215 research outputs found
Hydrothermal pressure-temperature control on CO2 emissions and seismicity at Campi Flegrei (Italy)
Fluids supplied by stored magma at depth are causal factors of volcanic unrest, as they can cause pressurization/heating of hydrothermal systems. However, evidence for links between hydrothermal pressurization, CO2 emission and volcano seismicity have remained elusive. Here, we use recent (2010−2020) observations at Campi Flegrei caldera (CFc) to show hydrothermal pressure, gas emission and seismicity at CFc share common source areas and well-matching temporal evolutions. We interpret the recent escalation in seismicity and surface gas emissions as caused by pressure-temperature increase at the top of a vertically elongated (0.3–2 km deep) gas front. Using mass (steam) balance considerations, we show hydrothermal pressurization is causing energy transfer from the fluids to the host rocks, ultimately triggering low magnitude earthquakes within a seismogenetic volume containing the hydrothermal system. This mechanism is probably common to other worldwide calderas in similar hydrothermal activity state
Measurement of the neutron detection efficiency of a 80% absorber - 20% scintillating fibers calorimeter
The neutron detection efficiency of a sampling calorimeter made of 1 mm
diameter scintillating fibers embedded in a lead/bismuth structure has been
measured at the neutron beam of the The Svedberg Laboratory at Uppsala. A
significant enhancement of the detection efficiency with respect to a bulk
organic scintillator detector with the same thickness is observed.Comment: 10 pages, 7 figure
Heavy-light decay topologies as a new strategy to discover a heavy gluon
We study the collider phenomenology of the lightest Kaluza-Klein excitation
of the gluon, G*, in theories with a warped extra dimension. We do so by means
of a two-site effective lagrangian which includes only the lowest-lying spin-1
and spin-1/2 resonances. We point out the importance of the decays of G* to one
SM plus one heavy fermion, that were overlooked in the previous literature. It
turns out that, when kinematically allowed, such heavy-light decays are
powerful channels for discovering the G*. In particular, we present a
parton-level Montecarlo analysis of the final state Wtb that follows from the
decay of G* to one SM top or bottom quark plus its heavy partner. We find that
at \sqrt{s} = 7 TeV and with 10 fb^{-1} of integrated luminosity, the LHC can
discover a KK gluon with mass in the range M_{G*} = (1.8 - 2.2) TeV if its
coupling to a pair of light quarks is g_{G*qqbar} = (0.2-0.5) g_3. The same
process is also competitive for the discovery of the top and bottom partners as
well. We find, for example, that the LHC at \sqrt{s} = 7 TeV can discover a 1
TeV KK bottom quark with an integrated luminosity of (5.3 - 0.61) fb^{-1} for
g_{G*qqbar} = (0.2-0.5) g_3.Comment: 36 pages, 13 figures. v2: a few typos corrected, comments added,
version published in JHE
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
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
Data acquisition and monitoring for the KLOE detector
none77siThe Data Acquisition system for the KLOE experiment, presently running at the Laboratori Nazionali di Frascati DAPhiNE collider, has been designed to sustain an acquisition throughput of 50 Mbyte/s for an event rate of 10 kHz. its two major components are the front end data readout, based on custom buses, and a complex network of computers and storage devices hosting a set of distributed processes. The end result is a seamless data transport from the readout system to the storage library, accompanied by concurrent on line calibrations and data quality control.openA. ALOISIO; F. AMBROSINO; S. CAVALIERE; F. CEVENINI; C. DI DONATO; A. DORIA; D. FIORE; L. MEROLA; G. PIROZZI; G. SARACINO; M. ANTONELLI; F. BOSSI; P. CIAMBRONE; P. DE SIMONE; S. DELL'AGNELLO; M.L. FERRER; G. FINOCCHIARO; C. FORTI; C. GATTI; S. GIOVANNELLA; W. GRANDEGGER; G. LANFRANCHI; B. MARTINI; W. MEI; S. MISCETTI; M. MOULSON; F. MURTAS; M. PALUTAN; L. PASSALACQUA; F. PELUCCHI; P. SANTANGELO; B. SCIASCIA; I. SFILIGOI; J. SHAN; T. SPADARO; P. VALENTE; Y ZHOU; C. BINI; V. BOCCI; G. CABIBBO; R. CALOI; A. CARDINI; E. DE LUCIA; A. DI DOMENICO; P. GAUZZI; E. PASQUALUCCI; M. PASSASEO; D. PICCA; L. PONTECORVO; E. VALENTE; S. VENEZIANO; P. BRANCHINI; E. GRAZIANI; A. PASSERI; A. FERRARI; E. SPIRITI; C. STANESCU; L. TORTORA; M. CASARSA; G. CATALDI; E. GORINI; M. PRIMAVERA; A. VENTURA; G. DE ROBERTIS; P. GUARNACCIA; A. DENIG; CHEN-CHENG KUO; S. MULLER; B. VALERIANI; S. DI FALCO; M. INCAGLI; G. VENANZONI; R. MESSI; L. PACCIANI; E. SANTOVETTI; J. LEE-FRANZINI; M. MARTEMIANOVA., Aloisio; F., Ambrosino; S., Cavaliere; F., Cevenini; C., DI DONATO; A., Doria; D., Fiore; L., Merola; G., Pirozzi; G., Saracino; M., Antonelli; F., Bossi; P., Ciambrone; P., DE SIMONE; S., Dell'Agnello; M. L., Ferrer; G., Finocchiaro; C., Forti; C., Gatti; S., Giovannella; W., Grandegger; G., Lanfranchi; B., Martini; W., Mei; S., Miscetti; M., Moulson; F., Murtas; M., Palutan; L., Passalacqua; F., Pelucchi; P., Santangelo; B., Sciascia; I., Sfiligoi; J., Shan; T., Spadaro; P., Valente; Y., Zhou; C., Bini; V., Bocci; G., Cabibbo; R., Caloi; A., Cardini; E., DE LUCIA; A., DI DOMENICO; P., Gauzzi; E., Pasqualucci; M., Passaseo; D., Picca; L., Pontecorvo; E., Valente; S., Veneziano; P., Branchini; E., Graziani; A., Passeri; A., Ferrari; E., Spiriti; C., Stanescu; L., Tortora; M., Casarsa; G., Cataldi; Gorini, Edoardo; Primavera, Margherita; Ventura, Andrea; G., DE ROBERTIS; P., Guarnaccia; A., Denig; CHEN CHENG, Kuo; S., Muller; B., Valeriani; S., DI FALCO; M., Incagli; G., Venanzoni; R., Messi; L., Pacciani; E., Santovetti; J., LEE FRANZINI; M., Martemiano
Determination of from radiative processes at DANE
We have measured the cross section with
the KLOE detector at DANE, at an energy GeV. From the
dependence of the cross section on , where
is the energy of the photon radiated from the initial state, we
extract for the mass range
GeV. From our result we extract the pion form
factor and the hadronic contribution to the muon anomaly, .Comment: Contributed paper to EPS 2003 and LP 200
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