We present a measurement of the slope parameter \(\alpha\) for the \(\eta\to 3\pi^{0}\) decay, with the KLOE experiment at the DA\(\Phi\)NE \(\phi\)-factory, based on a background free sample of ...\(\sim\) 17 millions \(\eta\) mesons produced in \(\phi\) 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.
Investigation at a \(\phi\)--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for ...the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta\(^\prime\) mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the \(e^+ e^-\) physics in the continuum with the measurements of (multi)hadronic cross sections and the study of gamma gamma processes.
We propose a new approach to the problem of the missing baryons. Building on the common assumption that the missing baryons are in the form of the warm hot intergalactic medium (WHIM), we also assume ...here that the galaxy luminosity density can be used as a tracer of the WHIM. This last assumption is supported by our discovery of a significant correlation between the WHIM density and the galaxy luminosity density in recent hydrodynamical simulations. We also found that the percentage of the gas mass in the WHIM phase is substantially higher (by a factor of ~1.6) within large-scale galactic filaments, i.e. ~70%, compared to the average in the full simulation volume of ~0.1 Gpc3. The relation between the WHIM overdensity and the galaxy luminosity overdensity within the galactic filaments is consistent with a linear one: δwhim = 0.7 ± 0.1 × δLD0.9±0.2. We then applied our procedure to the line of sight towards the blazar H2356-309 and found evidence of WHIM that corresponds to the Sculptor Wall (SW) (z ~ 0.03 and log NH = 19.9+ 0.1-0.3) and Pisces-Cetus (PC) superclusters (z ~ 0.06 and log NH = 19.7+ 0.2-0.3), in agreement with the redshifts and column densities of the X-ray absorbers identified recently. This agreement indicates that the galaxy luminosity density and galactic filaments are reliable signposts for the WHIM and that our method is robust for estimating WHIM density. The signal that we detected cannot originate in the halos of nearby galaxies because they cannot account for the high WHIM column densities that our method and X-ray analysis consistently find in the SW and PC superclusters.
Recently it has been demonstrated that particle factories, such as DAΦNE and PEP-II, operating at fixed center-of-mass energies, are able to measure hadronic cross sections as a function of the ...hadronic system energy using the radiative return. This paper is an experimental overview of the progress in this area. Preliminary results from KLOE for the process
e
+
e
− →
ϱγ →
π
+
π
−
γ and a fit to the pion form factor are presented. Some first results from the BABAR collaboration are also shown.
We have studied, with the KLOE detector at the DA\(\Phi\)NE \(\Phi\)-Factory, the dynamics of the decay \(\eta\to\pi^+\pi^-\pi^0\) using \(\eta\) mesons from the decay \(\phi\to\eta\gamma\) for an ...integrated luminosity \({\mathcal L}\) = 450 pb\(^{-1}\). From a fit to the Dalitz plot density distribution we obtain a precise measurement of the slope parameters. An alternative parametrization relates the \(\pi^+\pi^-\pi^0\) slopes to that for \(\eta\to 3\pi^0\) showing the consistency of KLOE results for both channels. We also obtain the best confirmation of the \(C\)-invariance in the \(\eta\to\pi^+\pi^-\pi^0\) decay.
Luciferases catalyze light-emitting reactions that produce a rainbow of colors from their substrates (luciferins), molecular oxygen, and often additional cofactors. These bioluminescence (BL) systems ...have afforded an incredible variety of basic research and medical applications. Driven by the importance of BL-based non-invasive animal imaging (BLI) applications, especially in support of cancer research, new BL systems have been developed by engineering beetle luciferase (Luc) variants and synthetic substrate combinations to produce red to near-infrared (nIR) light to improve imaging sensitivity and resolution. To stimulate the application of BLI research and advance the development of improved reagents for BLI, we undertook a systematic comparison of the spectroscopic and BL properties of seven beetle Lucs with LH
and nine substrates, which included two new quinoline ring-containing analogs. The results of these experiments with purified Luc enzymes in vitro and in live HEK293T cells transfected with
genes have enabled us to identify Luc/analog combinations with improved properties compared to those previously reported and to provide live cell BL data that may be relevant to in vivo imaging applications. Additionally, we found strong candidate enzyme/substrate pairs for in vitro biomarker applications requiring nIR sources with minimal visible light components. Notably, one of our new substrates paired with a previously developed Luc variant was demonstrated to be an excellent in vitro source of nIR and a potentially useful BL system for improved resolution in BLI.
