NMR at 900 MHz

An important factor in the development of solution state NMR has always been th e ability to produce stable and homogeneous magnetic fields. As higher and higher field strengths are reached the pressure is growing on manufacturers to produce NMR systems with greatly improved spectral resolution and signal to noise ratio. The introduction of the Varian 900 MHz INOVA system in August 2000 featuring Oxford Instruments 21.1 T magnet represents the latest pioneering development in NMR technology.     

J/ψ production at large transverse momentum at hadron colliders

We calculateJ/ψ hadroproduction and emphasize the importance of theJ/ψ signal as a measure ofb \(\bar b\) production via the decayB→ψX and of the gluon structure function at lowx via χ hadroproduction followed by χ→ψγ decay. We compare with UA1 data and data at ISR energies and make predictions for ψ production at TEVATRON energies.     

Meson-production experiments at COSY-Julich

Selected results from experiments at COSY-Jülich are presented： an attempt to measure the mass of the η meson with high precision （ANKE facility）,first steps towards the detection of rare η decays （WASA）,and several measurements of KK-pair production （ANKE,COSY-11,MOMO）.     

Fluorination Increases Hydrophobicity at the Macroscopic Level but not at the Microscopic Level

Hydrophobic interactions have been studied before in detail based on hydrophobic polymers, such as polystyrene(PS). Because fluorinated materials have relatively low surface energy, they often show both oleophobicity and hydrophobicity at the macroscopic level. However, it remains unknown how fluorination of hydrophobic polymer influences hydrophobicity at the microscopic level. We synthesized PS and fluorine-substituted PS(FPS) by employing the reversible addition-fragmentation chain transfer p...     

Neutron Wall at RIBLL Ⅱ

With the construction of the new Radioactive Ion Beam Line in Lanzhou (RIBLL Ⅱ) which connecting the CSRm and the CSRe, an experimental setup.The Time-of-Flight (ToF) technique was recognized as one of the best ways for neutron detection and it, is employed by the neutrons wall. Considering the high neutron multiplicity, the detector shouldal so have the ability to resolve the multiple hits. Moreover, a high detection efficiency for the neutrons with energies ranging from 100MeV to 1 GeV is also required besides the high granularity. In this case, the sampling hadronic calorimeter type of detector has been selected. In order to estimate the performance of the detector and     

N-Program at COSY-Jülich

The paper gives a brief introduction into the COSY-facility, the currently used detector systems （ANKE, TOF and WASA） and the targets （cluster jet, pellet and ABS）, and it presents some recent results, which were obtained in the field of baryon excited states.     

Event generators at BESⅢ

We present a brief remark and introduction to event generators for tau-charm physics currently used at BESⅢ,including KKMC,BesEvtGen,Bhlumi,Bhwide,Babayaga and inclusive Monte-Carlo event generators.This paper provides basic information on event generators for BESⅢ users.     

ψψ production at collider energies

We estimate ψψ production at collider energies in the framework of perturbative QCD. TheO(α _s ² )?(α _s ⁴ ) parton cross-sections, with the non-relativistic approximation for the heavy quark bound states, are used. This first insight into the characteristics of the kinematical distributions allows predictions on the predominance of the quark, gluon orB meson production mechanisms in particular kinematical regions.     

Single-Photon Detection at Telecom Wavelengths

A single-photon detector based on an InGaAs avalanche photodiode has been developed for use at telecom wavelengths. A suitable delay and sampling gate modulation circuit are used to prevent positive and negative transient pulses from influencing the detection of true photon induced avalanches. A monostable trigger circuit eliminates the influence of avalanche peak jitter, and a dead time modulation feedback control circuit decreases the afterpulsing. From performance tests we lind that at the optimum operation point, the quantum efficiency is 12% and the dark count rate 1.5 × 10^-6 ns^-1, with a detection rate of 500 kHz.     

Trigger efficiencies at BESⅢ

Trigger efficiencies at BESⅢ were determined for both the J/ψ and ψ' data taking of 2009. Both dedicated runs and physics datasets are used; efficiencies are presented for Bhabha-scattering events, generic hadronic decay events involving charged tracks, dimuon events and ψ'→π+π-J/ψ, J/ψ→ 1+1- events.The efficiencies are found to lie well above 99% for all relevant physics cases, thus fulfilling the BESⅢ design specifications.     

Trigger efficiencies at BESⅢ

Trigger efficiencies at BESⅢ were determined for both the J/ψ and ψ＇ data taking of 2009. Both dedicated runs and physics datasets are used; efficiencies are presented for Bhabha-scattering events, generic hadronic decay events involving charged tracks, dimuon events and ψ＇→π＋π-J/ψ, J/ψ→ 1＋1- events.The efficiencies are found to lie well above 99% for all relevant physics cases, thus fulfilling the BESⅢ design specifications.     

Event generators at BESⅢ

We present a brief remark and introduction to event generators for tau-charm physics currently used at BESⅢ, including KKMC, BesEvtGen, Bhlumi, Bhwide, Babayaga and inclusive Monte-Carlo event generators. This paper provides basic information on event generators for BESⅢ users.     

Precision measurements of strangeness photoproduction at threshold energies with the Crystal Ball at MAMI-C

The photoproduction of K＋ mesons from the nucleon provides important constraints on the nucleon excitation spectrum and at threshold energies challenges effective field theories based on chiral perturbation in the strange quark sector. Preliminary cross-section measurements for γ（P, K＋）A are presented at an unprecedented beam energy resolution. The data was collected at the MAMI-C facility in Mainz using the Crystal Ball Detector. A new method of K＋ detection was used in which the K＋ is tagged from its weak decay products in the detector crystals. This technique has application with other calorimeters at present and future hadron facilities.     

Čerenkov radiation at finite temperature

A power formula for erenkov radiation at finite temperature is derived in the framework of the generalized finite-temperature Cutkosky rules. Spins 1/2 and 0 are considered.     

J/ψ Physics at BES

Based on 9.0×10⁶ J/ψ data collected at BES, a systematic physics analysis has been Performed. We confirmed the existence of ξ(2230) in J/ψ→γKK and observed for the first time the non-strange decay modes ξ(2230)→π⁺π^－,π⁰π⁰,and pp. The resonance and polarization parameters of f₀(980) and f₂(1270) were measured. The moment stUdy on J/ψ→γK⁺K^－ revealed that the controversial f_J,(1710) is composed of two states, a 0⁺⁺ and a 2⁺⁺. With the help of PWA method, the spin-Parities for η(1440) and f₀(1500) were obtained, and their main decay modes were found.     

KAIUM at DAΦNE?

The possibility of producing and detecting at DAΦNE a new hydrogen isotope formed by a (K ^?+? e ^???) bound system (Kaium) is addressed, considering a dedicated, and relatively simple experiment of short duration. If Kaium will be detected, it could in perspective pave the way for a series of highly sophisticated experiments focused on the precision measurement of several observables, as the K ^?+????K ^??? mass difference, strictly related to CPT invariance.