16 research outputs found
Implicazioni di web design per Malesia e Paesi Scandinavi attraverso uno studio interculturale
Persone di culture differenti preferiscono pagine web caratterizzate dai valori della loro cultura e
tendono quindi a preferire differenti caratteristiche del sito web a seconda delle loro esigenze in
termini di navigazione, sicurezza, informazioni sui prodotti, servizio al cliente, strumenti di
shopping e design. Per un’impresa che intende globalizzare il proprio mercato è utile implementare
interfacce culturali country specific, ovvero utilizzare pagine web diverse per paesi con culture
differenti. Il presente studio si fonda sulle conclusioni proposte da due modelli di analisi culturale,
Hall (1976) e Hofstede (1980) e attraverso l’applicazione degli studi di Marcus e Gould (2000) e
l’analisi di un campione di siti web commerciali, arriva a definire le linee guida di web design per i
Paesi Scandinavi e Malesi
Magnetic dipoles and electric currents
We discuss several similarities and differences between the concepts of
electric and magnetic dipoles. We then consider the relation between the
magnetic dipole and a current loop and show that in the limit of a pointlike
circuit, their magnetic fields coincide. The presentation is accessible to
undergraduate students with a knowledge of the basic ideas of classical
electromagnetism.Comment: 7 pages, 1 figur
Model independent determination of the shape function for inclusive B decays and of the structure functions in DIS
We present a method to compute, by numerical simulations of lattice QCD, the
inclusive semileptonic differential decay rates of heavy hadrons and the
structure functions which occur in deep inelastic scattering. The method is
based on first principles and does not require any model assumption. It allows
the prediction of the differential rate in B semileptonic decays for values of
the recoiling hadronic mass W ~ sqrt(M_B Lambda_QCD), which is in the relevant
region to extract |V_ub| from the end-point of the lepton spectrum in inclusive
decays.Comment: 16 pages, LaTeX fil
Determination of HQET parameter \lambda_1 from Inclusive Semileptonic B Meson Decay Spectrum
We estimate the heavy quark effective theory parameter \lambda_1 from
inclusive semileptonic B-meson decay spectrum. By using recent CLEO double
lepton tagging data of B -> X e nu, which shows the lepton momentum as low as
0.6 GeV, we extracted \lambda_1 \sim -0.58 GeV^2. We also derived \bar\Lambda
\sim 0.46 GeV and |V_{cb}| = 0.041 \pm 0.002.Comment: 13 pages, 3 figures, LaTeX. Typos are corrected, and added one
commen
QCD Corrections and the Endpoint of the Lepton Spectrum in Semileptonic B Decays
Recently, Neubert has suggested that a certain class of nonperturbative
corrections dominates the shape of the electron spectrum in the endpoint region
of semileptonic decay. Perturbative QCD corrections are important in the
endpoint region. We study the effects of these corrections on Neubert's
proposal. The connection between the endpoint of the electron spectrum in
semileptonic decay and the photon spectrum in is
outlined.Comment: 18 pages, uses REVTeX, UCSD/PTH 93-38, CALT-68-1910, JHU-TIPAC-930029
(some changes to the discussion of subleading radiative corrections, and
minor typos fixed
Decay Constants and Semileptonic Decays of Heavy Mesons in Relativistic Quark Model
We investigate the and mesons in the relativistic quark model by
applying the variational method with the Gaussian wave function. We calculate
the Fermi momentum parameter , and obtain
GeV, which is almost independent of the input parameters, , ,
and . We then calculate the ratio /, and obtain the
result which is larger, by the factor of about 1.3, than
given by the naive nonrelativistic analogy. This result is in a good agreement
with the recent Lattice calculations. We also calculate the ratio
/. In these calculations the wave function at
origin is essential. We also determine by comparing the
theoretical prediction of the ACCMM model with the lepton energy spectrum of from the recent ARGUS analysis, and find that
GeV, when we use GeV. However, this
experimentally determined value of is strongly dependent on the value
of input parameter .Comment: 15 pages (Latex) (uses epsfig.sty, 1 figure appended as a uuencoded
compressed ps-file
QCD-Based Interpretation of the Lepton Spectrum in Inclusive Decays
We present a QCD-based approach to the endpoint region of the lepton spectrum
in decays. We introduce a genuinely
nonperturbative form factor, the shape function, which describes the fall-off
of the spectrum close to the endpoint. The moments of this function are related
to forward scattering matrix elements of local, higher-dimension operators. We
find that nonperturbative effects are dominant over a finite region in the
lepton energy spectrum, the width of which is related to the kinetic energy of
the -quark inside the meson. Applications of our method to the
extraction of fundamental standard model parameters, among them , are
discussed in detail.Comment: 17 pages LaTeX, 3 post- script figures available upon request,
CERN-TH.7087/9
Inclusive Semileptonic B and Polarized Lambda_b Decays from QCD
The differential decay spectrum for the semileptonic
decay of an unpolarized hadron containing a b-quark, and the decay spectrum
for polarized decay are computed
to second order in the expansion. Most of the corrections
have a simple physical interpretation, which is discussed in detail. The
implications of the results for the determination of are discussed.
The decay spectra for semileptonic decay of hadrons containing a c-quark are
also given. There is a subtlety in the use of the equations of motion at order
in the heavy quark expansion which is explained.Comment: (46 pages, 8 figs, uses harvmac and uufiles), UCSD/PTH 93-14,
CALT-68-1883 (REVISED VERSION: Some typos corrected, and one incorrect
paragraph deleted
Average Kinetic Energy of Heavy Quark in Semileptonic B Decay
Within the ACCMM model the average kinetic energy of heavy quark in a
heavy-light meson is calculated as , solely from the fact that the Gaussian momentum probability
distribution has been taken in the ACCMM model. Therefore, the Fermi momentum
parameter of the ACCMM model is not a truly free parameter, but is
closely related to the average kinetic energy of heavy quark, which is
theoretically calculable in principle. In this context, we determine
by comparing the theoretical prediction of the ACCMM model with the model
independent lepton energy spectrum of from the recent
CLEO analysis, and find that GeV. We also
calculate in the relativistic quark model by applying the quantum
mechanical variational method, and obtained GeV. We show
the correspondences between the relativistic quark model and the heavy quark
effective theory. We then clarify the importance of the value of in
the determination of .Comment: 23 pages(LaTeX), 2 Postscript figures, uses aps.st