Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for the $b\to u$ Transition $B^0\to D_s^+ pi^-$ and a Search
  for $B^0\to D_s^*+ pi^-$   We report evidence for the $b\to u$ transition $B^0 \to D_s^{+}\pi^-$ and the
results of a search for $B^0 \to D_s^{*+} \pi^-$ from a sample of $61.6\times
10^6$ $Y(4S)$ decays into $B$ meson pairs collected with the BaBar detector at
the PEP II asymmetric $e^{+}e^{-}$ collider.
  The observed $B^0 \to D_s^{+} \pi^-$ yield has a probability of $4.4 \times
10^{-4}$ to be a fluctuation of the background (3.5 $\sigma$) and we measure
the branching fraction $B^0 \to D_s^{+} \pi^-=3.1 \pm 1.0 ({\rm stat.})\pm 1.0
({\rm syst.})$.
  We also set a limit $B^0 \to D_s^{*+} \pi^- <~4.3\times 10^{-5}$ at 90% C.L.

28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph