4,273 research outputs found
Physics at the LHC Run-2 and Beyond
These lecture notes discuss methods, recent results and future prospects in
proton-proton physics at the Large Hadron Collider.Comment: Lecture notes from the 2016 European School of High-Energy Physics,
15-28 June 2016, Skeikampen, Norway (61 pages, 56 figures
Hadronic B Decays to Charmless Final States and to J/psi K*
Preliminary results from the BABAR experiment on charmless B decays to
charged pions or kaons, and the measurement of the B -> J/psi K* decay
amplitudes are presented. The data sample, collected at the asymmetric-energy
B-factory PEP-II at SLAC, comprises a total number of 22.7 million Y(4S)
decays, corresponding to an integrated on-resonance luminosity of approximately
21 fb-1. We measure the following CP-averaged branching fractions:
BR(B -> pi+pi-) = (4.1 +- 1.0(stat) +- 0.7(sys))xE-6 BR(B -> K+pi-) = (16.7
+- 1.6(stat) +1.2-1.7(sys))xE-6
and an upper limit of BR(B -> K+K-) < 2.5xE-6, at 90% confidence limit. The
measurement of the J/psi K* decay amplitudes results in R_\perp = 0.160 +-
0.032(stat) +- 0.036(sys), and reveals a dominant longitudinal component. The
phase of the longitudinal amplitude shows evidence for non-vanishing final
state interaction.Comment: 13 pages, 8 postscript figures, submitted to Proceedings for BCP
Evaluation of \alpha (M^2_Z) and (g-2)_\mu
This talk summarizes the recent development in the evaluation of the leading
order hadronic contributions to the running of the QED fine structure constant
\alpha(s), at , and to the anomalous magnetic moments of the
muon . The accuracy of the theoretical prediction of these
observables is limited by the uncertainties on the hadronic contributions.
Significant improvement has been achieved in a series of new analyses which is
presented historically in three steps: (I), use of spectral functions in
addition to e^+e^- cross sections, (II), extended use of perturbative QCD and
(III), application of QCD sum rule techniques. The most precise values obtained
are: , yielding
, and with which one finds for the complete
Standard Model prediction .
For the electron , the hadronic contribution is .Comment: 9 pages, Talk given at the ICHEP'98 Conference, Vancouver, Canada,
July 23-29, 199
Moriond Electroweak and Unified Theories 2016 - Experimental Summary
Summary of the experimental results presented at the 51st edition of the
Moriond Electroweak and Unified Theories conference held in March 2016 at La
Thuile, Italy.Comment: Proceedings of Moriond EW & UT 2016 (42 pages, 43 figures
FUNDING THE RESEARCH FOR THE EXPANDING ROLE OF THE FOOD DISTRIBUTION INDUSTRY
The keynoter discusses the funding process for government sponsored food distribution research and points out favorable and unfavorable factors affecting the future of research in this area. Recommendations to strengthen future efforts are also made.Marketing,
Estimating Spectroscopic Redshifts by Using k Nearest Neighbors Regression I. Description of Method and Analysis
Context: In astronomy, new approaches to process and analyze the
exponentially increasing amount of data are inevitable. While classical
approaches (e.g. template fitting) are fine for objects of well-known classes,
alternative techniques have to be developed to determine those that do not fit.
Therefore a classification scheme should be based on individual properties
instead of fitting to a global model and therefore loose valuable information.
An important issue when dealing with large data sets is the outlier detection
which at the moment is often treated problem-orientated. Aims: In this paper we
present a method to statistically estimate the redshift z based on a similarity
approach. This allows us to determine redshifts in spectra in emission as well
as in absorption without using any predefined model. Additionally we show how
an estimate of the redshift based on single features is possible. As a
consequence we are e.g. able to filter objects which show multiple redshift
components. We propose to apply this general method to all similar problems in
order to identify objects where traditional approaches fail. Methods: The
redshift estimation is performed by comparing predefined regions in the spectra
and applying a k nearest neighbor regression model for every predefined
emission and absorption region, individually. Results: We estimated a redshift
for more than 50% of the analyzed 16,000 spectra of our reference and test
sample. The redshift estimate yields a precision for every individually tested
feature that is comparable with the overall precision of the redshifts of SDSS.
In 14 spectra we find a significant shift between emission and absorption or
emission and emission lines. The results show already the immense power of this
simple machine learning approach for investigating huge databases such as the
SDSS.Comment: accepted for publication in A&
Interpreting CP Asymmetries in B->pi+ pi- Decays
We discuss methods used to interpret the measurements of CP-asymmetry in
B->pi+pi- within the framework of the Standard Model. Interpretations using
various theoretical inputs are given, ranging from the rather general, yet
unpredictive, properties based on strong isospin symmetry to highly predictive
calculations using QCD Factorization. The calculations are performed using the
software package CKMFitter and a frequentist method, Rfit.Comment: Invited talk at the Workshop on the CKM Unitarity Triangle, IPPP
Durham, April 2003 (eConf C0304052). 4 pages LaTeX, 4 eps figure
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