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A Study Of Τ Decays Involving Η And Ω Mesons, D. Buskulic, M. Thulasidas Jan 1997

A Study Of Τ Decays Involving Η And Ω Mesons, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The 132 pbt - 1 of data collected by ALEPH from 1991 to 1994 have been used to analyze η and ω production in τ decays. The following branching fractions have been measured: B(τ−→ντωh−)=(1.91±0.07±0.06)×10−2,B(τ−→ντωh−)=(1.91±0.07±0.06)×10−2, B(τ−→ντωh−π0)=(4.3±0.6±0.5)×10−3,B(τ−→ντωh−π0)=(4.3±0.6±0.5)×10−3, B(τ−→ντηK−)=(2.9+1.3−1.2±0.7)×10−4,B(τ−→ντηK−)=(2.9−1.2+1.3±0.7)×10−4, B(τ−→ντηh−π0)=(1.8±0.4±0.2)×10−3B(τ−→ντηh−π0)=(1.8±0.4±0.2)×10−3 and the 95% C.L. limit B(τ− → ντηπt -) t - 4 has been obtained. The ωπt- and ηπt -π0 rates and dynamics are found in agreement with the predictions made from e+e∼ - annihilation data with the help of isospin invariance (CVC).

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The Topology Dependence Of Charged Particle Multiplicities In Three-Jet Events, R. Barate, M. Thulasidas Jan 1997

The Topology Dependence Of Charged Particle Multiplicities In Three-Jet Events, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A study of individual jet and whole-event charged particle multiplicities in three-jet events measured in e + e − annihilation at the Z reveals a significant topology dependence. Mean jet multiplicities are inadequately described by jet energies; interjet angles must also be specified. Quantitative tests suggest that it is necessary to use transversemomentum- like scales to describe the data.

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Measurement Of The Spectral Functions Of Vector Current Hadronic Tau Decays, R. Barate, M. Thulasidas Jan 1997

Measurement Of The Spectral Functions Of Vector Current Hadronic Tau Decays, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A measurement of the spectral functions of non-strange τ vector current final states is presented, using 124 358 τ pairs recorded by the ALEPH detector at LEP during the years 1991 to 1994. The spectral functions of the dominant two- and four-pion τ decay channels are compared to published results of e + e - annihilation experiments via isospin rotation. A combined fit of the pion form factor from τ decays and e + e - data is performed using different parametrizations. The mass and the width of the ρ ±(770) and the ρ 0(770) are separately determined in order …

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Moderating Effects Of Tolerance For Ambiguity And Risktaking Propensity On The Role Conflict-Perceived Performance Relationship: Evidence From Singapore Entrepreneurs, Hai Yap Teoh, See Liang Foo Jan 1997

Moderating Effects Of Tolerance For Ambiguity And Risktaking Propensity On The Role Conflict-Perceived Performance Relationship: Evidence From Singapore Entrepreneurs, Hai Yap Teoh, See Liang Foo

Research Collection School Of Accountancy

This study investigates the effects of tolerance for ambiguity and risktaking propensity in mediating the relationships between role conflict and perceived performance among 70 entrepreneurs in small and medium-sized businesses in Singapore. Entrepreneurial activity has been widely recognized as a major factor driving Singapore's economic development. Further insights therefore can be gained by this study, which addresses the above issues from the perspective of Singaporean entrepreneurs. As founders of their enterprises, entrepreneurs are often involved with many aspects of activities that create a high potential for conflict, having to play multiple roles, coping with competing and conflicting demands, and overcoming …

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Measurement Of The Τ Lepton Lifetime With The Three-Dimensional Impact Parameter Method, R. Barate, M. Thulasidas Jan 1997

Measurement Of The Τ Lepton Lifetime With The Three-Dimensional Impact Parameter Method, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A new method is presented for the measurement of the mean lepton lifetime using events in which are pair-produced and both's decay to hadrons.

