119000964
Measurement of the cosmogenic 11C background with the Borexino Counting Test Facility
Within next year, two organic liquid scintillator detectors, Borexino and KamLAND, will start the measurement of the mono‐energetic 7Be solar neutrino flux in real time. Besides this objective, both of them have the potential to detect neutrinos from the pep fusion reaction and the CNO cycle in the Sun.For this purpose, two conditions are required: an extremely low radioactive contamination level and the efficient identification of the 11C background, produced in reactions induced by the residual cosmic muon flux on 12C. In the process, a free neutron is almost always produced. 11C can be tagged on an event by event basis by looking at the three‐fold coincidence with the parent muon track and the subsequent neutron capture on protons. We tested successfully this coincidence method with the Borexino Counting Test Facility. The results are reported here.Moreover, we discuss on the effective potential of Borexino and KamLAND in detecting pep+CNO neutrinos compared to SNO+, a detector specifically designed fo...
122838267
Neutrinos from the sun and from radioactive sources
Abstract A brief review of the solar neutrino observations is given. Future solar neutrino measurements are discussed. The use of an artificial neutrino source to be used with low threshold solar neutrino detectors is presented. At present the neutrino source is mainly planned for short baseline neutrino studies.
205240340
Neutrinos from the primary proton–proton fusion process in the Sun
In the core of the Sun, energy is released through sequences of nuclear reactions that convert hydrogen into helium. The primary reaction is thought to be the fusion of two protons with the emission of a low-energy neutrino. These so-called pp neutrinos constitute nearly the entirety of the solar neutrino flux, vastly outnumbering those emitted in the reactions that follow. Although solar neutrinos from secondary processes have been observed, proving the nuclear origin of the Sun’s energy and contributing to the discovery of neutrino oscillations, those from proton–proton fusion have hitherto eluded direct detection. Here we report spectral observations of pp neutrinos, demonstrating that about 99 per cent of the power of the Sun, 3.84 × 1033 ergs per second, is generated by the proton–proton fusion process.
121886974
Measurement of the solar 8B neutrino rate with 3 MeV energy threshold in the Borexino detector
Borexino detector, at Gran Sasso Laboratories, measured ν–e elastic scattering from 8B solar neutrinos with 3 MeV energy threshold. We summarize here the results.
116991669
Study of the Rare Processes with the BOREXINO Detector
The status of the search for rare processes with the Borexino detector is reviewed. The discussed experimental results include searches for violation of the Pauli exclusion principle in nuclei, 5.5 MeV axions from p+d → 3He+A reaction on the Sun and magnetic moments of solar neutrinos. New limits on the probability of non-Paulian transitions in 12C nuclei [3], on the axion-electron, axion-photon and axion-nucleon coupling constants [4] and on the neutrino magnetic moments [2] are presented. 1 The Borexino detector Borexino is a real-time detector for solar neutrino spectroscopy located at the Gran Sasso Underground Laboratory. Its main goalis to measure low energy solar neutrinos via (ν,e)-scattering in an ultra-pure liquid scintillator. The extremely high radiopurity of the detector and its large mass allow to simultaneously address other fundamental questions in particle physics and astrophysics. The main features of the Borexino detector have been thoroughly described in [1]. Borexino is a scintillator detector with an active mass of 278 tons of pseudocumene (PC, C9H12), doped with the light shifter (C15H11NO). The ae-mail: derbin@pnpi.spb.ru be-mail: fomenko@jinr.ru
119295910
The first year of Borexino
Borexino is an experiment designed to detect in real-time low energy solar neutrinos. It is installed at the Gran Sasso Underground Laboratory and has started taking data in May 2007. We report the direct measurement of the 7Be solar neutrino signal rate after 1 year of data taking. Implications and perspectives are discussed.
122211885
On the Renormalization of the Chiral Fermion Meson Model: An Algebraic Approach
We re-investigate the problem of the renormalizability of the chiral fermion meson model on the light of the regularization-independent algebraic method. The present letter is intended as a useful application of a modern technique in theory of current interest for the description of low energy hadron phenomenology. We show that the model is stable under radiative corrections and anomaly free in a regularization-free way without having to resort to the explicit calculation of Feynman diagrams.
119195751
No one-loop gauge anomalies for a Lorentz-violating quantum electrodynamics: evaluation of the three-photon vertex
Identification of the diagrams that can lead to gauge anomalies in the (minimal) Lorentz- and CPT-violating extension of quantum electrodynamics reveal these to be the electron self-energy and vertex correction (related to the Ward–Takahashi identity), the photon self-energy (related to the vacuum polarization tensor transversality) and the three-photon vertex diagrams. All but the latter were explicitly verified to be free of anomalies to first order in loop expansion. Here we provide this remaining evaluation and verify the absence of anomalies in this process.
121566901
Structural aspects of supersymmetric models on a supermanifold
Abstract We propose an extension of some structural aspects that have succesfully been applied in the development of the theory of quantum fields propagating on a general spacetime manifold so as to include superfield models on a supermanifold.
17954300
A note on Fourier–Laplace transform and analytic wave front set in theory of tempered ultrahyperfunctions
Abstract In this paper we study the Fourier–Laplace transform of tempered ultrahyperfunctions introduced by Sebastiao e Silva and Hasumi. We establish a generalization of Paley–Wiener–Schwartz theorem for this setting. This theorem is interesting in connection with the microlocal analysis. For this reason, the paper also contains a description of the singularity structure of tempered ultrahyperfunctions in terms of the concept of analytic wave front set.
119680908
All orders renormalizability of a Lorentz and CPT violating quantum electrodynamics
Renormalizability of the (minimal) single-fermion QED extension is investigated at all orders of perturbation theory in the framework of algebraic renormalization, a regularization-independent method. Relative to the standard QED, new structures that could lead to gauge anomalies are identified. Nevertheless, even if the anomaly coefficients fail to vanish in the general case, they shall be absent provided we require invariance of the action under $C$ and/or $PT$ transformations. Stability is also verified in this case, hence full renormalizability is attained.