The Experts below are selected from a list of 20313 Experts worldwide ranked by ideXlab platform
G Bellini - One of the best experts on this subject based on the ideXlab platform.
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first simultaneous precision spectroscopy of pp 7 be and pep Solar Neutrinos with borexino phase ii
Physical Review D, 2019Co-Authors: M Agostini, K. Altenmüller, S. Appel, G Bonfini, G Bellini, Jay Benziger, D. Basilico, V Atroshchenko, Z Bagdasarian, D BravoAbstract:We present the first simultaneous measurement of the interaction rates of $pp$, $^7$Be, and $pep$ Solar Neutrinos performed with a global fit to the Borexino data in an extended energy range (0.19-2.93)$\,$MeV. This result was obtained by analyzing 1291.51$\,$days of Borexino Phase-II data, collected between December 2011 and May 2016 after an extensive scintillator purification campaign. We find: rate($pp$)$\,$=$\,$$134$$\,$$\pm$$\,$$10$$\,$($stat$)$\,$$^{\rm +6}_{\rm -10}$$\,$($sys$)$\,$cpd/100$\,$t, rate($^7$Be)$\,$=$\,$$48.3$$\,$$\pm$$\,$$1.1$$\,$($stat$)$\,$$^{\rm +0.4}_{\rm -0.7}$$\,$($sys$)$\,$cpd/100$\,$t, and rate($pep$)$\,$=$\,$$2.43$$\pm$$\,$$0.36$$\,$($stat$)$^{+0.15}_{-0.22}$$\,$($sys$)$\,$cpd/100$\,$t. These numbers are in agreement with and improve the precision of our previous measurements. In particular, the interaction rate of $^7$Be $\nu$'s is measured with an unprecedented precision of 2.7%, showing that discriminating between the high and low metallicity Solar models is now largely dominated by theoretical uncertainties. The absence of $pep$ Neutrinos is rejected for the first time at more than 5$\,$$\sigma$. An upper limit of $8.1$$\,$cpd/100$\,$t (95%$\,$C.L.) on the CNO neutrino rate is obtained by setting an additional constraint on the ratio between the $pp$ and $pep$ neutrino rates in the fit. This limit has the same significance as that obtained by the Borexino Phase-I (currently providing the tightest bound on this component), but is obtained by applying a less stringent constraint on the $pep$ $\nu$ flux.
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comprehensive measurement of pp chain Solar Neutrinos
Nature, 2018Co-Authors: M Agostini, K. Altenmüller, S. Appel, G Bellini, Jay Benziger, D. Basilico, V Atroshchenko, Z Bagdasarian, D Bick, G BonfiniAbstract:About 99 per cent of Solar energy is produced through sequences of nuclear reactions that convert hydrogen into helium, starting from the fusion of two protons (the pp chain). The Neutrinos emitted by five of these reactions represent a unique probe of the Sun’s internal working and, at the same time, offer an intense natural neutrino beam for fundamental physics. Here we report a complete study of the pp chain. We measure the neutrino–electron elastic-scattering rates for Neutrinos produced by four reactions of the chain: the initial proton–proton fusion, the electron-capture decay of beryllium-7, the three-body proton–electron–proton (pep) fusion, here measured with the highest precision so far achieved, and the boron-8 beta decay, measured with the lowest energy threshold. We also set a limit on the neutrino flux produced by the$^{3}$He–proton fusion (hep). These measurements 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. We also determine the survival probability of Solar electron Neutrinos at different energies, thus probing simultaneously and with high precision the neutrino flavour-conversion paradigm, both in vacuum and in matter-dominated regimes.
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Real-time detection of Solar Neutrinos with Borexino
2016Co-Authors: S. Marcocci, Diego Bravo, K. Altenmüller, S. Appel, David Bick, G Bonfini, G Bellini, Jay Benziger, M Agostini, B CaccianigaAbstract:Solar Neutrinos have been fundamental in the discovery of neutrino flavor oscillations and are a unique tool to probe the nuclear reactions that fuel the Sun. The Borexino experiment, located in the Gran Sasso National Laboratory, is an ultra-pure liquid scintillator detector conceived for the real time spectroscopy of low energy Solar Neutrinos. Thanks to its unprecedented background levels, Borexino could measure in real time the fluxes of different components of the Solar neutrino spectrum, thus probing both Solar neutrino oscillations and the Standard Solar Model. We review these fundamental results and also discuss the prospects for the Phase-II of Borexino, which is entering the precision era of Solar neutrino measurements.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract:Borexino has been running since May 2007 at the Laboratori Nazionali del Gran Sasso laboratory in Italy 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 Phase-I (2007–2010), Borexino first detected and then precisely measured the flux of the Be 7 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 Solar Neutrinos produced in the CNO cycle (carbon, nitrogen, oxigen) where carbon, nitrogen, and oxygen serve as catalysts in the fusion process. 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 Be 7 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.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract: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.
