Suprabh Prakash, Ushak Rahaman, S. Uma Sankar
The moderately large value of \theta_{13}, measured recently by reactor experiments, is very welcome news for upcoming accelerator experiments. In particular, the NOvA experiment, with 3 years of {\nu} run followed by an equal \bar{\nu} run, will be able to determine the mass hierarchy if one of the following two favorable combinations is true: normal hierarchy with -180^\circ \leq \delta_{CP} \leq 0 or inverted hierarchy with 0\leq \delta_{CP} \leq 180^\circ. In this letter, we study the hierarchy reach of the first 3 years of NOvA data. Since \sin^22\theta_{23} is measured to be non-maximal, \theta_{23} can be either in the lower or higher octant. The true octant of \theta_{23} has a deep impact on the hierarchy reach of early NOvA data. With the present uncertainty of 10% in \sin^2 2 \theta_{13}, equal 1.5 year {\nu} and \bar{\nu} runs have better hierarchy determination capability compared to a pure 3 year {\nu} run. Daya Bay expects to reduce the uncertainty in \sin^22\theta_{13} to 5%. Such a reduction improves the hierarchy reach of a 3 year {\nu} run for two of the four octant-hierarchy combinations, but still fails to give any sensitivity for the other two. However, equal 1.5 year {\nu} and \bar{\nu} runs have reasonable hierarchy sensitivity for all four combinations.
View original:
http://arxiv.org/abs/1306.4125
No comments:
Post a Comment