11,927 research outputs found
Proposal of Direct Search for Strongly Bound States of ppbar, npbar Systems with High Intensity and Collective pbar beam
In this letter, we discuss the possibility to look for the direct evidence of
the existence of the ppbar and npbar bound states. Measurement of the single
\gamma ray from the ppbar and npbar systems at rest can directly confirm
whether the X(1860) and X(1835) are the resonances which are strongly coupled
to ppbar. In addition to the neutral candidate, a charged resonance is
also proposed to be searched for in npbar channel. We find that the data from
the Crystal Barrel experiment at LEAR/CERN can be used to confirm the X(1835)
observed by BES Collaboration. The possibility of measuring the
spectrum below 100 MeV at the new experiment with cold high intensity \pbar
beam at GSI is discussed. These new techniques can be used to probe the
structure of the X(1860) and X(1835) in the future.Comment: Accepted by Mod. Phys. Lett.
Study of Scalar Mesons at BES-II
Recent results from BES-II experiment on hadron spectroscopy using \jpsi
and data samples collected in annihilation are
presented, including study of the scalar particles in \jpsi radiative and
hadronic decays, the observation of X(1810) in ,
as well as pair productions of scalars in hadronic decays.Comment: Talk on "Hadron spectroscopy at BES" at "From Phi to Psi" Workshop
February 27 - March 2, 2006, Novosibirsk, Russi
On the Pulse Shaping for Delay-Doppler Communications
In this paper, we study the pulse shaping for delay-Doppler (DD)
communications. We start with constructing a basis function in the DD domain
following the properties of the Zak transform. Particularly, we show that the
constructed basis functions are globally quasi-periodic while locally
twisted-shifted, and their significance in time and frequency domains are then
revealed. We further analyze the ambiguity function of the basis function, and
show that fully localized ambiguity function can be achieved by constructing
the basis function using periodic signals. More importantly, we prove that time
and frequency truncating such basis functions naturally leads to approximate
delay and Doppler orthogonalities, if the truncating windows are periodic
within the support. Motivated by this, we propose a DD Nyquist pulse shaping
scheme considering signals with periodicity. Finally, our conclusions are
verified by using various strictly or approximately periodic pulses
An Investigation of University Students' Classroom Seating Choices
The classroom is crucial for students, and seating position within the classroom can affect students’ performance. This study conducted a survey to investigate the relationship between seating zones and academic performance among 174 university students in Beijing. The results revealed differences in student performance in terms of seating position in small- and medium-sized traditional classrooms. However, the results did not indicate a similar hierarchy of student performance in terms of seating zones in larger traditional classrooms, horseshoe classrooms, collaboration classrooms, and computer classrooms. Additionally, the results revealed that most students considered the layout of a classroom to affect their performance
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