scholarly journals Lifetimes and heavy quark expansion

2015 ◽  
Vol 30 (10) ◽  
pp. 1543005 ◽  
Author(s):  
Alexander Lenz
Keyword(s):  
Heavy Quark ◽  
Experimental Tests ◽  
Heavy Quarks ◽  
Experimental Results ◽  
Current Status ◽  
Matrix Elements ◽  
Weak Decays ◽  
The Subject

Kolya Uraltsev was one of the inventors of the Heavy Quark Expansion (HQE), that describes inclusive weak decays of hadrons containing heavy quarks and in particular lifetimes. Besides giving a pedagogic introduction to the subject, we review the development and the current status of the HQE, which just recently passed several non-trivial experimental tests with an unprecedented precision. In view of many new experimental results for lifetimes of heavy hadrons, we also update several theory predictions: [Formula: see text], τ(Bs)/τ(Bd) = 1.001 ±0.002, τ(Λb)/τ(Bd) = 0.935 ±0.054 and [Formula: see text]. The theoretical precision is currently strongly limited by the unknown size of the non-perturbative matrix elements of four-quark operators, which could be determined with lattice simulations.

scholarly journals CHARMED MESON PRODUCTION IN PROTON–(ANTI)PROTON COLLISIONS

2007 ◽  
Vol 22 (02n03) ◽  
pp. 555-560
Author(s):  
MARTA ŁUSZCZAK ◽  
ANTONI SZCZUREK
Keyword(s):  
Heavy Quark ◽  
Meson Production ◽  
Experimental Results ◽  
Charmed Meson ◽  
Matrix Elements ◽  
Unintegrated Gluon ◽  
Proton Collisions ◽  
Shell Matrix ◽  
Gluon Distributions

We discuss and compare different approaches to include gluon transverse momenta for heavy quark-antiquark pair and meson production. The results are illustrated with the help of different unintegrated gluon distributions (UGDF) from the literature. We compare results obtained with on-shell and off-shell matrix elements and kinematics. The results are compared with recent experimental results of the CDF collaboration.

SEMILEPTONIC WEAK DECAYS OF HEAVY BARYONS

2000 ◽  
Vol 15 (06) ◽  
pp. 821-831
Author(s):  
MANSOUR HAGHIGHAT
Keyword(s):  
Simple Model ◽  
Heavy Quark ◽  
Branching Ratio ◽  
Form Factors ◽  
Matrix Elements ◽  
Weak Decays ◽  
Heavy Baryons ◽  
Heavy Quark Limit

We propose a simple model to describe the semileptonic weak decays among heavy baryons in the heavy quark limit in a unified way. The current matrix elements of the heavy baryons, with spin-0 light diquark, are evaluated to give the ω-dependence of the form factors. The numerical values are also calculated and the branching ratio for [Formula: see text] is consequently obtained in the range (4.9–15.3)%.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

The Squire Law Library at Cambridge: the Historical Development and Current Status of the International Law Collections

2017 ◽  
Vol 17 (2) ◽  
pp. 78-91 ◽  
Author(s):  
Lesley Dingle
Keyword(s):  
International Law ◽  
Historical Development ◽  
Detailed Account ◽  
Current Status ◽  
Public International Law ◽  
The Public ◽  
The Subject ◽  
Law Library

AbstractIn this paper Lesley Dingle provides a detailed account of the historical development of the public international law collections at the Squire Law Library in Cambridge. She explains the close involvement of the academic lawyers and the librarians, past and present, in developing an important collection which reflects the significance of the subject at Cambridge's Faculty of Law. Finally, she brings things up-to-date by detailing the extent of the electronic provision which benefits the modern scholar in this discipline.

Reinforcement Learning for Cloud Computing Digital Library

2014 ◽  
Vol 571-572 ◽  
pp. 105-108
Author(s):  
Lin Xu
Keyword(s):  
Artificial Intelligence ◽  
Cloud Computing ◽  
Reinforcement Learning ◽  
Digital Library ◽  
Learning Algorithms ◽  
Experimental Results ◽  
Current Status ◽  
Self Learning ◽  
New Framework

This paper proposes a new framework of combining reinforcement learning with cloud computing digital library. Unified self-learning algorithms, which includes reinforcement learning, artificial intelligence and etc, have led to many essential advances. Given the current status of highly-available models, analysts urgently desire the deployment of write-ahead logging. In this paper we examine how DNS can be applied to the investigation of superblocks, and introduce the reinforcement learning to improve the quality of current cloud computing digital library. The experimental results show that the method works more efficiency.

scholarly journals Numerical and experimental evaluation of masonry prisms by finite element method

2017 ◽  
Vol 10 (2) ◽  
pp. 477-508 ◽  
Author(s):  
C. F.R. SANTOS ◽  
R. C. S. S. ALVARENGA ◽  
J. C. L. RIBEIRO ◽  
L. O CASTRO ◽  
R. M. SILVA ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
High Strength Concrete ◽  
Numerical Models ◽  
High Strength ◽  
Experimental Tests ◽  
Experimental Results ◽  
Concrete Blocks ◽  
Micro Modeling ◽  
Modeling Strategy

