106 research outputs found
B0s Oscillation Results
We review new studies of the time dependence of B0s - B0s-bar mixing by the
ALEPH, DELPHI and SLD Collaborations, with an emphasis on the different
analysis methods used. Combining all available results yields a preliminary
lower limit on the oscillation frequency of dms > 14.4 ps-1 at the 95% C.L.Comment: 4 pages, 2 figures, contributed to ICHEP2002 proceeding
Kinematic Evidence of an Embedded Protoplanet in HD 142666 Identified by Machine Learning
Observations of protoplanetary disks have shown that forming exoplanets leave
characteristic imprints on the gas and dust of the disk. In the gas, these
forming exoplanets cause deviations from Keplerian motion, which can be
detected through molecular line observations. Our previous work has shown that
machine learning can correctly determine if a planet is present in these disks.
Using our machine learning models, we identify strong, localized non-Keplerian
motion within the disk HD 142666. Subsequent hydrodynamics simulations of a
system with a 5 Jupiter-mass planet at 75 au recreates the kinematic structure.
By currently established standards in the field, we conclude that HD 142666
hosts a planet. This work represents a first step towards using machine
learning to identify previously overlooked non-Keplerian features in
protoplanetary disks.Comment: 7 pages, 3 figures, 1 table. Accepted to Ap
Critical Exponents and Particle Multiplicity Distributions in High Energy Collisions
Data from the L3, Tasso, Opal and Delphi collaborations are analyzed in terms
of a statistical model of high energy collisions. The model contains a power
law critical exponent tau and Levy index alpha. These data are used to study
values of tau and alpha. The very high multiplicity events in L3, Opal and
Delphi are consistent with a model based on a Feynman-Wilson gas which has a
tail exponent tau=3/2 and alpha=1/2.Comment: 10 pages, new table adde
suppression in Pb+Pb collisions and broadening
We have analysed the NA50 data, on the centrality dependence of
broadening of 's, in Pb+Pb collisions, at the CERN-SPS. The data were
analysed in a QCD based model, where 's are suppressed in 'nuclear'
medium. Without any free parameter, the model could explain the NA50
broadening data. The data were also analysed in a QGP based threshold model,
where suppression is 100% above a critical density. The QGP based
model could not explain the NA50 broadening data. We have also predicted
the centrality dependence of suppression and broadening at RHIC
energy. Both the models, the QGP based threshold model and the QCD based
nuclear absorption model, predict broadening very close to each other.Comment: The paper was completely revised. The conclusion is also changed. 5
pages, 4 figure
Remarks on Koba-Nielsen-Olesen Scaling
It is shown that there is a second properly normalized KNO scaling function,
, which has certain advantages in the analysis of
KNO scaling. First, the are not influenced by the statistical and
systematic uncertainties of hence provides more selective
power than the original KNO scaling function .
Second, the new scaling function generates scale parameter since it
depends only on the combination of and the scale parameter of . An
analysis of is given using annihilation data for charged
particle multiplicity distributions.Comment: 8 pages, Plain TeX, 1 figure using uufile
Heavy quark mass effects in e(+)e(-) into three jets
Next-to-leading order calculation for three jet heavy quark production in e^+e^- collisions, including complete quark mass effects, is reviewed. Its applications at LEP/SLC are also discussed
Measuring the Photon Helicity in Radiative B Decays
We propose a way of measuring the photon polarization in radiative B decays
into K resonance states decaying to K\pi\pi, which can test the Standard Model
and probe new physics. The photon polarization is shown to be measured by the
up-down asymmetry of the photon direction relative to the K\pi\pi decay plane
in the K resonance rest frame. The integrated asymmetry in K_1(1400)\to
K\pi\pi, calculated to be 0.34\pm 0.05 in the Standard Model, is measurable at
currently operating B factories.Comment: 4 pages, final version to appear in Physical Review Letter
Exclusive semileptonic B decays to radially excited D mesons
Exclusive semileptonic B decays to radially excited charmed mesons are
investigated at the first order of the heavy quark expansion. The arising
leading and subleading Isgur-Wise functions are calculated in the framework of
the relativistic quark model. It is found that the 1/m_Q corrections play an
important role and substantially modify results. An interesting interplay
between different corrections is found. As a result the branching ratio for the
B-> D'e\nu decay is essentially increased by 1/m_Q corrections, while the one
for B-> D*'e\nu is only slightly influenced by them.Comment: 19 pages, revtex, 6 figures, uses rotating.st
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