107065256
Networking with China
This paper presents the history and current status Of computer networking between IHEP in Beijing, China and the rest of the world, starting with no links at the beginning of 1987 thru X.25 public networks and dial up links, to the installing, in March 1993, of one of the first dedicated 64 kbps satellite computer links between China and the outside world. In May 1994, IHEP became the first Chinese institution to have a fully operational world-wide Internet connection. Experience with this dedicated link between SLAC and IHEP will be presented together with future plans to add a land line between KEK and IHEP and to extend the links within China.
125590985
Experimental study of f0(975) in J / psi decays
36536982
Measurements of J/ psi decays into a vector and a pseudoscalar meson.
We present measurements of the two-body decays of the J/psi into a vector and a pseudoscalar meson. The data, taken with the Mark III detector at the SLAC e/sup +/e/sup -/ storage ring SPEAR, consist of 5.8 x 10/sup 6/ produced J/psi's. The branching ratios for the J/psi decays into rho..pi.., rhoeta, rhoeta', ..omega pi../sup 0/, ..omega..eta, ..omega..eta', phieta, phieta', and K/sup */K are measured; an upper limit on J/psi..-->..phi..pi../sup 0/ is obtained. Using the measured branching ratios we obtain parameters of a phenomenological model of J/psi decays, indicating that the eta and eta' are consistent with being composed only of light and strange quarks. The model is used to obtain the mixing angle in the pseudoscalar nonet. The ..omega pi../sup 0/ electromagnetic form factor is determined. The upper limit on J/psi..-->..phi..pi../sup 0/ is used to study the contributions from electromagnetic doubly--Okubo-Zweig-Iizuka--suppressed decays of the J/psi. .AE
15600044
Measurement of the hadronic structure of semileptonic D0 and D+ decays.
Absolute branching fractions for the {ital D}{sub {ital l}3} and {ital D}{sub {ital l}4} decays {ital D}{sup +}{r arrow}{ital {bar K}} {sup 0}{ital e+}{nu}{sub {ital e}}, {ital D}{sup +}{r arrow}{ital {bar K}} {sup 0}{mu}{sup +}{nu}{sub {mu}}, {ital D}{sup +}{r arrow}{ital {bar K}} {sup *0}{ital e+}{nu}{sub {ital e}}, and {ital D}{sup 0}{r arrow}{ital K}{sup *{minus}}{ital e+}{nu}{sub {ital e}} are determined using completely reconstructed {ital D{bar D}} events at the {psi}(3770). Reconstructed {ital D}{sup 0}{r arrow}{ital K}{sup {minus}}{ital e+}{nu}{sub {ital e}} decays are used to determine the pole mass of the {ital f}{sub 4}({ital q}{sup 2}) form factor. Resonant {ital K}{sup *} production dominates the process {ital D}{r arrow}{ital K}{pi}{ital e}{nu}; the {ital K}{sup *} polarization is measured. Limits on several Cabibbo-suppressed channels are evaluated. A global fit imposing isospin symmetry is performed to the measured exclusive and inclusive semileptonic {ital D}{sup 0} and {ital D}{sup +} branching fractions to obtain an improved set of branching fractions.
22018283
Direct measurement of the J/ psi leptonic branching fraction.
The Mark III Collaboration has measured the {ital J}/{psi} leptonic branching fractions using the process {psi}(2{ital S}){r arrow}{pi}{sup +}{pi}{sup {minus}}{ital J}/{psi}, {ital J}/{psi}{r arrow}{ital l}{sup +}{ital l{minus}}. The results are {ital B}({ital J}/{psi}{r arrow}{ital e}{sup +}{ital e{minus}})=(5.92{plus minus}0.15{plus minus}0.20)% and {ital B}({ital J}/{psi}{r arrow}{mu}{sup +}{mu}{sup {minus}})=(5.90{plus minus}0.15{plus minus}0.19)%, where the first error is statistical and the second is systematic. Assuming lepton universality, the leptonic branching fraction of the {ital J}/{psi} is (5.91{plus minus}0.11{plus minus}0.20)%. This result is used to obtain the strong coupling constant {alpha}{sub {ital s}} and the QCD scale factor {Lambda}{sub MS} (M{bar S} denotes the modified minimal-subtraction scheme).
115754528
GEM technical design report
123101518
Studies of quantum chromodynamics with the ALEPH detector
Abstract Previously published and as yet unpublished QCD results obtained with the ALEPH detector at LEP1 are presented. The unprecedented statistics allows detailed studies of both perturbative and non-perturbative aspects of strong interactions to be carried out using hadronic Z and tau decays. The studies presented include precise determinations of the strong coupling constant, tests of its flavour independence, tests of the SU(3) gauge structure of QCD, study of coherence effects, and measurements of single-particle inclusive distributions and two-particle correlations for many identified baryons and mesons.
119085485
Heavy quark tagging with leptons in the ALEPH detector
This paper deals with sustainable development policies in the French South-Eastern Alps region (Digne-les-Bains). It aims to delineate the influence of communication and mediation practices which are used to implement such principles in a largely reluctant area. This approach combines the point of views of two sciences, media and communication on the one hand, geography , on the other hand
119250669
SWIFT J1749.4−2807: A neutron or quark star?
We investigate a unique accreting millisecond pulsar with X-ray eclipses, SWIFT J1749.4-2807 (hereafter J1749), and try to set limits on the binary system by various methods including use of the Roche lobe, the mass-radius relations of both main sequence (MS) and white dwarf (WD) companion stars, as well as the measured mass function of the pulsar. The calculations are based on the assumption that the radius of the companion star has reached its Roche radius (or is at 90%), but the pulsar's mass has not been assumed to be a certain value. Our results are as follows. The companion star should be an MS one. For the case that the radius equals its Roche one, we have a companion star with mass M ≃ 0.51 M ⊙ and radius R c ≃ 0.52 R ⊙ , and the inclination angle is i ≃ 76.5° ; for the case that the radius reaches 90% of its Roche one, we have M ≃ 0.43 M ⊙ , R c ≃ 0.44 R ⊙ and i ≃ 75.7° . We also obtain the mass of J1749, M p ≃ 1 M ⊙ , and conclude that the pulsar could be a quark star if the ratio of the critical frequency of rotation-mode instability to the Keplerian one is higher than ∼ 0.3. The relatively low pulsar mass (about ∼ M ⊙ ) may also challenge the conventional recycling scenario for the origin and evolution of millisecond pulsars. The results presented in this paper are expected to be tested by future observations.
7155127
An accretion disk model for periodic timing variations of pulsars
The long term, highly periodic and correlated variations in both the pulse shape and the rate of slow down of two isolated pulsars (PSRs) PSR B1828 11 and PSR B1642 03 were discovered recently. This phenomenon may provide evidence for "free precession" as suggested in the literature. Some authors presented various kinds of models to explain this phenomenon within the framework of free precession. Here we present an accretion disk model for this precession phenomenon instead. Under reasonable parameters, the observed phenomenon can be explained by an isolated pulsar with a fossil disk. This may link radio pulsars and anomalous X ray pulsars (AXPs) and present an indirect evidence for the existence of the fossil disk in nature.
7970069
Updated measurement of the tau lepton lifetime
A new measurement of the mean lifetime of the τ lepton is presented. Three different analysis methods are applied to a sample of 90 000 τ pairs, collected in 1993 and 1994 with the ALEPH detector at LEP. The average of this measurement and those previously published by ALEPH is ττ = 290.1 ± 1.5 ± 1.1 fs.