Electron antineutrino interactions above the inverse beta decay energy of protons (Eν̄e>1.8 MeV) were looked for with the Borexino counting test facility (CTF). One candidate event survived after ...rejection of background, which included muon-induced neutrons and random coincidences. An upper limit on the solar ν̄e flux, assumed having the 8B solar neutrino energy spectrum, of 1.1×105 cm-2 s-1 (90% C.L.) was set with a 7.8 ton × year exposure. This upper limit corresponds to a solar neutrino transition probability, νe→ν̄e, of 0.02 (90% C.L.). Predictions for antineutrino detection with Borexino, including geoneutrinos, are discussed on the basis of background measurements performed with the CTF.
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DOBA, FZAB, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The Extreme Energy Events (EEE) Collaboration is fully involved in an
ecological transition. The use of the standard gas mixture,
\ce{C_{2}H_{2}F_{4}}+ \ce{SF_{6}}, has stopped in favor of an ...alternative green
mixture based on \ce{C_{3}H_{2}F_{4}} with the addition of He or \ce{CO_{2}}.
The choise of these new mixtures is motivated by the significant lower Global
Warming Potential (GWP) to reduce the emission of gases potentially
contributing to the greenhouse effect. The EEE experiment consists of 61 muon
telescopes based on Multigap Resistive Plate Chambers (MRPCs), each telescope
composed of 3 chambers filled with gas. Several EEE detectors are today
completely fluxed with the new ecological mixture. This contribution will
report recent results about the telescope performance obtained from studies
with the eco-friendly alternative mixture carried out in the last years.
The prototype of the Borexino detector Counting Test Facility, located in the Gran-Sasso laboratory, has been used to obtain a bound on the stability of the electron. The new lower limit on the mean ...lifetime defined on 32.1 days of data set is τ(e−→νe+γ)⩾4.6×1026 yr (90% c.l.).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This Letter reports a direct measurement of the 7Be solar neutrino signal rate performed with the Borexino low background liquid scintillator detector at the Laboratori Nazionali del Gran Sasso. This ...is the first real-time spectral measurement of sub-MeV solar neutrinos. The result for 0.862 MeV 7Be neutrinos is 47±7stat±12sys counts/(day ⋅ 100 ton), consistent with predictions of Standard Solar Models and neutrino oscillations with LMA-MSW parameters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The results of background measurements with the prototype of the Borexino detector (CTF) have been used to obtain an upper bound on the neutrino magnetic moment, μν. The new upper limit for μν from ...pp and 7Be solar neutrinos is (5.5×10−10)μB (90% c.l.) in the Standard Solar Model scenario. This is the first limit on μν obtained using sub-MeV neutrinos. The sensitivity of the prototype to the neutrino charge radius and the neutrino radiative decay are also presented.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Borexino is an experiment for low-energy neutrino spectroscopy at the Gran Sasso underground laboratories. It is designed to measure the monoenergetic {sup 7}Be solar neutrino flux in real time, via ...neutrino-electron elastic scattering in an ultrapure organic liquid scintillator. Borexino has the potential to also detect neutrinos from the pep fusion process and the CNO cycle. For this measurement to be possible, radioactive contamination in the detector must be kept extremely low. Once sufficiently clean conditions are met, the main background source is {sup 11}C, produced in reactions induced by the residual cosmic muon flux on {sup 12}C. In the process, a free neutron is almost always produced. {sup 11}C can be tagged on an event-by-event basis by looking at the threefold coincidence with the parent muon track and the subsequent neutron capture on protons. This coincidence method has been implemented on the Borexino Counting Test Facility data. We report on the first event-by-event identification of in situ muon-induced {sup 11}C in a large underground scintillator detector. We measure a {sup 11}C production rate of 0.130 {+-} 0.026(stat) {+-} 0.014(syst) day{sup -1} ton{sup -1}, in agreement with predictions from both experimental studies performed with a muon beam on a scintillator target and ab initio estimations based on the {sup 11}C producing nuclear reactions.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
The flagella of the green alga Scherffelia dubia are covered by scales which consist of acidic polysaccharides and glycoproteins. Experimental deflagellation results in the regeneration of flagella ...complete with scales. During flagellar regeneration, scales are newly synthesized in the Golgi apparatus, exocytosed and deposited on the growing flagella. Flagellar regeneration is dependent upon protein synthesis and N-glycosylation, as it is blocked by cycloheximide and partially inhibited by tunicamycin. Metabolic labeling with 35Smethionine/cysteine demonstrated that scale-associated proteins were not newly synthesized during flagellar regeneration, suggesting that the proteins deposited on regenerating flagella were drawn from a pool. Quantitative immunoelectron microscopy using a monospecific antibody directed against a scale-associated protein of 126 kDa (SAP126) revealed that the pool of SAP126 was primarily located at the plasma membrane, with minor labeling of the scale reticulum and trans-Golgi cisternae, both before deflagellation and during flagellar regeneration. Since SAP126 was sequestered during flagellar regeneration into secretory vesicles together with newly synthesized scales, it is concluded that the persistent presence of SAP126 in the trans-Golgi cisternae during scale biogenesis requires retrograde transport of the protein from the plasma membrane to the Golgi apparatus.
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