Pion photoproduction on the nucleon

The $\gamma n \to \pi^- p$ and $\gamma p \to \pi^+ n$ reactions are essential probes of the transition from meson-nucleon degrees of freedom to quark-gluon degrees of freedom in exclusive processes. The cross sections of these processes are also advantageous, for the investigation of oscillatory behavior around the quark counting prediction, since they decrease relatively slower with energy compared with other photon-induced processes. In this talk, we discuss recent results on the $\gamma p \to \pi^+ n$ and $\gamma n \to \pi^{-}p$ processes from Jefferson Lab experiment E94-104. We also discuss a new experiment in which singles $\gamma p \to \pi^+ n$ measurement from hydrogen, and coincidence $\gamma n \to \pi^{-} p$ measurements at the quasifree kinematics from deuterium for center-of-mass energies between 2.3 GeV to 3.4 GeV in fine steps at a center-of-mass angle of $90^\circ$ are planned. The proposed measurement will allow a detailed investigation of the oscillatory scaling behavior in photopion production processes.Comment: 6 pages, 5 figures, Plenary talk presented at the HiX2004 Workshop, July 26-28, Marseille, France. References adde

Communication with Chinese International Students: Understanding Chinese International Students’ learning difficulties and communication barriers

The problems of communication with Chinese international students are reported in many academic publications related to international students in higher education in the UK. Majority of these problems links to teaching and learning activities: Chinese international students are quiet in classroom, not active in group discussion or group work, and passive in tutorials etc. Such problems not only cause misunderstandings between Chinese international students and their tutors but also have negative influence on their learning outcome. This article is based on an empirical study on Chinese international students’ learning experience in University of Huddersfield. 34 Chinese international students from foundation to PhD participate in focus group discussion and personal interview. The participants generally have learning difficulties to some degree, which associate to their communication problems. English proficiency is not a primary factor cause their learning difficulties. External and internal communication and cultural barriers are the key factors behind Chinese international students learning difficulties. The findings of the research can help academic tutors in higher education understand where the communication problems with Chinese international students come from and how to resolve these problems

X(1835): A Possible Baryonium?

We point out that (1) the large $p\bar p$ coupling and suppressed mesonic coupling of X(1835) and (2) the suppression of the three-body strange final states strongly indicate that X(1835) may be a $p\bar p$ baryonium. We also point out that the branching ratio of $X(1835)\to\eta \pi\pi$ should be bigger than that of $X(1835)\to\eta^\prime \pi\pi$. If BES further confirms the non-observation of X(1835) in the $\eta\pi\pi$ channel, that will be very puzzling. Finally, X(1835) may be used a tetraquark generator if X(1835) is really established as a baryonium state.Comment: Comments and suggestions welcom