18319959
Paley-Wiener-Schwartz Theorem and Microlocal Analysis in Theory of Tempered Ultrahyperfunctions
We give some precisions on the Fourier-Laplace transform theorem for tempered ultrahyperfunctions introduced by Sebastiao e Silva and Hasumi, by considering the theorem in its simplest form: the equivalence between support properties of a distribution in a closed convex cone and the holomorphy of its Fourier-Laplace transform in a suitable tube with conical basis. We establish a generalization of Paley-Wiener-Schwartz theorem for this setting. This theorem is interesting in connection with the microlocal analysis, where a description of the singularity structure of tempered ultrahyperfunctions in terms of the concept of analytic wave front set is given. We also suggest a physical application of the results obtained in the construction and study of field theories with fundamental length.
119291520
The ultraviolet and infrared perturbative finiteness of massless QED$_3$
The perturbative ﬁniteness is one of the most peculiarproperties of topological ﬁeld theories in three space-time dimensions [1]. Thanks to a by-product of super-renormalizability and the presence of topological terms,Yang-Mills-Chern-SimonsandBF-Yang-Millstheoriesarealso ﬁnite at all orders in perturbation theory—in the senseof a vanishing function [2]. In spite of not being atopological ﬁeld theory, the massless QED
197441123
On the Geometry of Two-Dimensional Anisotropic Non-Linear Sigma Models
119528722
Gauge independence of the effective potential revisited
We apply the formalism of extended BRS symmetry to the investigation of the gauge dependence of the effective potential in a spontaneously symmetry broken gauge theory. This formalism, which includes a set of Grassmann parameters defined as the BRS variations of the gauge-fixing parameters, allows us to derive in a quick and unambiguous way the related Nielsen identities, which express the physical gauge independence, in a class of generalized 't Hooft gauges, of the effective potential. We show in particular that the validity of the Nielsen identities does not require any constraint on the gauge-fixing parameters, contrary to some claims found in the literature. We use the method of algebraic renormalization, which leads to results independent of the particular renormalization scheme used.
17124386
Exact scale invarianmce of the BF-Yang-Mills theory in three dimensions
The ``extended'' BF-Yang-Mills theory in 3 dimensions, which contains a minimally coupled scalar field, is shown to be ultraviolet finite. It obeys a trivial Callan-Symanzik equation, with all β-functions and anomalous dimensions vanishing. The proof is based on an anomaly-free trace identity valid to all orders of perturbation theory.
119307919
Finite one-loop radiative corrections in the Lorentz- and CPT-violating QED extension
We report on our current progress in the study of finite one-loop radiative corrections in the minimal Lorentz- and CPT-violating QED extension.
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...
124545258
The Borexino experiment: Test of the purification systems and data analysis in the counting test facility
The work I carried out in the last three years was focused on the development and test of purification systems and data analysis techniques for the Borexino experiment, a detector specifically designed for low energy neutrino spectroscopy. I participated to the study of the adsorption technique based on activated carbons for removing krypton from nitrogen and to the investigation of the purity of nitrogen available on the market. I analyzed the data from the third campaign of the Borexino prototype detector, the Counting Test Facility (CTF), to identify each contamination source in the scintillator and to evaluate the efficiency of the purification system. 11C represents the main background source in the CNO and pep neutrino energy range. I investigated on the possibility to apply the three-fold coincidence technique with the parent muon track and the subsequent neutron capture on protons in Borexino in order to tag and remove 11C nuclides on a one-by-one basis. Furthermore, I implemented and tested such technique on the CTF data.
120536446
Performances and calibrations of the Borexino detector
Borexino is a real-time detector for low energy Solar neutrino spectroscopy installed in the underground laboratories (3800 mwe depth) at Gran Sasso, Italy (LNGS). Borexino is specifically designed to measure the mono-energetic (866 keV) 7Be flux via neutrino-electron elastic scattering in ultra-pure organic scintillation liquid. The separation of signal and background relies on the identification of the Compton-like edge in the recoil electron energy spectrum at 667 keV. The physics potential of Borexino strongly depends on the unprecedented requirements of low level background. The exceptional radio-purity reached by the Borexino, in order to guarantee the success of the experiment, must be complemented with the identification and discrimination of the residual intrinsic contaminants, as well as of the external and cosmogenic backgrounds. Crucial in this respect are the energy and spatial reconstruction capabilities of the detector, which thus require a careful and precise assessment. We report on the Borexino performances after 1 year of data taking in reconstructing event energy and position, in discriminating on the nature of the contaminant with the pulse shape analysis and in the identification of fast coincidences looking at time and space correlations.
121396997
Measurement of CNGS muon neutrino speed with Borexino
Abstract We have measured the speed of muon neutrinos with the Borexino detector using short-bunch CNGS beams. The final result for the difference in time-of-flight between an 〈 E 〉 = 17 GeV muon neutrino and a particle moving at the speed of light in vacuum is δ t = 0.8 ± 0.7 stat ± 2.9 sys ns , well consistent with zero.
118390776
Final results of Borexino Phase-I on low energy solar neutrino spectroscopy
Borexino has been running since May 2007 at the LNGS with the primary goal of detecting solar neutrinos. The detector, a large, unsegmented liquid scintillator calorimeter characterized by unprecedented low levels of intrinsic radioactivity, is optimized for the study of the lower energy part of the spectrum. During the Phase-I (2007-2010) Borexino first detected and then precisely measured the flux of the 7Be solar neutrinos, ruled out any significant day-night asymmetry of their interaction rate, made the first direct observation of the pep neutrinos, and set the tightest upper limit on the flux of CNO neutrinos. In this paper we discuss the signal signature and provide a comprehensive description of the backgrounds, quantify their event rates, describe the methods for their identification, selection or subtraction, and describe data analysis. Key features are an extensive in situ calibration program using radioactive sources, the detailed modeling of the detector response, the ability to define an innermost fiducial volume with extremely low background via software cuts, and the excellent pulse-shape discrimination capability of the scintillator that allows particle identification. We report a measurement of the annual modulation of the 7 Be neutrino interaction rate. The period, the amplitude, and the phase of the observed modulation are consistent with the solar origin of these events, and the absence of their annual modulation is rejected with higher than 99% C.L. The physics implications of phase-I results in the context of the neutrino oscillation physics and solar models are presented.