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1. Novel techniques for alpha/beta pulse shape discrimination in Borexino

Author

Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., D'Angelo, D., Derbin, A., Di Giacintov, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, L., Penek, O., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Rossi, N., Schoenert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics, Physics - Instrumentation and Detectors
Abstract

Borexino could efficiently distinguish between alpha and beta radiation in its liquid scintillator by the characteristic time profile of their scintillation pulse. This alpha/beta discrimination, first demonstrated at the tonne scale in the Counting Test Facility prototype, was used throughout the lifetime of the experiment between 2007 and 2021. With this method, alpha events are identified and subtracted from the beta-like solar neutrino events. This is particularly important in liquid scintillator as alpha scintillation is quenched many-fold. In Borexino, the prominent Po-210 decay peak was a background in the energy range of electrons scattered from Be-7 solar neutrinos. Optimal alpha-beta discrimination was achieved with a "multi-layer perceptron neural network", which its higher ability to leverage the timing information of the scintillation photons detected by the photomultiplier tubes. An event-by-event, high efficiency, stable, and uniform pulse shape discrimination was essential in characterising the spatial distribution of background in the detector. This benefited most Borexino measurements, including solar neutrinos in the \pp chain and the first direct observation of the CNO cycle in the Sun. This paper presents the key milestones in alpha/beta discrimination in Borexino as a term of comparison for current and future large liquid scintillator detectors, Comment: 13 pages, 14 figures

Published
2023
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2. Final results of Borexino on CNO solar neutrinos

Author

Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., D'Angelo, D., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Villante, F. L., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We report the first measurement of CNO solar neutrinos by Borexino that uses the Correlated Integrated Directionality (CID) method, exploiting the sub-dominant Cherenkov light in the liquid scintillator detector. The directional information of the solar origin of the neutrinos is preserved by the fast Cherenkov photons from the neutrino scattered electrons, and is used to discriminate between signal and background. The directional information is independent from the spectral information on which the previous CNO solar neutrino measurements by Borexino were based. While the CNO spectral analysis could only be applied on the Phase-III dataset, the directional analysis can use the complete Borexino data taking period from 2007 to 2021. The absence of CNO neutrinos has been rejected with >5{\sigma} credible level using the Bayesian statistics. The directional CNO measurement is obtained without an external constraint on the $^{210}$Bi contamination of the liquid scintillator, which was applied in the spectral analysis approach. The final and the most precise CNO measurement of Borexino is then obtained by combining the new CID-based CNO result with an improved spectral fit of the Phase-III dataset. Including the statistical and the systematic errors, the extracted CNO interaction rate is $R(\mathrm{CNO})=6.7^{+1.2}_{-0.8} \, \mathrm{cpd/100 \, tonnes}$. Taking into account the neutrino flavor conversion, the resulting CNO neutrino flux at Earth is $\Phi_\mathrm{CNO}=6.7 ^{+1.2}_{-0.8} \times 10^8 \, \mathrm{cm^{-2} s^{-1}}$, in agreement with the high metallicity Standard Solar Models. The results described in this work reinforce the role of the event directional information in large-scale liquid scintillator detectors and open up new avenues for the next-generation liquid scintillator or hybrid neutrino experiments.

Published
2023
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3. Borexino's search for low-energy neutrinos associated with gravitational wave events from GWTC-3 database

Author

BOREXINO Collaboration, Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., Angelo, D. D', Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, L., Penek, O., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Rossi, N., Schonert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

The search for neutrino events in correlation with gravitational wave (GW) events for three observing runs (O1, O2 and O3) from 09/2015 to 03/2020 has been performed using the Borexino data-set of the same period. We have searched for signals of neutrino-electron scattering with visible energies above 250 keV within a time window of 1000 s centered at the detection moment of a particular GW event. The search was done with three visible energy thresholds of 0.25, 0.8 and 3.0 MeV.Two types of incoming neutrino spectra were considered: the mono-energetic line and the spectrum expected from supernovae. The same spectra were considered for electron antineutrinos detected through inverse beta-decay (IBD) reaction. GW candidates originated by merging binaries of black holes (BHBH), neutron stars (NSNS) and neutron star and black hole (NSBH) were analysed separately. Additionally, the subset of most intensive BHBH mergers at closer distances and with larger radiative mass than the rest was considered. In total, follow-ups of 74 out of 93 gravitational waves reported in the GWTC-3 catalog were analyzed and no statistically significant excess over the background was observed. As a result, the strongest upper limits on GW-associated neutrino and antineutrino fluences for all flavors (\nu_e, \nu_\mu, \nu_\tau) have been obtained in the (0.5 - 5.0) MeV neutrino energy range., Comment: 13 pages, 8 figures

Published
2023
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4. Status and prospects of SABRE North

Author

Mariani, A., Benziger, J. B., Calaprice, F., Copello, S., Dafinei, I., D'Angelo, D., D'Imperio, G., Di Carlo, G., Diemoz, M., Di Giacinto, A., Di Ludovico, A., Ianna, M., Ianni, A., Milana, S., Orlandi, D., Pettinacci, V., Pietrofaccia, L., Rahatlou, S., Suerfu, B., Tomei, C., Vignoli, C., and Zani, A.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We present the characterization of a low background NaI(Tl) crystal for the SABRE North experiment. The crystal NaI-33, was studied in two different setups at Laboratori Nazionali del Gran Sasso, Italy. The Proof-of-Principle (PoP) detector was equipped with a liquid scintillator veto and collected data for about one month (90 kg$\times$days). The PoP-dry setup consisted of NaI-33 in a purely passive shielding and collected data for almost one year (891 kg$\times$days). The average background in the energy region of interest (1-6 keV) for dark matter search was 1.20 $\pm$ 0.05 and 1.39 $\pm$ 0.02 counts/day/kg/keV within the PoP and the PoP-dry setup, respectively. This result opens to a new shielding design for the physics phase of the SABRE North detector, that does not foresee the use of an organic liquid scintillator external veto., Comment: 5 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:2205.13876

Published
2022

5. Improved measurement of solar neutrinos from the Carbon-Nitrogen-Oxygen cycle by Borexino and its implications for the Standard Solar Model

Author

Appel, S., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Pelicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Villante, F. L., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

We present an improved measurement of the CNO solar neutrino interaction rate at Earth obtained with the complete Borexino Phase-III dataset. The measured rate R$_{\rm CNO}$ = $6.7^{+2.0}_{-0.8}$ counts/(day$ \cdot$ 100 tonnes), allows us to exclude the absence of the CNO signal with about 7$\sigma$ C.L. The correspondent CNO neutrino flux is $6.6^{+2.0}_{-0.9} \times 10^8$ cm$^{-2}$ s$^{-1}$, taking into account the neutrino flavor conversion. We use the new CNO measurement to evaluate the C and N abundances in the Sun with respect to the H abundance for the first time with solar neutrinos. Our result of $N_{\rm CN}$ = $(5.78^{+1.86}_{-1.00})\times10^{-4}$ displays a $\sim$2$\sigma$ tension with the "low metallicity" spectroscopic photospheric measurements. On the other hand, our result used together with the $^7$Be and $^8$B solar neutrino fluxes, also measured by Borexino, permits to disfavour at 3.1$\sigma$ C.L. the "low metallicity" SSM B16-AGSS09met as an alternative to the "high metallicity" SSM B16-GS98., Comment: 8 pages, 6 figures

Published
2022
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6. Performance of the SABRE detector module in a purely passive shielding

Author

Calaprice, F., Benziger, J. B., Copello, S., Dafinei, I., D'Angelo, D., D'Imperio, G., Di Carlo, G., Diemoz, M., Di Giacinto, A., Di Ludovico, A., Ianna, M., Ianni, A., Mariani, A., Milana, S., Orlandi, D., Pettinacci, V., Pietrofaccia, L., Rahatlou, S., Suerfu, B., Tomei, C., Vignoli, C., and Zani, A.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We present here a characterization of the low background NaI(Tl) crystal NaI-33 based on a period of almost one year of data taking (891 kgxdays exposure) in a detector configuration with no use of organic scintillator veto. This remarkably radio-pure crystal already showed a low background in the SABRE Proof-of-Principle (PoP) detector, in the low energy region of interest (1-6 keV) for the search of dark matter interaction via the annual modulation signature. As the vetoable background components, such as $^{40}$K, are here sub-dominant, we reassembled the PoP setup with a fully passive shielding. We upgraded the selection of events based on a Boosted Decision Tree algorithm that rejects most of the PMT-induced noise while retaining scintillation signals with > 90% efficiency in 1-6 keV. We find an average background of 1.39 $\pm$ 0.02 counts/day/kg/keV in the region of interest and a spectrum consistent with data previously acquired in the PoP setup, where the external veto background suppression was in place. Our background model indicates that the dominant background component is due to decays of $^{210}$Pb, only partly residing in the crystal itself. The other location of $^{210}$Pb is the reflector foil that wraps the crystal. We now proceed to design the experimental setup for the physics phase of the SABRE North detector, based on an array of similar crystals, using a low radioactivity PTFE reflector and further improving the passive shielding strategy, in compliance with the new safety and environmental requirements of Laboratori Nazionali del Gran Sasso., Comment: 8 pages, 9 figures

Published
2022
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7. Independent determination of the Earth's orbital parameters with solar neutrinos in Borexino

Author

Appel, S., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., D'Angelo, D., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Goettel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, L., Penek, O., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Rossi, N., Schoenert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics, High Energy Physics - Phenomenology
Abstract

Since the beginning of 2012, the Borexino collaboration has been reporting precision measurements of the solar neutrino fluxes, emitted in the proton-proton chain and in the Carbon-Nitrogen-Oxygen cycle. The experimental sensitivity achieved in Phase-II and Phase-III of the Borexino data taking made it possible to detect the annual modulation of the solar neutrino interaction rate due to the eccentricity of Earth's orbit, with a statistical significance greater than 5$\sigma$. This is the first precise measurement of the Earth's orbital parameters based solely on solar neutrinos and an additional signature of the solar origin of the Borexino signal. The complete periodogram of the time series of the Borexino solar neutrino detection rate is also reported, exploring frequencies between one cycle/year and one cycle/day. No other significant modulation frequencies are found. The present results were uniquely made possible by Borexino's decade-long high-precision solar neutrino detection., Comment: 12 pages, 10 figures

