Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The role of spin-flipping terms in hadronic transitions of
  $\Upsilon(4S)$   Recent experimental data on the $\Upsilon(4S)\to\Upsilon(1S)\eta$ and
$\Upsilon(4S)\to h_{b}(1P)\eta$ processes seem to contradict the naive
expectation that hadronic transitions with spin-flipping terms should be
suppressed with respect those without spin-flip. We analyze these transitions
using the QCD Multipole Expansion (QCDME) approach and within a constituent
quark model framework that has been applied successfully to the heavy-quark
sectors during the last years. The QCDME formalism requires the computation of
hybrid intermediate states which has been performed in a natural,
parameter-free extension of our constituent quark model based on the Quark
Confining String (QCS) scheme. We show that i) the M1-M1 contribution in the
decay rate of the $\Upsilon(4S)\to\Upsilon(1S)\eta$ is important and its
supression until now is not justified; ii) the role played by the $L=0$ hybrid
states, which enter in the calculation of the M1-M1 contribution, explains the
enhancement in the $\Upsilon(4S)\to\Upsilon(1S)\eta$ decay rate; and iii) the
anomalously large decay rate of the $\Upsilon(4S)\to h_{b}(1P)\eta$ process has
the same physical origin.

11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn