824 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 $D^0$ and $\bar{D}^0 \to\pi^+\pi^-\pi^+\pi^-$ amplitudes

For the first time, the strong phase difference between $D^0$ and
$\bar{D}^0\to\pi^+\pi^-\pi^+\pi^-$ amplitudes is determined in bins of the
decay phase space. The measurement uses $818\,\mathrm{pb}^{-1}$ of $e^+e^-$
collision data that is taken at the $\psi(3770)$ resonance and collected by the
CLEO-c experiment. The measurement is important for the determination of the $C
P$-violating phase $\gamma$ in $B^{\pm}\to D K^{\pm}$ (and similar) decays ,
where the $D$ meson (which represents a superposition of $D^0$ and $\bar{D}^0$)
subsequently decays to $\pi^+\pi^-\pi^+\pi^-$. To obtain optimal sensitivity to
$\gamma$, the phase space of the $D \to \pi^+\pi^-\pi^+\pi^-$ 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 $CP$-even fraction of the $D \to \pi^+\pi^-\pi^+\pi^-$
decay is determined to be $F_{+}^{4\pi} = 0.769 \pm 0.021 \pm 0.010$, where the
uncertainties are statistical and systematic, respectively. Using simulated
$B^{\pm}\to D K^{\pm}, D \to \pi^+\pi^-\pi^+\pi^-$ decays, it is estimated that
by the end of the current LHC run, the LHCb experiment could determine $\gamma$
from this decay mode with an uncertainty of $(\pm10\pm7)^\circ$, 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

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