Published
2022
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8. First Directional Measurement of sub-MeV Solar Neutrinos with Borexino

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Pellicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wessel, A., Wojcik, M., Wonsak, B., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We report the measurement of sub-MeV solar neutrinos through the use of their associated Cherenkov radiation, performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The measurement is achieved using a novel technique that correlates individual photon hits of events to the known position of the Sun. In an energy window between 0.54 MeV to 0.74 MeV, selected using the dominant scintillation light, we have measured 10887$^{+2386}_{-2103} (\mathrm{stat.})\pm 947 (\mathrm{syst.})$ ($68\%$ confidence interval) solar neutrinos out of 19904 total events. This corresponds to a $^{7}$Be neutrino interaction rate of 51.6$^{+13.9}_{-12.5}$ counts/(day$\cdot$ 100 ton), which is in agreement with the Standard Solar Model predictions and the previous spectroscopic results of Borexino. The no-neutrino hypothesis can be excluded with $>$5$\sigma$ confidence level. For the first time, we have demonstrated the possibility of utilizing the directional Cherenkov information for sub-MeV solar neutrinos, in a large-scale, high light yield liquid scintillator detector. This measurement provides an experimental proof of principle for future hybrid event reconstruction using both Cherenkov and scintillation signatures simultaneously., Comment: 6 pages, 4 figures, short letter of arXiv:2109.04770

Published
2021
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9. Search for Low-Energy Signals from Fast Radio Bursts with the Borexino Detector

Author

Appel, S., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., D'Angelo, D., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gottel, A. S., Gromov, M., Guffantic, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, L., Penek, O., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Rossi, N., Schonert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zhutikov, I., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Phenomenology
Abstract

The search for neutrino events in correlation with several of the most intense fast radio bursts (FRBs) has been performed using the Borexino data. We have searched for signals with visible energies above $250$~keV within a time window of $\pm$1000~s corresponding to the detection time of a particular FRB. We also applied an alternative approach based on searching for specific shapes of neutrino-electron scattering spectra in the full exposure spectrum of the Borexino detector. In particular, two incoming neutrino spectra were considered: the monoenergetic line and the spectrum expected from supernovae. The same spectra were considered for electron antineutrinos detected through the inverse beta-decay reaction. No statistically significant excess over the background was observed. As a result, the strongest upper limits on FRB-associated neutrino fluences of all flavors have been obtained in the $0.5 - 50$~MeV neutrino energy range., Comment: 14 pages, 10 figures

Published
2021
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10. Correlated and Integrated Directionality for sub-MeV solar neutrinos in Borexino

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Pellicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wessel, A., Wojcik, M., Wonsak, B., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

Liquid scintillator detectors play a central role in the detection of neutrinos from various sources. In particular, it is the only technique used so far for the precision spectroscopy of sub-MeV solar neutrinos, as demonstrated by the Borexino experiment at the Gran Sasso National Laboratory in Italy. The benefit of a high light yield, and thus a low energy threshold and a good energy resolution, comes at the cost of the directional information featured by water Cherenkov detectors, measuring $^8$B solar neutrinos above a few MeV. In this paper we provide the first directionality measurement of sub-MeV solar neutrinos which exploits the correlation between the first few detected photons in each event and the known position of the Sun for each event. This is also the first signature of directionality in neutrinos elastically scattering off electrons in a liquid scintillator target. This measurement exploits the sub-dominant, fast Cherenkov light emission that precedes the dominant yet slower scintillation light signal. Through this measurement, we have also been able to extract the rate of $^{7}$Be solar neutrinos in Borexino. The demonstration of directional sensitivity in a traditional liquid scintillator target paves the way for the possible exploitation of the Cherenkov light signal in future kton-scale experiments using liquid scintillator targets. Directionality is important for background suppression as well as the disentanglement of signals from various sources., Comment: 19 pages, 15 Figures, revised version after comments from PRD Referees, shorter letter submitted with the title: "First Directional Measurement of sub-MeV Solar Neutrinos with Borexino"

Published
2021
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11. Identification of the cosmogenic $^{11}$C background in large volumes of liquid scintillators with Borexino

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacintio, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Pelicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Porcelli, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singha, A., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

Cosmogenic radio-nuclei are an important source of background for low-energy neutrino experiments. In Borexino, cosmogenic $^{11}$C decays outnumber solar $pep$ and CNO neutrino events by about ten to one. Highly efficient identification of this background is mandatory for these neutrino analyses. We present here the details of the most consolidated strategy, used throughout Borexino solar neutrino measurements. It hinges upon finding the space-time correlations between $^{11}$C decays, the preceding parent muons and the accompanying neutrons. This article describes the working principles and evaluates the performance of this Three-Fold Coincidence (TFC) technique in its two current implementations: a hard-cut and a likelihood-based approach. Both show stable performances throughout Borexino Phases II (2012-2016) and III (2016-2020) data sets, with a $^{11}$C tagging efficiency of $\sim$90 % and $\sim$63-66 % of the exposure surviving the tagging. We present also a novel technique that targets specifically $^{11}$C produced in high-multiplicity during major spallation events. Such $^{11}$C appear as a burst of events, whose space-time correlation can be exploited. Burst identification can be combined with the TFC to obtain about the same tagging efficiency of $\sim$90 % but with a higher fraction of the exposure surviving, in the range of $\sim$66-68 %., Comment: 21 pages, 14 figures (but 15 files, one figure being made of 2 images), 3 tables

Published
2021
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12. The Low Polonium Field of Borexino and its significance for the CNO neutrino detection

Author

Kumaran, S., Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Pellicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Villante, F. L., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

Borexino is a liquid scintillator detector located at the Laboratori Nazionale del Gran Sasso, Italy with the main goal to measure solar neutrinos. The experiment recently provided the first direct experimental evidence of CNO-cycle neutrinos in the Sun, rejecting the no-CNO signal hypothesis with a significance greater than 5$\sigma$ at 99\%C.L. The intrinsic $^{210}$Bi is an important background for this analysis due to its similar spectral shape to that of CNO neutrinos. $^{210}$Bi can be measured through its daughter $^{210}$Po which can be distinguished through an event-by-event basis via pulse shape discrimination. However, this required reducing the convective motions in the scintillator that brought additional $^{210}$Po from peripheral sources. This was made possible through the thermal insulation and stabilization campaign performed between 2015 and 2016. This article will explain the strategy and the different methods performed to extract the $^{210}$Bi upper limit in Phase-III (Jul 2016- Feb 2020) of the experiment through the analysis of $^{210}$Po in the cleanest region of the detector called the Low Polonium Field., Comment: Contribution to the 2021 Neutrinos session of the 55th Rencontres de Moriond

Published
2021

13. First detection of CNO neutrinos with Borexino

Author

Settanta, G., Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Pelicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Schönert, S., Semenov, D., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Villante, F. L., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment
Abstract

Neutrinos are elementary particles which are known since many years as fundamental messengers from the interior of the Sun. The Standard Solar Model, which gives a theoretical description of all nuclear processes which happen in our star, predicts that roughly 99% of the energy produced is coming from a series of processes known as the "pp chain". Such processes have been studied in detail over the last years by means of neutrinos, thanks also to the important measurements provided by the Borexino experiment. The remaining 1% is instead predicted to come from a separate loop-process, known as the "CNO cycle". This sub-dominant process is theoretically well understood, but has so far escaped any direct observation. Another fundamental aspect is that the CNO cycle is indeed the main nuclear engine in stars more massive than the Sun. In 2020, thanks to the unprecedented radio-purity and temperature control achieved by the Borexino detector over recent years, the first ever detection of neutrinos from the CNO cycle has been finally announced. The milestone result confirms the existence of this nuclear fusion process in our Universe. Here, the details of the detector stabilization and the analysis techniques adopted are reported., Comment: 7 pages, 3 figures. Contribution to the 2021 Neutrinos session of the 55th Rencontres de Moriond

Published
2021

14. Characterization of SABRE crystal NaI-33 with direct underground counting

Author

Antonello, M., Arnquist, I. J., Barberio, E., Baroncelli, T., Benziger, J., Bignell, L. J., Bolognino, I., Calaprice, F., Copello, S., Dafinei, I., D'Angelo, D., D'Imperio, G., D'Incecco, M., Di Carlo, G., Diemoz, M., Di Giacinto, A., Di Ludovico, A., Dix, W., Duffy, A. R., Hoppe, E., Ianni, A., Iannone, M., Ioannucci, L., Krishnan, S., Lane, G. J., Mahmood, I., Mariani, A., Milana, S., Mould, J., Nuti, F., Orlandi, D., Pettinacci, V., Pietrofaccia, L., Rahatlou, S., Scutti, F., Souza, M., Stuchbery, A. E., Suerfu, B., Tomei, C., Urquijo, P., Vignoli, C., Wallner, A., Wada, M., Williams, A. G., Zani, A., and Zurowski, M.

