Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revisiting Final State Interaction in Charmless $B_q\to P P$ Decays   Various new measurements in charmless $B_{u,d,s}\to PP$ modes, where $P$ is a
low lying pseudoscalar meson, are reported by Belle and LHCb. These include the
rates of $B^0\to\pi^0\pi^0$, $\eta\pi^0$, $B_s\to\eta'\eta'$, $B^0\to K^+K^-$
and $B^0_s\to\pi^+\pi^-$ decays. Some of these modes are highly suppressed and
are among the rarest $B$ decays. Direct CP asymmetries on various modes are
constantly updated. It is well known that direct CP asymmetries and rates of
suppressed modes are sensitive to final state interaction (FSI). As new
measurements are reported and more data will be collected, it is interesting
and timely to revisit the rescattering effects in $B_{u,d,s}\to PP$ states. We
perform a $\chi^2$ analysis with all available data on CP-averaged rates and CP
asymmetries in $\overline B{}_{u,d,s}\to PP$ decays. Our numerical results are
compared to data and those from factorization approach. The quality of the fit
is improved significantly from the factorization results in the presence of
rescattering. The relations on topological amplitudes and rescattering are
explored and they help to provide a better understanding of the effects of FSI.
As suggested by U(3) symmetry on topological amplitudes and FSI, a vanishing
exchange rescattering scenario is considered. The exchange, annihilation,
$u$-penguin, $u$-penguin annihilation and some electroweak penguin amplitudes
are enhanced significantly via annihilation and total annihilation
rescatterings. In particular, the $u$-penguin annihilation amplitude is sizably
enhanced by the tree amplitude via total annihilation rescattering. These
enhancements affect rates and CP asymmetries. Predictions can be checked in the
near future.

4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg