nucl-th digest · Jul 2, 2020

[Submitted on 1 Jul 2020] (cross-list from hep-ph)

Active-sterile neutrino mixing constraint using reactor antineutrinos with the ISMRAN set-up

S. P. Behera🇮🇳 · D. K. Mishra🇮🇳 · L. M. Pant🇮🇳

In this work, we present an analysis of the sensitivity to the active-sterile neutrino mixing with the Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) experimental set-up at very short baseline. In this article, we have considered the measurement of electron antineutrino induced events employing a single detector which can be placed either at a single position or moved between near and far positions from the given reactor core. Results extracted in the later case are independent of the theoretical prediction of the reactor anti-neutrino spectrum and detector related systematic uncertainties. Our analysis shows that the results obtained from the measurement carried out at a combination of the near and far detector positions are improved significantly at higher $Δ m_{41}^{2}$ compared to the ones obtained with the measurement at a single detector position only. It is found that the best possible combination of near and far detector positions from a 100 MW $_{t h}$ power DHRUVA research reactor core are 7 m and 9 m, respectively, for which ISMRAN set-up can exclude in the range 1.4 $e V^{2} \leq Δ m_{41}^{2} \leq$ 4.0 $e V^{2}$ of reactor antineutrino anomaly region along with the present best-fit point of active-sterile neutrino oscillation parameters. At those combinations of detector positions, the ISMRAN set-up can observe the active sterile neutrino oscillation with a 95 $%$ confidence level provided that $sin^{2} 2 θ_{14} \geq 0.09$ at $Δ m_{41}^{2}$ = 1 eV $^{2}$ for an exposure of 1 ton-yr. The active-sterile neutrino mixing sensitivity can be improved by about 22\% at the same exposure by placing the detector at near and far distances of 15 m and 17 m, respectively, from the compact proto-type fast breeder reactor (PFBR) facility which has a higher thermal power of 1250 MW $_{t h}$ .

Comments:: 11 pages, 6 figures, Minor text corrections similar to Published version
Subjects:: High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Instrumentation and Detectors (physics.ins-det)
arXiv:: 2007.00392 [pdf]

PRD(2020)·15 citations

Sensitivity of

^{229}

Th nuclear clock transition to variation of the fine-structure constant

Peik and Tamm [Europhys. Lett. 61, 181 (2003)] proposed a nuclear clock based on the isomeric transition between the ground state and the first excited state of thorium-229. This transition was recognized as a potentially sensitive probe of possible temporal variation of the fine-structure constant,

α

. The sensitivity to such a variation can be determined from measurements of the mean-square charge radius and quadrupole moment of the different isomers. However, current measurements of the quadrupole moment are yet to achieve an accuracy high enough to resolve non-zero sensitivity. Here we determine this sensitivity using existing measurements of the change in the mean-square charge radius, coupled with the ansatz of constant nuclear density. The enhancement factor for

α

variation is

K = - (0.82 \pm 0.25) \times 1 0^{4}

. For the current experimental limit,

δ α / α ≲ 1 0^{- 17}

per year, the corresponding frequency shift is

\sim 200

Hz per year. This shift is six orders of magnitude larger than the projected accuracy of the nuclear clock, paving the way for increased accuracy of the determination of

δ α

and interaction strength with low-mass scalar dark matter. We verify that the constant-nuclear-density ansatz is supported by nuclear theory and propose how to verify it experimentally. We also consider a possible effect of the octupole deformation on the sensitivity to

α

variation, and calculate the effects of

α

variation in a number of Mössbauer transitions.

Comments:: 6 pages, 2 figures, published version
Subjects:: Atomic Physics (physics.atom-ph); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:: 2007.00408 [pdf]

PRA(2020)·65 citations

Thursday·July 2, 2020

Active-sterile neutrino mixing constraint using reactor antineutrinos with the ISMRAN set-up

Sensitivity of $^{229}$ Th nuclear clock transition to variation of the fine-structure constant

Affiliations

Active-sterile neutrino mixing constraint using reactor antineutrinos with the ISMRAN set-up

Sensitivity of 229Th nuclear clock transition to variation of the fine-structure constant

Affiliations

Sensitivity of $^{229}$ Th nuclear clock transition to variation of the fine-structure constant