Abstract This work developed experimental tests and numerical models able to represent the mechanical behavior of prisms made of ordinary and high strength concrete blocks. Experimental tests of prisms were performed and a detailed micro-modeling strategy was adopted for numerical analysis. In this modeling technique, each material (block and mortar) was represented by its own mechanical properties. The validation of numerical models was based on experimental results. It was found that the obtained numerical values of compressive strength and modulus of elasticity differ by 5% from the experimentally observed values. Moreover, mechanisms responsible for the rupture of the prisms were evaluated and compared to the behaviors observed in the tests and those described in the literature. Through experimental results it is possible to conclude that the numerical models have been able to represent both the mechanical properties and the mechanisms responsible for failure.

scholarly journals Progress on semi-leptonic B(s) decays

2014 ◽  
Vol 29 (20) ◽  
pp. 1430019 ◽  
Author(s):  
Giulia Ricciardi
Keyword(s):  
Rare Decays ◽  
Current Status ◽  
Matrix Elements ◽  
Ckm Matrix ◽  
The Absolute ◽  
Ckm Matrix Elements

We report on the current status of semi-leptonic B(s) decays, including rare decays, and the extraction of the absolute values of the CKM matrix elements |Vcb| and |Vub|.

Structures and phase transitions in barium sodium niobate tungsten bronze (BNN)

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Thomas A. Whittle ◽  
Christopher J. Howard ◽  
Siegbert Schmid
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Tungsten Bronze ◽  
Standard Setting ◽  
Experimental Results ◽  
Temperature Structure ◽  
Sodium Niobate ◽  
Tetragonal Tungsten Bronze ◽  
Space Group ◽  
The Subject

The room-temperature structure of the filled tetragonal tungsten bronze, Ba2NaNb5O15 (BNN), has been the subject of a number of studies, and these studies have given an almost corresponding number of different results. From a group theoretical examination of the different possibilities and a review of the published experimental results we conclude that the room-temperature structure is that proposed by Labbé et al. [J. Phys. Condens. Matter (1989), 2, 25–43] in the space group Bbm2 (Ama2 in standard setting) on a 2\sqrt{2}a × \sqrt{2}a × 2c cell. Upon heating, the structure remains ferroelectric but becomes tetragonal (space group P4bm) at 550 K, then paraelectric (space group P4/mbm) at and above 860 K.

Immunochemical Investigation of the Serum Proteins in Chick Embryos

Development ◽  
1963 ◽  
Vol 11 (4) ◽  
pp. 683-688
Author(s):  
F. Peetoom ◽  
W. J. A. TH. Kraijenhoff Sloot ◽  
M. W. Woerdeman
Keyword(s):  
Serum Proteins ◽  
Experimental Results ◽  
Chick Embryos ◽  
Lens Proteins ◽  
Embryonic Antigens ◽  
Specific Antisera ◽  
Precipitation Band ◽  
Immunochemical Investigation ◽  
The Subject ◽  
Chick Lens

The use of specific antisera against different embryonic antigens to detect a correlation between morphological and immunochemical differentiation in ontogenesis has proved to be a valuable technique. In a study of the appearance of lens proteins in chick embryos, using various antisera and agar precipitation methods, we observed the development of precipitation lines which did not correspond to specific lens proteins. These lines were encountered in the Ouchterlony and immunoelectrophoretic pictures obtained with young (up to 120 hr.) embryo or lens extracts when these were tested with antiserum to 24-hr, embryo extract or to adult chick serum. However, this type of precipitation band was never found when antiserum against adult chick lens was used. Some of our experimental results which clarify the nature of these precipitation reactions are summarized below. Full details of these experiments are the subject of another publication.

Studies Concerning the Corrosion Behaviour of the Cast Stainless Steel Used for Chemical Industry

2013 ◽  
Vol 371 ◽  
pp. 338-342
Author(s):  
Gheorghe Simionescu ◽  
Mirela Gheorghian
Keyword(s):  
Chemical Industry ◽  
Room Temperature ◽  
Corrosion Behaviour ◽  
Research Work ◽  
Experimental Tests ◽  
Hot Environment ◽  
Chemical Agents ◽  
The Subject ◽  
Materials Used ◽  
Cast Stainless Steel

The current work deals with experimental tests concerning the behaviour of different materials used in chemical industry when are exposed to diverse corrosions environments. During the research work four different metals have been tested, namely T15NiCr180, T15MoNiCr180, W4027 and W4059. The presented work is trying to classify the tested materials function to different chemical environment, different concentration of the environment, different temperature of the environment, and different expose time. Some of the substances which were considered as corrosion environment are: HNO3, H3PO4, NaCl, NH4Cl, C2H5OH, Petrol, NH4NO3, KNO3, K2CO3, Na2CO3, KMnO4, KOH and Ca (OH)2. The concentration of the corrosion solutions varies between 1% and 96%. Tests have been done at room temperature and hot environment of 100°C. Time is playing an important role on evolution of the corrosion. For this reason the samples have been analyzed after 48, 336, 720 and 2160 hours of exposes to chemical agents. To understand the comportment of the subject metals when are used in industry, samples have been tested for longer period of time, respectively 1, 3, 6 and 12 months. After each selected period of time the metallic samples were analyzed and measured to quantify the effect of the environment on the corrosion speed.

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