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Improved Measurement Of The Bd0 -B̄D0 Oscillation Frequency, D. Buskulic, M. Thulasidas Jan 1997

Improved Measurement Of The Bd0 -B̄D0 Oscillation Frequency, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The time dependence of B0 d {B 0 d oscillations is measured by the ALEPH experiment at LEP, using three techniques, two of which are updates of previous measurements. In all cases the charge of the decaying b quark and its decay time are measured in one hemisphere of the event; the quark charge at production is tagged mainly using the opposite hemisphere. The first method uses the charge correlation between a D and a lepton in the opposite hemisphere; if no lepton is present, the produced quark charge is determined from the hemisphere charges. In the second method, the …

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Four-Fermion Production In E+E- Collisions At Centre-Of-Mass Energies Of 130 And 136 Gev, D. Buskulic, Manoj Thulasidas Nov 1996

Four-Fermion Production In E+E- Collisions At Centre-Of-Mass Energies Of 130 And 136 Gev, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Four-fermion events have been selected in a data sample of 5.8 pb−1 collected with the aleph detector at centre-of-mass energies of 130 and 136 GeV. The final states ℓ+ℓ−qq, ℓ+ℓ−ℓ+ℓ−, ννqq, and ννℓ+ℓ− have been examined. Five events are observed in the data, in agreement with the Standard Model predictions of 6.67±0.38 events from four-fermion processes and 0.14−0.05+0.19 from background processes.

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An Evidential Reasoning Approach To Attribute Value Conflict Resolution In Database Integration, Ee Peng Lim, Jaideep Srivastava, Shashi Shekhar Oct 1996

An Evidential Reasoning Approach To Attribute Value Conflict Resolution In Database Integration, Ee Peng Lim, Jaideep Srivastava, Shashi Shekhar

Research Collection School Of Computing and Information Systems

Resolving domain incompatibility among independently developed databases often involves uncertain information. DeMichiel [1] showed that uncertain information can be generated by the mapping of conflicting attributes to a common domain, based on some domain knowledge. In this paper, we show that uncertain information can also arise when the database integration process requires information not directly represented in the component databases, but can be obtained through some summary of data. We therefore propose an extended relational model based on Dempster-Shafer theory of evidence [2] to incorporate such uncertain knowledge about the source databases. The extended relation uses evidence sets to represent …

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Observation Of Charmless Hadronic B Decays, Buskulic, D.; Et Al., M. Thulasidas Sep 1996

Observation Of Charmless Hadronic B Decays, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.

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An On-The-Fly Decoding Technique For Reed-Solomon Codes, Yuan Xing Lee, Robert H. Deng, Eng Hean Koh Sep 1996

An On-The-Fly Decoding Technique For Reed-Solomon Codes, Yuan Xing Lee, Robert H. Deng, Eng Hean Koh

Research Collection School Of Computing and Information Systems

An on-the-fly error correction technique for double-byte-error-correction (DBEC) and triple-byte-error-detection (TBED) Reed-Solomon (RS) codes is presented in this paper. This new algorithm finds number of byte-errors (single byte-error, double-byte errors, and triple-byte errors) by simply testing the values of a few syndrome functions, and locates and corrects the byte-errors directly without using the standard iterative algorithms for finding the error location polynomial. More importantly, it neither suffers from malfunctions incurred in Deng-Costello algorithm (1987), nor requires syndrome re-calculation as in Koksal-Yucel's modification (1992). It is also much more simpler and faster than the original Deng-Costello algorithm. It has found applications …

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Measurement Of The B Forward-Backward Asymmetry And Mixing Using High-P⊥ Leptons, Buskulic, D., M. Thulasidas Sep 1996

Measurement Of The B Forward-Backward Asymmetry And Mixing Using High-P⊥ Leptons, Buskulic, D., M. Thulasidas

Research Collection School Of Computing and Information Systems

The B0 - B̄0 average mixing parameter χ and b forward-backward asymmetry AFB0(b) are measured from a sample of about 4 200 000 Z → qq̄ events recorded with the ALEPH detector at LEP in the years 1990–1995. High transverse momentum electrons and muons produced in b semileptonic decays provide the tag of the quark flavour and of its charge.The average mixing parameter and the pole b asymmetry are measured to be χ = 0.1246 ± 0.0051stat ± 0.0052syst, AFB0(b) = 0.1008 ± 0.0043stat ± 0.0028syst. The value of sin2θweff = 0.23198 ± 0.00092 is extracted from the asymmetry measurement.

