Sensitivity to sterile neutrino mixing using reactor antineutrinos

Abstract

The reactor antineutrinos are used for the precise measurement of oscillation parameters in the 3-neutrino model, and also used to investigate active-sterile neutrino mixing sensitivity in the 3+1 neutrino framework. In the present work, we study the feasibility of sterile neutrino search with the Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) experimental set-up using electron antineutrinos(νe) produced from reactor as a source. The so-called 3+1 scenario is considered for active-sterile neutrino mixing, which leads to projected exclusion curves in the sterile neutrino mass and mixing angle plane. The analysis is performed considering both the reactor and detector related parameters. It is found that, the ISMRAN set-up can observe the active-sterile neutrino mixing sensitivity for sin 2 2θ14 ≥ 0.064 and ∆m 2 41 = 1.0 eV 2 at 90% confidence level for an exposure of 1 ton-year by using neutrinos produced from the DHRUVA reactor with thermal power of 100 MW th . It is also observed that, there is a significant improvement of the active-sterile neutrino mixing parameter sin 2 2θ14 to ∼ 0.03 at the same ∆m 2 41 by putting the ISMRAN detector set-up at a distance of 20 m from the compact proto-type fast breeder reactor (PFBR) facility with thermal power of 1250 MW th .

Active-sterile neutrino mixing constraints using reactor antineutrinos with the ISMRAN setup

“…A study on active-sterile neutrino mixing sensitivity has been performed previously with the ISMRAN setup placed at a fixed distance from the reactor core while varying both the reactor and detector related parameters [24]. In the present study, we have considered the system in which the measurement will be carried out by placing the same detector at multiple positions with respect to the reactor core in order to cancel out the systematic uncertainties.…”

“…The order of rotation and elements of the mixing matrix are given in Ref. [24]. At a small value of mixing angle θ 14 and source to detector distance of few meters (< 100m), the 3+1 oscillation scheme can be simplified to a two neutrino scheme and the ν survival probability is approximated to…”

“…The existence of active-sterile neutrino oscillation with mass squared difference ∆m 2 41 (= m 2 4 −m 2 1 ) ∼1 eV 2 can be explored at the SBL experiment by measuring the reactor ν e flux which is reduced due to the fast active to sterile neutrino oscillation that is otherwise absent in the 3-neutrino mixing scheme. A similar study has been performed previously, considering a single detector which will be placed at a fixed distance from the reactor core by varying both reactor and detector related parameters [24]. To reduce the systematic uncertainties mentioned earlier, in this work we have considered various possible combinations of near and far positions for the same 1-ton detector which will be placed for a period of six months at each distance while constraining active-sterile neutrino oscillation parameters.…”

Measurements using a prototype array of plastic scintillator bars for reactor based electron anti-neutrino detection

“…The ISMRAN detector can observe the active-sterile neutrino mixing sensitivity for sin 2 2θ 14 ≥ 0.064 and ∆m 2 41 = 1.0 eV 2 at 90% confidence level for an exposure of 1 ton-year by using neutrinos produced from the DHRUVA reactor with thermal power of 100MWth [15]. With the combination of an array of plastic scintillator bars at near ( 7m) and far ( 9m) positions from reactor core, ISMRAN can exclude the active-sterile neutrino mixing in the range 1.4 eV 2 ≤ ∆m 2 41 ≤ 4.0 eV 2 with present best fit parameters.…”

Machine learning technique to improve anti-neutrino detection efficiency for the ISMRAN experiment

“…The Indian Scintillator Matrix for Reactor Anti-Neutrinos (ISMRAN) experiment is one such detector consisting of plastic scintillator (PS) bars in an array forming an active detection volume of 1.0 ton by weight [10]. ISMRAN is proposed to measure reactor ν e s for non-intrusive monitoring of reactor along with the possibility of very short baseline oscillation searches of ν e to sterile states [11]. ISMRAN is an above ground experiment comprising of 100 PS bars, each of dimension 100cm × 10cm × 10cm.…”