Subjects
Physics - Instrumentation and Detectors
Abstract

Ultra-pure NaI(Tl) crystals are the key element for a model-independent verification of the long standing DAMA result and a powerful means to search for the annual modulation signature of dark matter interactions. The SABRE collaboration has been developing cutting-edge techniques for the reduction of intrinsic backgrounds over several years. In this paper we report the first characterization of a 3.4 kg crystal, named NaI-33, performed in an underground passive shielding setup at LNGS. NaI-33 has a record low $^{39}$K contamination of 4.3$\pm$0.2 ppb as determined by mass spectrometry. We measured a light yield of 11.1$\pm$0.2 photoelectrons/keV and an energy resolution of 13.2% (FWHM/E) at 59.5 keV. We evaluated the activities of $^{226}$Ra and $^{228}$Th inside the crystal to be $5.9\pm0.6 \mu$Bq/kg and $1.6\pm0.3 \mu$Bq/kg, respectively, which would indicate a contamination from $^{238}$U and $^{232}$Th at part-per-trillion level. We measured an activity of 0.51$\pm$0.02 mBq/kg due to $^{210}$Pb out of equilibrium and a $\alpha$ quenching factor of 0.63$\pm$0.01 at 5304 keV. We illustrate the analyses techniques developed to reject electronic noise in the lower part of the energy spectrum. A cut-based strategy and a multivariate approach indicated a rate, attributed to the intrinsic radioactivity of the crystal, of $\sim$1 count/day/kg/keV in the [5-20] keV region.

Published
2020
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15. Experimental evidence of neutrinos produced in the CNO fusion cycle in the Sun

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Pellicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Villante, F. L., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Collaboration, G. Zuzel. The BOREXINO

Subjects
High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics, Physics - Instrumentation and Detectors, G.3.1
Abstract

For most of their existence stars are fueled by the fusion of hydrogen into helium proceeding via two theoretically well understood processes, namely the $pp$ chain and the CNO cycle. Neutrinos emitted along such fusion processes in the solar core are the only direct probe of the deep interior of the star. A complete spectroscopy of neutrinos from the {\it pp} chain, producing about 99\% of the solar energy, has already been performed \cite{bib:Nature-2018}. Here, we report the direct observation, with a high statistical significance, of neutrinos produced in the CNO cycle in the Sun. This is the first experimental evidence of this process obtained with the unprecedentedly radio-pure large-volume liquid-scintillator Borexino detector located at the underground Laboratori Nazionali del Gran Sasso in Italy. The main difficulty of this experimental effort is to identify the excess of the few counts per day per 100 tonnes of target due to CNO neutrino interactions above the backgrounds. A novel method to constrain the rate of \bi contaminating the scintillator relies on the thermal stabilisation of the detector achieved over the past 5 years. In the CNO cycle, the hydrogen fusion is catalyzed by the carbon (C) - nitrogen (N) - oxygen (O) and thus its rate, as well as the flux of emitted CNO neutrinos, directly depends on the abundance of these elements in solar core. Therefore, this result paves the way to a direct measurement of the solar metallicity by CNO neutrinos. While this result quantifies the relative contribution of the CNO fusion in the Sun to be of the order of 1\%, this process is dominant in the energy production of massive stars. The occurrence of the primary mechanism for the stellar conversion of hydrogen into helium in the Universe has been proven., Comment: 43 pages, 14 figures

Published
2020
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16. Sensitivity to neutrinos from the solar CNO cycle in Borexino

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Villante, F. L., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics, Physics - Instrumentation and Detectors
Abstract

Neutrinos emitted in the carbon, nitrogen, oxygen (CNO) fusion cycle in the Sun are a sub-dominant, yet crucial component of solar neutrinos whose flux has not been measured yet. The Borexino experiment at the Laboratori Nazionali del Gran Sasso (Italy) has a unique opportunity to detect them directly thanks to the detector's radiopurity and the precise understanding of the detector backgrounds. We discuss the sensitivity of Borexino to CNO neutrinos, which is based on the strategies we adopted to constrain the rates of the two most relevant background sources, pep neutrinos from the solar pp-chain and Bi-210 beta decays originating in the intrinsic contamination of the liquid scintillator with Pb-210. Assuming the CNO flux predicted by the high-metallicity Standard Solar Model and an exposure of 1000 daysx71.3 t, Borexino has a median sensitivity to CNO neutrino higher than 3 sigma. With the same hypothesis the expected experimental uncertainty on the CNO neutrino flux is 23%, provided the uncertainty on the independent estimate of the Bi-210 interaction rate is 1.5 cpd/100t. Finally, we evaluated the expected uncertainty of the C and N abundances and the expected discrimination significance between the high and low metallicity Standard Solar Models (HZ and LZ) with future more precise measurement of the CNO solar neutrino flux., Comment: 16 pages, 12 figures

Published
2020
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17. Characterization of SABRE crystal NaI-33 with direct underground counting

Author

Antonello, M, Arnquist, IJ, Barberio, E, Baroncelli, T, Benziger, J, Bignell, LJ, Bolognino, I, Calaprice, F, Copello, S, Dafinei, I, D’Angelo, D, D’Imperio, G, D’Incecco, M, Di Carlo, G, Diemoz, M, Di Giacinto, A, Di Ludovico, A, Dix, W, Duffy, AR, Hoppe, E, Ianni, A, Iannone, M, Ioannucci, L, Krishnan, S, Lane, GJ, Mahmood, I, Mariani, A, Milana, S, Mould, J, Nuti, F, Orlandi, D, Pettinacci, V, Pietrofaccia, L, Rahatlou, S, Scutti, F, Souza, M, Stuchbery, AE, Suerfu, B, Tomei, C, Urquijo, P, Vignoli, C, Wallner, A, Wada, M, Williams, AG, Zani, A, and Zurowski, M

Subjects
Nuclear and Plasma Physics, Physical Sciences, physics.ins-det, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract

Abstract: Ultra-pure NaI(Tl) crystals are the key element for a model-independent verification of the long standing DAMA result and a powerful means to search for the annual modulation signature of dark matter interactions. The SABRE collaboration has been developing cutting-edge techniques for the reduction of intrinsic backgrounds over several years. In this paper we report the first characterization of a 3.4 kg crystal, named NaI-33, performed in an underground passive shielding setup at LNGS. NaI-33 has a record low $$^{39}$$ 39 K contamination of 4.3 ± 0.2 ppb as determined by mass spectrometry. We measured a light yield of 11.1 ± 0.2 photoelectrons/keV and an energy resolution of 13.2% (FWHM/E) at 59.5 keV. We evaluated the activities of $$^{226}$$ 226 Ra and $$^{228}$$ 228 Th inside the crystal to be $$5.9\pm 0.6~\upmu $$ 5.9 ± 0.6 μ Bq/kg and $$1.6\pm 0.3~\upmu $$ 1.6 ± 0.3 μ Bq/kg, respectively, which would indicate a contamination from $$^{238}$$ 238 U and $$^{232}$$ 232 Th at part-per-trillion level. We measured an activity of 0.51 ± 0.02 mBq/kg due to $$^{210}$$ 210 Pb out of equilibrium and a $$\alpha $$ α quenching factor of 0.63 ± 0.01 at 5304 keV. We illustrate the analyses techniques developed to reject electronic noise in the lower part of the energy spectrum. A cut-based strategy and a multivariate approach indicated a rate, attributed to the intrinsic radioactivity of the crystal, of $$\sim $$ ∼ 1 count/day/kg/keV in the [5–20] keV region.

Published
2021

18. Search for low-energy neutrinos from astrophysical sources with Borexino

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cappelli, L., Cavalcante, P., Cavanna, F., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Gabriele, F., Galbiati, C., Gschwender, M., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kumaran, S., Kobychev, V., Korga, G., Lachenmaier, T., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Manuzio, G., Marcocci, S., Maricic, J., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Rottenanger, S., Schönert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos ($\bar{\nu}_e$) are detected in an organic liquid scintillator through the inverse $\beta$-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8-16.8 MeV on neutrino fluxes from unknown sources that improve our previous results, on average, by a factor 2.5. Using the same data set, we first obtain experimental constraints on the diffuse supernova $\bar{\nu}_e$ fluxes in the previously unexplored region below 8 MeV. A search for $\bar{\nu}_e$ in the solar neutrino flux is also presented: the presence of $\bar{\nu}_e$ would be a manifestation of a non-zero anomalous magnetic moment of the neutrino, making possible its conversion to antineutrinos in the strong magnetic field of the Sun. We obtain a limit for a solar $\bar{\nu}_e$ flux of 384 cm$^{-2}$s$^{-1}$ (90% C.L.), assuming an undistorted solar $^{8}$B neutrinos energy spectrum, that corresponds to a transition probability $p_{ \nu_e \rightarrow \bar\nu_{e}}<$ 7.2$\times$10$^{-5}$ (90% C.L.) for E$_{\bar {\nu}_e}$ $>$ 1.8 MeV. At lower energies, by investigating the spectral shape of elastic scattering events, we obtain a new limit on solar $^{7}$Be-$\nu_e$ conversion into $\bar{\nu}_e$ of $p_{ \nu_e \rightarrow \bar \nu_{e}}<$ 0.14 (90% C.L.) at 0.862 keV. Last, we investigate solar flares as possible neutrino sources and obtain the strongest up-to-date limits on the fluence of neutrinos of all flavor neutrino below 3-7 ,MeV. Assuming the neutrino flux to be proportional to the flare's intensity, we exclude an intense solar flare as the cause of the observed excess of events in run 117 of the Cl-Ar Homestake experiment., Comment: 18 pages, 8 figures, 4 tables, 73 references

Published
2019

19. Comprehensive geoneutrino analysis with Borexino

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cappelli, L., Cavalcante, P., Cavanna, F., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Fiorentini, G., Formozov, A., Franco, D., Gabriele, F., Galbiati, C., Gschwender, M., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kumaran, S., Kobychev, V., Korga, G., Lachenmaier, T., Lasserre, T., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Mantovani, F., Manuzio, G., Marcocci, S., Maricic, J., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Muratova, V., Neumair, B., Nieslony, M., Oberauer, L., Onillon, A., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Ricci, B., Romani, A., Rossi, N., Rottenanger, S., Schönert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Strati, V., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Vishneva, A., Vivier, M., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Geophysics
Abstract

