4,494 research outputs found
Exclusive Hadronic D Decays to eta' and eta
Hadronic decay modes and
are studied in the generalized
factorization approach. Form factors for transitions
are carefully evaluated by taking into account the wave function normalization
of the eta and eta'. The predicted branching ratios are generally in agreement
with experiment except for and
; the calculated decay rates for the first two decay modes
are too small by an order of magnitude. We show that the weak decays and followed by resonance-induced final-state
interactions (FSI), which are amenable technically, are able to enhance the
branching ratios of and dramatically
without affecting the agreement between theory and experiment for and . We argue that it is difficult to understand
the observed large decay rates of and
simultaneously; FSI, W-annihilation and the production of excess eta' from
gluons are not helpful in this regard. The large discrepancy between the
factorization hypothesis and experiment for the ratio of
and remains as an enigma.Comment: 15 pages, 1 figure, to appear in Phys. Rev. D. Form factors for D to
eta and eta' transitions are slightly change
Developing a Typological Theory Using a Quantitative Approach: A Case of Information Security Deviant Behavior
Different from classification and taxonomy, typology meets the criteria of a theory and is a unique form of theory building. Typology is a good first step in exploring a research topic, and, therefore, we are concerned with building typological theories for underdeveloped topics with limited studies. We propose a four-step approach involving content analysis, multidimensional scaling, judgmental analysis, and empirical testing to guide researchers in developing typological theories in their domains of interest using a quantitative approach that rides on empirical methods and industry wisdom. Previous research in information security has paid little attention to employees’ deviant behavior in the workplace. We, therefore, built a typology of information security deviant behavior as an example to illustrate the theory development process. We discuss the theoretical, methodological, and practical implications of this study
Flavor SU(3) symmetry and QCD factorization in and decays
Using flavor SU(3) symmetry, we perform a model-independent analysis of
charmless decays. All the relevant
topological diagrams, including the presumably subleading diagrams, such as the
QCD- and EW-penguin exchange diagrams and flavor-singlet weak annihilation
ones, are introduced. Indeed, the QCD-penguin exchange diagram turns out to be
important in understanding the data for penguin-dominated decay modes. In this
work we make efforts to bridge the (model-independent but less quantitative)
topological diagram or flavor SU(3) approach and the (quantitative but somewhat
model-dependent) QCD factorization (QCDF) approach in these decays, by
explicitly showing how to translate each flavor SU(3) amplitude into the
corresponding terms in the QCDF framework. After estimating each flavor SU(3)
amplitude numerically using QCDF, we discuss various physical consequences,
including SU(3) breaking effects and some useful SU(3) relations among decay
amplitudes of and .Comment: 47 pages, 3 figures, 28 table
Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme
We give a general formulation of the quark-diagram scheme for the nonleptonic
weak decays of baryons. We apply it to all the decays of the antitriplet and
sextet charmed baryons and express their decay amplitudes in terms of the
quark-diagram amplitudes. We have also given parametrizations for the effects
of final-state interactions. For SU(3) violation effects, we only parametrize
those in the horizontal -loop quark diagrams whose contributions are solely
due to SU(3)-violation effects. In the absence of all these effects, there are
many relations among various decay modes. Some of the relations are valid even
in the presence of final-state interactions when each decay amplitude in the
relation contains only a single phase shift. All these relations provide useful
frameworks to compare with future experiments and to find out the effects of
final-state interactions and SU(3) symmetry violations.Comment: 28 pages, 20 Tables in landscape form, 4 figures. Main changes are:
(i) some errors in the Tables and in the relations between the quark-diagram
amplitudes of this paper and those of Ref.[10] are corrected, (ii)
improvements are made in the presentation so that comparisons with previous
works and what have been done to include SU(3) breaking and final-state
interactions are more clearly stated; to appear in the Physical Review
The evolution of time use approaches for understanding activities of daily living in a public health context
This Supplement aims to raise awareness and knowledge of how time use surveys may be applied to studying health behaviours such as physical activity, sedentary behaviour, and eating. This commentary provides an overview and discussion of the papers in this Supplement about time use and health research, and considers possible future directions for the field
入院患者のサルモネラ保菌率およびその分離のための増菌培地の比較
