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Register a new userDecay widthes of $^3 P_J$ charmonium to $DD,DD^*,D^*D^*$ and corresponding mass shifts of $^3 P_J$ charmonium
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In this work, we calculate the amplitudes of the processes $cbar c({^3P_J}) rightarrow DD,DD^*, D^*D^* rightarrow cbar c({^3P_J})$ in the leading order of the nonrelativistic expansion. The imaginary parts of the amplitudes are corresponding to the branch decay widthes of the charmonium $cbar c({^3P_J}) rightarrow DD,DD^*, D^*D^*$ and the real parts are corresponding to the mass shifts of the charmonium $cbar c({^3P_J})$ due to these decay channels. After absorbing the polynomial contributions which are pure real and include the UV divergences, the ratios between the branch decay widthes and the corresponding mass shifts are only dependent on the center-of-mass energy. We find the decay widthes and the mass shifts of the $^3P_2$ states are exact zero in the leading order. The ratios between the branch decay widthes and the mass shifts for the $^3P_0, {^3P_1}$ states are larger than 5 when the center-of-mass energy is above the $DD,DD^*, D^*D^*$ threshold. The dependence of the mass shifts on the center-of-mass energy is nontrivial especially when the center-of-mass energy is below the threshold. The analytic results can be extended to the $b$ quark sector directly.
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We describe our experience porting the Regensburg implementation of the DD-$alpha$AMG solver from QPACE 2 to QPACE 3. We first review how the code was ported from the first generation Intel Xeon Phi processor (Knights Corner) to its successor (Knights Landing). We then describe the modifications in the communication library necessitated by the switch from InfiniBand to Omni-Path. Finally, we present the performance of the code on a single processor as well as the scaling on many nodes, where in both cases the speedup factor is close to the theoretical expectations.
We explore the quantum Coulomb problem for two-body bound states, in $D=3$ and $D=3-2epsilon$ dimensions, in detail, and give an extensive list of expectation values that arise in the evaluation of QED corrections to bound state energies. We describe the techniques used to obtain these expectation values and give general formulas for the evaluation of integrals involving associated Laguerre polynomials. In addition, we give formulas for the evaluation of integrals involving subtracted associated Laguerre polynomials--those with low powers of the variable subtracted off--that arise when evaluating divergent expectation values. We present perturbative results (in the parameter $epsilon$) that show how bound state energies and wave functions in $D=3-2epsilon$ dimensions differ from their $D=3$ dimensional counterparts and use these formulas to find regularized expressions for divergent expectation values such as $big langle bar V^3 big rangle$ and $big langle (bar V)^2 big rangle$ where $bar V$ is the $D$-dimensional Coulomb potential. We evaluate a number of finite $D$-dimensional expectation values such as $big langle r^{-2+4epsilon} partial_r^2 big rangle$ and $big langle r^{4epsilon} p^4 big rangle$ that have $epsilon rightarrow 0$ limits that differ from their three-dimensional counterparts $big langle r^{-2} partial_r^2 big rangle$ and $big langle p^4 big rangle$. We explore the use of recursion relations, the Feynman-Hellmann theorem, and momentum space brackets combined with $D$-dimensional Fourier transformation for the evaluation of $D$-dimensional expectation values. The results of this paper are useful when using dimensional regularization in the calculation of properties of Coulomb bound systems.
In this article, we assign the newly reported state $X(3842)$ to be a D-wave $overline{c}c$ meson, and study its mass and decay constant with the QCD sum rules by considering the contributions of the vacuum condensates up to dimension-6 in the operator product expansion. The predicted mass $M_{X(3842)}=(3.844^{+0.0675}_{-0.0823}pm0.020)GeV$ is in agreement well with the experimental data $M_{X(3842)}=(3842.71pm0.16pm0.12)MeV$ from the LHCb collaboration. This result supports assigning $X(3842)$ to be a $1^{3}D_{3}$ charmonium meson. As the $1^{3}D_{3}$ $overline{c}c$ meson, its predicted strong decay width with the $^{3}P_{0}$ decay model is compatible with the experimental data.
Differential cross sections of $^{2}$H(d, d)d elastic scattering and proton transfer $^{2}$H(d, $^{3}$He)n reactions at 160 MeV beam energy have been obtained. They have been normalized relative to the existing cross-section data for the $^{2}$H(d, d)d elastic scattering at 180 and 130 MeV, benefiting from the negligible energy dependence of this observable at certain range of the four momentum transfer. The experiment was performed at KVI in Groningen, the Netherlands using the BINA detector. The elastic scattering data are compared to theoretical predictions based on the lowest-order term in the Neumann series expansion for four-nucleon transition operators. The calculations underpredict the data. The data presented in this paper can be used to validate the future theoretical findings.
Using proton-proton collision data, corresponding to an integrated luminosity of 9$fb^{-1}$, collected with the~LHCb detector between 2011 and 2018, a new narrow charmonium state, the $X(3842)$ resonance, is observed in the decay modes $X(3842)rightarrow D^0bar{D}^0$ and $X(3842)rightarrow D^+D^-$. The mass and the natural width of this state are measured to be begin{eqnarray*} m_{X(3842)} & = & 3842.71 pm 0.16 pm 0.12 MeV/c^2,, Gamma_{X(3842)} & = & 2.79 pm 0.51 pm 0.35 MeV,, end{eqnarray*} where the first uncertainty is statistical and the~second is systematic. The observed mass and narrow natural width suggest the~interpretation of the new state as the~unobserved spin obreakdash-3 $psi_3mathrm{left(1^3D_3right)}$ charmonium state. In addition, prompt hadroproduction of the $psi(3770)$~and $chi_{c2}(3930)$ states is observed for the first time, and the parameters of these~states are measured to be begin{eqnarray*} m_{psi(3770)} & = & 3778.1 pm 0.7 pm 0.6 MeV/c^2,, m_{chi_{c2}(3930)} & = & 3921.9 pm 0.6 pm 0.2 MeV/c^2,, Gamma_{chi_{c2}(3930)} & = &36.6 pm 1.9 pm 0.9 MeV,, end{eqnarray*} where the first uncertainty is statistical and the~second is systematic.
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