13873742
A new derivation of the CPT and spin-statistics theorems in noncommutative field theories
We propose an alternative axiomatic description for noncommutative field theories (NCFT) based on some ideas by Soloviev to nonlocal quantum fields. The local commutativity axiom is replaced by the weaker condition that the fields commute at sufficiently large spatial separations, called asymptotic commutativity, formulated in terms of the theory of analytic functionals. The question of a possible violation of the CPT and spin-statistics theorems caused by nonlocality of the commutation relations [xμ,xν]=iθμν is investigated. In spite of this inherent nonlocality, we show that the modification aforementioned is sufficient to ensure the validity of these theorems for NCFT. We restrict ourselves to the simplest model of a scalar field in the case of only space–space noncommutativity.
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
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.
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.
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.
119266920
No parity anomaly in massless QED3: A BPHZL approach
Abstract In this Letter we call into question the perturbatively parity breakdown at 1-loop for the massless QED 3 frequently claimed in the literature. As long as perturbative quantum field theory is concerned, whether a parity anomaly owing to radiative corrections exists or not shall be definitely proved by using a renormalization method independent of any regularization scheme. Such a problem has been investigated in the framework of BPHZL renormalization method, by adopting the Lowenstein–Zimmermann subtraction scheme. The 1-loop parity-odd contribution to the vacuum-polarization tensor is explicitly computed in the framework of the BPHZL renormalization method. It is shown that a Chern–Simons term is generated at that order induced through the infrared subtractions — which violate parity. We show then that, what is called “parity anomaly”, is in fact a parity-odd counterterm needed for restauring parity.
121999403
Recent results and future development of Borexino
Abstract This paper summarizes the main recent results of the Borexino experiment, a liquid scintillator neutrino detector of unprecedented radiopurity currently running at the Laboratori Nazionali del Gran Sasso in Italy. Particularly, the paper is focused on the precision measurement of the 7Be solar neutrino flux, on the search of its day–night modulation, and on the first detection of pep neutrinos. The paper also covers a recent measurement of the CNGS neutrinos speed made in May 2012. A short discussion about the forthcoming scientific program on solar neutrinos, geoneutrinos, and sterile neutrino searches is included at the end.
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
122075081
Solar neutrino results from borexino
Abstract Borexino is a large-volume liquid scintillator experiment for low energy neutrino detection, operating since May 2007, and installed at the National Laboratory of Gran Sasso. Borexino is the first experiment able to observe in real-time Solar neutrino interactions also in the sub-MeV range. We report with this work the main results achieved in the Solar neutrino sector by Borexino. In particular, we report the results on the measured interaction rates of 7 Be, 8 B, and pep neutrinos, and their impacts on the physics of neutrino oscillations.
121625849
High precision Be-7 solar neutrinos measurement and day night effect obtained with Borexino
Abstract We report the direct measurement of the 7 Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso and the search for a day–night asymmetry of this interaction rate. The interaction rate of the 0.862 MeV 7 Be neutrinos is 46 ± 1.6 ( stat ) − 1.6 + 1.5 ( syst ) counts/(day · 100 ton). The hypothesis of no oscillation for this solar neutrinos is inconsistent with our measurement at the 5.8 σ C.L. Our result is the first direct measurement of solar neutrinos with an accuracy better than 5%. We report the survival probability for solar ν e in the transition region between matter-enhanced and vacuum-driven oscillations. The measured day night asymmetry is A dn = 0.001 ± 0.012 (stat)±0.007 (syst), in agreement with the predicition of MSW–LMA neutrino [13] oscillations. This result discourages MSW oscillations with mixing parameters in the LOW region at more than 8.5 σ , meaning that this region is, for the first time, strongly rejected without the assumption of CPT symmetry. The result can also be used to constrain some neutrino oscillation scenarios involving new physics.
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.