This paper presents a geoneutrino measurement using 3262.74 days of data taken with the Borexino detector at LNGS in Italy. By observing $52.6 ^{+9.4}_{-8.6} ({\rm stat}) ^{+2.7}_{-2.1}({\rm sys})$ geoneutrinos (68% interval) from $^{238}$U and $^{232}$Th, a signal of $47.0^{+8.4}_{-7.7}\,({\rm stat)}^{+2.4}_{-1.9}\,({\rm sys})$ TNU with $^{+18.3}_{-17.2}$% total precision was obtained. This result assumes the same Th/U mass ratio found in chondritic CI meteorites but compatible results were found when contributions from $^{238}$U and $^{232}$Th were fit as free parameters. Antineutrino background from reactors is fit unconstrained and found compatible with the expectations. The null-hypothesis of observing a signal from the mantle is excluded at a 99.0% C.L. when exploiting the knowledge of the local crust. Measured mantle signal of $21.2 ^{+9.6}_{-9.0} ({\rm stat})^{+1.1}_{-0.9} ({\rm sys})$ TNU corresponds to the production of a radiogenic heat of $24.6 ^{+11.1}_{-10.4}$ TW (68% interval) from $^{238}$U and $^{232}$Th in the mantle. Assuming 18% contribution of $^{40}$K in the mantle and $8.1^{+1.9}_{-1.4}$ TW of radiogenic heat of the lithosphere, the Borexino estimate of the total Earth radiogenic heat is $38.2 ^{+13.6}_{-12.7}$ TW, corresponding to a convective Urey ratio of 0.78$^{+0.41}_{-0.28}$. These values are compatible with different geological models, however there is a 2.4$\sigma$ tension with those which predict the lowest concentration of heat-producing elements. By fitting the data with a constraint on the reactor antineutrino background, the existence of a hypothetical georeactor at the center of the Earth having power greater than 2.4 TW at 95% C.L. is excluded. Particular attention is given to all analysis details, which should be of interest for the next generation geoneutrino measurements., Comment: 69 pages, 56 Figures (some composed of multiple files), 17 Tables, 135 References

Published
2019
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20. Constraints on Flavor-Diagonal Non-Standard Neutrino Interactions from Borexino Phase-II

Author

Agarwalla, S. K., Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cappelli, L., Cavalcante, P., Cavanna, F., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Fomenko, K., Formozov, A., Franco, D., Gabriele, F., Galbiati, C., Gschwender, M., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kumaran, S., Kobychev, V., Korga, G., Lachenmaier, T., Laubenstein, M., Litvinovich, E., Lombardi, P., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Manuzio, G., Marcocci, S., Maricic, J., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Rottenanger, S., Schönert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sun, C., Suvorov, Y., Takeuchi, T., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Phenomenology, Astrophysics - Solar and Stellar Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

The Borexino detector measures solar neutrino fluxes via neutrino-electron elastic scattering. Observed spectra are determined by the solar-$\nu_{e}$ survival probability $P_{ee}(E)$, and the chiral couplings of the neutrino and electron. Some theories of physics beyond the Standard Model postulate the existence of Non-Standard Interactions (NSI's) which modify the chiral couplings and $P_{ee}(E)$. In this paper, we search for such NSI's, in particular, flavor-diagonal neutral current interactions that modify the $\nu_e e$ and $\nu_\tau e$ couplings using Borexino Phase II data. Standard Solar Model predictions of the solar neutrino fluxes for both high- and low-metallicity assumptions are considered. No indication of new physics is found at the level of sensitivity of the detector and constraints on the parameters of the NSI's are placed. In addition, with the same dataset the value of $\sin^2\theta_W$ is obtained with a precision comparable to that achieved in reactor antineutrino experiments., Comment: 28 pages, 7 figures. Slight modifications in the title, abstract, and conclusion. Few references added. Text expanded for clarity. Accepted in JHEP

Published
2019
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21. Borexino’s search for low-energy neutrinos associated with gravitational wave events from GWTC-3 database: Borexino Collaboration

Author

Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., D’Angelo, D., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Re, A., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Published
2023
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22. Modulations of the Cosmic Muon Signal in Ten Years of Borexino Data

Author

The Borexino Collaboration, Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bolognino, I., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Caprioli, S., Carlini, M., Cavalcante, P., Cavanna, F., Chepurnov, A., Choi, K., Collica, L., D'Angelo, D., Davini, S., Derbin, A., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Fomenko, K., Formozov, A., Franco, D., Gabriele, F., Galbiati, C., Gschwender, M., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kudryavtsev, V. A., Kumaran, S., Lachenmaier, T., Laubenstein, M., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Manuzio, G., Marcocci, S., Maricic, J., Martyn, J., Meighen-Berger, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Oberauer, L., Opitz, B., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Porcelli, A., Raikov, G., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Rottenanger, S., Schönert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Stokes, L. F. F., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Weinz, S., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We have measured the flux of cosmic muons in the Laboratori Nazionali del Gran Sasso at 3800\,m\,w.e. to be $(3.432 \pm 0.003)\cdot 10^{-4}\,\mathrm{{m^{-2}s^{-1}}}$ based on ten years of Borexino data acquired between May 2007 and May 2017. A seasonal modulation with a period of $(366.3 \pm 0.6)\,\mathrm{d}$ and a relative amplitude of $(1.36 \pm0.04)\%$ is observed. The phase is measured to be $(181.7 \pm 0.4)\,\mathrm{d}$, corresponding to a maximum at the 1$^\mathrm{st}$ of July. Using data inferred from global atmospheric models, we show the muon flux to be positively correlated with the atmospheric temperature and measure the effective temperature coefficient $\alpha_\mathrm{T} = 0.90 \pm 0.02$. The origin of cosmic muons from pion and kaon decays in the atmosphere allows to interpret the effective temperature coefficient as an indirect measurement of the atmospheric kaon-to-pion production ratio $r_{\mathrm{K}/\pi} = 0.11^{+0.11}_{-0.07}$ for primary energies above $18\,\mathrm{TeV}$. We find evidence for a long-term modulation of the muon flux with a period of $\sim 3000\,\mathrm{d}$ and a maximum in June 2012 that is not present in the atmospheric temperature data. A possible correlation between this modulation and the solar activity is investigated. The cosmogenic neutron production rate is found to show a seasonal modulation in phase with the cosmic muon flux but with an increased amplitude of $(2.6 \pm 0.4)\%$., Comment: 30 pages, 16 figures, proofreading for publication in JCAP

Published
2018
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23. The SABRE project and the SABRE PoP

Author

Antonello, M., Barberio, E., Baroncelli, T., Benziger, J., Bignell, L. J., Bolognino, I., Calaprice, F., Copello, S., D'Angelo, D., D'Imperio, G., Dafinei, I., Di Carlo, G., Diemoz, M., Di Ludovico, A., Dix, W., Duffy, A. R., Froborg, F., Giovanetti, G. K., Hoppe, E., Ianni, A., Ioannucci, L., Krishnan, S., Lane, G. J., Mahmood, I., Mariani, A., Mastrodicasa, M., Montini, P., Mould, J., Nuti, F., Orlandi, D., Paris, M., Pettinacci, V., Pietrofaccia, L., Prokopovic, D., Rahatlou, S., Rossi, N., Sarbutt, A., Shields, E., Souza, M. J., Stuchbery, A. E., Suerfu, B., Tomei, C., Toso, V., Urquijo, P., Vignoli, C., Wada, M., Wallner, A., Williams, A. G., and Xu, J.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

SABRE aims to directly measure the annual modulation of the dark matter interaction rate with NaI(Tl) crystals. A modulation compatible with the standard hypothesis in which our Galaxy is embedded in a dark matter halo has been measured by the DAMA experiment in the same target material. Other direct detection experiments, using different target materials, seem to exclude the interpretation of such modulation in the simplest scenario of WIMP-nucleon elastic scattering. The SABRE experiment aims to carry out an independent search with sufficient sensitivity to confirm or refute the DAMA claim. The SABRE concept and goal is to obtain a background rate of the order of 0.1 cpd/kg/keVee in the energy region of interest. This challenging goal is achievable by operating high-purity crystals inside a liquid scintillator veto for active background rejection. In addition, twin detectors will be located in the northern and southern hemispheres to identify possible contributions to the modulation from seasonal or site-related effects. The SABRE project includes an initial Proof-of-Principle phase at LNGS (Italy), to assess the radio-purity of the crystals and the efficiency of the liquid scintillator veto. This paper describes the general concept of SABRE and the expected sensitivity to WIMP annual modulation., Comment: 7 pages, 4 figures

Published
2018
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24. Monte Carlo simulation of the SABRE PoP background

Author

Antonello, M., Barberio, E., Baroncelli, T., Benziger, J., Bignell, L. J., Bolognino, I., Calaprice, F., Copello, S., D'Angelo, D., D'Imperio, G., Dafinei, I., Di Carlo, G., Diemoz, M., Di Ludovico, A., Duffy, A. R., Froborg, F., Giovanetti, G. K., Hoppe, E., Ianni, A., Ioannucci, L., Krishnan, S., Lane, G. J., Mahmood, I., Mariani, A., McGee, P., Montini, P., Mould, J., Nuti, F., Orlandi, D., Paris, M., Pettinacci, V., Pietrofaccia, L., Prokopovich, D., Rahatlou, S., Rossi, N., Sarbutt, A., Shields, E., Souza, M. J., Stuchbery, A. E., Suerfu, B., Tomei, C., Urquijo, P., Vignoli, C., Wada, M., Wallner, A., Williams, A. G., Xu, J., and Zurowski, M.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

SABRE (Sodium-iodide with Active Background REjection) is a direct dark matter search experiment based on an array of radio-pure NaI(Tl) crystals surrounded by a liquid scintillator veto. Twin SABRE experiments in the Northern and Southern Hemispheres will differentiate a dark matter signal from seasonal and local effects. The experiment is currently in a Proof-of-Principle (PoP) phase, whose goal is to demonstrate that the background rate is low enough to carry out an independent search for a dark matter signal, with sufficient sensitivity to confirm or refute the DAMA result during the following full-scale experimental phase. The impact of background radiation from the detector materials and the experimental site needs to be carefully investigated, including both intrinsic and cosmogenically activated radioactivity. Based on the best knowledge of the most relevant sources of background, we have performed a detailed Monte Carlo study evaluating the expected background in the dark matter search spectral region. The simulation model described in this paper guides the design of the full-scale experiment and will be fundamental for the interpretation of the measured background and hence for the extraction of a possible dark matter signal., Comment: 13 pages, 5 figures