Jay Benziger - One of the best experts on this subject based on the ideXlab platform.
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first simultaneous precision spectroscopy of pp 7 be and pep Solar Neutrinos with borexino phase ii
Physical Review D, 2019Co-Authors: M Agostini, K. Altenmüller, S. Appel, G Bonfini, G Bellini, Jay Benziger, D. Basilico, V Atroshchenko, Z Bagdasarian, D BravoAbstract:We present the first simultaneous measurement of the interaction rates of $pp$, $^7$Be, and $pep$ Solar Neutrinos performed with a global fit to the Borexino data in an extended energy range (0.19-2.93)$\,$MeV. This result was obtained by analyzing 1291.51$\,$days of Borexino Phase-II data, collected between December 2011 and May 2016 after an extensive scintillator purification campaign. We find: rate($pp$)$\,$=$\,$$134$$\,$$\pm$$\,$$10$$\,$($stat$)$\,$$^{\rm +6}_{\rm -10}$$\,$($sys$)$\,$cpd/100$\,$t, rate($^7$Be)$\,$=$\,$$48.3$$\,$$\pm$$\,$$1.1$$\,$($stat$)$\,$$^{\rm +0.4}_{\rm -0.7}$$\,$($sys$)$\,$cpd/100$\,$t, and rate($pep$)$\,$=$\,$$2.43$$\pm$$\,$$0.36$$\,$($stat$)$^{+0.15}_{-0.22}$$\,$($sys$)$\,$cpd/100$\,$t. These numbers are in agreement with and improve the precision of our previous measurements. In particular, the interaction rate of $^7$Be $\nu$'s is measured with an unprecedented precision of 2.7%, showing that discriminating between the high and low metallicity Solar models is now largely dominated by theoretical uncertainties. The absence of $pep$ Neutrinos is rejected for the first time at more than 5$\,$$\sigma$. An upper limit of $8.1$$\,$cpd/100$\,$t (95%$\,$C.L.) on the CNO neutrino rate is obtained by setting an additional constraint on the ratio between the $pp$ and $pep$ neutrino rates in the fit. This limit has the same significance as that obtained by the Borexino Phase-I (currently providing the tightest bound on this component), but is obtained by applying a less stringent constraint on the $pep$ $\nu$ flux.
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comprehensive measurement of pp chain Solar Neutrinos
Nature, 2018Co-Authors: M Agostini, K. Altenmüller, S. Appel, G Bellini, Jay Benziger, D. Basilico, V Atroshchenko, Z Bagdasarian, D Bick, G BonfiniAbstract:About 99 per cent of Solar energy is produced through sequences of nuclear reactions that convert hydrogen into helium, starting from the fusion of two protons (the pp chain). The Neutrinos emitted by five of these reactions represent a unique probe of the Sun’s internal working and, at the same time, offer an intense natural neutrino beam for fundamental physics. Here we report a complete study of the pp chain. We measure the neutrino–electron elastic-scattering rates for Neutrinos produced by four reactions of the chain: the initial proton–proton fusion, the electron-capture decay of beryllium-7, the three-body proton–electron–proton (pep) fusion, here measured with the highest precision so far achieved, and the boron-8 beta decay, measured with the lowest energy threshold. We also set a limit on the neutrino flux produced by the$^{3}$He–proton fusion (hep). These measurements 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. We also determine the survival probability of Solar electron Neutrinos at different energies, thus probing simultaneously and with high precision the neutrino flavour-conversion paradigm, both in vacuum and in matter-dominated regimes.
