3,064 research outputs found
Analytical results for O(\alpha_s) radiative corrections to e+ e- -> tbar t(pol.) up to a given gluon energy cut
We determine the O(\alpha_s) radiative corrections to polarized top quark
pair production in e+ e- -annihilations with a specified gluon energy cut. We
write down fully analytical results for the unpolarized and polarized
O(\alpha_s) cross sections e+ e- -> tbar t (G) and e+ e- -> tbar t(pol.) (G)
including their polar orientation dependence relative to the beam direction. In
the soft gluon limit we recover the usual factorizing form known from the soft
gluon approximation. In the limit when the gluon energy cut takes its maximum
value we recover the totally inclusive unpolarized and polarized cross sections
calculated previously. We provide some numerical results on the cut-off
dependence of the various polarized and unpolarized cross sections and discuss
how the exact results numerically differ from the approximate soft-gluon
results.Comment: 49 pages in LaTeX, including 17 encapsulated PostScript figure
SUSY-QCD corrections in the squark-gluino sector
A status report is given of the calculations of next-to-leading-order ()
supersymmetric QCD corrections to the production of squarks and gluinos in
collisions. The implementation of these SUSY-QCD corrections
leads to more stable theoretical predictions and to a substantial increase of
the production cross-sections. In addition we give a discussion of the use of
the scheme for renormalizing the coupling constants in the QCD
sector of () supersymmetric theories.Comment: 6 two-column pages, tar'ed gzip'ed uuencoded files, LaTeX, 7
Encapsulated Postscript figures, uses epsfig and espcrc2. To appear in the
proceedings of the 1996 Zeuthen Workshop on Elementary Particle Theory: "QCD
and QED in Higher Orders", J.Bl\"umlein, F.Jegerlehner, and T.Riemann eds.
Complete postscript file available at
http://rulgm4.LeidenUniv.nl/preprints.htm
How the Linguistic Styles of Donald Trump and Joe Biden Reflect Different Forms of Power
Can theories of power be used to explain differences in the linguistic styles of Donald Trump and Joe Biden? We argue that the two candidates possess and use different forms of power—and that this is associated with typical language patterns. Based on their personal history, news reports, and empirical studies, we expect that Trump’s approach to power is characterized by coercive power forms and Biden’s by collaborative power forms. Using several LIWC categories and the moral foundations dictionary, we analyzed over 500 speeches and 15,000 tweets made during the 2020 election battle. Biden’s speeches can be described as analytical and frequently relating to moral values, whereas Trump’s speeches were characterized by a positive emotional tone. In tweets, Biden used more social words and words related to virtue, honesty, and achievement than Trump did. Trump’s coercive power and Biden’s collaborative power were more observable in tweets than speeches, which may reflect the fact that tweets are more spontaneous than speeches
SU(3)_flavor analysis of two-body weak decays of charmed baryons
We study two-body weak decays of charmed baryons \Lambda_c and \Xi_c into an
octet or decuplet baryon and a pseudoscalar meson employing the SU(3) flavor
symmetry. Using certain measured Cabibbo-favored modes, we fix the reduced
amplitudes and predict the branching ratios of various decays of charmed
baryons in the Cabibbo-enhanced, -suppressed and -doubly suppressed modes.Comment: 25 pages, No figure, Phys. Rev. D (to appear
Helicity Analysis of Semileptonic Hyperon Decays Including Lepton Mass Effects
Using the helicity method we derive complete formulas for the joint angular
decay distributions occurring in semileptonic hyperon decays including lepton
mass and polarization effects. Compared to the traditional covariant
calculation the helicity method allows one to organize the calculation of the
angular decay distributions in a very compact and efficient way. In the
helicity method the angular analysis is of cascade type, i.e. each decay in the
decay chain is analyzed in the respective rest system of that particle. Such an
approach is ideally suited as input for a Monte Carlo event generation program.
As a specific example we take the decay () followed by the nonleptonic decay for which we show a few examples of decay distributions which are
generated from a Monte Carlo program based on the formulas presented in this
paper. All the results of this paper are also applicable to the semileptonic
and nonleptonic decays of ground state charm and bottom baryons, and to the
decays of the top quark.Comment: Published version. 40 pages, 11 figures included in the text. Typos
corrected, comments added, references added and update
Order and nFl Behavior in UCu4Pd
We have studied the role of disorder in the non-Fermi liquid system UCu4Pd
using annealing as a control parameter. Measurement of the lattice parameter
indicates that this procedure increases the crystallographic order by
rearranging the Pd atoms from the 16e to the 4c sites. We find that the low
temperature properties depend strongly on annealing. Whereas the non-Fermi
liquid behavior in the specific heat can be observed over a larger temperature
range after annealing, the clear non-Fermi liquid behavior of the resistivity
of the unannealed sample below 10 K disappears. We come to the conclusion that
this argues against the Kondo disorder model as an explanation for the
non-Fermi liquid properties of both as-prepared and annealed UCu4Pd
Exclusive semileptonic decays of and mesons in the covariant confining quark model
Recently, the BESIII collaboration has reported numerous measurements of
various meson semileptonic decays with significantly improved
precision. Together with similar studies carried out at BABAR, Belle, and CLEO,
new windows to a better understanding of weak and strong interactions in the
charm sector have been opened. In light of new experimental data, we review the
theoretical description and predictions for the semileptonic decays of
to a pseudoscalar or a vector meson. This review is essentially an
extended discussion of our recently published results obtained in the framework
of the covariant confining quark model.Comment: 51 pages, 12 figures, 29 tables, to be submitted to Frontiers of
Physics as a revie
Engineering Quantum States, Nonlinear Measurements, and Anomalous Diffusion by Imaging
We show that well-separated quantum superposition states, measurements of
strongly nonlinear observables, and quantum dynamics driven by anomalous
diffusion can all be achieved for single atoms or molecules by imaging
spontaneous photons that they emit via resonance florescence. To generate
anomalous diffusion we introduce continuous measurements driven by L\'evy
processes, and prove a number of results regarding their properties. In
particular we present strong evidence that the only stable L\'evy density that
can realize a strictly continuous measurement is the Gaussian.Comment: revtex4-1, 17 pages, 7 eps figure
- …