Published
2018
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25. Speeding up complex multivariate data analysis in Borexino with parallel computing based on Graphics Processing Unit

Author

Ding, X. F., Agostini, M., Altenmuller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Caprioli, S., Carlini, M., Cavalcante, P., Chepurnov, A., Choi, K., Collica, L., D'Angelo, D., Davini, S., Derbin, A., Di Ludovico, A., Di Noto, L., Drachnev, I., Fomenko, K., Formozov, A., Franco, D., Froborg, F., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Manuzio, G., Marcocci, S., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Oberauer, L., Opitz, B., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, O., Pilipenko, N., Pocar, A., Porcelli, A., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Roncin, R., Rossi, N., Schonert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Stokes, L. F. F., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Physics - Data Analysis, Statistics and Probability, High Energy Physics - Experiment, Physics - Computational Physics
Abstract

A spectral fitter based on the graphics processor unit (GPU) has been developed for Borexino solar neutrino analysis. It is able to shorten the fitting time to a superior level compared to the CPU fitting procedure. In Borexino solar neutrino spectral analysis, fitting usually requires around one hour to converge since it includes time-consuming convolutions in order to account for the detector response and pile-up effects. Moreover, the convergence time increases to more than two days when including extra computations for the discrimination of $^{11}$C and external $\gamma$s. In sharp contrast, with the GPU-based fitter it takes less than 10 seconds and less than four minutes, respectively. This fitter is developed utilizing the GooFit project with customized likelihoods, pdfs and infrastructures supporting certain analysis methods. In this proceeding the design of the package, developed features and the comparison with the original CPU fitter are presented., Comment: 5 pages, 2 figures, proceeding for TAUP 2017 XV International Conference on Topics in Astroparticle and Underground Physics

Published
2018
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26. Improved measurement of $^8$B solar neutrinos with 1.5 kt y of Borexino exposure

Author

The Borexino Collaboration, Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Giacinto, A., Di Marcello, V., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Formozov, A., Franco, D., Galbiati, C., Gschwender, M., Ghiano, C., Giammarchi, M., Gromov, A. Goretti M., Guffanti, D., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korga, G., Kumaran, S., Lachenmaier, T., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Marcocci, S., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Nieslony, M., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Rossi, N., Rottenanger, S., Schönert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wojcik, M., Wurm, M., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

We report on an improved measurement of the $^8$B solar neutrino interaction rate with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. Neutrinos are detected via their elastic scattering on electrons in a large volume of liquid scintillator. The measured rate of scattered electrons above 3 MeV of energy is $0.223\substack{+0.015 \\ -0.016}\,(stat)\,\substack{+0.006 \\ -0.006}\,(syst)$ cpd/100 t, which corresponds to an observed solar neutrino flux assuming no neutrino flavor conversion of $\Phi\substack{\rm ES \\ ^8\rm B}=2.57\substack{+0.17 \\ -0.18}(stat)\substack{+0.07\\ -0.07}(syst)\times$10$^6$ cm$^{-2}\,$s$^{-1}$. This measurement exploits the active volume of the detector in almost its entirety for the first time, and takes advantage of a reduced radioactive background following the 2011 scintillator purification campaign and of novel analysis tools providing a more precise modeling of the background. Additionally, we set a new limit on the interaction rate of solar $hep$ neutrinos, searched via their elastic scattering on electrons as well as their neutral current-mediated inelastic scattering on carbon, $^{12}$C($\nu,\nu'$)$^{12}$C* ($E_{\gamma}$= 15.1 MeV)., Comment: 14 pages, 13 figures, 4 tables

Published
2017
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27. Simultaneous Precision Spectroscopy of $pp$, $^7$Be, and $pep$ Solar Neutrinos with Borexino Phase-II

Author

Agostini, M., Altenmuller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Caprioli, S., Carlini, M., Cavalcante, P., Chepurnov, A., Choi, K., Collica, L., D'Angelo, D., Davini, S., Derbin, A., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Fomenko, K., Formozov, A., Franco, D., Froborg, F., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Manuzio, G., Marcocci, S., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Oberauer, L., Opitz, B., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, O., Pilipenko, N., Pocar, A., Porcelli, A., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Roncin, R., Rossi, N., Schonert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Stokes, L. F. F., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

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., Comment: 8 pages, 7 figures

Published
2017
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28. Limiting neutrino magnetic moments with Borexino Phase-II solar neutrino data

Author

Agostini, M., Altenmüller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Caprioli, S., Carlini, M., Cavalcante, P., Chepurnov, A., Choi, K., Collica, L., D'Angelo, D., Davini, S., Derbin, A., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Fomenko, K., Formozov, A., Franco, D., Froborg, F., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Guffanti, D., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Manuzio, G., Marcocci, S., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Oberauer, L., Opitz, B., Orekhov, V., Ortica, F., Pallavicini, M., Papp, L., Penek, Ö., Pilipenko, N., Pocar, A., Porcelli, A., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Romani, A., Roncin, R., Rossi, N., Schönert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Stokes, L. F. F., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

A search for the solar neutrino effective magnetic moment has been performed using data from 1291.5 days exposure during the second phase of the Borexino experiment. No significant deviations from the expected shape of the electron recoil spectrum from solar neutrinos have been found, and a new upper limit on the effective neutrino magnetic moment of $\mu_{\nu}^{eff}$ $<$ 2.8$\cdot$10$^{-11}$ $\mu_{B}$ at 90\% c.l. has been set using constraints on the sum of the solar neutrino fluxes implied by the radiochemical gallium experiments.Using the limit for the effective neutrino moment, new limits for the magnetic moments of the neutrino flavor states, and for the elements of the neutrino magnetic moments matrix for Dirac and Majorana neutrinos, are derived., Comment: 7 pages, 2 figures

Published
2017
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29. A search for low-energy neutrinos correlated with gravitational wave events GW150914, GW151226 and GW170104 with the Borexino detector

Author

Agostini, M., Altenmuller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Caprioli, S., Carlini, M., Cavalcante, P., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., Derbin, A., Ding, X. F., Di Ludovico, A., Di Noto, L., Drachnev, I., Fomenko, K., Formozov, A., Franco, D., Froborg, F., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Gromov, M., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Lukyanchenko, L., Machulin, I., Manuzio, G., Marcocci, S., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Oberauer, L., Opitz, B., Ortica, F., Pallavicini, M., Papp, L., Pilipenko, N., Pocar, A., Porcelli, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Roncin, R., Rossi, N., Schonert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Stokes, L. F. F., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

We present the results of a low-energy neutrino search using the Borexino detector in coincidence with the gravitational wave (GW) events GW150914, GW151226 and GW170104. We searched for correlated neutrino events with energies greater than 250 keV within a time window of $\pm500$ s centered around the GW detection time. A total of five candidates were found for all three GW150914, GW151226 and GW170104. This is consistent with the number of expected solar neutrino and background events. As a result, we have obtained the best current upper limits on the GW event neutrino fluence of all flavors ($\nu_e, \nu_{\mu}, \nu_{\tau}$) in the energy range $(0.5 - 5.0)$ MeV., Comment: 8 pages, 5 figures

Published
2017
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30. The Monte Carlo simulation of the Borexino detector

Author

Agostini, M., Altenmuller, K., Appel, S., Atroshchenko, V., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Borodikhina, L., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Caprioli, S., Carlini, M., Cavalcante, P., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., Derbin, A., Ding, X. F., Di Noto, L., Drachnev, I., Fomenko, K., Formozov, A., Franco, D., Froborg, F., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manuzio, G., Marcocci, S., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Muratova, V., Neumair, B., Oberauer, L., Opitz, B., Ortica, F., Pallavicini, M., Papp, L., Pocar, A., Ranucci, G., Re, A., Romani, A., Roncin, R., Rossi, N., Schonert, S., Semenov, D., Shakina, P., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Stokes, L. F. F., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We describe the Monte Carlo (MC) simulation package of the Borexino detector and discuss the agreement of its output with data. The Borexino MC 'ab initio' simulates the energy loss of particles in all detector components and generates the resulting scintillation photons and their propagation within the liquid scintillator volume. The simulation accounts for absorption, reemission, and scattering of the optical photons and tracks them until they either are absorbed or reach the photocathode of one of the photomultiplier tubes. Photon detection is followed by a comprehensive simulation of the readout electronics response. The algorithm proceeds with a detailed simulation of the electronics chain. The MC is tuned using data collected with radioactive calibration sources deployed inside and around the scintillator volume. The simulation reproduces the energy response of the detector, its uniformity within the fiducial scintillator volume relevant to neutrino physics, and the time distribution of detected photons to better than 1% between 100 keV and several MeV. The techniques developed to simulate the Borexino detector and their level of refinement are of possible interest to the neutrino community, especially for current and future large-volume liquid scintillator experiments such as Kamland-Zen, SNO+, and Juno.