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Real-time detection of Solar Neutrinos with Borexino
2016Co-Authors: S. Marcocci, Diego Bravo, K. Altenmüller, S. Appel, David Bick, G Bonfini, G Bellini, Jay Benziger, M Agostini, B CaccianigaAbstract:Solar Neutrinos have been fundamental in the discovery of neutrino flavor oscillations and are a unique tool to probe the nuclear reactions that fuel the Sun. The Borexino experiment, located in the Gran Sasso National Laboratory, is an ultra-pure liquid scintillator detector conceived for the real time spectroscopy of low energy Solar Neutrinos. Thanks to its unprecedented background levels, Borexino could measure in real time the fluxes of different components of the Solar neutrino spectrum, thus probing both Solar neutrino oscillations and the Standard Solar Model. We review these fundamental results and also discuss the prospects for the Phase-II of Borexino, which is entering the precision era of Solar neutrino measurements.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract:Borexino has been running since May 2007 at the Laboratori Nazionali del Gran Sasso laboratory in Italy 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 Phase-I (2007–2010), Borexino first detected and then precisely measured the flux of the Be 7 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 Solar Neutrinos produced in the CNO cycle (carbon, nitrogen, oxigen) where carbon, nitrogen, and oxygen serve as catalysts in the fusion process. 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 Be 7 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.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract: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.
B Caccianiga - One of the best experts on this subject based on the ideXlab platform.
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Real-time detection of Solar Neutrinos with Borexino
2016Co-Authors: S. Marcocci, Diego Bravo, K. Altenmüller, S. Appel, David Bick, G Bonfini, G Bellini, Jay Benziger, M Agostini, B CaccianigaAbstract:Solar Neutrinos have been fundamental in the discovery of neutrino flavor oscillations and are a unique tool to probe the nuclear reactions that fuel the Sun. The Borexino experiment, located in the Gran Sasso National Laboratory, is an ultra-pure liquid scintillator detector conceived for the real time spectroscopy of low energy Solar Neutrinos. Thanks to its unprecedented background levels, Borexino could measure in real time the fluxes of different components of the Solar neutrino spectrum, thus probing both Solar neutrino oscillations and the Standard Solar Model. We review these fundamental results and also discuss the prospects for the Phase-II of Borexino, which is entering the precision era of Solar neutrino measurements.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract:Borexino has been running since May 2007 at the Laboratori Nazionali del Gran Sasso laboratory in Italy 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 Phase-I (2007–2010), Borexino first detected and then precisely measured the flux of the Be 7 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 Solar Neutrinos produced in the CNO cycle (carbon, nitrogen, oxigen) where carbon, nitrogen, and oxygen serve as catalysts in the fusion process. 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 Be 7 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.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract: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.
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first evidence of pep Solar Neutrinos by direct detection in borexino
Physical Review Letters, 2012Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, S Bonetti, D Bravo, D Bick, L Cadonati, Buizza M Avanzini, F CalapriceAbstract:0.3) 10 8 cm 2 s 1 and <7.7 10 8 cm 2 s 1 (95% C.L.), respectively, in agreement with the Standard Solar Model. These results represent the rst mea
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first real time detection of 7be Solar Neutrinos by borexino
Physics Letters B, 2008Co-Authors: C Arpesella, G Bellini, Jay Benziger, B Caccianiga, S Bonetti, F Calaprice, F Dalnokiveress, D Dangelo, H De Kerret, A DerbinAbstract:Abstract This Letter reports a direct measurement of the 7Be Solar neutrino signal rate performed with the Borexino low background liquid scintillator detector at the Laboratori Nazionali del Gran Sasso. This is the first real-time spectral measurement of sub-MeV Solar Neutrinos. The result for 0.862 MeV 7Be Neutrinos is 47 ± 7 stat ± 12 sys counts/(day ⋅ 100 ton), consistent with predictions of Standard Solar Models and neutrino oscillations with LMA-MSW parameters.
G Bonfini - One of the best experts on this subject based on the ideXlab platform.
