  Using an exact solution with the hyperbolic-tangent profile for the electron
density in the sun, which is developed by N\"{o}tzold and later modified by
Nakagawa, we have analyzed the solar neutrino problem. An interference term in
their approach is correctly taken into account. Combining the
hyperbolic-tangent profile with the BP2000, we obtain a phenomenological
fitting in the analytic form. Combining recent observed results for survival
probability $P(\nu_e \to \nu_e)$ by the SNO, SK, SAGE, Gallex, GNO and
Homestake Collaborations, we obtain a large mixing angle (LMA) whose figure is
looking like a shoulder.

High Energy Physics - Phenomenology