Published
2017
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31. Seasonal Modulation of the $^7$Be Solar Neutrino Rate in Borexino

Author

Agostini, M., Altenmuller, K., Appel, S., Atroshchenko, V., Basilico, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Borodikhina, L., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Caprioli, S., Carlini, M., Cavalcante, P., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., Derbin, A., Ding, X. F., Di Noto, L., Drachnev, I., Fomenko, K., Franco, D., Froborg, F., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Houdy, T., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Manuzio, G., Marcocci, S., Martyn, J., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Muratova, V., Neumair, B., Oberauer, L., Opitz, B., Ortica, F., Pallavicini, M., Papp, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Roncin, R., Rossi, N., Schonert, S., Semenov, D., Shakina, P., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Stokes, L. F. F., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We detected the seasonal modulation of the $^7$Be neutrino interaction rate with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. The period, amplitude, and phase of the observed time evolution of the signal are consistent with its solar origin, and the absence of an annual modulation is rejected at 99.99\% C.L. The data are analyzed using three methods: the sinusoidal fit, the Lomb-Scargle and the Empirical Mode Decomposition techniques, which all yield results in excellent agreement., Comment: 11 palese, 13 figures

Published
2017
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32. A search for low-energy neutrino and antineutrino signals correlated with gamma-ray bursts with Borexino

Author

Agostini, M., Altenmeuller, K., Appel, S., Atroshchenko, V., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Carlini, M., Cavalcante, P., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., de Kerret, H., Derbin, A., Di Noto, L., Drachnev, I., Etenko, A., Fomenko, K., Franco, D., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jany, A., Jedrzejczak, K., Jeschke, D., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Marcocci, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Mosteiro, P., Muratova, V., Neumair, B., Oberauer, L., Obolensky, M., Ortica, F., Pallavicini, M., Papp, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Roncin, R., Rossi, N., Scheonert, S., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Winter, J., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

A search for neutrino and antineutrino events correlated with 2,350 gamma-ray bursts (GRBs) is performed with Borexino data collected between December 2007 and November 2015. No statistically significant excess over background is observed. We look for electron antineutrinos ($\bar{\nu}_e$) that inverse beta decay on protons with energies from 1.8\,MeV to 15\,MeV and set the best limit on the neutrino fluence from GRBs below 8\,MeV. The signals from neutrinos and antineutrinos from GRBs that scatter on electrons are also searched for, a detection channel made possible by the particularly radio-pure scintillator of Borexino. We obtain currently the best limits on the neutrino fluence of all flavors and species below 7\,MeV. Finally, time correlations between GRBs and bursts of events are investigated. Our analysis combines two semi-independent data acquisition systems for the first time: the primary Borexino readout optimized for solar neutrino physics up to a few MeV, and a fast waveform digitizer system tuned for events above 1\,MeV., Comment: 10 pages, 6 figures

Published
2016
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33. The Main Results of the Borexino Experiment

Author

Derbin, A., Muratova, V., Agostini, M., Altenmuller, K., Appel, S., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Carlini, M., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Di Noto, L., Drachnev, I., Etenko, A., Fomenko, K., Formozov, A., Franco, D., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jedrzejczak, K., Jeschke, D., Kaiser, M., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Marcocci, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Mosteiro, P., Neumair, B, Oberauer, L., Obolensky, M., Ortica, F., Pallavicini, M., Papp, L., Perasso, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Roncin, R., Rossi, N., Schonert, S., Semenov, D., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Winter, J., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology, Physics - Instrumentation and Detectors
Abstract

The main physical results on the registration of solar neutrinos and the search for rare processes obtained by the Borexino collaboration to date are presented., Comment: 8 pages, 8 figgures, To be published as Proceedings of the Third Annual Large Hadron Collider Physics Conference, St. Petersburg, Russia, 2015

Published
2016

34. A test of electric charge conservation with Borexino

Author

Borexino Collaboration, Agostini, M., Appel, S., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Noto, L., Drachnev, I., Empl, A., Etenko, A., Fomenko, K., Franco, D., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jedrzejczak, K., Kaiser, M., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Marcocci, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Mosteiro, P., Muratova, V., Neumair, B., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Roncin, R., Rossi, N., Schoenert, S., Semenov, D., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Winter, J., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

Borexino is a liquid scintillation detector located deep underground at the Laboratori Nazionali del Gran Sasso (LNGS, Italy). Thanks to the unmatched radio-purity of the scintillator, and to the well understood detector response at low energy, a new limit on the stability of the electron for decay into a neutrino and a single mono-energetic photon was obtained. This new bound, tau > 6.6 10**28 yr at 90 % C.L., is two orders of magnitude better than the previous limit., Comment: 5 pages, 1 figure

Published
2015
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35. Low-energy (anti)neutrino physics with Borexino: Neutrinos from the primary proton-proton fusion process in the Sun

Author

Mosteiro, P., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Cadonati, L., Calaprice, F., Caminata, A., Cavalcante, P., Chavarria, A., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Empl, A., Etenko, A., Fomenko, K., Franco, D., Gabriele, F., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Al., Ianni, An., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Lewke, T., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Marcocci, S., Meindl, Q., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Saldanha, R., Salvo, C., Schoenert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Winter, J., Wojcik, M., Wright, A., Wurm, M., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

The Sun is fueled by a series of nuclear reactions that produce the energy that makes it shine. The primary reaction is the fusion of two protons into a deuteron, a positron and a neutrino. These neutrinos constitute the vast majority of neutrinos reaching Earth, providing us with key information about what goes on at the core of our star. Several experiments have now confirmed the observation of neutrino oscillations by detecting neutrinos from secondary nuclear processes in the Sun; this is the first direct spectral measurement of the neutrinos from the keystone proton-proton fusion. This observation is a crucial step towards the completion of the spectroscopy of pp-chain neutrinos, as well as further validation of the LMA-MSW model of neutrino oscillations., Comment: Proceedings from NOW (Neutrino Oscillation Workshop) 2014

Published
2015
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36. Measurement of neutrino flux from the primary proton--proton fusion process in the Sun with Borexino detector

Author

Smirnov, O. Y., Agostini, M., Appel, S., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., Choi, K., D'Angelo, D., Davini, S., Derbin, A., Di Noto, L., Drachnev, I., Empl, A., Etenko, A., Fomenko, K., Franco, D., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jedrzejczak, K., Kaiser, M., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Marcocci, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Mosteiro, P., Muratova, V., Neumair, B., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pagani, L., Pallavicini, M., Papp, L., Perasso, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Roncin, R., Rossi, N., Schönert, S., Semenov, D., Simgen, H., Skorokhvatov, M., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Winter, J., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

Neutrino produced in a chain of nuclear reactions in the Sun starting from the fusion of two protons, for the first time has been detected in a real-time detector in spectrometric mode. The unique properties of the Borexino detector provided an oppurtunity to disentangle pp-neutrino spectrum from the background components. A comparison of the total neutrino flux from the Sun with Solar luminosity in photons provides a test of the stability of the Sun on the 10$^{5}$ years time scale, and sets a strong limit on the power production in the unknown energy sources in the Sun of no more than 4\% of the total energy production at 90\% C.L., Comment: 15 pages, 2 tables, 3 figures

Published
2015
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37. Spectroscopy of geo-neutrinos from 2056 days of Borexino data

Author

Borexino collaboration, Agostini, M., Appel, S., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., Choi, K., DAngelo, D., Davini, S., Derbin, A., Di Noto, L., Drachnev, I., Empl, A., Etenko, A., Fiorentini, G., Fomenko, K., Franco, D., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jedrzejczak, K., Kaiser, M., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Mantovani, F., Marcocci, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pagani, L., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Ranucci, G., Razeto, A., Re, A., Ricci, B., Romani, A., Roncin, R., Rossi, N., Schoenert, S., Semenov, D., Simgen, H., Skorokhavatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Winter, J., Woicik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We report an improved geo-neutrino measurement with Borexino from 2056 days of data taking. The present exposure is $(5.5\pm0.3)\times10^{31}$ proton$\times$yr. Assuming a chondritic Th/U mass ratio of 3.9, we obtain $23.7 ^{+6.5}_{-5.7} (stat) ^{+0.9}_{-0.6} (sys)$ geo-neutrino events. The null observation of geo-neutrinos with Borexino alone has a probability of $3.6 \times 10^{-9}$ (5.9$\sigma$). A geo-neutrino signal from the mantle is obtained at 98\% C.L. The radiogenic heat production for U and Th from the present best-fit result is restricted to the range 23-36 TW, taking into account the uncertainty on the distribution of heat producing elements inside the Earth., Comment: 4 pages, 4 figures

Published
2015
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38. Search for low-energy signals from fast radio bursts with the Borexino detector

Author

Appel, S., Bagdasarian, Z., Basilico, D., Bellini, G., Benziger, J., Biondi, R., Caccianiga, B., Calaprice, F., Caminata, A., Chepurnov, A., D’Angelo, D., Derbin, A., Giacinto, A. Di, Marcello, V. Di, Ding, X. F., Ludovico, A. Di, Noto, L. Di, Drachnev, I., Franco, D., Galbiati, C., Ghiano, C., Giammarchi, M., Goretti, A., Göttel, A. S., Gromov, M., Guffanti, D., Ianni, Aldo, Ianni, Andrea, Jany, A., Kobychev, V., Korga, G., Kumaran, S., Laubenstein, M., Litvinovich, E., Lombardi, P., Lomskaya, I., Ludhova, L., Lukyanchenko, G., Machulin, I., Martyn, J., Meroni, E., Miramonti, L., Misiaszek, M., Muratova, V., Nugmanov, R., Oberauer, L., Orekhov, V., Ortica, F., Pallavicini, M., Pelicci, L., Penek, Ö., Pietrofaccia, L., Pilipenko, N., Pocar, A., Raikov, G., Ranalli, M. T., Ranucci, G., Razeto, A., Re, A., Redchuk, M., Rossi, N., Schönert, S., Semenov, D., Settanta, G., Skorokhvatov, M., Singhal, A., Smirnov, O., Sotnikov, A., Tartaglia, R., Testera, G., Unzhakov, E., Vishneva, A., Vogelaar, R. B., Feilitzsch, F. von, Wojcik, M., Wurm, M., Zavatarelli, S., Zhutikov, I., Zuber, K., and Zuzel, G.

