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.
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.
55822151
Measurement of geo-neutrinos from 1353 days of Borexino
Abstract We present a measurement of the geo-neutrino signal obtained from 1353 days of data with the Borexino detector at Laboratori Nazionali del Gran Sasso in Italy. With a fiducial exposure of ( 3.69 ± 0.16 ) × 10 31 proton × year after all selection cuts and background subtraction, we detected ( 14.3 ± 4.4 ) geo-neutrino events assuming a fixed chondritic mass Th/U ratio of 3.9. This corresponds to a geo-neutrino signal S geo = ( 38.8 ± 12.0 ) TNU with just a 6 × 10 − 6 probability for a null geo-neutrino measurement. With U and Th left as free parameters in the fit, the relative signals are S Th = ( 10.6 ± 12.7 ) TNU and S U = ( 26.5 ± 19.5 ) TNU . Borexino data alone are compatible with a mantle geo-neutrino signal of ( 15.4 ± 12.3 ) TNU , while a combined analysis with the KamLAND data allows to extract a mantle signal of ( 14.1 ± 8.1 ) TNU . Our measurement of 31.2 − 6.1 + 7.0 reactor anti-neutrino events is in agreement with expectations in the presence of neutrino oscillations.
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.
27175903
New limits on heavy sterile neutrino mixing in 8B decay obtained with the Borexino detector
If heavy neutrinos with mass $m_{\nu_{H}}\geq$2$ m_e $ are produced in the Sun via the decay ${^8\rm{B}} \rightarrow {^8\rm{Be}} + e^+ + \nu_H$ in a side branch of pp-chain, they would undergo the observable decay into an electron, a positron and a light neutrino $\nu_{H}\rightarrow\nu_{L}+e^++e^-$. In the present work Borexino data are used to set a bound on the existence of such decays. We constrain the mixing of a heavy neutrino with mass 1.5 MeV $\leq m_{\nu_{H}} \le$ 14 MeV to be $|U_{eH}|^2\leq (10^{-3}-4\times10^{-6})$ respectively. These are tighter limits on the mixing parameters than obtained in previous experiments at nuclear reactors and accelerators.
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.
17290178
Scale invariance in a non-Abelian Chern–Simons-matter model
Abstract The general method of reduction in the number of coupling parameters is applied to a Chern–Simons-matter model with several independent couplings. We claim that considering the asymptotic region, and expressing all dimensionless coupling parameters as functions of the Chern–Simons coupling, it is possible to show that all β-functions vanish to any order of the perturbative series. Therefore, the model is asymptotically scale invariant.
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.
14322363
On the Borchers Class of a Non-Commutative Field
In this paper, we arrive at the notion of equivalence classes of a non-commutative field exploring some ideas by Soloviev to nonlocal quantum fields. Specifically, an equivalence relation between non-commutative fields is formulated by replacing the weak relative locality condition by a weak relative asymptotic commutativity property, generalizing the notion of relative locality proved by Borchers in the framework of local QFT. We restrict ourselves to the simplest case of a scalar field theory with space-space non-commutativity.
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.
13936057
Microlocal Analysis and Renormalization in Finite Temperature Field Theory
We reassess the problem of renormalization in finite temperature field theory (FTFT). A new point of view elucidates the relation between the ultraviolet divergences for T = 0 and T ¬ = 0 theories and makes clear the reason why the ultraviolet behavior keeps unaffected when we consider the FTFT version associated to a given quantum field theory (QFT). The strength of the derivation one lies on the Hörmander’s criterion for the existence of products of distributions in terms of the wavefront sets of the respective distributions. The approach allows us to regard the FTFT both imaginary and real time formalism at once in a unified way in the contour ordered formalism.