| Full text | |
| Author(s): |
Fong, Chee Sheng
;
Minakata, Hisakazu
;
Nunokawa, Hiroshi
Total Authors: 3
|
| Document type: | Journal article |
| Source: | Journal of High Energy Physics; v. N/A, n. 2, p. 52-pg., 2019-02-04. |
| Abstract | |
We present a comprehensive study of the three-active plus N sterile neutrino model as a framework for constraining leptonic unitarity violation induced at energy scales much lower than the electroweak scale. We formulate a perturbation theory with expansion in small unitarity violating matrix element W while keeping (non-W suppressed) matter effect to all orders. We show that under the same condition of sterile state masses 0.1 eV(2) ae(2) m (J) (2) ae(2) (1-10) GeV2 as in vacuum, assuming typical accelerator based long-baseline neutrino oscillation experiment, one can derive a very simple form of the oscillation probability which consists only of zeroth-order terms with the unique exception of probability leaking term (alpha beta) of (W (4)). We argue, based on our explicit computation to fourth-order in W, that all the other terms are negligibly small after taking into account the suppression due to the mass condition for sterile states, rendering the oscillation probability sterile-sector model independent. Then, we identify a limited energy region in which this suppression is evaded and the effects of order W (2) corrections may be observable. Its detection would provide another way, in addition to detecting (alpha beta) , to distinguish between low-scale and high-scale unitarity violation. We also solve analytically the zeroth-order system in matter with uniform density to provide a basis for numerical evaluation of non-unitary neutrino evolution. (AU) | |
| FAPESP's process: | 16/01343-7 - ICTP South American Institute for Fundamental Research: a regional center for theoretical physics |
| Grantee: | Nathan Jacob Berkovits |
| Support Opportunities: | Special Projects |
| 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 |
| FAPESP's process: | 12/10995-7 - Particle physics phenomenology |
| Grantee: | Gustavo Alberto Burdman |
| Support Opportunities: | Research Projects - Thematic Grants |