5,875 research outputs found
Bose-Einstein correlations in WW events at LEP
The current status of the LEP results on Bose-Einstein correlations is
discussed. Emphasis is given to the measurement of Bose-Einstein correlations
between decay products from different W's, in an energy range between 172 and
209 GeV, dependent on the experiment. For the first time all four LEP
experiments conclude that no evidence for correlations between pions from
different W's is seen at the current level of precision.Comment: 6 pages, 4 figures, Talk given at XXXVI Rencontres de Moriond, Les
Arcs, France, March 17-24 200
Bose-Einstein correlations in WW pair production at LEP
This paper presents an overview of the latest results from the L3 and DELPHI
collaborations concerning the measurement of Bose-Einstein correlations between
identical bosons coming from different W's in fully hadronic WW decays. Using
the same method, L3 sees no indication of any inter-W BEC effect, while DELPHI
reports an indication of inter-W BEC between like-charged particles of the
order of three standard deviations.Comment: 5 pages, 4 figures, Talk given at the XXXVIIIth Rencontres de Moriond
(QCD), Les Arcs, France, March 22-29 200
Investigation of Bose-Einstein Correlations in 3 jet events with the DELPHI detector
A preliminary investigation of Bose-Einstein correlations in 3 jet events has
been made by analysing the collected data at the peak from '94 and '95
and the calibration runs during the LEP2 period from '97 to 2000. Three methods
were used to extract two-particle correlation functions. No significant
difference was found between quark and gluon jets for all three methods.Comment: 6 pages, 2 figures in ps and 1 in eps, talk given at XXXI
International Symposium on Multiparticle Dynamics, Sept 1-7, 2001, Datong
China. see http://ismd31.ccnu.edu.cn
Particle production in pp collisions at the LHC as studied by CMS
This is a report on the study of hadron production in non-singlediffractive events by using minimum bias and jet triggered data collected with the CMS experiment in the first year of LHC running. The importance of these measurements lies in the understanding of the dynamics of multi-hadron production which is described by non-perturbative QCD. The modeling via Monte Carlo generators,
and their respective re-tuning, is necessary to describe the underlying event and pileup, having impact on many measurements that rely on an accurate measurement of hadron jets or missing transverse energy. I present an overview of the inclusive single particle spectra, the yields of strange hadrons and the charged hadron multiplicity
distributions measured at several center-of-mass energies that show a fast growth of particle densities at the highest energies, especially for low transverse momenta,
and a strong violation of KNO scaling in large pseudorapidity intervals
SoLid : Search for Oscillations with Lithium-6 Detector at the SCK-CEN BR2 reactor
Sterile neutrinos have been considered as a possible explanation for the recent reactor and Gallium anomalies arising from reanalysis of reactor flux and calibration data of previous neutrino experiments. A way to test this hypothesis is to look for distortions of the anti-neutrino energy caused by oscillation from active to sterile neutrino at close stand-off (similar to 6-8m) of a compact reactor core. Due to the low rate of anti-neutrino interactions the main challenge in such measurement is to control the high level of gamma rays and neutron background.
The SoLid experiment is a proposal to search for active-to-sterile anti-neutrino oscillation at very short baseline of the SCK center dot CEN BR2 research reactor.
This experiment uses a novel approach to detect anti-neutrino with a highly segmented detector based on Lithium-6. With the combination of high granularity, high neutron-gamma discrimination using 6LiF:ZnS(Ag) and precise localization of the Inverse Beta Decay products, a better experimental sensitivity can be achieved compared to other state-of-the-art technology. This compact system requires minimum passive shielding allowing for very close stand off to the reactor. The experimental set up of the SoLid experiment and the BR2 reactor will be presented. The new principle of neutrino detection and the detector design with expected performance will be described. The expected sensitivity to new oscillations of the SoLid detector as well as the first measurements made with the 8 kg prototype detector deployed at the BR2 reactor in 2013-2014 will be reported
Validating module network learning algorithms using simulated data
In recent years, several authors have used probabilistic graphical models to
learn expression modules and their regulatory programs from gene expression
data. Here, we demonstrate the use of the synthetic data generator SynTReN for
the purpose of testing and comparing module network learning algorithms. We
introduce a software package for learning module networks, called LeMoNe, which
incorporates a novel strategy for learning regulatory programs. Novelties
include the use of a bottom-up Bayesian hierarchical clustering to construct
the regulatory programs, and the use of a conditional entropy measure to assign
regulators to the regulation program nodes. Using SynTReN data, we test the
performance of LeMoNe in a completely controlled situation and assess the
effect of the methodological changes we made with respect to an existing
software package, namely Genomica. Additionally, we assess the effect of
various parameters, such as the size of the data set and the amount of noise,
on the inference performance. Overall, application of Genomica and LeMoNe to
simulated data sets gave comparable results. However, LeMoNe offers some
advantages, one of them being that the learning process is considerably faster
for larger data sets. Additionally, we show that the location of the regulators
in the LeMoNe regulation programs and their conditional entropy may be used to
prioritize regulators for functional validation, and that the combination of
the bottom-up clustering strategy with the conditional entropy-based assignment
of regulators improves the handling of missing or hidden regulators.Comment: 13 pages, 6 figures + 2 pages, 2 figures supplementary informatio
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Measurement of double-differential cross sections for top quark pair production in pp collisions at [Formula: see text][Formula: see text] and impact on parton distribution functions.
Normalized double-differential cross sections for top quark pair ([Formula: see text]) production are measured in pp collisions at a centre-of-mass energy of 8[Formula: see text] with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 19.7[Formula: see text]. The measurement is performed in the dilepton [Formula: see text] final state. The [Formula: see text] cross section is determined as a function of various pairs of observables characterizing the kinematics of the top quark and [Formula: see text] system. The data are compared to calculations using perturbative quantum chromodynamics at next-to-leading and approximate next-to-next-to-leading orders. They are also compared to predictions of Monte Carlo event generators that complement fixed-order computations with parton showers, hadronization, and multiple-parton interactions. Overall agreement is observed with the predictions, which is improved when the latest global sets of proton parton distribution functions are used. The inclusion of the measured [Formula: see text] cross sections in a fit of parametrized parton distribution functions is shown to have significant impact on the gluon distribution
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