“School of Particles”
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| Paper IPM / Particles / 15651 |
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| Abstract: | |||||||
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We study semileptonic decays of the scalar tetraquark Zbc;―u―d0 to final states Tbs;―u―d−e+νe and Tbs;―u―d−μ+νμ, which run through the weak transitions c→ se+νe and c→sμ+νμ, respectively. To this end, we calculate the mass and
coupling of the final-state scalar tetraquark Tbs;―u―d− by means of the QCD two-point sum rule method: these spectroscopic
parameters are used in our following investigations. In calculations we take
into account the vacuum expectation values of the quark, gluon, and mixed
operators up to dimension ten. We use also three-point sum rules to evaluate
the weak form factors Gi(q2) (i=1, 2) that describe these decays.
The sum rule predictions for Gi(q2) are employed to construct fit
functions Fi(q2), which allow us to extrapolate the form factors to
the whole region of kinematically accessible q2. These functions are
required to get partial width of the semileptonic decays Γ(Zbc0→ Te+νe) and Γ(Zbc0→ Tμ+νμ) by integrating
corresponding differential rates. The obtained results for the total width Γtot.=(2.37±0.36)×10−11 MeV and mean
lifetime 27.8−3.7+4.9 ps of the tetraquark Zbc;―u―d0 can be used in experimental investigations of this
exotic state.
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