739 research outputs found
Visceral leishmaniasis with cardiac involvement in a dog: a case report
A dog presented with cutaneous nodules, enlarged lymph nodes and oedema in limbs, face and abdomen. The diagnosis of visceral leishmaniasis was established by identification of Leishmania amastigotes within macrophages from skin and popliteal lymph node biopsies. At necropsy, lesions were found in different organs, but it was particularly striking to observe large areas of pallor in the myocardium. Histological examination revealed an intense chronic inflammatory reaction in many organs, and numerous macrophages were found to contain amastigote forms of Leishmania. The inflammatory reaction was especially severe in the heart, where large areas of the myocardium appeared infiltrated with huge numbers of mononuclear immune cells, causing cardiac muscle atrophy and degeneration. Despite the severe inflammation, the number of parasitized macrophages was low in the myocardium, as revealed by immunohistochemical staining of Leishmania amastigotes. Because cardiac involvement is not usually described in this condition, this dog represents a very rare case of canine visceral leishmaniasis with affection of the myocardium
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
Measurement of {\eta} meson production in {\gamma}{\gamma} interactions and {\Gamma}({\eta}-->{\gamma}{\gamma}) with the KLOE detector
We present a measurement of {\eta} meson production in photon-photon
interactions produced by electron-positron beams colliding with \sqrt{s}=1 GeV.
The measurement is done with the KLOE detector at the \phi-factory DA{\Phi}NE
with an integrated luminosity of 0.24 fb^{-1}. The e^+e^- --> e^+e^-{\eta}
cross section is measured without detecting the outgoing electron and positron,
selecting the decays {\eta}-->{\pi}^+{\pi}^-{\pi}^0 and
{\eta}-->{\pi}^0{\pi}^0{\pi}^0. The most relevant background is due to e^+e^-
--> {\eta}{\gamma} when the monochromatic photon escapes detection. The cross
section for this process is measured as {\sigma}(e^+e^- -->{\eta}{\gamma}) =
(856 \pm 8_{stat} \pm 16_{syst}) pb. The combined result for the e^+e^-
-->e^+e^-{\eta} cross section is {\sigma}(e^+e^- -->e^+e^-{\eta}) = (32.72 \pm
1.27_{stat} \pm 0.70_{syst}) pb. From this we derive the partial width
{\Gamma}({\eta}-->{\gamma}{\gamma}) = (520 \pm 20_{stat} \pm 13_{syst}) eV.
This is in agreement with the world average and is the most precise measurement
to date.Comment: Version accepted by JHE
A new limit on the CP violating decay KS -> 3pi0 with the KLOE experiment
We have carried out a new direct search for the CP violating decay KS -> 3pi0
with 1.7 fb^-1 of e+e- collisions collected by the KLOE detector at the
phi-factory DAFNE. We have searched for this decay in a sample of about 5.9 x
10^8 KS KL events tagging the KS by means of the KL interaction in the
calorimeter and requiring six prompt photons. With respect to our previous
search, the analysis has been improved by increasing of a factor four the
tagged sample and by a more effective background rejection of fake KS tags and
spurious clusters. We find no candidates in data and simulated background
samples, while we expect 0.12 standard model events. Normalizing to the number
of KS -> 2pi0 events in the same sample, we set the upper limit on BR(KS ->
3pi0 < 2.6 x 10^-8 at 90% C.L., five times lower than the previous limit. We
also set the upper limit on the eta_000 parameter, |eta_000 | < 0.0088 at 90%
C.L., improving by a factor two the latest direct measurement.Comment: Accepted for publication in Physics Letters B (15 pages, 13 figures
Proposal for taking data with the KLOE-2 detector at the DANE collider upgraded in energy
This document reviews the physics program of the KLOE-2 detector at
DANE upgraded in energy and provides a simple solution to run the
collider above the -peak (up to 2, possibly 2.5 GeV). It is shown how a
precise measurement of the multihadronic cross section in the energy region up
to 2 (possibly 2.5) GeV would have a major impact on the tests of the Standard
Model through a precise determination of the anomalous magnetic moment of the
muon and the effective fine-structure constant at the scale. With a
luminosity of about cms, DANE upgraded in energy
can perform a scan in the region from 1 to 2.5 GeV in one year by collecting an
integrated luminosity of 20 pb (corresponding to a few days of data
taking) for single point, assuming an energy step of 25 MeV. A few years of
data taking in this region would provide important tests of QCD and effective
theories by physics with open thresholds for pseudo-scalar (like
the ), scalar (, etc...) and axial-vector (, etc...)
mesons; vector-mesons spectroscopy and baryon form factors; tests of CVC and
searches for exotics. In the final part of the document a technical solution
for the energy upgrade of DANE is proposed.Comment: 19 pages, 8 figure
Measurement of \Gamma(\eta -> \pi^+\pi^-\gamma)/\Gamma(\eta -> \pi^+\pi^-\pi^0) with the KLOE Detector
The ratio R_{\eta}=\Gamma(\eta -> \pi^+\pi^-\gamma)/\Gamma(\eta ->
\pi^+\pi^-\pi^0) has been measured by analyzing 22 million \phi \to \eta \gamma
decays collected by the KLOE experiment at DA\PhiNE, corresponding to an
integrated luminosity of 558 pb^{-1}. The \eta \to \pi^+\pi^-\gamma proceeds
both via the \rho resonant contribution, and possibly a non-resonant direct
term, connected to the box anomaly. Our result, R_{\eta}= 0.1856\pm
0.0005_{stat} \pm 0.0028_{syst}, points out a sizable contribution of the
direct term to the total width. The di-pion invariant mass for the \eta ->
\pi^+\pi^-\gamma decay could be described in a model-independent approach in
terms of a single free parameter, \alpha. The determined value of the parameter
\alpha is \alpha = (1.32 \pm 0.08_{stat} +0.10/-0.09_{syst}\pm 0.02_{theo})
GeV^{-2}Comment: Paper in press, accepted by PL
KLOE results in kaon physics and prospects for KLOE-2
The phi-factory DAPHNE offers a possibility to select pure kaon beams,
charged and neutral ones. In particular, neutral kaons from phi->KS KL are
produced in pairs and the detection of a KS (KL) tags the presence of a KL
(KS). This allows to perform precise measurements of kaon properties by means
of KLOE detector. Another advantage of a phi-factory consists in fact that the
neutral kaon pairs are produced in a pure quantum state (J^(PC) = 1^(--)),
which allowsto investigate CP and CPT symmetries via quantum interference
effects, as well as the basic principles of quantum mechanics.A review of the
most recent results of the KLOE experiment at DAPHNE using pure kaon beams or
via quantum interferometry is presented together with prospects for kaon
physics at KLOE-2.Comment: 5 pages, 4 figures, From Phi To Psi 2011 conference, to be published
in Nuclear Physics B (Proceedings Supplements
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
Measurement of the slope parameter with the KLOE detector
We present a measurement of the slope parameter for the decay, with the KLOE experiment at the DANE -factory,
based on a background free sample of 17 millions mesons produced
in radiative decays. By fitting the event density in the Dalitz plot we
determine \alpha = -0.0301 \pm 0.0035\,stat\;_{-0.0035}^{+0.0022}\,syst\,.
The result is in agreement with recent measurements from hadro- and
photo-production experiments.Comment: 14 pages, 11 figure
Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector
The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
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