Published
2022
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39. Solar neutrino with Borexino: results and perspectives

Author

Smirnov, O., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chavarria, A., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Empl, A., Etenko, A., Fomenko, K., Franco, D., Fiorentini, G., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Lewke, T., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Mantovani, F., Marcocci, S., Meindl, Q., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Ricci, B., Romani, A., Rossi, N., Saldanha, R., Salvo, C., Schoenert, S., Simgen, H., Skorokhvatov, M., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Winter, J., Wojcik, M., Wright, A., Wurm, M., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

Borexino is a unique detector able to perform measurement of solar neutrinos fluxes in the energy region around 1 MeV or below due to its low level of radioactive background. It was constructed at the LNGS underground laboratory with a goal of solar $^{7}$Be neutrino flux measurement with 5\% precision. The goal has been successfully achieved marking the end of the first stage of the experiment. A number of other important measurements of solar neutrino fluxes have been performed during the first stage. Recently the collaboration conducted successful liquid scintillator repurification campaign aiming to reduce main contaminants in the sub-MeV energy range. With the new levels of radiopurity Borexino can improve existing and challenge a number of new measurements including: improvement of the results on the Solar and terrestrial neutrino fluxes measurements; measurement of pp and CNO solar neutrino fluxes; search for non-standard interactions of neutrino; study of the neutrino oscillations on the short baseline with an artificial neutrino source (search for sterile neutrino) in context of SOX project., Comment: 15 pages, 4 figures

Published
2014
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40. Recent Borexino results and prospects for the near future

Author

D'Angelo, D., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Cavalcante, P., Chavarria, A., Chepurnov, A., Davini, S., Derbin, A., Empl, A., Etenko, A., von Feilitzsch, F., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Grandi, L., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Lewke, T., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Saldanha, R., Salvo, C., Schoenert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

The Borexino experiment, located in the Gran Sasso National Laboratory, is an organic liquid scintillator detector conceived for the real time spectroscopy of low energy solar neutrinos. The data taking campaign phase I (2007 - 2010) has allowed the first independent measurements of 7Be, 8B and pep fluxes as well as the first measurement of anti-neutrinos from the earth. After a purification of the scintillator, Borexino is now in phase II since 2011. We review here the recent results achieved during 2013, concerning the seasonal modulation in the 7Be signal, the study of cosmogenic backgrounds and the updated measurement of geo-neutrinos. We also review the upcoming measurements from phase II data (pp, pep, CNO) and the project SOX devoted to the study of sterile neutrinos via the use of a 51Cr neutrino source and a 144Ce-144Pr antineutrino source placed in close proximity of the active material., Comment: 8 pages, 11 figures. To be published as proceedings of Rencontres de Moriond EW 2014

Published
2014

41. Recent results from Borexino on solar neutrinos

Author

Basilico D., Appel S., Bagdasarian Z., Bellini G., Benziger J., Biondi R., Caccianiga B., Calaprice F., Caminata A., Chepurnov A., D’Angelo D., Derbin A., Di Giacinto A., Di Marcello V., Ding X.F., Di Ludovico A., Di Noto L., Drachnev I., Franco D., Galbiati C., Ghiano C., Giammarchi M., Goretti A., Göttel A.S., Gromov L., Guffanti D., Ianni Aldo, Ianni Andrea, Jany A., Kobychev V., Korga G., Kumaran S., Laubenstein M., Litvinovich E., Lombardi P., Lomskaya I., Ludhova L., Lukyanchenko G., Machulin I., Martyn J., Meroni E., Miramonti L., Misiaszek M., Muratova V., Nugmanov R., Oberauer L., Orekhov V., Ortica F., Pallavicini M., Pelicci L., Penek Ö., Pietrofaccia L., Pilipenko N., Pocar A., Raikov G., Ranalli M.T., Ranucci G., Razeto A., Re A., Redchuk M., Rossi N., Schönert S., Semenov D., Settanta G., Skorokhvatov M., Singhal A., Smirnov O., Sotnikov A., Tartaglia R., Testera G., Unzhakov E., Villante F., Vishneva A., Vogelaar R.B., von Feilitzsch F., Wojcik M., Wurm M., Zavatarelli S., Zuber K., and Zuzel G.

Subjects
Physics, QC1-999
Abstract

Borexino has been a neutrino detector based on ultrapure liquid scintillator, located at the Laboratori Nazionali del Gran Sasso, Italy. Its main scientific goal was the real-time measurement of solar neutrino fluxes, which play an irreplaceable role for the comprehension of the mechanisms powering our star. Over the past two years, the Borexino collaboration has pursued the improvement of the CNO flux measurement, obtaining further indications about the solar metallicity. In a parallel way, Borexino has demonstrated for the first time the possibility of exploiting the directional Cherenkov information, in a liquid scintillator detector, for the detection of sub-MeV solar neutrinos.

Published
2023
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42. New limits on heavy sterile neutrino mixing in ${^{8}\rm{B}}$-decay obtained with the Borexino detector

Author

Borexino collaboration, Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Cavalcante, P., Chavarria, A., Chepurnov, A., DAngelo, D., Davini, S., Derbin, A., Drachnev, I., Empl, A., Etenko, A., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goger-Neff, M., Goretti, A., Grandi, L., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lewke, T., Litvinovich, E., Loer, B., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Saldanha, R., Salvo, C., Schonert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., von Feilitzsch, F., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology, Nuclear Experiment
Abstract

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., Comment: 7 pages, 6 figures

Published
2013
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43. Final results of Borexino Phase-I on low energy solar neutrino spectroscopy

Author

Borexino Collaboration, Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. B., Caccianiga, B., Cadonati, L., Calaprice, F., Cavalcante, P., Chavarria, A., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Empl, A., Etenko, A., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Grandi, L., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lewke, T., Litvinovich, E., Loer, B., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Pena-Garay, C., Perasso, L., Perasso, S., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Saldanha, R., Salvo, C., Schoenert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., von Feilitzsch, F., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

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.

Published
2013
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44. Cosmogenic Backgrounds in Borexino at 3800 m water-equivalent depth

Author

Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Cavalcante, P., Chavarria, A., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Empl, A., Etenko, A., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Göger-Neff, M., Goretti, A., Grandi, L., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lewke, T., Litvinovich, E., Loer, B., Lombardi, P., Lombardi, F., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Möllenberg, R., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Saldanha, R., Salvo, C., Schönert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., von Feilitzsch, F., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

The solar neutrino experiment Borexino, which is located in the Gran Sasso underground laboratories, is in a unique position to study muon-induced backgrounds in an organic liquid scintillator. In this study, a large sample of cosmic muons is identified and tracked by a muon veto detector external to the liquid scintillator, and by the specific light patterns observed when muons cross the scintillator volume. The yield of muon-induced neutrons is found to be Yn =(3.10+-0.11)10-4 n/({\mu} (g/cm2)). The distance profile between the parent muon track and the neutron capture point has the average value {\lambda} = (81.5 +- 2.7)cm. Additionally the yields of a number of cosmogenic radioisotopes are measured for 12N, 12B, 8He, 9C, 9Li, 8B, 6He, 8Li, 11Be, 10C and 11C. All results are compared with Monte Carlo simulation predictions using the Fluka and Geant4 packages. General agreement between data and simulation is observed for the cosmogenic production yields with a few exceptions, the most prominent case being 11C yield for which both codes return about 50% lower values. The predicted {\mu}-n distance profile and the neutron multiplicity distribution are found to be overall consistent with data., Comment: 26 pages, 13 figures (in 14 files), 4 tables. 3 extra data files. accepted by JCAP

Published
2013
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45. Measurement of geo-neutrinos from 1353 days of Borexino

Author

Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Cavalcante, P., Chavarria, A., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Empl, A., Etenko, A., Fiorentini, G., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Grandi, L., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Kobychev, V. V., Korablev, D., Korga, G., Koshio, Y., Kryn, D., Laubenstein, M., Lewke, T., Litvinovich, E., Loer, B., Lombardi, P., Lombardi, F., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Mantovani, F., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Ranucci, G., Razeto, A., Re, A., Ricci, B., Romani, A., Rossi, N., Sabelnikov, A., Saldanha, R., Salvo, C., Schoenert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., von Feilitzsch, F., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
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 $\pm$ 0.16) $\times$ $10^{31}$ proton $\times$ year after all selection cuts and background subtraction, we detected (14.3 $\pm$ 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 $\pm$ 12.0) TNU with just a 6 $\times$ $10^{-6}$ probability for a null geo-neutrino measurement. With U and Th left as free parameters in the fit, the relative signals are $S_{\mathrm{Th}}$ = (10.6 $\pm$ 12.7) TNU and $S_\mathrm{U}$ = (26.5 $\pm$ 19.5) TNU. Borexino data alone are compatible with a mantle geo--neutrino signal of (15.4 $\pm$ 12.3) TNU, while a combined analysis with the KamLAND data allows to extract a mantle signal of (14.1 $\pm$ 8.1) TNU. Our measurement of a reactor anti--neutrino signal $S_{react}$ = 84.5$^{+19.3}_{-18.9}$ TNU is in agreement with expectations in the presence of neutrino oscillations., Comment: 9 pages, 6 figures

Published
2013
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46. Lifetime measurements of 214Po and 212Po with the CTF liquid scintillator detector at LNGS

Author

Borexino Collaboration, Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Carraro, C., Cavalcante, P., Chavarria, A., Chepurnov, A., Chubakov, V., D'Angelo, D., Davini, S., Derbin, A., Etenko, A., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Göger-Neff, M., Goretti, A., Grandi, L., Guardincerri, E., Hardy, S., Ianni, Aldo, Ianni, Andrea, Kobychev, V., Korablev, D., Korga, G., Koshio, Y., Kryn, D., Laubenstein, M., Lewke, T., Lissia, Marcello, Litvinovich, E., Loer, B., Lombardi, F., Lombardi, P., Ludhova, L., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Montanari, D., Mosteiro, P., Mantovani, F., Muratova, V., Nisi, S., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Sabelnikov, A., Saldanha, R., Salvo, C., Schönert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vogelaar, R. B., von Feilitzsch, F., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xhixha, G., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
Nuclear Experiment, High Energy Physics - Phenomenology, Nuclear Theory, Physics - Instrumentation and Detectors
Abstract

