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Allowed region for NSI parameters in ε L/R e plane obtained in the present work. The parameters ε L τ and ε R τ are fixed to zero. Both HZ-(filled red) and LZ-(dashed red) SSM's were assumed. The bounds from LSND [54, 79] and TEXONO [80] are provided for comparison. Besides, the contour obtained from the global analysis of solar neutrino experiments is presented by dashed black line (ref. [63], NSI's are included in detection and propagation). All contours correspond to 90% C.L. (2 d.o.f.). The dotted gray lines represent the corresponding range of ε parameter, relevant for NSI's at propagation.
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A bstract
The Borexino detector measures solar neutrino fluxes via neutrino-electron elastic scattering. Observed spectra are determined by the solar- ν 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 (NS...
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... Searching for signals of physics beyond the standard model (SM) is an active field in particle physics, which is mainly focused on the precision or energy frontier. Recent observed astrophysical neutrino events in the TeV-PeV energy range [1][2][3][4][5] provide a probe to explore new physics such as Lorentz invariance violation [6][7][8][9][10], neutrino decay [11][12][13][14][15][16][17][18], pseudo-Dirac neutrinos [19][20][21][22][23], nonunitary leptonic mixing matrix [24][25][26], non-standard interaction (NSI) [27][28][29][30][31][32][33][34][35]. Based on a direct modification of the Lagrangian of SM, NSIs of neutrinos could change their flavor oscillation. ...
The recently reported astrophysical neutrinos events in the TeV-PeV energy range open a winder to explore new physics at energy frontiers. In this paper, we examine effects of non-standard interactions (NSIs) on the PeV neutrinos events. We consider NSIs with and without a gauge symmetry - . We find that, for typical damping and decay sources, the NSI with an extra gauge symmetry has more noticeable effects on the PeV events. Therefore, the detection of the events in the upcoming experiments could set stringent constraints on the NSI parameters in the - symmetric case.
... This objective can be achieved through complementary studies involving data from different detectors. For example, comparing the results of day/night asymmetry in neutrino matter interactions [92] and those obtained in the context of Non-Standard Interactions (NSI) in the solar sector [93] with the constraints imposed on LIV [57]. ...
In this paper, we aim to explore the interplay between neutrinos and quantum gravity, illustrating some proposals about the use of these particles as probes for the supposed quantized structure of spacetime. The residual signatures of a more fundamental theory of quantum gravity can manifest themselves modifying the free particle dispersion relations and the connected velocity. In neutrino sector these supposed effects can modify the time of flight for astrophysical particles with different energies and can affect the usual neutrino oscillation pattern introducing species depending perturbations. We will highlight how perturbations caused by non-standard interactions in the solar neutrino sector can mimic the presumed quantum gravity effects. In fact, the mathematical formulation of non-standard interactions is equivalent to that of CPT-odd perturbations. We will, therefore, emphasize the need to identify the nature of different contributions in order to disentangle them in the search for quantum gravity effects. As a final point we will discuss the possibility to detect in the neutrino sector decoherence effects caused by the quantum gravity supposed perturbations. By reviewing current experimental constraints and observations, we seek to shed light on the intricate relationship between neutrinos and quantum gravity, and discuss the challenges and future directions in this fascinating field of research.
... The most important solar neutrino results in terms of interaction rate and corresponding fluxes are summarized in I. Thanks to its unprecedented radio-purity, Borexino has also set a lot of limits on rare processes, such as potential electron decay [18], non-standard neutrino interaction [19], high energy neutrinos correlated with astrophysical events [20], neutrino magnetic moment [21] and sterile neutrino [22]; and performed other neutrino physics studies, such as, e.g., geo-neutrino detection (for review, see [23]). As will be highlighted in Sec. ...
Borexino could efficiently distinguish between α and β radiation in its liquid scintillator by the characteristic time profile of its scintillation pulse. This α / β discrimination, first demonstrated on the ton scale in the counting test facility prototype, was used throughout the lifetime of the experiment between 2007 and 2021. With this method, the α events are identified and subtracted from the solar neutrino events similar to β . This is particularly important in liquid scintillators, as the α scintillation is strongly quenched. In Borexino, the prominent Po 210 decay peak was a background in the energy range of electrons scattered from Be 7 solar neutrinos. Optimal α / β discrimination was achieved with a , with a 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 characterizing the spatial distribution of background in the detector. This benefited most Borexino measurements, including solar neutrinos in the p p chain and the first direct observation of the CNO cycle in the Sun. This paper presents key milestones in α / β discrimination in Borexino as a term of comparison for current and future large liquid scintillator detectors.
