出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We identify open charm effects in a direct production process e+e¡ !J=yp0. A unique feature of this process is that the D¯D¤ +c:c: threshold is located at a relatively isolated energy region, i.e. » 3:876 GeV, which is far away from the well-established charmonia y(3770) and y(4040). Therefore, the cross section line-shape of this reaction provides an opportunity for singling out the open charm effects. A model-independent narrow enhancement between the thresholds of D0¯D¤0 +c:c: and D+D¤¡ +c:c: is predicted. This study can also help understand the X(3900) enhancement recently observed by the Belle and BaBar Collaboration in e+e¡ !D¯D +c:c: We also show that the open charm effects play a crucial role for our understanding of the long-standing “rp puzzle"
