Bounds on neutrino mixing with exotic singlet neutrinos

Pramana

N K Sharma²  J K Singhal1¹  Sardar Singh³  Ashok K Nagawat² 

[1] Department of Physics, Government College, Sawai Madhopur 322 001, India$$;2Department of Physics, University of Rajasthan, Jaipur 302 004, India$$;Department of Physics, University of Rajasthan, Jaipur 302 004, India$$

关键词: Neutrino;    neutrino mixing;    exotic neutrino;    singlet neutrino.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

We examine the effects of mixing induced non-diagonal light–heavy neutrino weak neutral currents on the amplitude for the process $v_{a}overline{v}_{a}→ ZZ$ (with $a = e$; 𝜇 or 𝜏). By imposing constraint that the amplitude should not exceed the perturbative unitarity limit at high energy $(sqrt{s}=𝛬)$, we obtain bounds on light–heavy neutrino mixing parameter $sin^{2}𝜃^{v_{a}}_{L}$ where $𝜃^{v_{a}}_{L}$ is the mixing angle. In the case of one heavy neutrino (mass $m_{𝜉}$) or mass degenerate heavy neutrinos, for $𝛬 = 1$ TeV, no bound is obtained for $m_{𝜉} < 0:50$ TeV. However, $sin^{2}𝜃^{v_{a}}_{L}≤ 3:8× 10^{-6}$ for $m_{𝜉} = 5$ TeV and $sin^{2} 𝜃^{v_{a}}_{L}≤ 6.0× 10^{-8}$ for $m_{𝜉} = 10$ TeV. For 𝛬 = ∞, no constraint is obtained for $m_{𝜉} < 0:99$ TeV and $sin^{2} 𝜃^{v_{a}}_{L}≤ 3.8× 10^{-2}$ (for $m_{𝜉} = 5$ TeV) and $sin^{2}𝜃^{v_{a}}_{L}≤ 9.6× 10^{-3}$ (for $m_{𝜉} = 10$ TeV).

【 授权许可】

Unknown