Abstract
Abstract
We investigate the inverse moment of the Bs-meson light-cone distribution amplitude (LCDA), denoted as $$ {\lambda}_{B_s} $$
λ
B
s
and defined within the heavy quark effective theory, through the calculation of Bs → ηs form factors. The presence of the s-quark inside the Bs-meson dictates a notable departure of approximately 20% in the $$ {\lambda}_{B_s} $$
λ
B
s
value compared to the non-strange case $$ {\lambda}_{B_q} $$
λ
B
q
, as computed within the QCD sum rule approach, albeit with significant uncertainty. First, we compute the decay constant of the ηs-meson utilizing two-point sum rules while retaining finite s-quark mass contributions. Next, we constrain the parameter $$ {\lambda}_{B_s} $$
λ
B
s
by calculating Bs → ηs form factors within the light-cone sum rule approach, using Bs-meson LCDAs, and leveraging Lattice QCD estimates at zero momentum transfer from the HPQCD collaboration. Our findings yield $$ {\lambda}_{B_s} $$
λ
B
s
= 480 ± 92 MeV when expressing the Bs-meson LCDAs in the Exponential model, consistent with previous QCD sum rule estimate yet exhibiting a 1.5-fold improvement in uncertainty. Furthermore, we compare the form factor predictions, based on the extracted $$ {\lambda}_{B_s} $$
λ
B
s
value, with earlier analyses for other channels such as Bs → Ds and Bs → K.
Publisher
Springer Science and Business Media LLC
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