Published by the American Physical Society 2024
... Although experiments utilizing lower energy neutrinos seem more suitable for constraining β 0 through the related NSI, the present experimental sensitivities are far from casting stringent bounds. For instance, the COHER-ENT [69][70][71][72] and BOREXINO [73] experiments yield |ε| ≲ 10 and essentially result in no bound on the GUP parameter of interest. However, the future experiments Hyper-K [74] and JUNO [75] are expected to probe neutrino oscillation parameters related to the solar flux-with neutrino energies of a few MeV-reaching a combined sensitivity to NSI that would constrain |ε| ≲ 0.1, corresponding to β 0 ≲ 10 35 . ...
Generalized uncertainty principles are effective changes to the Heisenberg uncertainty principle that emerge in several quantum gravity models. In the present letter, we study the consequences that two classes of these modifications yield on the physics of neutrinos. Besides analyzing the change in the oscillation probabilities that the generalized uncertainty principles entail, we assess their impact on the neutrino coherence length and their possible interpretation as nonstandard neutrino interactions. Constraints cast by present and planned neutrino experiments on the generalized uncertainty principles parameters are also derived.
... it has allowed to determine the oscillation parameters ∆m 2 12 and θ 12 [2] and to probe new physics beyond the Standard Model [3]. Solar neutrinos have been originally studied by radiochemical experiments (Homestake [4], Gallex [5], GNO [6], and SAGE [7]) and by large water Cherenkov detectors (Kamiokande [8], Super-Kamiokande [9], and SNO [10]). ...
The Jiangmen Underground Neutrino Observatory (JUNO), the first multi-kton liquid scintillator detector, which is under construction in China, will have a unique potential to perform a real-time measurement of solar neutrinos well below the few MeV threshold typical of Water Cherenkov detectors. JUNO's large target mass and excellent energy resolution are prerequisites for reaching unprecedented levels of precision. In this paper, we provide estimation of the JUNO sensitivity to ⁷ Be, pep , and CNO solar neutrinos that can be obtained via a spectral analysis above the 0.45 MeV threshold. This study is performed assuming different scenarios of the liquid scintillator radiopurity, ranging from the most optimistic one corresponding to the radiopurity levels obtained by the Borexino experiment, up to the minimum requirements needed to perform the neutrino mass ordering determination with reactor antineutrinos — the main goal of JUNO. Our study shows that in most scenarios, JUNO will be able to improve the current best measurements on ⁷ Be, pep , and CNO solar neutrino fluxes. We also perform a study on the JUNO capability to detect periodical time variations in the solar neutrino flux, such as the day-night modulation induced by neutrino flavor regeneration in Earth, and the modulations induced by temperature changes driven by helioseismic waves.
... The Borexino was the first experiment that has detected and then precisely measured all solar neutrino fluxes (except for the hep-neutrino) [28][29][30][31][32][33][34] and has also registered antineutrinos emitted in decay of radionuclides naturally occurring within the Earth [38][39][40][41]. The Borexino detector is perfectly suited for the study of other fundamental problems, as well as searching for rare and exotic processes in particle physics and astrophysics [42][43][44][45][46][47][48][49]. Additionally, temporal correlations with transient astrophysical sources such as γ -ray bursts [50], gravitational wave events [9], solar flares [44], and fast radio burst [51] have been performed. ...
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 and inverse beta-decay (IBD) 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 supernova-like spectrum. GW candidates originated by merging binaries of black holes (BHBH), neutron stars (NSNS) and neutron star and black hole (NSBH) were analyzed 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 ( ν e , ν μ , ν τ ) at the level 10 9 - 10 15 cm - 2 GW - 1 have been obtained in the 0.5–5 MeV neutrino energy range.
... Their χ 2analysis takes into account the data from LEP experiments (ALEPH, DELPHI, L3, and OPAL), LSND experiment, reactor experiments (MUNU and Rovno), and CHARM II experiment. The Borexino experiment has performed oneparameter fits [34] leading to the loosest bound. ...
