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I. V. Danilkin

Publications and source records attributed to I. V. Danilkin.

23 records · Page 2Linked to original sources
arXiv2009

Di-electron and two-photon widths in charmonium

The vector and pseudoscalar decay constants are calculated in the framework of the Field Correlator Method. Di-electron widths: $Γ_{ee}(J/ψ)=5.41$ keV, $Γ_{ee}(ψ'(3686))=2.47$ keV, $Γ_{ee}(ψ''(3770))=0.248$ keV, in good agreement with experiment, are obtained with the same coupling, $α_s=0.165$, in QCD radiative corrections. We show that the larger $α_s=0.191\pm 0.004$ is needed to reach agreement with experiment for $Γ_{γγ}(η_c)=7.22$ keV, $Γ_{γγ} (χ(^3P_0))=3.3$ keV, $Γ_{γγ}(χ(^3P_2))= 0.54$ keV, and also for $Γ(J/ψ\to 3g)=59.5$ keV, $Γ(J/ψ\to γ2g)=5.7$ keV. Meanwhile even larger $α_s=0.238$ gives rise to good description of $Γ(ψ'\to 3g)=52.7$ keV, $Γ(ψ'\to γ2g)= 3.5$ keV, and provides correct ratio of the branching fractions: $\frac{\mathcal{B}(J/ψ\to light hadrons)}{\mathcal{B}(ψ'\to light hadrons)}=0.24.$

hep-ph↗
arXiv2009

On the possibility to observe higher $n^3D_1$ bottomonium states in the $e^+e^-$ processes

The possibility to observe new bottomonium states with $J^{PC}= 1^{--}$ in the region $10.7-11.1$ GeV is discussed. The analysis of the di-electron widths shows that the $(n+1)^3S_1$ and $n^3D_1$ states ($n\geq 3$) may be mixed with a rather large mixing angle, $θ\sim30^\circ$ and this effect provides the correct values of $Γ_{ee}(Υ(10580))$ and $Γ_{ee}(Υ(11020))$. On the other hand, the $S-D$ mixing gives rise to an increase by two orders of magnitude of the di-electron widths of the mixed $\tildeΥ(n^3D_1$) resonances ($n=3,4,5$), which originate from pure $D-$wave states. The value $Γ_{ee}(\tildeΥ(3D))=0.095^{+0.028}_{-0.025}$ keV is obtained, being only $\sim 3$ times smaller than the di-electron width of $Υ(10580)$, while $Γ_{ee}(\tildeΥ(5D))\sim 135$ eV appears to be close to $Γ_{ee}(Υ(11020))$ and therefore this resonance may become manifest in the $e^+e^-$ experiments. The mass differences between $M(nD)$ and $M((n+1)S) (n=4,5)$ are shown to be rather small, $50\pm 10$ MeV.

hep-ph↗
arXiv2009

Dielectron widths of the S-, D-vector bottomonium states

The dielectron widths of $Υ(nS) (n=1,...,7)$ and vector decay constants are calculated using the Relativistic String Hamiltonian with a universal interaction. For $Υ(nS) (n=1,2,3)$ the dielectron widths and their ratios are obtained in full agreement with the latest CLEO data. For $Υ(10580)$ and $Υ(11020)$ a good agreement with experiment is reached only if the 4S--3D mixing (with a mixing angle $θ=27^\circ\pm 4^\circ$) and 6S--5D mixing (with $θ=40^\circ\pm 5^\circ$) are taken into account. The possibility to observe higher "mixed $D$-wave" resonances, $\tildeΥ(n {}^3D_1)$ with $n=3,4,5$ is discussed. In particular, $\tildeΥ(\approx 11120)$, originating from the pure $5 {}^3D_1$ state, can acquire a rather large dielectron width, $\sim 130$ eV, so that this resonance may become manifest in the $e^+e^-$ experiments. On the contrary, the widths of pure $D$-wave states are very small, $Γ_{ee}(n{}^3 D_1) \leq 2$ eV.

hep-ph↗
arXiv2009

The $\mathbf{S}-\mathbf{D}$ mixing and di-electron widths of higher charmonium $\mathbf{1^{--}}$ states

The di-electron widths of $ψ(4040)$, $ψ(4160)$, and $ψ(4415)$, and their ratios are shown to be in good agreement with experiment, if in all cases the $S-D$ mixing with a large mixing angle $θ\approx 34^\circ$ is taken. Arguments are presented why continuum states give small contributions to the wave functions at the origin. We find that the Y(4360) resonance, considered as a pure $3 {}^3D_1$ state, would have very small di-electron width, $Γ_{ee}(Y(4360))=0.060$ keV. On the contrary, for large mixing between the $4 {}^3S_1$ and $3 {}^3D_1$ states with the mixing angle $θ=34.8^\circ$, $Γ_{ee}(ψ(4415))=0.57$ keV coincides with the experimental number, while a second physical resonance, probably Y(4360), has also a rather large $Γ_{ee} (Y(\sim 4400))=0.61$ keV. For the higher resonance Y(4660), considered as a pure $5 {}^3S_1$ state, we predict the di-electron width $Γ_{ee}(Y(4660))=0.70$ keV, but it becomes significantly smaller, namely 0.31 keV, if the mixing angle between the $5 {}^3S_1$ and $4 {}^3D_1$ states $θ=34^\circ$. The mass and di-electron width of the $6 {}^3S_1$ charmonium state are calculated.

hep-ph↗