17 research outputs found
Measurement of event shape distributions and moments in e+e- -> hadrons at 91-209 GeV and a determination of alpha_s
We have studied hadronic events from e+e- annihilation data at centre-of-mass
energies from 91 to 209 GeV. We present distributions of event shape
observables and their moments at each energy and compare with QCD Monte Carlo
models. From the event shape distributions we extract the strong coupling
alpha_s and test its evolution with energy scale. The results are consistent
with the running of alpha_s expected from QCD. Combining all data, the value of
alpha_s(M_Z) is determined to be alpha_s(M_Z) = 0.1191 +- 0.0005 (stat.) +-
0.0010 (expt.) +- 0.0011 (hadr.) +- 0.0044 (theo.). The energy evolution of the
moments is also used to determine a value of alpha_s with slightly larger
errors: alpha_s(M_Z) = 0.1223 +- 0.0005 (stat.) +- 0.0014 (expt.) +- 0.0016
(hadr.) +0.0054 -0.0036 (theo.).Comment: 63 pages 26 fi
Searches for Gauge-Mediated Supersymmetry Breaking Topologies in e+e- collisions at LEP2
In gauge-mediated supersymmetry (SUSY) breaking (GMSB) models the lightest
supersymmetric particle (LSP) is the gravitino and the phenomenology is driven
by the nature of the next-to-lightest SUSY particle (NLSP) which is either the
lightest neutralino, the stau or mass degenerate sleptons. Since the NLSP decay
length is effectively unconstrained, searches for all possible lifetime and
NLSP topologies predicted by GMSB models in e+e- collisions are performed on
the data sample collected by OPAL at centre-of-mass energies up to 209 GeV at
LEP. Results independent of the NLSP lifetime are presented for all relevant
final states including direct NLSP pair-production and, for the first time,
also NLSP production via cascade decays of heavier SUSY particles. None of the
searches shows evidence for SUSY particle production. Cross-section limits are
presented at the 95% confidence level both for direct NLSP production and for
cascade decays, providing the most general, almost model independent results.
These results are then interpreted in the framework of the minimal GMSB (mGMSB)
model, where large areas of the accessible parameter space are excluded. In the
mGMSB model, the NLSP masses are constrained to be larger than 53.5 GeV/c^2,
87.4 GeV/c^2 and 91.9 GeV/c^2 in the neutralino, stau and slepton co-NLSP
scenarios, respectively. A complete scan on the parameters of the mGMSB model
is performed, constraining the universal SUSY mass scale Lambda from the direct
SUSY particle searches: Lambda > 40, 27, 21, 17, 15 TeV/c^2 for messenger
indices N=1, 2, 3, 4, 5 respectively, for all NLSP lifetimes.Comment: 4 pages, 2 figures. To appear in Proceedings of SUSY06, the 14th
International Conference on Supersymmetry and the Unification of Fundamental
Interactions, UC Irvine, California, 12-17 June 200
Flavour Independent hA Search and Two Higgs Doublet Model Interpretation of Neutral Higgs Boson Searches at LEP
Upper limits on the cross-section of the pair-production process e+e- -> h0A0
assuming 100% decays into hadrons, are derived from a new search for the h0A0
-> hadrons topology, independent of the hadronic flavour of the decay products.
Searches for the neutral Higgs bosons h0 and A0, are used to obtain constraints
on the Type II Two Higgs Doublet Model (2HDM(11)) with no CP violation in the
Higgs sector and no additional non Standard Model particles besides the five
Higgs bosons. The analysis combines LEP1 and LEP2 data collected with the OPAL
detctor up to the highest available centre-of-mass energies. The searches are
sensitive to the h0, A0 -> qq, gg,tau+tau- and h0 -> A0A0 decay modes of the
Higgs bosons. The 2HDM(II) parameter space is explored in a detailed scan.
Large regions of the 2HDM(II) parameter space are excluded at the 95% CL in the
(mh, mA), (mh, tanb) and (mA, tanb) planes, using both direct neutral Higgs
boson searches and indirect limits derived from Standard Model high precision
measurements. The region 1 lesssim mh lesssim 55 GeV and 3 lesssim mA lesssim
63 GeV is excluded at 95% CL independently of the choice of the 2HDM(II)
parameters.Comment: 37 pages, 11 figures, Submitted to Eur. Phys. J.
Artificial Intelligence and Backshoring Strategies: A German-Italian Comparison
The Industry 4.0 technologies, such as artificial intelligence (AI), are transforming the manufacturing processes and affecting the location of manufacturing activities across countries, with a potentially positive impact on the backshoring of production processes. The chapter aims at providing empirical evidence on the relationship between AI and relocation, exploring how AI is related to both the offshor- ing and backshoring strategies, using data from an international sample of 124 German and Italian manufacturing companies. Following the investigation of AI use by German and Italian manufacturing companies, the study analyses the differences in some strategic factors and the offshoring and backshor- ing decisions between German and Italian companies, AI users and non-users, and between the German and Italian AI users. Results show that the most important differences concern AI users and non-users and indicate a higher value of AI use for backshoring rather than offshoring strategies. The findings enable the derivation of both theoretical and managerial contributions
Envisioning Mobile Learning as the Future of Teaching and Learning via Technology: A Literature Review of Mobile Learning
Technology has played a key role in reshaping the way education is being delivered in university environments. Mobile technologies are one of the latest technologies to enter the higher education arenas around the world, offering great potential for teaching and learning. Students and teachers have been using mobile devices for formal and informal collaboration, communication, and connectivity within learning environments for a couple of decades without recognizing it as mobile learning. Mobile learning needs to be researched and theorized in order to be included in formal educational Information and Communication Technologies and its full potential harnessed for the future generations. A number of mobile learning researchers borrowed traditional learning models as theoretical foundations for mobile learning research. However, theories from a diverse range of subject areas such as Education, Information Systems, Human-Computer Interaction, and Telecommunication Engineering have also been used as the basis for mobile learning projects around the world. This incorporation of a diversity of disciplines and subjects has made mobile learning a multidisciplinary research field. This chapter aims to review the current mobile learning theories, models, and frameworks with the lens of mobile learning characteristics and challenges pointed out by prominent mobile learning researchers across the world in order to present the case of mobile learning as the future of teaching and learning