The efficiencies of Rappaport medium, strontium chloride, strontium selenite and selenite F broths for enrichment in the isolation of salmonellas from human stools were compared. The study showed that Rappaport medium when used in conjunction with strontium selenite broth gave the most satisfactory result, because they covered the isolation of a wider range of salmonellas. With these media, the carriage rate of Salmonella serotypes of 3,325 hospital patients who were admitted without complaints of diarrhoea or gastroenteritis or enteric fever, were tested. The result revealed that 5.6% of them carried Salmonella serotypes ranging from those that may produce food-poisoning to those which are causal agents of enteric fever. Moreover, patients who were infected with the liver-fluke, Clonorchis sinensis, had a higher carriage rate than those who were infected with other intestinal parasites or non-infected.サルモネラ分離に際してRappaport培地,strontium chlorideブイヨン,strontium seleniteブイヨンおよびselenite Fブイヨンの4種の増菌培地を用い,その成績を比較した.その結果,Rappaport培地にstrontium seleniteブイヨンを併用すると,サルモネラの各種類の分離に最も満足すべき成績がえられた.これらの培地を用いて,下痢を全く伴わない患者,胃腸炎あるいはチフス性疾患の患者3,325名についてサルモネラ保菌率を検査した.その結果,22の血清型に属する189株のサルモネラを分離した.検出率は5.6%である.その血清型は,食中毒の原因と推定されたものから,チフス性疾患の原因菌に至るさまぎまの型が含まれていたが,最も多く分離されたのはS. derbyとS. anatumであった.また,Clonorchis sinensisに感染していた患者は,他の腸寄生虫感染者あるいは非感染者より高率にサルモネラを保有していた
Final-State Phases in Baryon-Antibaryon Decays
The recent observation of the decay \ob \to \Lambda_c^+ \bar p suggests
that related decays may soon be visible at colliders. It is shown how
these decays can shed light on strong final-state phases and amplitudes
involving the spectator quark, both of which are normally expected to be small
in B decays.Comment: 14 pages, LaTeX, 2 figures, submitted to Phys. Rev. D, references and
discussion of helicity amplitudes adde
Branching ratios of decays in perturbative QCD approach
We study the rare decays , which can occur only via
annihilation type diagrams in the standard model. We calculate all of the four
modes, , in the framework of perturbative QCD approach
and give the branching ratios of the order about .Comment: 18 pages, 1 figure, Revte
Implications of Recent Measurements
The recent measurements of the color-suppressed modes imply non-vanishing relative final-state interaction (FSI)
phases among various decay amplitudes. Depending on whether or
not FSIs are implemented in the topological quark-diagram amplitudes, two
solutions for the parameters and are extracted from data using
various form-factor models. It is found that is not universal:
and with a relative phase
of order between and . If FSIs are not included in
quark-diagram amplitudes from the outset, and
will become smaller. The large value of compared to
or naive expectation implies the importance of
long-distance FSI contributions to color-suppressed internal -emission via
final-state rescatterings of the color-allowed tree amplitude.Comment: 17 pages. The Introduction is substantially revised and the order of
the presentation in Sec. 2 is rearranged. To appear in Phys. Re
Sustainable resorts: Learning from the 2004 tsunami
Purpose - Given the extensive destruction resulting from the devastating 2004 Indian Ocean tsunami that destroyed and damaged resort complexes in southern Thailand, the purpose of this research paper is to focus on the planning of architecture of resorts in two layers: the relationship of structures and land use to the natural environment, and the identification of specific design flaws that resulted in the loss of life. Design/methodology/ approach - An international collaborative effort led to site visits by our research team to the hardest-hit resort areas of Khao Lak, Takua Pa, and Ko Phi Phi on December 29, 2004-January 6, 2005, and in February 2005. The research team had direct contact with the adverse effects of the tsunami and gained insightful understanding on how structures and faulty architectural designs worsened the disaster and obstructed the process of saving lives. Analysis of these effects were then compiled and used to underpin subsequent proposals for resort reconstruction to minimize future destruction which may result from such calamities. Findings - Close scrutiny and subsequent analysis of various factors which magnified the destruction and damage caused by the tsunami resulted in action plan proposals for sustainable resort development aimed at avoiding a repeat of the tragedy. These include responses to site, architecture, structures, building services and landscaping. More specifically proposals were made on issues of relocation, modifications of design flaws, introduction of escape routes, safer rooms, restoration of waterways, co-generation, tree plantation and incorporation of natural landscape. Research limitations/ implications - Most of the information and data were gathered first hand at the location mentioned. More studies are needed to reinforce and further validate the proposed measures as generally applicable in similar locations. Originality/value - An action plan outlining measures aimed at minimizing damage from such natural disasters could provide a useful resource in future planning of resorts in tsunami prone locations. © Emerald Group Publishing Limited.published_or_final_versio
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