3,751 research outputs found
Symmetry violations at BABAR
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd.2014 J. Phys.: Conf. Ser. 556 012042
(http://iopscience.iop.org/1742-6596/556/1/012042
CKM Matrix: Status and New Developments
An analysis of the CKM matrix parameters within the {\it R}fit approach is
presented using updated input values with special emphasis on the recent
measurements from BABAR and Belle. The QCD Factorisation
Approach describing decays has been implemented in the
software package CKMfitter. Fits using branching ratios and CP asymmetries are
discussed.Comment: 5 pages, 6 postscript figures, contribution to the proceedings of the
9th International Symposium on Heavy Flavour Physics, September 2001,
Pasadena, US
A New Approach to a Global Fit of the CKM Matrix
We report on a global CKM matrix analysis taking into account most recent
experimental and theoretical results. The statistical framework (Rfit)
developed in this paper advocates formal frequentist statistics. Other
approaches, such as Bayesian statistics or the 95% CL scan method are also
discussed. We emphasize the distinction of a model testing and a model
dependent, metrological phase in which the various parameters of the theory are
determined. Measurements and theoretical parameters entering the global fit are
thoroughly discussed, in particular with respect to their theoretical
uncertainties. Graphical results for confidence levels are drawn in various one
and two-dimensional parameter spaces. Numerical results are provided for all
relevant CKM parameterizations, the CKM elements and theoretical input
parameters. Predictions for branching ratios of rare K and B meson decays are
obtained. A simple, predictive SUSY extension of the Standard Model is
discussed.Comment: 66 pages, added figures, corrected typos, no quantitative change
Rare K decay: results and prospects
Recent results on rare kaon decays are reviewed and prospects for future
experiments are discussed.Comment: 14 pages, 11 figures, submitted to the Proc. 9th Intl. Symp. on Heavy
Flavor Physic
Reply to: ''Improved Determination of the CKM Angle alpha from B -> pipi decays''
In reply to hep-ph/0701204 we demonstrate why the arguments made therein do
not address the criticism exposed in hep-ph/0607246 on the fundamental
shortcomings of the Bayesian approach when it comes to the extraction of
parameters of Nature from experimental data. As for the isospin analysis and
the CKM angle alpha it is shown that the use of uniform priors for the observed
quantities in the Explicit Solution parametrization is equivalent to a
frequentist construction resulting from a change of variables, and thus relies
neither on prior PDFs nor on Bayes' theorem. This procedure provides in this
particular case results that are similar to the Confidence Level approach, but
the treatment of mirror solutions remains incorrect and it is far from being
general. In a second part it is shown that important differences subsist
between the Bayesian and frequentist approaches, when following the proposal of
hep-ph/0701204 and inserting additional information on the hadronic amplitudes
beyond isospin invariance. In particular the frequentist result preserves the
exact degeneracy that is expected from the remaining symmetries of the problem
while the Bayesian procedure does not. Moreover, in the Bayesian approach
reducing inference to the 68% or 95% credible interval is a misconception of
the meaning of the posterior PDF, which in turn implies that the significant
dependence of the latter to the chosen parametrization cannot be viewed as a
minor effect, contrary to the claim in hep-ph/0701204.Comment: 5 pages, 1 figure. Fig. 1 corrected (wrong file
Bayesian Statistics at Work: the Troublesome Extraction of the CKM Phase alpha
In Bayesian statistics, one's prior beliefs about underlying model parameters
are revised with the information content of observed data from which, using
Bayes' rule, a posterior belief is obtained. A non-trivial example taken from
the isospin analysis of B-->PP (P = pi or rho) decays in heavy-flavor physics
is chosen to illustrate the effect of the naive "objective" choice of flat
priors in a multi-dimensional parameter space in presence of mirror solutions.
It is demonstrated that the posterior distribution for the parameter of
interest, the phase alpha, strongly depends on the choice of the
parameterization in which the priors are uniform, and on the validity range in
which the (un-normalizable) priors are truncated. We prove that the most
probable values found by the Bayesian treatment do not coincide with the
explicit analytical solution, in contrast to the frequentist approach. It is
also shown in the appendix that the alpha-->0 limit cannot be consistently
treated in the Bayesian paradigm, because the latter violates the physical
symmetries of the problem.Comment: 17 pages, 10 figure
The estimation of neutrino fluxes produced by proton-proton collisions at TeV of the LHC
Intense and collimated neutrino beams are produced by charm and beauty
particle decays from proton-proton collisions at the LHC. A neutrino experiment
would be run parasitically without interrupting the LHC physics program during
the collider run. We estimate the neutrino fluxes from proton-proton collisions
at TeV of the LHC with the designed luminosity, 10^{34} \lumi.
By mounting about 200 tons of fiducial volume of a neutrino detector at 300
\m away from the interaction point, about 150,000 of charged current neutrino
events per year can be observable.Comment: 8 pages, Accepted in JHE
Model uncertainties in top-quark physics
The ATLAS and CMS collaborations at the Large Hadron Collider (LHC) are
studying the top quark in pp collisions at 7 and 8 TeV. Due to the large
integrated luminosity, precision measurements of production cross-sections and
properties are often limited by systematic uncertainties. An overview of the
modeling uncertainties for simulated events is given in this report.Comment: Proceedings from the 7th International Workshop on Top Quark Physics,
Cannes, Franc
Results from TopFitter
We discuss a global fit of top quark BSM couplings, phrased in the
model-independent language of higher-dimensional effective operators, to the
currently available data from the LHC and Tevatron. We examine the interplay
between inclusive and differential measurements, and the complementarity of LHC
and Tevatron results. We conclude with a discussion of projections for
improvement over LHC Run II.Comment: 5 pages, 4 figures, proceedings of the 9th International Workshop on
the CKM Unitarity Triangle, 28 November - 3 December 2016, Tata Institute for
Fundamental Research (TIFR), Mumbai, Indi
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