4,437 research outputs found
B Physics at CDF
Due to the large b-bbar cross section at 1.96 TeV p-pbar collisions, the
Tevatron is currently the most copious source of B hadrons. Recent detector
upgrades for Run II have made these more accessible, allowing for a wide range
of B and CP violation physics with B hadrons of all flavours. In this paper we
present B-physics results, and, using the versatile hadronic Two Track Trigger,
a search for Xi(1860), from up to 240/pb of data.Comment: To appear in the proceedings of 39th Rencontres de Moriond on
Electroweak Interactions and Unified Theories, La Thuile, Aosta Valley,
Italy, 21-28 March 200
Reduction of Statistical Power Per Event Due to Upper Lifetime Cuts in Lifetime Measurements
A cut on the maximum lifetime in a lifetime fit not only reduces the number
of events, but also, in some circumstances dramatically, decreases the
statistical significance of each event. The upper impact parameter cut in the
hadronic B trigger at CDF, which is due to technical limitations, has the same
effect. In this note we describe and quantify the consequences of such a cut on
lifetime measurements. We find that even moderate upper lifetime cuts, leaving
event numbers nearly unchanged, can dramatically increase the statistical
uncertainty of the fit result.Comment: Changes to latest revision: added DOI link, took the opportunity to
correct some minor typos added one small clarificatio
Heavy Flavour Lifetimes and Lifetime Differences
We give an overview of heavy flavour lifetime measurements, focusing on
recent results from the Tevatron and the B factories.Comment: Invited talk at the Workshop on the CKM Unitarity Triangle, IPPP
Durham, April 2003 (eConf C0304052). 8 pages LaTeX, 12 figure
Charm (and Beauty) Production at the Tevatron
We present recent results on heavy flavour production at Tevatron Run II for
typically ~1/fb of analysed proton-antiproton data at a c.m. energy of 1.96
TeV. This includes results on single and correlated open charm and bottom cross
sections, charm pair production kinematics, J/psi, psi(2S) and chi cross
sections and polarisation measurements in J/psi, psi(2S), Upsilon(1S), and
Upsilon(2S).Comment: To be published in the proceedings of CHARM07, Ithaca, NY, August
2007, eConf C07080
An Exact Formula to Describe the Amplification Process in a Photomultiplier Tube
An analytical function is derived that exactly describes the amplification
process due to a series of discrete, Poisson-like amplifications like those in
a photo multiplier tube (PMT). A numerical recipe is provided that implements
this function as a computer program. It is shown how the program can be used as
the core-element of a faster, simplified routine to fit PMT spectra with high
efficiency. The functionality of the method is demonstrated by fitting both,
Monte Carlo generated and measured PMT spectra.Comment: 12 pages, 5 figures, with cut-and-paste FORTRAN implementatio
Model-independent determination of the strong phase difference between and amplitudes
For the first time, the strong phase difference between and
amplitudes is determined in bins of the
decay phase space. The measurement uses of
collision data that is taken at the resonance and collected by the
CLEO-c experiment. The measurement is important for the determination of the -violating phase in (and similar) decays ,
where the meson (which represents a superposition of and )
subsequently decays to . To obtain optimal sensitivity to
, the phase space of the decay is divided
into bins based on a recent amplitude model of the decay. Although an amplitude
model is used to define the bins, the measurements obtained are
model-independent. The -even fraction of the
decay is determined to be , where the
uncertainties are statistical and systematic, respectively. Using simulated
decays, it is estimated that
by the end of the current LHC run, the LHCb experiment could determine
from this decay mode with an uncertainty of , where the
first uncertainty is statistical based on estimated LHCb event yields, and the
second is due to the uncertainties on the parameters determined in this paper
Evaluation of the LHCb RICH detectors and a measurement of the CKM angle
The future LHCb experiment at the Large Hadron Collider (LHC) at CERN will perform precision measurements of CP violation parameters in the neutral B systems. In this thesis the performance of the LHCb RICH system is evaluated, and the feasibility of a measurement of the CP violation parameter #gamma#, using the decays B_d"0 #-># D*"-#pi#"+, B_d"0 #-># D*"-#pi#"+ and their CP conjugates, is investigated. Efficient methods for the reconstruction of B_d"0 #-># D*"-#pi#"+ decays at LHCb are developed. Using the GEANT-based LHCb detector simulation program SICb, the reconstruction efficiencies and signal to background ratios are estimated. It is demonstrated that the decay channel B_d"0 #-># D*"-#pi#"+ can provide a precision in #gamma# of a few degrees after one year of LHCb data taking. A full-scale prototype of the LHCb RICH 2 detector has been tested in a testbeam at CERN in Summer 1998. It is shown to work according to expectation, in particular in the defining aspects of a RICH detector, the photon yield and the Cherenkov angle resolution. These results demonstrate that the LHCb RICH detectors are well understood and give confidence in the model of the RICH system used in the simulation studies for LHCb detector optimisation. In a testbeam in Summer 1999 a RICH prototype was tested using a 3x3 cluster of Multi-anode Photo Multiplier Tubes equipped with lenses. The tubes were read out within the LHC bunch-crossing interval of 25 ns for the first time. It is demonstrated that the MaPMT performs well and is a suitable photodetector for the LHCb RICH. (author)Available from British Library Document Supply Centre-DSC:D213936 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
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