CHARM-2007: day 4 (last) August 10, 2007Posted by apetrov in Particle Physics, Physics, Science.
The first section started with the talk by Mikhail (Borisovich) Voloshin about charmed meson spectroscopy. I really enjoyed his talk. He talked about mass splittings among ground and exciting states in D-system both from quark mass difference and from electromagnetic effects. Kinda bread-and-butter physics. At the end he also talked difficulties with interpretation of Ds(2317) states as parity doublers of usual pseudoscalar D-states. In particular, he explained that the old calculation of E. Eichten et al from 2003 actually is not self-consistent and requires extra assumptions (now, of course, we explained the existence of this state via a mixture of 2-quark and 4-quark states). Then he proposed something that I didn’t quite understood: that these states are really 0- states with “charm quark dressed up by 0- glue field.” He referred to an old paper by NSVZ (Novikov, Shifman, Vainshtein and Zakharov) from the 80’s, where the idea was explained. I don’t know how this mechanism works, maybe someone can teach me… Then A. Polosa talked about modification of the 4-quark picture to explain X(3872) charmonium state. They propose 2 states around 3872 MeV instead of one — one containing c, anti-c and u and anti-u and another one containing c, anti-c and d and anti-d. So these states decay into different decay channels. The way I see it, their mechanism cannot be right, as those states must mix among themselves, so both states would decay into both channels. The session ened with two experimental talks about spectroscopy of charmed particles.
The second section contained several talks about future experimental facilities: BESIII, LHC-b, PANDA, and Super-B. Take a look at the slides yourself. The conference ended with a question-and-answer section about the future of flavor physics.
I must say that contrary to recent claims, flavor physics is not dead, it just moved to Europe and Asia with the rest of high energy experimental particle physics.