  Since 7Li is easily destroyed in low temperatures, the surface lithium
abundance decreases as stars evolve. This is supported by the lithium depletion
observed in the atmosphere of most red giants. However, recent studies show
that almost all of red clump stars have high lithium abundances A(Li)>-0.9,
which are not predicted by the standard theory of the low-mass stellar
evolution. In order to reconcile the discrepancy between the observations and
the model, we consider additional energy loss channels which may come from
physics beyond the Standard Model. A(Li) slightly increases near the tip of the
red giant branch even in the standard model with thermohaline mixing because of
the 7Be production by the Cameron-Fowler mechanism, but the resultant 7Li
abundance is much lower than the observed values. We find that the production
of 7Be becomes more active if there are additional energy loss channels,
because themohaline mixing becomes more efficient and a heavier helium core is
formed.
