1,031 research outputs found
Small Angle Polarization in High Energy P--P Scattering Through Nonperturbative Chiral Symmetry Breaking
We show that a large anomalous contribution due to nonperturbative
instanton-like gluonic field configurations to the axial charge of the proton
implies high-energy spin effects in elastic scattering. This is the same
mechanism which is responsible for anomalous baryon number violation at high
energy in the standard model. We compute the proton polarization due to these
effects and we show that it is proportional to the center-of-mass scattering
angle with a universal (energy-independent) slope of order unity.Comment: (13 pages, 2 figures
Measurement of the neutron electric dipole moment by crystal diffraction
An experiment using a prototype setup to search for the neutron electric
dipole moment by measuring spin-rotation in a non-centrosymmetric crystal
(quartz) was carried out to investigate statistical sensitivity and systematic
effects of the method. It has been demonstrated that the concept of the method
works. The preliminary result of the experiment is ecm. The experiment showed that an accuracy of ecm can be obtained in 100 days data taking, using available
quartz crystals and neutron beams.Comment: 13 pages, 4 figure
Measurement of the neutron electric dipole moment via spin rotation in a non-centrosymmetric crystal
We have measured the neutron electric dipole moment using spin rotation in a
non-centrosymmetric crystal. Our result is d_n = (2.5 +- 6.5(stat) +-
5.5(syst)) 10^{-24} e cm. The dominating contribution to the systematic
uncertainty is statistical in nature and will reduce with improved statistics.
The statistical sensitivity can be increased to 2 10^{-26} e cm in 100 days
data taking with an improved setup. We state technical requirements for a
systematic uncertainty at the same level.Comment: submitted to Phys. Lett.
Anyons as quon particles
The momentum operator representation of nonrelativistic anyons is developed
in the Chern - Simons formulation of fractional statistics. The connection
between anyons and the q-deformed bosonic algebra is established.Comment: 10 pages,Late
The Globular Cluster System of NGC 1399: III. VLT Spectroscopy and Database
Radial velocities of 468 globular clusters around NGC 1399, the central
galaxy in the Fornax cluster, have been obtained with FORS2 and the Mask
Exchange Unit (MXU) at the ESO Very Large Telescope. This is the largest sample
of globular cluster velocities around any galaxy obtained so far. The mean
velocity uncertainty is 50 km/sec. This data sample is accurate and large
enough to be used in studies of the mass distribution of NGC 1399 and the
properties of its globular cluster system. Here we describe the observations,
the reduction procedure, and discuss the uncertainties of the resulting
velocities. The complete sample of cluster velocities which is used in a
dynamical study of NGC 1399 is tabulated. A subsample is compared with
previously published values.Comment: 34 pages, 9 figures, 2 tables, accepted by A
Expectation values of four-quark operators in pions
The values of four-quark operators averaged over pions are expressed through
those averaged over vacuum. The specific values are obtained in the framework
of the factorization assumption. For the condensates of the light quarks of the
same flavour \bar q\Gamma q\bar q\Gamma q the scalar condensate is shown to be
an order of magnitude larger than the other ones. The condensates containing
the strange quarks \bar q q\bar s s appear to be only about twice smaller than
those of the light quarks. The degeneracy of the ground state in the
Nambu--Jona--Lasinio model is shown explicitly.Comment: 9 pages, no figures, typos correcte
Sugawara-type constraints in hyperbolic coset models
In the conjectured correspondence between supergravity and geodesic models on
infinite-dimensional hyperbolic coset spaces, and E10/K(E10) in particular, the
constraints play a central role. We present a Sugawara-type construction in
terms of the E10 Noether charges that extends these constraints infinitely into
the hyperbolic algebra, in contrast to the truncated expressions obtained in
arXiv:0709.2691 that involved only finitely many generators. Our extended
constraints are associated to an infinite set of roots which are all imaginary,
and in fact fill the closed past light-cone of the Lorentzian root lattice. The
construction makes crucial use of the E10 Weyl group and of the fact that the
E10 model contains both D=11 supergravity and D=10 IIB supergravity. Our
extended constraints appear to unite in a remarkable manner the different
canonical constraints of these two theories. This construction may also shed
new light on the issue of `open constraint algebras' in traditional canonical
approaches to gravity.Comment: 49 page
Neural network parametrization of spectral functions from hadronic tau decays and determination of QCD vacuum condensates
The spectral function is determined from ALEPH and OPAL data
on hadronic tau decays using a neural network parametrization trained to retain
the full experimental information on errors, their correlations and chiral sum
rules: the DMO sum rule, the first and second Weinberg sum rules and the
electromagnetic mass splitting of the pion sum rule. Nonperturbative QCD vacuum
condensates can then be determined from finite energy sum rules. Our method
minimizes all sources of theoretical uncertainty and bias producing an estimate
of the condensates which is independent of the specific finite energy sum rule
used. The results for the central values of the condensates and are
both negative.Comment: 29 pages, 18 ps figure
Accuracy of elastic fusion biopsy in daily practice: results of a multicenter study of 2115 patients
OBJECTIVES:
To assess the accuracy of Koelis fusion biopsy for the detection of prostate cancer and clinically significant prostate cancer in the everyday practice.
METHODS:
We retrospectively enrolled 2115 patients from 15 institutions in four European countries undergoing transrectal Koelis fusion biopsy from 2010 to 2017. A variable number of target (usually 2-4) and random cores (usually 10-14) were carried out, depending on the clinical case and institution habits. The overall and clinically significant prostate cancer detection rates were assessed, evaluating the diagnostic role of additional random biopsies. The cancer detection rate was correlated to multiparametric magnetic resonance imaging features and clinical variables.
RESULTS:
The mean number of targeted and random cores taken were 3.9 (standard deviation 2.1) and 10.5 (standard deviation 5.0), respectively. The cancer detection rate of Koelis biopsies was 58% for all cancers and 43% for clinically significant prostate cancer. The performance of additional, random cores improved the cancer detection rate of 13% for all cancers (P < 0.001) and 9% for clinically significant prostate cancer (P < 0.001). Prostate cancer was detected in 31%, 66% and 89% of patients with lesions scored as Prostate Imaging Reporting and Data System 3, 4 and 5, respectively. Clinical stage and Prostate Imaging Reporting and Data System score were predictors of prostate cancer detection in multivariate analyses. Prostate-specific antigen was associated with prostate cancer detection only for clinically significant prostate cancer.
CONCLUSIONS:
Koelis fusion biopsy offers a good cancer detection rate, which is increased in patients with a high Prostate Imaging Reporting and Data System score and clinical stage. The performance of additional, random cores seems unavoidable for correct sampling. In our experience, the Prostate Imaging Reporting and Data System score and clinical stage are predictors of prostate cancer and clinically significant prostate cancer detection; prostate-specific antigen is associated only with clinically significant prostate cancer detection, and a higher number of biopsy cores are not associated with a higher cancer detection rate
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