Measurement of Nucleon-Nucleon Elastic Scattering at Small Angles using the ANKE spectrometer

A fundamental understanding of the nucleon-nucleon (NN) interaction is one of the ultimate goals of nuclear and hadron physics. Apart from their intrinsic importance for the study of nuclear forces, NN elastic scattering data are necessary, for example, in the modelling of meson production and other nuclear reactions at intermediate energies. Quantum chromodynamics, the theory of strong interactions, is not able to determine the NN interaction from first principles because of its non-perturbative nature at intermediate energies (the coupling constants are too strong). Hence, phenomenological approaches are necessary to describe the NN interaction. Partial wave analyses (PWA), such as the ones regularly performed by the SAID (Scattering Analysis Interactive Dial-in) group, have proved to be truly invaluable tools over many years for researchers in this area. These analyses rely on the quantity and quality of the experimental measurements of various proton-proton (pp) and proton-neutron (pn) scattering observables at different energies over the full angular ranges. The goal of many experiments conducted at Cooler Synchrotron (COSY) has been to provide PWA with the precision measurements of NN observables that are essential for these analyses. The experiments presented in this thesis have been carried out within the ANKE collaboration at COSY-Jülich, Germany. Data were obtained using polarised or unpolarised proton beams with kinetic energies from 0.8 GeV up to 2.8 GeV and unpolarised hydrogen or deuterium cluster-jet targets. The detection system of the ANKE spectrometer is the ideal set-up for carrying out refined measurements at the small scattering angles that had not previously been investigated. The thesis comprises the measurements of the analysing power Ay and differential cross section in pp elastic scattering, and preliminary results for the analysing power in the pn quasi-free elastic scattering. These new data close an important gap in the NN database at scattering angles up to 30�° and energies up to 2.8 GeV. The results obtained are compared to the predictions from the SAID PWA published in 2007 that were based on data from earlier experiments. The impact of the present results is demonstrated by the significant changes in the low partial waves of the updated SAID PWA, which includes the new ANKE measurements as well as the existing global data

Borexino’s guide into the solar core and neutrinos

The Borexino experiment is located at the Laboratori Nazionali del Gran Sasso in Italy with the primary goal of detecting solar neutrinos, particularly those below 2 MeV, with unprecedentedly high sensitivity. The Borexino collaboration has recently published the comprehensive measurement of solar neutrinos produced along the pp-chain, a sequence of nuclear reactions responsible for about 99 percent of solar energy. The solar neutrinos produced in different fusion reactions are affected to a different extent (due to their different energies) by the so-called Mikheyev, Smirnov, and Wolfenstein effect. As neutrinos propagate from the core of Sun to the photosphere, the oscillation parameters acquire effective values in an energy-dependent fashion. As a result, by measuring the solar neutrinos at different energies, Borexino probes the neutrino flavor-transition phenomena simultaneously both in a vacuum and matter-dominated regimes. The neutrino fluxes also provide a direct determination of the relative intensity of the two primary terminations of the pp-chain (pp-I and pp-II) and an indication that the temperature profile in the Sun is more compatible with solar models that assume high surface metallicity. In short, we explore the solar neutrinos measurements in Borexino as a unique probe of both the Sun's internal working, as well as fundamental physics

"Dive into the deep Earth with neutrinos: Borexino latest results

Borexino experiment is a 280-ton liquid scintillator detector located at a 3800 m w.e. depth in the Laboratori Nazionali del Gran Sasso (Italy). Borexino is one of only two detectors in the world who have measured geoneutrinos, antineutrinos originating from the radioactive decays of long-lived isotopes naturally present in the crust and mantle. The new geoneutrino measurement, published in January 2020, features increased statistics and the new elaborate analysis. With this update, we have now been able to access 53 geoneutrino events – almost twice as many as in the result published by the collaboration in 2015. The improvements in the analysis and geological interpretations of the results will be discussed in the talk

Borexino: Latest Results and Future Opportunities

The Borexino experiment, located at the Laboratori Nazionali del Gran Sasso in Italy, is the liquid-scintillator experiment that has tackled an extensive physics program for more than ten years. Its distinctive technical feature, the ultra-low radioactive background of the inner scintillating core, has exceeded all expectations and became the basis of the outstanding achievements obtained so far. The Borexino collaboration has recently published the first comprehensive measurement of solar neutrinos produced along the pp-chain, a sequence of nu- clear reactions responsible for about 99 percent of solar energy. We present the measurements of pp, 7Be, pep, and 8B solar neutrino interaction rates, as well as the limits on hep and CNO-cycle contributions. Besides these solar neutrino results and their implications we explore the possible strategies on CNO-neutrino measurements

Solar Neutrinos with Borexino: First evidence of CNO fusion cycle

The prime energy producer in the sun is the fusion of hydrogen to formhelium. However, there is more than one way for this fusion to takeplace: for stars the size of the sun or smaller, the proton-proton (pp)chain reactions dominate (~99%), while in heavier stars, thecarbon-nitrogen-oxygen (CNO) cycle is expected to play a more importantrole. Not only these fusion reactions would not have been possiblewithout the emission of neutrinos, neutrinos are the only way todirectly access the processes in the core of the sun.Borexino experiment, located at the Laboratori Nazionali del Gran Sasso,was built with a primary goal of the Be7 solar neutrinos (part of ppchain) detection. In more than a decade of data taking, Borexino has notonly demonstrated the unprecedentedly high sensitivity towards Be7 solarneutrinos (<3%) but performed a comprehensive study of low-energyneutrinos from the complete pp-chain. After a number of developments inboth hardware and software, Borexino presents the first experimentalevidence of the up-to-now elusive CNO fusion cycle in the Sun. Theabsence of the CNO neutrinos signal is disfavoured by the Borexinoexperiment at 5σ