Open charm scenarios

Abstract

We discuss possibilities of identifying open charm effects in direct production processes, and propose that direct evidence for the open charm effects can be found in $e^{+}{e}^{-}\to J/\psi {\pi }^0$. A unique feature with this process is that the $D\overline{D^{\ast }}+c.c.$ open channel is located in a relatively isolated energy, i.e. $\sim 3.876$ GeV, which is sufficiently far away from the known charmonia $\psi (3770)$ and $\psi (4040)$. Due to the dominance of the isospin-0 component at the charmonium energy region, an enhanced model-independent cusp effect between the thresholds of $D^0\overline{D^{\ast 0}}+c.c.$ and $D^{+}{D}^{\ast -}+c.c.$ can be highlighted. An energy scan over this energy region in the $e^{+}{e}^{-}$ annihilation reaction can help us to understand the nature of X(3900) recently observed by Belle Collaboration in $e^{+}{e}^{-}\to D\bar{D}+c.c.$, and establish the open charm effects as an important non-perturbative mechanism in the charmonium energy region.

6 pages, Proceeding contribution to the Rutherford Centennial Conference, Aug. 8-12, 2011, Manchester, U.K

References in corpus (12)

• Heavy quarkonium: progress, puzzles, and opportunities
• Charmonium
• Quarkonia and their transitions
• Effect of charmed meson loops on charmonium transitions
• Measurement of the near-threshold $e^{+}{e}^{-}\to D\bar{D}$ cross section using initial-state radiation
• Extraction of the light quark mass ratio from the decays psi' --> J/psi pi^0 (eta)
• The evasion of helicity selection rule in ${\chi }_{c1}\to VV$ and ${\chi }_{c2}\to VP$ via intermediate charmed meson loops
• Further study of the helicity selection rule evading mechanism in ${\eta }_c$, ${\chi }_{c0}$ and $h_c$ decaying to baryon anti-baryon pairs
• The lineshape of $\psi (3770)$ and low-lying vector charmonium resonance parameters in $e^{+}{e}^{-}\to D\bar{D}$
• Open charm effects in $e^{+}{e}^{-}\to J/\psi \eta$, $J/\psi {\pi }^0$ and $\varphi {\eta }_c$
• Lineshape of $e^{+}{e}^{-}\to D^{\ast }\bar{D}+c.c.$ and electromagnetic form factor of $D^{\ast }\to D$ transition in the time-like region
• Puzzles in charmonium decays