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first simultaneous precision spectroscopy of pp 7 be and pep Solar Neutrinos with borexino phase ii
Physical Review D, 2019Co-Authors: M Agostini, K. Altenmüller, S. Appel, G Bonfini, G Bellini, Jay Benziger, D. Basilico, V Atroshchenko, Z Bagdasarian, D BravoAbstract:We present the first simultaneous measurement of the interaction rates of $pp$, $^7$Be, and $pep$ Solar Neutrinos performed with a global fit to the Borexino data in an extended energy range (0.19-2.93)$\,$MeV. This result was obtained by analyzing 1291.51$\,$days of Borexino Phase-II data, collected between December 2011 and May 2016 after an extensive scintillator purification campaign. We find: rate($pp$)$\,$=$\,$$134$$\,$$\pm$$\,$$10$$\,$($stat$)$\,$$^{\rm +6}_{\rm -10}$$\,$($sys$)$\,$cpd/100$\,$t, rate($^7$Be)$\,$=$\,$$48.3$$\,$$\pm$$\,$$1.1$$\,$($stat$)$\,$$^{\rm +0.4}_{\rm -0.7}$$\,$($sys$)$\,$cpd/100$\,$t, and rate($pep$)$\,$=$\,$$2.43$$\pm$$\,$$0.36$$\,$($stat$)$^{+0.15}_{-0.22}$$\,$($sys$)$\,$cpd/100$\,$t. These numbers are in agreement with and improve the precision of our previous measurements. In particular, the interaction rate of $^7$Be $\nu$'s is measured with an unprecedented precision of 2.7%, showing that discriminating between the high and low metallicity Solar models is now largely dominated by theoretical uncertainties. The absence of $pep$ Neutrinos is rejected for the first time at more than 5$\,$$\sigma$. An upper limit of $8.1$$\,$cpd/100$\,$t (95%$\,$C.L.) on the CNO neutrino rate is obtained by setting an additional constraint on the ratio between the $pp$ and $pep$ neutrino rates in the fit. This limit has the same significance as that obtained by the Borexino Phase-I (currently providing the tightest bound on this component), but is obtained by applying a less stringent constraint on the $pep$ $\nu$ flux.
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comprehensive measurement of pp chain Solar Neutrinos
Nature, 2018Co-Authors: M Agostini, K. Altenmüller, S. Appel, G Bellini, Jay Benziger, D. Basilico, V Atroshchenko, Z Bagdasarian, D Bick, G BonfiniAbstract:About 99 per cent of Solar energy is produced through sequences of nuclear reactions that convert hydrogen into helium, starting from the fusion of two protons (the pp chain). The Neutrinos emitted by five of these reactions represent a unique probe of the Sun’s internal working and, at the same time, offer an intense natural neutrino beam for fundamental physics. Here we report a complete study of the pp chain. We measure the neutrino–electron elastic-scattering rates for Neutrinos produced by four reactions of the chain: the initial proton–proton fusion, the electron-capture decay of beryllium-7, the three-body proton–electron–proton (pep) fusion, here measured with the highest precision so far achieved, and the boron-8 beta decay, measured with the lowest energy threshold. We also set a limit on the neutrino flux produced by the$^{3}$He–proton fusion (hep). These measurements 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. We also determine the survival probability of Solar electron Neutrinos at different energies, thus probing simultaneously and with high precision the neutrino flavour-conversion paradigm, both in vacuum and in matter-dominated regimes.
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Real-time detection of Solar Neutrinos with Borexino
2016Co-Authors: S. Marcocci, Diego Bravo, K. Altenmüller, S. Appel, David Bick, G Bonfini, G Bellini, Jay Benziger, M Agostini, B CaccianigaAbstract:Solar Neutrinos have been fundamental in the discovery of neutrino flavor oscillations and are a unique tool to probe the nuclear reactions that fuel the Sun. The Borexino experiment, located in the Gran Sasso National Laboratory, is an ultra-pure liquid scintillator detector conceived for the real time spectroscopy of low energy Solar Neutrinos. Thanks to its unprecedented background levels, Borexino could measure in real time the fluxes of different components of the Solar neutrino spectrum, thus probing both Solar neutrino oscillations and the Standard Solar Model. We review these fundamental results and also discuss the prospects for the Phase-II of Borexino, which is entering the precision era of Solar neutrino measurements.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract:Borexino has been running since May 2007 at the Laboratori Nazionali del Gran Sasso laboratory in Italy 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 Phase-I (2007–2010), Borexino first detected and then precisely measured the flux of the Be 7 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 Solar Neutrinos produced in the CNO cycle (carbon, nitrogen, oxigen) where carbon, nitrogen, and oxygen serve as catalysts in the fusion process. 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 Be 7 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.