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Search For Charginos And Neutralinos With R-Parity Violation At √S = 130 And 136 Gev, Buskulic, D.; Et Al., M. Thulasidas Sep 1996

Search For Charginos And Neutralinos With R-Parity Violation At √S = 130 And 136 Gev, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Searches for charginos and neutralinos produced in e +e - collisions at centre-of-mass energies of 130 and 136 GeV have been performed under the assumptions that R-parity is not conserved, that the dominant R-parity violating coupling involves only leptonic fields, and that the lifetime of the lightest supersymmetric particle can be neglected. In the 5.7 pb -1 data sample collected by ALEPH, no candidate events were found. As a result, chargino and neutralino masses and couplings are constrained and the domains previously excluded at LEP1 are extended.

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The Evolution Of International Norms, Ann Florini Sep 1996

The Evolution Of International Norms, Ann Florini

Research Collection School of Social Sciences

This article puts forward a theoretical explanation for why norms of international behavior change over time. It argues that the mainstream neorealist and neoliberal arguments on the static nature of state interests are implausible, as the recent empirical work of the growing constructivist school has convincingly shown. But the constructivists have not yet provided a theoretical basis for understanding why one norm rather than another becomes institutionalized, nor has learning theory yet provided an adequate explanation. An evolutionary approach that draws its hypotheses from an analogy to population genetics offers a promising alternative. This article briefly outlines the constructivist critique …

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Search For Cp Violation In The Decay Z → B B̄ G, Buskulic, D.; Et Al., M. Thulasidas Sep 1996

Search For Cp Violation In The Decay Z → B B̄ G, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

About three million hadronic decays of the Z collected by ALEPH in the years 1991 to 1994 are used to search for anomalous CP violation beyond the Standard Model in the decay Z → bb̄g. The study is performed by analyzing angular correlations between the two quarks and the gluon in three-jet events and by measuring the differential two-jet rate. No signal of CP violation is found. For the combinations of anomalous CP violating couplings, ĥb = ĥAbgVh - ĥVbgAb and hb* = √ĥVb2 + ĥAb2, limits of | ĥb | b*

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Mass Limit For The Standard Model Higgs Boson With The Full Lep I Aleph Data Sample, Buskulic, D.; Et Al., M. Thulasidas Sep 1996

Mass Limit For The Standard Model Higgs Boson With The Full Lep I Aleph Data Sample, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

The reaction e+e− → HZ∗ is used to search for the standard model Higgs boson in the Hνν and the Hℓ+ℓ− channels. The data sample corresponds to about 4.5 million hadronic Z decays collected by the ALEPH experiment at LEP from 1989 to 1995 at centre-of-mass energies at and around the Z peak. Three candidate events are found in the Hμ+μ− channel, in agreement with the expected background from the electroweak process e+e− ℓ+ℓ−qq. This search results in a 95% C.L. lower limit on the Higgs boson mass of 63.9 GeV/c2.

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Measurement Of The Mass Of The Λb Baryon, Buskulic, D.; Et Al., M. Thulasidas Jul 1996

Measurement Of The Mass Of The Λb Baryon, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.

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Measurement Of Hadron And Lepton-Pair Production From E+E- Annihilation At Centre-Of-Mass Energies Of 130 And 136 Gev, Buskulic, D.; Et Al., M. Thulasidas Jun 1996

Measurement Of Hadron And Lepton-Pair Production From E+E- Annihilation At Centre-Of-Mass Energies Of 130 And 136 Gev, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.

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Specifying Object-Oriented Federated Database From Existing Databases, Ee Peng Lim, M. L. Lim, J. Srivastava Jun 1996

Specifying Object-Oriented Federated Database From Existing Databases, Ee Peng Lim, M. L. Lim, J. Srivastava

Research Collection School Of Computing and Information Systems

In this paper, we present a mapping strategy that is based on a proposed set of DB integration operations. We first define an OO federated DB as a virtual view on multiple OO export DBs. Our DB mapping strategy systematically derives each of the class extents, deep class extents and relationships of the federated DB using an operator tree consisting of the integration operations. This mapping approach differs from the other existing approaches in that it is algebraic based, and is therefore very suitable for implementing federated query processing.

