Invisible neutrino decay: first vs second oscillation maximum

Author(s)

Chakraborty, Kaustav ^[1] ; Dutta, Debajyoti ^[2] ; Goswami, Srubabati ^[1] ; Pramanik, Dipyaman ^{[3, 1]}

Affiliation

^[1] Phys Res Lab, Theoret Phys Div, Ahmadabad 380009, Gujarat - India

^[2] Assam Don Bosco Univ, Tapesia Campus, Sonapur 782402, Assam - India

^[3] Inst Fis Gleb Wataghin UNICAMP, BR-13083859 Campinas, SP - Brazil

• Document type: Journal article
• Source: Journal of High Energy Physics; n. 5 MAY 12 2021.
• Web of Science Citations: 1

Abstract

We study the physics potential of the long-baseline experiments T2HK, T2HKK and ESS nu SB in the context of invisible neutrino decay. We consider normal mass ordering and assume the state nu (3) as unstable, decaying into sterile states during the flight and obtain constraints on the neutrino decay lifetime (tau (3)). We find that T2HK, T2HKK and ESS nu SB are sensitive to the decay-rate of nu (3) for tau (3)/m(3) <= 2.72 x 10(-11)s/eV, tau (3)/m(3) <= 4.36 x 10(-11)s/eV and tau (3)/m(3) <= 2.43 x 10(-11)s/eV respectively at 3 sigma C.L. We compare and contrast the sensitivities of the three experiments and specially investigate the role played by the mixing angle theta (23). It is seen that for experiments with flux peak near the second oscillation maxima, the poorer sensitivity to theta (23) results in weaker constraints on the decay lifetime. Although, T2HKK has one detector close to the second oscillation maxima, having another detector at the first oscillation maxima results in superior sensitivity to decay. In addition, we find a synergy between the two baselines of the T2HKK experiment which helps in giving a better sensitivity to decay for theta (23) in the higher octant. We discuss the octant sensitivity in presence of decay and show that there is an enhancement in sensitivity which occurs due to the contribution from the survival probability P-mu mu is more pronounced for the experiments at the second oscillation maxima. We also obtain the combined sensitivity of T2HK+ESS nu SB and T2HKK+ESS nu SB as tau (3)/m(3) <= 4.36 x 10(-11)s/eV and tau (3)/m(3) <= 5.53 x 10(-11)s/eV respectively at 3 sigma C.L. (AU)

• FAPESP's process: 14/19164-6 - Challenges in the 21st century in neutrino physics and astrophysics
• Grantee: Orlando Luis Goulart Peres
• Support Opportunities: Special Projects