The Kloe experiment has measured the radiative decays of the φ meson into
π
0, η and
η′(958); these measurements are relevant to assess the mixing in the pseudoscalar nonet as well as to evaluate the ...gluon content in the
η′(958). Moreover also the radiative decays into
π
0
π
0
γ and
ηπ
0
γ have been measured. These decays are dominated by the final states
f
0(980) and
α
0(980). The measurement of the branching ratios and of the
π
0 −
π
0 or
η −
π
0 invariant mass spectrum helps to understand the controversial nature of the above scalar mesons.
We present the general real- and redshift-space clustering properties of galaxies as measured in the first data release of the VIPERS survey. VIPERS is a large redshift survey designed to probe in ...detail the distant Universe and its large-scale structure at 0.5 < z < 1.2. We describe in this analysis the global properties of the sample and discuss the survey completeness and associated corrections. This sample allows us to measure the galaxy clustering with an unprecedented accuracy at these redshifts. From the redshift-space distortions observed in the galaxy clustering pattern we provide a first measurement of the growth rate of structure at z = 0.8: fsigma8 = 0.47 + or - 0.08. This is completely consistent with the predictions of standard cosmological models based on Einstein gravity, although this measurement alone does not discriminate between different gravity models.
•Experimental characterization of novel micro-ORC driven by radial piston expander.•Performance evaluation in off-design conditions.•Steady-state detection algorithm tested on-line.•Feed pump ...electric consumption accurately measured.•Effect of variable electrical load on expander speed and power output analyzed.
In this paper, a full experimental characterization of a micro-scale ORC system is presented. The facility under investigation is driven by a piston expander prototype, made of three cylinders arranged radially around the drive shaft. The system is rated for a thermal input around 30 kW, being suitable for residential, tertiary sector or small industry applications. It is conceived for exploiting low temperature heat sources, such as solar collectors, biomass boilers, geothermal energy or waste heat streams. The facility was provided with an electric boiler as heat source, which warms water up to 90 °C, and cold water at ambient temperature as heat sink. A test campaign was performed varying the hot source temperature and the organic fluid feed pump velocity, in order to characterize the system behavior at different off-design working conditions. The electric consumption of the ORC feed pump was measured, in order to quantify the actual impact of the auxiliaries on the overall efficiency. Moreover, the number of electric loads connected to the generator was varied, changing the equivalent phase impedance value, for evaluating the effect on the expander rotating speed and power output.
The experimental analysis demonstrated that small reciprocating expander is suitable for exploiting low enthalpy heat sources, with quite good performances compared to other architectures like scroll and screw expanders, more applied within low temperature sources. The results show that the gross electric power output varied between 250 W and 1150 W, depending on the expander speed and on the number of electric loads activated. The expander total efficiency showed a barely constant trend around 40%. The pump total efficiency varied between 10% and 20%, increasing with the pump rotational speed. The maximum ORC gross and net efficiency were 4.5% and 2.2% respectively, confirming that the auxiliaries impact cannot be considered negligible in such type of systems.
We present new constraints on the relationship between galaxies and their host dark matter haloes, measured from the location of the peak of the stellar-to-halo mass ratio (SHMR), up to the most ...massive galaxy clusters at redshift z ∼ 0.8 and over a volume of nearly 0.1 Gpc3. We use a unique combination of deep observations in the CFHTLenS/VIPERS field from the near-UV to the near-IR, supplemented by ∼60 000 secure spectroscopic redshifts, analysing galaxy clustering, galaxy–galaxy lensing and the stellar mass function. We interpret our measurements within the halo occupation distribution (HOD) framework, separating the contributions from central and satellite galaxies. We find that the SHMR for the central galaxies peaks at
$M_{\rm h, peak} = 1.9^{+0.2}_{-0.1}\times 10^{12}{\,{\rm M}_{{\odot }}}$
with an amplitude of 0.025, which decreases to ∼0.001 for massive haloes (
${{{M}_{\rm h}}}> 10^{14} {\,{\rm M}_{{\odot }}}$
). Compared to central galaxies only, the total SHMR (including satellites) is boosted by a factor of 10 in the high-mass regime (cluster-size haloes), a result consistent with cluster analyses from the literature based on fully independent methods. After properly accounting for differences in modelling, we have compared our results with a large number of results from the literature up to z = 1: we find good general agreement, independently of the method used, within the typical stellar-mass systematic errors at low to intermediate mass (
${{{M}_{\rm \star }}}<10^{11} {\,{\rm M}_{{\odot }}}$
) and the statistical errors above. We have also compared our SHMR results to semi-analytic simulations and found that the SHMR is tilted compared to our measurements in such a way that they over- (under-) predict star formation efficiency in central (satellite) galaxies.
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