scholarly journals Radiogenic neutron background in reactor neutrino experiments

2021 ◽  
Vol 104 (9) ◽  
Author(s):  
Zhiyuan Chen ◽  
Xin Zhang ◽  
Zeyuan Yu ◽  
Jun Cao ◽  
Changgen Yang
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.


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.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Mario A. Acero ◽  
Alexis A. Aguilar-Arevalo ◽  
Dairo J. Polo-Toledo

We present a neutrino oscillation analysis of two particular data sets from the Daya Bay and RENO reactor neutrino experiments aiming to study the increase in precision in the oscillation parameters sin22θ13 and the effective mass splitting Δmee2 gained by combining two relatively simple to reproduce analyses available in the literature. For Daya Bay, the data from 217 days between December 2011 and July 2012 were used. For RENO, we used the data from 500 live days between August 2011 and January 2012. We reproduce reasonably well the results of the individual analyses, both rate-only and spectral, defining a suitable χ2 statistic for each case. Finally, we performed a combined spectral analysis and extract tighter constraints on the parameters, with an improved precision between 30 and 40% with respect to the individual analyses considered.


2014 ◽  
Vol 736 ◽  
pp. 110-118 ◽  
Author(s):  
Emilio Ciuffoli ◽  
Jarah Evslin ◽  
Zhimin Wang ◽  
Changgen Yang ◽  
Xinmin Zhang ◽  
...  

2018 ◽  
Vol 191 ◽  
pp. 01001
Author(s):  
Yury Kudenko

The present status of accelerator and reactor neutrino experiments and new results are presented. A short overview of future projects is also given. The experimental status of sterile neutrino searches is briefly discussed.


2018 ◽  
Vol 46 ◽  
pp. 1860001
Author(s):  
J. P. Ochoa-Ricoux

Nuclear reactors provide an excellent environment for studying neutrinos and continue to play a critical role in unveiling the secrets of these elusive particles. A rich experimental program with reactor antineutrinos is currently ongoing, and leads the way in precision measurements of several oscillation parameters and in searching for new physics, such as the existence of light sterile neutrinos. Ongoing experiments have also been able to measure the flux and spectral shape of reactor antineutrinos with unprecedented statistics and as a function of core fuel evolution, uncovering anomalies that will lead to new physics and/or to an improved understanding of antineutrino emission from nuclear reactors. The future looks bright, with an aggressive program of next generation reactor neutrino experiments that will go after some of the biggest open questions in the field. This includes the JUNO experiment, the largest liquid scintillator detector ever constructed which will push the limits of this detection technology.


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