Nonstandard neutrino interactions (NSI) arising from light and heavy mediators probe different sectors of the parameter space of models focusing on phenomena that require the extension of the standard model. High-energy scattering experiments are not relevant on constraining the NSI hiding a light mediator at the fundamental level, while flavor-universal NSI cannot be probed with neutrino oscillation experiments. Currently the only way to measure flavor-universal NSI with a light mediator is to rely on coherent elastic neutrino-nucleon scattering experiments, which we use to derive bounds for light mediator flavor-universal NSI. For light NSI, we obtain ϵu∈[−14.85,14.79] and ϵd=[−13.19,13.84] (90% CL.). We also derive constraints on flavor-universal heavy NSI and find a 2σ tension. Finally, we discuss the implications of the experiments on the allowed parameter space of a specific example model, called superweak extension of the standard model.
... This would impact the data at both SK and Borexino, and makes the problem much more demanding from the computational point of view. Constraints on NC NSI with electrons were obtained from the analysis of Borexino Phase-II spectrum by the Borexino Collaboration [42] assuming only one NC NSI coupling at a time. Recently, in Ref. [43] we performed an analysis of the Borexino Phase-II spectral data including all NC NSI operators involving electrons simultaneously in the fit. ...
We derive new constraints on effective four-fermion neutrino non-standard interactions with both quarks and electrons. This is done through the global analysis of neutrino oscillation data and measurements of coherent elastic neutrino-nucleus scattering (CEvNS) obtained with different nuclei. In doing so, we include not only the effects of new physics on neutrino propagation but also on the detection cross section in neutrino experiments which are sensitive to the new physics. We consider both vector and axial-vector neutral-current neutrino interactions and, for each case, we include simultaneously all allowed effective operators in flavour space. To this end, we use the most general parametrization for their Wilson coefficients under the assumption that their neutrino flavour structure is independent of the charged fermion participating in the interaction. The status of the LMA-D solution is assessed for the first time in the case of new interactions taking place simultaneously with up quarks, down quarks, and electrons. One of the main results of our work are the presently allowed regions for the effective combinations of non-standard neutrino couplings, relevant for long-baseline and atmospheric neutrino oscillation experiments.
... The Borexino experiment has obtained new results on neutrino properties: ruled out any significant day-night asymmetry of the 7 Be neutrino interaction rate [42], it has set new limits on the effective magnetic moment of neutrinos [28], on the flux ofν e from the Sun [43,44] and on the non-standard neutrino interactions [45]. A search for a number of rare low-energy processes has been carried out: possible violation of the Pauli exclusion principle [46], high-energy solar axions [47], heavy sterile neutrino mixing in the 8 B β +decay [48], decay of an electron into a neutrino and a photon [49]. ...
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. 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. 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.
... In spite of their copious flux at Earth (about 6 × 10 10 νcm −2 s −1 ), detecting solar neutrinos is experimentally challenging: it requires large volume detectors and lowbackground environment. Nonetheless, the study of solar neutrinos has been very rewarding: on one hand, it has provided a confirmation of the Standard Solar Model (SSM) flux predictions [1]; on the other hand, it has proven that neutrinos oscillate (and therefore have mass), it has allowed to determine the oscillation parameters ∆m 2 12 and θ 12 [2] and to probe new physics beyond the Standard Model [3]. ...
The Jiangmen Underground Neutrino Observatory (JUNO), the first multi-kton liquid scintillator detector, which is under construction in China, will have a unique potential to perform a real-time measurement of solar neutrinos well below the few MeV threshold typical for Water Cherenkov detectors. JUNO's large target mass and excellent energy resolution are prerequisites for reaching unprecedented levels of precision. In this paper, we provide estimation of the JUNO sensitivity to 7Be, pep, and CNO solar neutrinos that can be obtained via a spectral analysis above the 0.45 MeV threshold. This study is performed assuming different scenarios of the liquid scintillator radiopurity, ranging from the most opti mistic one corresponding to the radiopurity levels obtained by the Borexino experiment, up to the minimum requirements needed to perform the neutrino mass ordering determination with reactor antineutrinos - the main goal of JUNO. Our study shows that in most scenarios, JUNO will be able to improve the current best measurements on 7Be, pep, and CNO solar neutrino fluxes. We also perform a study on the JUNO capability to detect periodical time variations in the solar neutrino flux, such as the day-night modulation induced by neutrino flavor regeneration in Earth, and the modulations induced by temperature changes driven by helioseismic waves.