arXiv subjects

Borexino collaboration

Publications and source records attributed to Borexino collaboration.

8 recordsLinked to original sources

arXiv2026

New limits on the Pauli forbidden transitions in 12C nuclei obtained with the complete Borexino dataset

The Pauli exclusion principle (PEP) was tested for nucleons in $\rm{^{12}C}$ nuclei using the Borexino dataset from 2007 to 2021. %the complete Borexino detector data. The approach consists of searching for $γ$-quanta, neutrons, protons, as well as electrons and positrons emitted in non-Paulian transitions of nucleons from the $1P_{3/2}$ shell to the filled $1S_{1/2}$ shell. Due to the uniquely low background level, the large mass, and long measurement time of the Borexino detector, the most stringent experimental constraints to date on the lifetime of the $\rm{^{12}C}$ nucleus with respect to PEP-forbidden transitions were obtained: $τ({^{12}\rm{C}}\rightarrow{^{12}\widetilde{\rm{C}}}+γ) \geq {1.1\times10^{32}}$ y, $τ({^{12}\rm{C}}\rightarrow{^{11}\widetilde{\rm{B}}}+ p) \geq {1.0\times10^{31}}$ y, $τ({^{12}\rm{C}}\rightarrow{^{11}\widetilde{\rm{C}}}+ n) \geq 2.0 \times 10^{31}$ y, $τ({^{12}\rm{C}}\rightarrow{^{12}\widetilde{\rm{N}}}+ e^- + \widetilde{ν_e}) \geq 6.4 \times 10^{30}$ y and $τ({^{12}\rm{C}}\rightarrow{^{12}\widetilde{\rm{B}}}+ e^+ + ν_e) \geq 6.6 \times 10^{30}$ y (90\% C.L.). The upper limits on the relative strengths for the non-Paulian electromagnetic, strong, and weak transitions have been obtained: $δ^2_γ\leq 1.0\times 10^{-57}$, $δ^2_{N}\leq 7.0\times 10^{-61}$ and $δ^2_β\leq 9.6\times 10^{-36}$, all at 90\% C.L..

nucl-ex↗

arXiv2015

Spectroscopy of geo-neutrinos from 2056 days of Borexino data

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$σ$). 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.

hep-ex↗

arXiv2013

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

If heavy neutrinos with mass $m_{ν_{H}}\geq$2$ m_e $ are produced in the Sun via the decay ${^8\rm{B}} \rightarrow {^8\rm{Be}} + e^+ + ν_H$ in a side branch of pp-chain, they would undergo the observable decay into an electron, a positron and a light neutrino $ν_{H}\rightarrowν_{L}+e^++e^-$. 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 $\leq m_{ν_{H}} \le$ 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.

hep-ex↗

arXiv2012

Borexino calibrations: Hardware, Methods, and Results

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.

physics.ins-det↗

arXiv2007

Response to a critique of the Borexino result in "A new experimental limit for the stability of the electron" by H.V. Klapdor-Kleingrothaus, I.V. Krivosheina and I.V. Titkova

A recently published article by Klapdor-Kleingrothaus et al. critiques the limit on the stability of the electron obtained by the Borexino collaboration. We respond here to the criticisms raised by Klapdor-Kleingrothaus and his colleagues, and re-establish that our result is based on very conservative premises and that the "indication of a signal of 1.4 $σ$" for the decay of the electron in the $γ+ν$ channel, reported by Klapdor-Kleingrothaus and colleagues, is excluded by the Borexino result.

hep-ex↗

arXiv2006

Search for electron antineutrino interactions with the Borexino Counting Test Facility at Gran Sasso

Electron antineutrino interactions above the inverse beta decay energy of protons ($E_\barν_e>$1.8) where looked for with the Borexino Counting Test Facility (CTF). One candidate event survived after rejection of background, which included muon-induced neutrons and random coincidences. An upper limit on the solar $\barν_{e}$ flux, assumed having the $^8$B solar neutrino energy spectrum, of 1.1$\times10^{5}$ cm$^{-2}$~s$^{-1}$ (90% C.L.) was set with a 7.8 ton $\times$ year exposure. This upper limit corresponds to a solar neutrino transition probability, $ν_{e} \to \barν_{e}$, of 0.02 (90% C.L.). Predictions for antineutrino detection with Borexino, including geoneutrinos, are discussed on the basis of background measurements performed with the CTF.

hep-ex↗

arXiv2004

New experimental limits on violations of the Pauli exclusion principle obtained with the Borexino Counting Test Facility

The Pauli exclusion principle (PEP) has been tested for nucleons ($n,p$) in $^{12}C$ and $^{16}O$ nuclei, using the results of background measurements with the prototype of the Borexino detector, the Counting Test Facility (CTF). The approach consisted of a search for $γ$, $n$, $p$ and/or $α$'s emitted in a non-Paulian transition of 1$P$- shell nucleons to the filled 1$S_{1/2}$ shell in nuclei. Similarly, the Pauli-forbidden $β^{\pm}$ decay processes were searched for. Due to the extremely low background and the large mass (4.2 tons) of the CTF detector, the following most stringent up-to-date experimental bounds on PEP violating transitions of nucleons have been established: $τ(^{12}C\to^{12}\widetilde{C}+γ) > 2.1\cdot10^{27}$ y, $τ(^{12}C\to^{11}\widetilde{B}+ p) > 5.0\cdot10^{26}$ y, $τ(^{12}C(^{16}O)\to^{11}\widetilde{C}(^{15}\widetilde{O})+ n) > 3.7 \cdot 10^{26}$ y, $τ(^{12}C\to^{8}\widetilde{Be}+α) > 6.1 \cdot 10^{23}$ y, $τ(^{12}C\to^{12}\widetilde{N}+ e^- + \widetilde{ν_e})> 7.6 \cdot 10^{27}$ y and $τ(^{12}C\to^{12}\widetilde{B}+ e^+ + ν_e)> 7.7 \cdot 10^{27}$ y, all at 90% C.L.

hep-ph↗

arXiv2003

New limits on nucleon decays into invisible channels with the BOREXINO Counting Test Facility

The results of background measurements with the second version of the BOREXINO Counting Test Facility (CTF-II), installed in the Gran Sasso Underground Laboratory, were used to obtain limits on the instability of nucleons, bounded in nuclei, for decays into invisible channels ($inv$): disappearance, decays to neutrinos, etc. The approach consisted of a search for decays of unstable nuclides resulting from $N$ and $NN$ decays of parents $^{12}$C, $^{13}$C and $^{16}$O nuclei in the liquid scintillator and the water shield of the CTF. Due to the extremely low background and the large mass (4.2 ton) of the CTF detector, the most stringent (or competitive) up-to-date experimental bounds have been established: $τ(n \to inv) > 1.8 \cdot 10^{25}$ y, $τ(p \to inv) > 1.1 \cdot 10^{26}$ y, $τ(nn \to inv) > 4.9 \cdot 10^{25}$ y and $τ(pp \to inv) > 5.0 \cdot 10^{25}$ y, all at 90% C.L.

hep-ex↗