2,251 research outputs found
The Low Energy Tagger for the KLOE-2 experiment
The KLOE experiment at the upgraded DAFNE e+e- collider in Frascati (KLOE-2)
is going to start a new data taking at the beginning of 2010 with its detector
upgraded with a tagging system for the identification of gamma-gamma
interactions. The tagging stations for low-energy e+e- will consist in two
calorimeters The calorimeter used to detect low-energy e+e- will be placed
between the beam-pipe outer support structure and the inner wall of the KLOE
drift chamber. This calorimeter will be made of LYSO crystals readout by
Silicon Photomultipliers, to achieve an energy resolution better than 8% at 200
MeV.Comment: 4 pages, 5 figures, in the proceedings of "Frontier detectors for
frontier physics", isola d'Elba, Italy, May 200
Enhanced shot noise in resonant tunneling: theory and experiment
We show that shot noise in a resonant tunneling diode biased in the negative
differential resistance regions of the I-V characteristic is enhanced with
respect to ``full'' shot noise. We provide experimental results showing a Fano
factor up to 6.6, and show that it is a dramatic effect caused by
electron-electron interaction through Coulomb force, enhanced by the particular
shape of the density of states in the well. We also present numerical results
from the proposed theory, which are in agreement with the experiment,
demonstrating that the model accounts for the relevant physics involved in the
phenomenon.Comment: 4 pages, 4 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.
Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency
A method is described which allows to deduce the dead-time of the front-end
electronics of the LHCb muon detector from a series of measurements performed
at different luminosities at a bunch-crossing rate of 20 MHz. The measured
values of the dead-time range from 70 ns to 100 ns. These results allow to
estimate the performance of the muon detector at the future bunch-crossing rate
of 40 MHz and at higher luminosity
A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta' meson
We update the values of the eta-eta' mixing angle and of the eta' gluonium
content by fitting our measurement R_phi = BR(phi to eta' gamma)/ BR(phi to eta
gamma) together with several vector meson radiative decays to pseudoscalars (V
to P gamma), pseudoscalar mesons radiative decays to vectors (P to V gamma) and
the eta' to gamma gamma, pi^0 to gamma gamma widths. From the fit we extract a
gluonium fraction of Z^2_G = 0.12 +- 0.04, the pseudoscalar mixing angle psi_P
= (40.4 +- 0.6) degree and the phi-omega mixing angle psi_V = (3.32 +- 0.09)
degree. Z^2_G and psi_P are fairly consistent with those previously published.
We also evaluate the impact on the eta' gluonium content determination of
future experimental improvements of the eta' branching ratios and decay width.Comment: 13 pages, 7 figures to submit to JHE
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
Precision measurement of and determination of the contribution to the muon anomaly with the KLOE detector
We have measured the ratio
, with the KLOE detector at DANE for a total integrated
luminosity of 240 pb. From this ratio we obtain the cross section
. From the cross section we determine the
pion form factor and the two-pion contribution to the muon anomaly
for GeV, = . This result confirms the
current discrepancy between the Standard Model calculation and the experimental
measurement of the muon anomaly.Comment: 18 pages, 8 figures, minor text corrections, one table added, version
to appear on Physics Letters
Charged kaon lifetime at KLOE
Preliminary result on the charged kaon lifetime, obtained by the KLOE
experiment operating at DANE, the Frascati -factory, is presentedComment: 3 pages, 3 figures, to appear in the proceedings of 42nd Rencontres
de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta
Valley, Italy, 10-17 Mar 200
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