We have studied the alpha decays of 214Po into 210Pb and of 212Po into 208Pb tagged by the coincidence with the preceding beta decays from 214Bi and 212Bi, respectively. The employed 222Rn, 232Th, and 220Rn sources were sealed inside quartz vials and inserted in the Counting Test Facility at the underground Gran Sasso National Laboratory in Italy. We find that the mean lifetime of 214Po is (236.00 +- 0.42(stat) +- 0.15(syst)) \mu s and that of 212Po is (425.1 +- 0.9(stat) +- 1.2(syst)) ns. Our results, obtained from data with signal-to-background ratio larger than 1000, reduce the overall uncertainties and are compatible with previous measurements., Comment: RevTex, 11 pages, 5 figures, 3 tables. This second version matches the one accepted for publication in EPJA: minor stylistic changes plus a discussion of calibration of TDC time scale

Published
2012

47. Borexino calibrations: Hardware, Methods, and Results

Author

Borexino collaboration, Back, H., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Carraro, C., Cavalcante, P., Chavarria, A., D'Angelo, D., Davini, S., Derbin, A., Etenko, A., von Feilitzsch, F., Fernandes, G., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Grandi, L., Guardincerri, E., Hardy, S., Ianni, Aldo, Ianni, Andrea, Kayunov, A., Kidner, S., Kobychev, V., Korablev, D., Korga, G., Koshio, Y., Kryn, D., Laubenstein, M., Lewke, T., Litvinovich, E., Loer, B., Lombardi, F., Lombardi, P., Ludhova, L., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Montanari, D., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Raghavan, R. S., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Rountree, D., Sabelnikov, A., Saldanha, R., Salvo, C., Schonert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors
Abstract

Borexino was the first experiment to detect solar neutrinos in real-time in the sub-MeV region. In order to achieve high precision in the determination of neutrino rates, the detector design includes an internal and an external calibration system. This paper describes both calibration systems and the calibration campaigns that were carried out in the period between 2008 and 2011. We discuss some of the results and show that the calibration procedures preserved the radiopurity of the scintillator. The calibrations provided a detailed understanding of the detector response and led to a significant reduction of the systematic uncertainties in the Borexino measurements.

Published
2012
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48. Solar neutrino physics with Borexino I

Author

Ludhova, L., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Carraro, C., Cavalcante, P., Chavarria, A., D'Angelo, D., Davini, S., Derbin, A., Etenko, A., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Nef, M., Goretti, A., Grandi, L., Guardincerri, E., Hardy, S., Ianni, Aldo, Ianni, Andrea, Kayunov, A., Kobychev, V., Korablev, D., Korga, G., Koshio, Y., Kryn, D., Laubenstein, M., Lewke, T., Litvinovich, E., Loer, B., Lombardi, F., Lombardi, P., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Montanari, D., Mosteiro, P., Muratova, V., Oberauer, L., Obolenksy, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Raghavan, R. S., Ranucci, G., Razeto, A., Re, A., Romani, P. A., Sabelnikov, A., Saldanha, R., Salvo, C., Schoenert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., Von Feilitzsch, F., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics
Abstract

Borexino is a large-volume liquid scintillator detector installed in the underground halls of the Laboratori Nazionali del Gran Sasso in Italy. After several years of construction, data taking started in May 2007. The Borexino phase I ended after about three years of data taking. Borexino provided the first real time measurement of the $^{7}$Be solar neutrino interaction rate with accuracy better than 5% and confirmed the absence of its day-night asymmetry with 1.4% precision. This latter Borexino results alone rejects the LOW region of solar neutrino oscillation parameters at more than 8.5 $\sigma$ C.L. Combined with the other solar neutrino data, Borexino measurements isolate the MSW-LMA solution of neutrino oscillations without assuming CPT invariance in the neutrino sector. Borexino has also directly observed solar neutrinos in the 1.0-1.5 MeV energy range, leading to the first direct evidence of the $pep$ solar neutrino signal and the strongest constraint of the CNO solar neutrino flux up to date. Borexino provided the measurement of the solar $^{8}$B neutrino rate with 3 MeV energy threshold., Comment: 6 pages, 4 figures, proceedings to Moriond 2012 EW session

Published
2012

49. Light Yield in DarkSide-10: a Prototype Two-phase Liquid Argon TPC for Dark Matter Searches

Author

Alexander, T., Alton, D., Arisaka, K., Back, H. O., Beltrame, P., Benziger, J., Bonfini, G., Brigatti, A., Brodsky, J., Cadonati, L., Calaprice, F., Candela, A., Cao, H., Cavalcante, P., Chavarria, A., Chepurnov, A., Cline, D., Cocco, A. G., Condon, C., D'Angelo, D., Davini, S., De Haas, E., Derbin, A., Di Pietro, G., Dratchnev, I., Durben, D., Empl, A., Etenko, A., Fan, A., Fiorillo, G., Fomenko, K., Gabriele, F., Galbiati, C., Gazzana, S., Ghag, C., Ghiano, C., Goretti, A., Grandi, L., Gromov, M., Guan, M., Guo, C., Guray, G., Hungerford, E. V., Ianni, Al., Ianni, An., Kayunov, A., Keeter, K., Kendziora, C., Kidner, S., Kobychev, V., Koh, G., Korablev, D., Korga, G., Shields, E., Li, P., Loer, B., Lombardi, P., Love, C., Ludhova, L., Lukyanchenko, L., Lund, A., Lung, K., Ma, Y., Machulin, I., Maricic, J., Martoff, C. J., Meng, Y., Meroni, E., Meyers, P. D., Mohayai, T., Montanari, D., Montuschi, M., Mosteiro, P., Mount, B., Muratova, V., Nelson, A., Nemtzow, A., Nurakhov, N., Orsini, M., Ortica, F., Pallavicini, M., Pantic, E., Parmeggiano, S., Parsells, R., Pelliccia, N., Perasso, L., Perfetto, F., Pinsky, L., Pocar, A., Pordes, S., Ranucci, G., Razeto, A., Romani, A., Rossi, N., Saggese, P., Saldanha, R., Salvo, C., Sands, W., Seigar, M., Semenov, D., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Tatarowicz, J., Testera, G., Teymourian, A., Thompson, J., Unzhakov, E., Vogelaar, R. B., Wang, H., Westerdale, S., Wojcik, M., Wright, A., Xu, J., Yang, C., Zavatarelli, S., Zehfus, M., Zhong, W., and Zuzel, G.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract

As part of the DarkSide program of direct dark matter searches using liquid argon TPCs, a prototype detector with an active volume containing 10 kg of liquid argon, DarkSide-10, was built and operated underground in the Gran Sasso National Laboratory in Italy. A critically important parameter for such devices is the scintillation light yield, as photon statistics limits the rejection of electron-recoil backgrounds by pulse shape discrimination. We have measured the light yield of DarkSide-10 using the readily-identifiable full-absorption peaks from gamma ray sources combined with single-photoelectron calibrations using low-occupancy laser pulses. For gamma lines of energies in the range 122-1275 keV, we get consistent light yields averaging 8.887+-0.003(stat)+-0.444(sys) p.e./keVee. With additional purification, the light yield measured at 511 keV increased to 9.142+-0.006(stat) p.e./keVee., Comment: 10 pages, 7 figures, Accepted for publication in Astroparticle Physics

Published
2012
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50. Cosmic-muon flux and annual modulation in Borexino at 3800 m water-equivalent depth

Author

Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Avanzini, M. Buizza, Caccianiga, B., Cadonati, L., Calaprice, F., Carraro, C., Cavalcante, P., Chavarria, A., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Etenko, A., von Feilitzsch, F., Fomenko, K., Franco, D., Galbiati, C., Gazzana, S., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Grandi, L., Guardincerri, E., Hagner, C., Hardy, S., Ianni, Aldo, Ianni, Andrea, Korablev, D., Korga, G., Koshio, Y., Kryn, D., Laubenstein, M., Lewke, T., Litvinovich, E., Loer, B., Lombardi, F., Lombardi, P., Ludhova, L., Machulin, I., Manecki, S., Maneschg, W., Manuzio, G., Meindl, Q., Meroni, E., Miramonti, L., Misiaszek, M., Montanari, D., Mosteiro, P., Muratova, V., Oberauer, L., Obolensky, M., Ortica, F., Otis, K., Pallavicini, M., Papp, L., Perasso, L., Perasso, S., Pocar, A., Raghavan, R. S., Ranucci, G., Razeto, A., Re, A., Romani, A., Sabelnikov, A., Saldanha, R., Salvo, C., Schönert, S., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Vignaud, D., Vogelaar, R. B., Winter, J., Wojcik, M., Wright, A., Wurm, M., Xu, J., Zaimidoroga, O., Zavatarelli, S., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Atmospheric and Oceanic Physics
Abstract

We have measured the muon flux at the underground Gran Sasso National Laboratory (3800 m w.e.) to be (3.41 \pm 0.01) \times 10-4m-2s-1 using four years of Borexino data. A modulation of this signal is observed with a period of (366\pm3) days and a relative amplitude of (1.29 \pm 0.07)%. The measured phase is (179 \pm 6) days, corresponding to a maximum on the 28th of June. Using the most complete atmospheric data models available, muon rate fluctuations are shown to be positively correlated with atmospheric temperature, with an effective coefficient {\alpha}T = 0.93 \pm 0.04. This result represents the most precise study of the muon flux modulation for this site and is in good agreement with expectations., Comment: 14 pages, 8 figures, published on JCAP as JCAP05(2012)015 on May 15th 2012

Published
2012
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