms are resuspended into the water column due to natural turbulence or human recreational activity.

scholarly journals A new stability result for a thermoelastic Bresse system with viscoelastic damping

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Soh Edwin Mukiawa ◽  
Cyril Dennis Enyi ◽  
Tijani Abdulaziz Apalara
Keyword(s):  
Stability Result ◽  
Bending Moment ◽  
Decay Rates ◽  
Viscoelastic Damping ◽  
Physical Parameters ◽  
Bresse System ◽  
Solution Energy ◽  
Optimal Decay Rates ◽  
Optimal Decay ◽  
Weaker Conditions

AbstractWe investigate a thermoelastic Bresse system with viscoelastic damping acting on the shear force and heat conduction acting on the bending moment. We show that with weaker conditions on the relaxation function and physical parameters, the solution energy has general and optimal decay rates. Some examples are given to illustrate the findings.

scholarly journals Longitudinal analysis of antibody decay in convalescent COVID-19 patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weiming Xia ◽  
Mingfei Li ◽  
Ying Wang ◽  
Lewis E. Kazis ◽  
Kim Berlo ◽  
...  
Keyword(s):  
Immune Response ◽  
Reduction Rate ◽  
Mixed Linear Model ◽  
Decay Rates ◽  
Primary Study ◽  
Igg Antibody ◽  
Blood Samples ◽  
Response Capacity ◽  
Index Level ◽  
Abbott Architect

AbstractDetermining the sustainability of antibodies targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for predicting immune response against the Coronavirus disease 2019 (COVID-19). To quantify the antibody decay rates among the varying levels of anti-nucleocapsid (anti-N) Immunoglobulin G (IgG) in convalescent COVID-19 patients and estimate the length of time they maintained SARS-CoV-2 specific antibodies, we have collected longitudinal blood samples from 943 patients over the course of seven months after their initial detection of SARS-CoV-2 virus by RT-PCR. Anti-N IgG levels were then quantified in these blood samples. The primary study outcome was the comparison of antibody decay rates from convalescent patients with high or low initial levels of antibodies using a mixed linear model. Additional measures include the length of time that patients maintain sustainable levels of anti-N IgG. Antibody quantification of blood samples donated by the same subject multiple times shows a gradual decrease of IgG levels to the cutoff index level of 1.4 signal/cut-off (S/C) on the Abbott Architect SARS-CoV-2 IgG test. In addition, this study shows that antibody reduction rate is dependent on initial IgG levels, and patients with initial IgG levels above 3 S/C show a significant 1.68-fold faster reduction rate compared to those with initial IgG levels below 3 S/C. For a majority of the donors naturally occurring anti-N antibodies were detected above the threshold for only four months after infection with SARS-CoV-2. This study is clinically important for the prediction of immune response capacity in COVID-19 patients.

scholarly journals Influence of Tsunami Aspect Ratio on Near and Far-Field Tsunami Amplitude

Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 178
Author(s):  
Natalia K. Sannikova ◽  
Harvey Segur ◽  
Diego Arcas
Keyword(s):  
Aspect Ratio ◽  
Near Field ◽  
Decay Rates ◽  
Far Field ◽  
Present Evidence ◽  
Positive Wave ◽  
Initial Wave ◽  
N Wave ◽  
Tsunami Amplitude ◽  
Wave Shapes

This study presents a numerical investigation of the source aspect ratio (AR) influence on tsunami decay characteristics with an emphasis in near and far-field differences for two initial wave shapes Pure Positive Wave and N-wave. It is shown that, when initial total energy for both tsunami types is kept the same, short-rupture tsunami with more concentrated energy are likely to be more destructive in the near-field, whereas long rupture tsunami are more dangerous in the far-field. The more elongated the source is, the stronger the directivity and the slower the amplitude decays in the intermediate- and far-fields. We present evidence of this behavior by comparing amplitude decay rates from idealized sources and showing their correlation with that observed in recent historical events of similar AR.

Proton inelastic scattering in inverse kinematics as a mean for determining decay rates in continuum: The 9Be + p case

2021 ◽  
Vol 1008 ◽  
pp. 122155
Author(s):  
A. Pakou ◽  
O. Sgouros ◽  
V. Soukeras ◽  
F. Cappuzzello ◽  
L. Acosta ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Inverse Kinematics ◽  
Decay Rates ◽  
Proton Inelastic Scattering

Stabilization of the wave equation with a nonlinear delay term in the boundary conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wassila Ghecham ◽  
Salah-Eddine Rebiai ◽  
Fatima Zohra Sidiali
Keyword(s):  
Wave Equation ◽  
Original Problem ◽  
Existence Of Solutions ◽  
Semigroup Theory ◽  
Decay Rates ◽  
Uniform Decay ◽  
Delay Term ◽  
Nonlinear Semigroup Theory ◽  
Nonlinear Boundary Feedback ◽  
Nonlinear Delay

Abstract A wave equation in a bounded and smooth domain of ℝ n {\mathbb{R}^{n}} with a delay term in the nonlinear boundary feedback is considered. Under suitable assumptions, global existence and uniform decay rates for the solutions are established. The proof of existence of solutions relies on a construction of suitable approximating problems for which the existence of the unique solution will be established using nonlinear semigroup theory and then passage to the limit gives the existence of solutions to the original problem. The uniform decay rates for the solutions are obtained by proving certain integral inequalities for the energy function and by establishing a comparison theorem which relates the asymptotic behavior of the energy and of the solutions to an appropriate dissipative ordinary differential equation.

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