Mon·Nov 28, 2022Monday·November 28, 2022

1. 01*

   Double parton distributions in the nucleon on the lattice: Flavor interference effects

   Christian Zimmermann🇫🇷 · Daniel Reitinger🇩🇪

   Information about double parton distributions (DPDs) can be obtained by calculating four-point functions on the lattice. We continue our study on the first DPD Mellin moment of the unpolarized proton by considering interference effects w.r.t. the quark flavor. In our simulation we employ an $n_f=2+1$ ensemble with inverse coupling $\beta =3.4$, and pseudoscalar masses of $m_{\pi }=355\mathrm{MeV}$ and $m_K=441\mathrm{MeV}$. The results are converted to the $\overline{\mathrm{MS}}$-scheme at the scale $\mu =2\mathrm{GeV}$. We analyze the dependence of the considered Mellin moments on the quark polarization and compare our results with quark model predictions.

   hep-latPoS(2023)·1 citation
2. 02*

   Chromopolarizabilities of fully-heavy baryons

   Xiang-Kun Dong🇨🇳 · Feng-Kun Guo🇨🇳 · Alexey Nefediev🇸🇮 · Jaume Tarrús Castellà🇺🇸

   We compute the chromopolarizabilities of the fully heavy baryons ${\Omega }_{QQ{Q}^{\prime }}$ ($Q,Q^{\prime }=b,c$) in the framework of potential nonrelativistic quantum chromodynamics. At leading order, the fully heavy hadrons are considered as ground chromo-Coulombic bound states. We find that the chromopolarizability ${\beta }_{\Omega }$ of a fully heavy baryon $QQQ$ is 2.6 times the chromopolarizability ${\beta }_{\psi }$ of the quarkonium $\bar{Q}Q$ with the same heavy quark flavor $Q$. This result is accurate up to the correction of the order 0.3 for $Q=b$ and provides an order-of-magnitude estimate for $Q=c$. We discuss the dependence of the ratio ${\beta }_{\Omega }/{\beta }_{\psi }$ on the heavy quark mass $m_Q$ and the strong coupling constant ${\alpha }_s$ as well as on the ratio of the masses $m_{Q^{\prime }}/m_Q$, in the case not all quarks in the baryon are identical. Since the chromopolarizability of heavy hadrons defines the strength of their interaction at low energies mediated by soft gluons, which at long range hadronize into pairs of pions and kaons, our findings argue in favor of the existence of near-threshold states composed of pairs of fully heavy baryons.

   ↳ hep-phhep-exhep-latPRD(2023)·12 citations
3. 03*

   Resonance $X(3960)$ as a hidden charm-strange scalar tetraquark

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   We investigate features of the hidden charm-strange scalar tetraquark $c\overline{c}s\overline{s}$ by calculating its spectral parameters and width, and we compare the obtained results with the mass and width of the resonance $X(3960)$ discovered recently in the LHCb experiment. We model the tetraquark as a diquark-antidiquark state $X=[cs][\overline{c}\overline{s}]$ with spin-parities $J^{\mathrm{PC}}=0^{++}$. The mass and current coupling of $X$ are calculated using the QCD two-point sum rules by taking into account various vacuum condensates up to dimension $10$. The width of the tetraquark $X$ is estimated via the decay channels $X\to D_s^{+}{D}_s^{-}$ and $X\to {\eta }_c{\eta }^{(\prime )}$. The partial widths of these processes are expressed in terms of couplings $G$, $g_1$ and $g_2$ which describe the strong interactions of particles at the vertices $X{D}_s^{+}{D}_s^{-}$, $X{\eta }_c{\eta }^{\prime }$ and $X{\eta }_c\eta$, respectively. Numerical values of $G$, $g_1$ and $g_2$ are evaluated by employing the three-point sum rule method. Comparing the results $m=(3976\pm 85)\mathrm{MeV}$ and ${\Gamma }_{\mathrm{X}}=(42.2\pm 12.0)\mathrm{MeV}$ obtained for parameters of the tetraquark $X$ and experimental data of the LHCb Collaboration, we conclude that the resonance $X(3960)$ can be considered as a candidate to a scalar diquark-antidiquark state.

   ↳ hep-phhep-exhep-latPRD(2023)·19 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.