527 research outputs found
Measurement of the cross section with the CMD-3 detector at the VEPP-2000 collider
The process has been studied in the
center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23
pb collected with the CMD-3 detector at the VEPP-2000 collider.
Using about 24000 selected events, the cross
section has been measured with a systematic uncertainty decreasing from 11.7\%
at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of
production dynamics has been performed
Study of the process in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector
Using a data sample of 6.8 pb collected with the CMD-3 detector at the
VEPP-2000 collider we select about 2700 events of the process and measure its cross section at 12 energy ponts with about
6\% systematic uncertainty. From the angular distribution of produced nucleons
we obtain the ratio
Monte-Carlo Generator Photon Jets for the process e+e- -> gamma gamma
Monte-Carlo generator with photon jets radiation in collinear regions for the
process \eegg is described in detail. Radiative corrections in the first order
of are treated exactly. Large leading logarithmic corrections coming
from collinear regions are taken into account in all orders of by
applying the Structure Function approach. Theoretical precision of the cross
section with radiative corrections is estimated to be 0.2%. This process is
considered as an additional tool to measure luminosity in forthcoming
experiments with the CMD-3 detector at the collider VEPP-2000.Comment: 6 pages, 5 figure
Measurement of the Pion Form Factor in the Energy Range 1.04-1.38 GeV with the CMD-2 Detector
The cross section for the process is measured in the
c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events
including 860000 events, 82000 events, and 33000
events. The systematic and statistical errors of measuring the
pion form factor are equal to 1.2-4.2 and 5-13%, respectively.Comment: 5 pages, 2 figure
Measurement of hadronic cross section and preliminary results on the pion form factor using the radiative return at DAPHNE
In the fixed energy environment of the collider DANE, KLOE
can measure the cross section of the process hadrons as a
function of the hadronic system energy using the radiative return. At energies
below 1 GeV, is the dominating
hadronic process. We report here on the status of the analysis for the
e^{+}e^{-} \to \ppg channel, which allows to obtain a preliminary measurement
of the pion form factor using an integrated luminosity of .Comment: Invited talk at the Seventh International Workshop on Tau Lepton
Physics (TAU02-WE07), Santa Cruz, Ca, USA, Sept 2002, 9 pages, LaTeX, 9 eps
figure
Precision Measurement of KS Meson Lifetime with the KLOE detector
Using a large sample of pure, slow, short lived K0 mesons collected with KLOE
detector at DaFne, we have measured the KS lifetime. From a fit to the proper
time distribution we find tau = (89.562 +- 0.029_stat +- 0.043_syst) ps. This
is the most precise measurement today in good agreement with the world average
derived from previous measurements. We observe no dependence of the lifetime on
the direction of the Ks.Comment: 5 pages, 7 figure
Study of the a_0(980) meson via the radiative decay phi->eta pi^0 gamma with the KLOE detector
We have studied the phi->a_0(980) gamma process with the KLOE detector at the
Frascati phi-factory DAPhNE by detecting the phi->eta pi^0 gamma decays in the
final states with eta->gamma gamma and eta->pi^+ pi^- pi^0. We have measured
the branching ratios for both final states: Br(phi->eta pi^0 gamma)=(7.01 +/-
0.10 +/- 0.20)x10^-5 and (7.12 +/- 0.13 +/- 0.22)x10^-5 respectively. We have
also extracted the a_0(980) mass and its couplings to eta pi^0, K^+ K^-, and to
the phi meson from the fit of the eta pi^0 invariant mass distributions using
different phenomenological models.Comment: 17 pages, 6 figures, submitted to Physics Letters B. Corrected typos
in eq.
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