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On The Use Of The Complexity Index As A Measure Of Complexity In Activity Networks, Bert De Reyck, Willy Herroelen Jun 1996

On The Use Of The Complexity Index As A Measure Of Complexity In Activity Networks, Bert De Reyck, Willy Herroelen

Research Collection Lee Kong Chian School Of Business

A large number of optimal and suboptimal procedures have been developed for solving combinatorial problems modeled as activity networks. The need to differentiate between easy and hard problem instances and the interest in isolating the fundamental factors that determine the computing effort required by these procedures, inspired a number of researchers to develop various complexity measures. In this paper we investigate the relation between the hardness of a problem instance and the topological structure of its underlying network, as measured by the complexity index. We demonstrate through a series of experiments that the complexity index, defined as the minimum number …

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Study Of The B0sb0s Oscillation Frequency Using D-S ℓ+ Combinations In Z Decays, Buskulic, D.; Et Al., M. Thulasidas Jun 1996

Study Of The B0sb0s Oscillation Frequency Using D-S ℓ+ Combinations In Z Decays, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

A lower limit on the oscillation frequency of the B s 0 B s 0 system is obtained from approximately four million hadronic Z decays accumulated using the ALEPH detector at LEP from 1991 to 1995. Leptons are combined with opposite sign D s − candidates reconstructed in seven different decay modes as evidence of semileptonic B s 0 decays. Criteria designed to ensure precise proper time reconstruction select 277D s − ℓ + combinations. The initial state of these B s 0 candidates is determined using an algorithm optimized to efficiently utilise the tagging information available for each event. …

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Semiparametric Exploration Of Long Memory In Stock Prices, David K. C. Lee, Peter M. Robinson Mar 1996

Semiparametric Exploration Of Long Memory In Stock Prices, David K. C. Lee, Peter M. Robinson

Research Collection Lee Kong Chian School Of Business

New or modified methods for semiparametric analysis of fractional long memory in time series are described and applied to twenty-six stock prices and two stock indices. Evidence is found that some, but not all, of the stocks have long memory, while one of the indices exhibits mean reversion.

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Moorean Absurdities And The Nature Of Assertion, John N. Williams Mar 1996

Moorean Absurdities And The Nature Of Assertion, John N. Williams

Research Collection School of Social Sciences

I argue that Moore's propositions, for example, 'I went to the pictures last Tuesday but I don't believe that I did' cannot be rationally believed. Their assertors either cannot be rationally believed or cannot be believed to be rational. This analysis is extended to Moorean propositions such as God knows that I am an atheist and I believe that this proposition is false. I then defend the following definition of assertion: anyone asserts that p iff that person expresses a belief that p with the intention of causing relevant epistemic change in the cognition of an actual or potential audience.

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Policies Of Secrecy And Denial: Barriers To Jury Reform, Mark Findlay Mar 1996

Policies Of Secrecy And Denial: Barriers To Jury Reform, Mark Findlay

Research Collection Yong Pung How School Of Law

The jury is that institution of justice most highly regarded in the communities in which it features. However, it remains little understood. The difficulties associated with researching the jury are well known. The barriers raised against an actual appreciation of the "jury" and juries, are diverse and formidable in all their operational contexts. Yet debates about jury reform are a common feature of criminal justice administration.

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Entity Identification In Database Integration, Ee Peng Lim, Jaideep Srivastava, Satya Prabhakar, James Richardson Feb 1996

Entity Identification In Database Integration, Ee Peng Lim, Jaideep Srivastava, Satya Prabhakar, James Richardson

Research Collection School Of Computing and Information Systems

The objective of entity identification is to determine the correspondence between objective instances from more than one database. This paper examines the problem at the instance level assuming that schema level heterogeneity has been resolved a priori. Soundness and completeness are defined as the desired properties of any entity-identification technique. To achieve soundness, a set of identity and distinctness rules have to be established for the entities in the integrated world. We then propose the use of extended key, which is the union of keys (and possibly other attributes) from the relations to be matched, and its corresponding identity rule …

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A Precise Measurement Of The Average B Hadron Lifetime, D. Buskulic, M. Thulasidas Feb 1996

A Precise Measurement Of The Average B Hadron Lifetime, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

An improved measurement of the average b hadron lifetime is performed using a sample of 1.5 million hadronic Z decays, collected during the 1991–1993 runs of ALEPH, with the silicon vertex detector fully operational. This uses the three-dimensional impact parameter distribution of lepton tracks coming from semileptonic b decays and yields an average b hadron lifetime of 1.533 ± 0.013 ± 0.022 ps.

