scholarly journals Reactor Neutrino Anomalies and Possible Solutions

2021 ◽  
Author(s):  
Yufeng Li ◽  
Zhao Xin
Keyword(s):  
2019 ◽  
Vol 219 ◽  
pp. 08003
Author(s):  
Maja Verstraeten

The SoLid Collaboration is currently operating a 1.6 ton neutrino detector near the Belgian BR2 reactor. Its main goal is the observation of the oscillation of electron antineutrinos to previously undetected flavour states. The highly segmented SoLid detector employs a compound scintillation technology based on PVT scintillator in combination with LiF-ZnS(Ag) screens containing the 6Li isotope. The experiment has demonstrated a channel-to-channel response that can be controlled to the level of a few percent, an energy resolution of better than 14% at 1 MeV, and a determination of the interaction vertex with a precision of 5 cm. This contribution highlights the major outcomes of the R&D program, the quality control during component manufacture and integration, the current performance and stability of the full-scale system, as well as the in-situ calibration of the detector with various radioactive sources.


2015 ◽  
Vol 2015 (11) ◽  
Author(s):  
Thamys Abrahão ◽  
Hisakazu Minakata ◽  
Hiroshi Nunokawa ◽  
Alexander A. Quiroga

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yong Du ◽  
Hao-Lin Li ◽  
Jian Tang ◽  
Sampsa Vihonen ◽  
Jiang-Hao Yu

Abstract The Standard Model Effective Field Theory (SMEFT) provides a systematic and model-independent framework to study neutrino non-standard interactions (NSIs). We study the constraining power of the on-going neutrino oscillation experiments T2K, NOνA, Daya Bay, Double Chooz and RENO in the SMEFT framework. A full consideration of matching is provided between different effective field theories and the renormalization group running at different scales, filling the gap between the low-energy neutrino oscillation experiments and SMEFT at the UV scale. We first illustrate our method with a top- down approach in a simplified scalar leptoquark model, showing more stringent constraints from the neutrino oscillation experiments compared to collider studies. We then provide a bottom-up study on individual dimension-6 SMEFT operators and find NSIs in neutrino experiments already sensitive to new physics at ∼20 TeV when the Wilson coefficients are fixed at unity. We also investigate the correlation among multiple operators at the UV scale and find it could change the constraints on SMEFT operators by several orders of magnitude compared with when only one operator is considered. Furthermore, we find that accelerator and reactor neutrino experiments are sensitive to different SMEFT operators, which highlights the complementarity of the two experiment types.


2012 ◽  
Vol 396 (2) ◽  
pp. 022061 ◽  
Author(s):  
Qingmin Zhang ◽  
Miao He ◽  
Jilei Xu ◽  
Jiaheng Zou ◽  
Zhe Ning ◽  
...  

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Pilar Coloma ◽  
Patrick Huber ◽  
Thomas Schwetz

AbstractA considerable experimental effort is currently under way to test the persistent hints for oscillations due to an eV-scale sterile neutrino in the data of various reactor neutrino experiments. The assessment of the statistical significance of these hints is usually based on Wilks’ theorem, whereby the assumption is made that the log-likelihood is $$\chi ^2$$ χ 2 -distributed. However, it is well known that the preconditions for the validity of Wilks’ theorem are not fulfilled for neutrino oscillation experiments. In this work we derive a simple asymptotic form of the actual distribution of the log-likelihood based on reinterpreting the problem as fitting white Gaussian noise. From this formalism we show that, even in the absence of a sterile neutrino, the expectation value for the maximum likelihood estimate of the mixing angle remains non-zero with attendant large values of the log-likelihood. Our analytical results are then confirmed by numerical simulations of a toy reactor experiment. Finally, we apply this framework to the data of the Neutrino-4 experiment and show that the null hypothesis of no-oscillation is rejected at the 2.6 $$\sigma $$ σ level, compared to 3.2 $$\sigma $$ σ obtained under the assumption that Wilks’ theorem applies.


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