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final results of borexino phase i on low energy Solar neutrino spectroscopy
Physical Review D, 2014Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, F Calaprice, D Bravo, D Bick, Margherita Buizza Avanzini, L Cadonati, P CavalcanteAbstract: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.
S Bonetti - One of the best experts on this subject based on the ideXlab platform.
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first evidence of pep Solar Neutrinos by direct detection in borexino
Physical Review Letters, 2012Co-Authors: G Bellini, G Bonfini, Jay Benziger, B Caccianiga, S Bonetti, D Bravo, D Bick, L Cadonati, Buizza M Avanzini, F CalapriceAbstract:0.3) 10 8 cm 2 s 1 and <7.7 10 8 cm 2 s 1 (95% C.L.), respectively, in agreement with the Standard Solar Model. These results represent the rst mea
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direct measurement of the 7be Solar neutrino flux with 192 days of borexino data
Physical Review Letters, 2008Co-Authors: C Arpesella, G Bellini, H O Back, M Balata, S Bonetti, A Brigatti, J Benzinger, B Cacciangia, L Candonati, S CalapriceAbstract:We report the direct measurement of the 7Be Solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV 7Be Neutrinos is 49+/-3stat+/-4syst counts/(day.100 ton). The hypothesis of no oscillation for 7Be Solar Neutrinos is inconsistent with our measurement at the 4sigma C.L. Our result is the first direct measurement of the survival probability for Solar nu(e) in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of 7Be, pp, and CNO Solar nu(e), and the limit on the effective neutrino magnetic moment using Solar Neutrinos.
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direct measurement of the 7be Solar neutrino flux with 192 days of borexino data
Physical Review Letters, 2008Co-Authors: C Arpesella, G Bellini, H O Back, M Balata, S Bonetti, A Brigatti, J Benzinger, B Cacciangia, L Candonati, S CalapriceAbstract:We report the direct measurement of the {sup 7}Be Solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV {sup 7}Be Neutrinos is 49{+-}3{sub stat}{+-}4{sub syst} counts/(day{center_dot}100 ton). The hypothesis of no oscillation for {sup 7}Be Solar Neutrinos is inconsistent with our measurement at the 4{sigma} C.L. Our result is the first direct measurement of the survival probability for Solar {nu}{sub e} in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of {sup 7}Be, pp, and CNO Solar {nu}{sub e}, and the limit on the effective neutrino magnetic moment using Solar Neutrinos.
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first real time detection of 7be Solar Neutrinos by borexino
Physics Letters B, 2008Co-Authors: C Arpesella, G Bellini, Jay Benziger, B Caccianiga, S Bonetti, F Calaprice, F Dalnokiveress, D Dangelo, H De Kerret, A DerbinAbstract:Abstract This Letter reports a direct measurement of the 7Be Solar neutrino signal rate performed with the Borexino low background liquid scintillator detector at the Laboratori Nazionali del Gran Sasso. This is the first real-time spectral measurement of sub-MeV Solar Neutrinos. The result for 0.862 MeV 7Be Neutrinos is 47 ± 7 stat ± 12 sys counts/(day ⋅ 100 ton), consistent with predictions of Standard Solar Models and neutrino oscillations with LMA-MSW parameters.
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science and technology of borexino a real time detector for low energy Solar Neutrinos
Astroparticle Physics, 2002Co-Authors: G Alimonti, G Bellini, Jay Benziger, C Arpesella, H O Back, M Balata, T Beau, S Bonetti, A Brigatti, B CaccianigaAbstract:Abstract Borexino, a real-time device for low energy neutrino spectroscopy is nearing completion of construction in the underground laboratories at Gran Sasso, Italy (LNGS). The experiment's goal is the direct measurement of the flux of 7 Be Solar Neutrinos of all flavors via neutrino–electron scattering in an ultra-pure scintillation liquid. Seeded by a series of innovations which were brought to fruition by large-scale operation of a 4-ton test detector at LNGS, a new technology has been developed for Borexino. It enables sub-MeV Solar neutrino spectroscopy for the first time. This paper describes the design of Borexino, the various facilities essential to its operation, its spectroscopic and background suppression capabilities and a prognosis of the impact of its results towards resolving the Solar neutrino problem. Borexino will also address several other frontier questions in particle physics, astrophysics and geophysics.
