725 research outputs found
MOZART\u27S OPERAS FOR HARMONIE: THREE CONTEMPORARY ARRANGEMENTS COMPARED
This thesis examines three approaches to arranging Mozart\u27s operas for Harmonie by Johann Nepomuk Went, Josef Triebensee, and Joseph Heidenreich through an analysis of selections from their arrangements. It consists of two chapters. Chapter One discusses the historical background of the Harmonie ensemble in Vienna and an introduction to the complicated publishing history of Mozart\u27s original works for the Harmoniemusik ensemble. A summary of the scant biographical information about the three arrangers of the works to be studied concludes Chapter One. Chapter Two covers the arrangements of Mozart\u27s operas by Johann Nepomuk Went, Josef Triebensee, and Joseph Heidenreich. The Harmonie arrangements of Mozart\u27s operas made by Went, Triebensee, and Heidenreich provide vital information in analyzing the writing style of Harmoniemusik at the end of the eighteenth century.
Advisor: Pamela F. Star
A search for solar-like oscillations in K giants in the globular cluster M4
To expand the range in the colour-magnitude diagram where asteroseismology
can be applied, we organized a photometry campaign to find evidence for
solar-like oscillations in giant stars in the globular cluster M4. The aim was
to detect the comb-like p-mode structure characteristic for solar-like
oscillations in the amplitude spectra. The two dozen main target stars are in
the region of the bump stars and have luminosities in the range 50-140 Lsun. We
collected 6160 CCD frames and light curves for about 14000 stars were
extracted. We obtain high quality light curves for the K giants, but no clear
oscillation signal is detected. High precision differential photometry is
possible even in very crowded regions like the core of M4. Solar-like
oscillations are probably present in K giants, but the amplitudes are lower
than classical scaling laws predict.Comment: 14 pages, 16 figures, accepted for publication in A&
Localization of Events in Space-Time
The present paper deals with the quantum coordinates of an event in
space-time, individuated by a quantum object. It is known that these
observables cannot be described by self-adjoint operators or by the
corresponding spectral projection-valued measure. We describe them by means of
a positive-operator-valued (POV) measure in the Minkowski space-time,
satisfying a suitable covariance condition with respect to the Poincare' group.
This POV measure determines the probability that a measurement of the
coordinates of the event gives results belonging to a given set in space-time.
We show that this measure must vanish on the vacuum and the one-particle
states, which cannot define any event. We give a general expression for the
Poincare' covariant POV measures. We define the baricentric events, which lie
on the world-line of the centre-of-mass, and we find a simple expression for
the average values of their coordinates. Finally, we discuss the conditions
which permit the determination of the coordinates with an arbitrary accuracy.Comment: 31 pages, latex, no figure
Events in a Non-Commutative Space-Time
We treat the events determined by a quantum physical state in a
noncommutative space-time, generalizing the analogous treatment in the usual
Minkowski space-time based on positive-operator-valued measures (POVMs). We
consider in detail the model proposed by Snyder in 1947 and calculate the POVMs
defined on the real line that describe the measurement of a single coordinate.
The approximate joint measurement of all the four space-time coordinates is
described in terms of a generalized Wigner function (GWF). We derive lower
bounds for the dispersion of the coordinate observables and discuss the
covariance of the model under the Poincare' group. The unusual transformation
law of the coordinates under space-time translations is interpreted as a
failure of the absolute character of the concept of space-time coincidence. The
model shows that a minimal length is compatible with Lorents covariance.Comment: 13 pages, revtex. Introductory part shortened and some arguments made
more clea
Optical and Near-IR Spectra of O-rich Mira Variables : a Comparison between Models and Observations
Pulsation models are crucial for the interpretation of spectrophotometric and
interferometric observations of Mira variables. Comparing predicted and
observed spectra is one way of establishing the validity of such models. In
this paper, we focus on the models published between 1996 and 1998 by Bessell,
Hofmann, Scholz and Wood. A few new model spectra are added, to improve
available phase coverage. We compare the synthetic spectra with observed low
resolution spectra of optically selected oxygen-rich Miras, over a range of
optical and near-IR wavelengths that encompasses most of the stellar energy
output. We investigate the overall energy distributions, and specific spectral
features in the near-IR wavelength range. The agreement between the observed
and the model-predicted properties is found to be reasonably good. However,
there are discrepancies seen especially in various molecular bands. We find
that different combinations of stellar parameters and pulsation phases often
result in very similar model spectra. Therefore the problem of deriving
parameters of a Mira variable from its spectrum has no unique solution. More
advanced models than presently available, providing even better fits to the
data and covering a wider range of parameters, would be needed to achieve
better discrimination.Comment: Accepted for publication in A &
Bose-Einstein Correlations of Three Charged Pions in Hadronic Z^0 Decays
Bose-Einstein Correlations (BEC) of three identical charged pions were
studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP.
The genuine three-pion correlations, corrected for the Coulomb effect, were
separated from the known two-pion correlations by a new subtraction procedure.