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Tau Hadronic Branching Ratios, D. Buskulic, M. Thulasidas Jan 1996

Tau Hadronic Branching Ratios, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

From 64492 selected τ-pair events, produced at the Z0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and π0s, and the removal of fake photons. A detailed study of the systematics entering the π0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test τ-μ, universality in …

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Tau Leptonic Branching Ratios, D. Buskulic, M. Thulasidas Jan 1996

Tau Leptonic Branching Ratios, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

A sample of 62249 τ-pair events is selected from data taken with the ALEPH detector in 1991, 1992 and 1993. The measurement of the branching fractions for τ decays into electrons and muons is presented with emphasis on the study of systematic effects from selection, particle identification and decay classification. The results obtained are: B e = 17.79±0.12(stat)±0.06(syst)(%) and Bμ = 17.31±0.11(stat)±0.05(syst)(%). Combined with the most recent ALEPH determination of the τ lifetime, these results provide a relative measurement of the leptonic couplings in the weak charged current for transverse W bosons: ${cal G}_{ώ}/{cal G}_{e}=1.0002pm 0.0051$ and ${cal G}_{∢u}/{cal G}_{u}=0.9943pm …

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Organization Structure And Structural Change In European Manufacturing Organisations, Derek Pugh, Timothy Adrian Robert Clark, Geoff Mallory Jan 1996

Organization Structure And Structural Change In European Manufacturing Organisations, Derek Pugh, Timothy Adrian Robert Clark, Geoff Mallory

Research Collection Lee Kong Chian School Of Business

The paper considers two approaches to thestudy of the impact of national cultures on thestructure of organizations; viz: culture free andculture bound approaches. Af ter a discussionof the problems of obtaining comparable datain cross-cultural research, the preliminary results of a comparative study of large manufacturing organizations in six countries in Europeare presented. The results suggest that whileformal organizational authority structures appear to be culture free reflecting the impact ofstrategic contingencies, use of coordinationtechniques, such as regular top managementmeetings and task forces, is more affected bycultural factors.

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Improved Measurement Of The B0 And B+ Meson Lifetimes, D. Buskulic, M. Thulasidas Jan 1996

Improved Measurement Of The B0 And B+ Meson Lifetimes, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

Updated measurements of the B0 and B+ meson lifetimes are presented. From a data sample of 1.72 million hadronic Z0 decays recorded during the period 1991 to 1993, a sample of approximately 1000 semileptonic B meson decays containing a D0, D+ or D*+ has been isolated. From the distribution of decay times in the different samples the lifetimes of the B0 and B+ mesons are determined to be 1.53±0.12±0.08 ps and 1.52±0.14±0.09 ps, respectively, where the first error is statistical and the second systematic. The ratio of the B+ to B0 lifetimes is measured to be 0.99±0.14+0.05−0.04, confirming expectations that …

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Determination Of Sin2Θw Eff Using Jet Charge Measurements In Hadronic Z Decays, D. Buskulic, M. Thulasidas Jan 1996

Determination Of Sin2Θw Eff Using Jet Charge Measurements In Hadronic Z Decays, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The electroweak mixing angle is determined with high precision from measurements of the mean difference between forward and backward hemisphere charges in hadronic decays of the Z. A data sample of 2.5 million hadronic Z decays recorded over the period 1990 to 1994 in the ALEPH detector at LEP is used. The mean charge separation between event hemispheres containing the original quark and antiquark is measured forbb¯bb¯ andcc¯cc¯ events in subsamples selected by their long lifetimes or using fastD*’s. The corresponding average charge separation for light quarks is measured in an inclusive sample from the anticorrelation between charges of opposite …

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