A significant genuine three-pion BEC enhancement near threshold was observed
having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029
(syst.) fm and a strength of \lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041
(syst.). The Coulomb correction was found to increase the \lambda_3 value by
\~9% and to reduce r_3 by ~6%. The measured \lambda_3 corresponds to a value of
0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the
three-pion sample purity. A relation between the two-pion and the three-pion
source parameters is discussed.Comment: 19 pages, LaTeX, 5 eps figures included, accepted by Eur. Phys. J.
Measurements of Flavour Dependent Fragmentation Functions in Z^0 -> qq(bar) Events
Fragmentation functions for charged particles in Z -> qq(bar) events have
been measured for bottom (b), charm (c) and light (uds) quarks as well as for
all flavours together. The results are based on data recorded between 1990 and
1995 using the OPAL detector at LEP. Event samples with different flavour
compositions were formed using reconstructed D* mesons and secondary vertices.
The \xi_p = ln(1/x_E) distributions and the position of their maxima \xi_max
are also presented separately for uds, c and b quark events. The fragmentation
function for b quarks is significantly softer than for uds quarks.Comment: 29 pages, LaTeX, 5 eps figures (and colour figs) included, submitted
to Eur. Phys. J.
Bose-Einstein Correlations in e+e- to W+W- at 172 and 183 GeV
Bose-Einstein correlations between like-charge pions are studied in hadronic
final states produced by e+e- annihilations at center-of-mass energies of 172
and 183 GeV. Three event samples are studied, each dominated by one of the
processes W+W- to qqlnu, W+W- to qqqq, or (Z/g)* to qq. After demonstrating the
existence of Bose-Einstein correlations in W decays, an attempt is made to
determine Bose-Einstein correlations for pions originating from the same W
boson and from different W bosons, as well as for pions from (Z/g)* to qq
events. The following results are obtained for the individual chaoticity
parameters lambda assuming a common source radius R: lambda_same = 0.63 +- 0.19
+- 0.14, lambda_diff = 0.22 +- 0.53 +- 0.14, lambda_Z = 0.47 +- 0.11 +- 0.08, R
= 0.92 +- 0.09 +- 0.09. In each case, the first error is statistical and the
second is systematic. At the current level of statistical precision it is not
established whether Bose-Einstein correlations, between pions from different W
bosons exist or not.Comment: 24 pages, LaTeX, including 6 eps figures, submitted to European
Physical Journal
W+W- production and triple gauge boson couplings at LEP energies up to 183 GeV
A study of W-pair production in e+e- annihilations at Lep2 is presented,
based on 877 W+W- candidates corresponding to an integrated luminosity of 57
pb-1 at sqrt(s) = 183 GeV. Assuming that the angular distributions of the
W-pair production and decay, as well as their branching fractions, are
described by the Standard Model, the W-pair production cross-section is
measured to be 15.43 +- 0.61 (stat.) +- 0.26 (syst.) pb. Assuming lepton
universality and combining with our results from lower centre-of-mass energies,
the W branching fraction to hadrons is determined to be 67.9 +- 1.2 (stat.) +-
0.5 (syst.)%. The number of W-pair candidates and the angular distributions for
each final state (qqlnu,qqqq,lnulnu) are used to determine the triple gauge
boson couplings. After combining these values with our results from lower
centre-of-mass energies we obtain D(kappa_g)=0.11+0.52-0.37,
D(g^z_1)=0.01+0.13-0.12 and lambda=-0.10+0.13-0.12, where the errors include
both statistical and systematic uncertainties and each coupling is determined
setting the other two couplings to the Standard Model value. The fraction of W
bosons produced with a longitudinal polarisation is measured to be
0.242+-0.091(stat.)+-0.023(syst.). All these measurements are consistent with
the Standard Model expectations.Comment: 48 pages, LaTeX, including 13 eps or ps figures, submitted to
European Physical Journal
Search for Neutral Higgs Bosons in e+e- Collisions at sqrt(s) ~189GeV
A search for neutral Higgs bosons has been performed with the OPAL detector
at LEP, using approximately 170 pb-1 of e+e- collision data collected at
sqrt(s)~189GeV. Searches have been performed for the Standard Model (SM)
process e+e- to H0Z0 and the MSSM processes e+e- to H0Z0, A0h0. The searches
are sensitive to the b b-bar and tau antitau decay modes of the Higgs bosons,
and also to the MSSM decay mode h0 to A0A0. OPAL search results at lower
centre-of-mass energies have been incorporated in the limits we set, which are
valid at the 95% confidence level. For the SM Higgs boson, we obtain a lower
mass bound of 91.0 GeV. In the MSSM, our limits are mh>74.8GeV and mA>76.5GeV,
assuming tan(beta)>1, that the mixing of the scalar top quarks is either zero
or maximal, and that the soft SUSY-breaking masses are 1 TeV. For the case of
zero scalar top mixing, we exclude values of tan(beta) between 0.72 and 2.19.Comment: 38 pages, 15 figures, submitted Euro. Phys. J.
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