Using the ARGUS detector at the DORIS II storage ring at DESY, we have observed a charmed meson of mass (2455±3±5) MeV/c2, decaying to D + π − . The natural width of this state is determined to be (15 +13+5 −10−10 ) MeV c 2 . The fragmentation function is hard, as expected for a leading charmed particle from nonresonant e + e − annihilation. Analysis of the decay angular distribution supports the hypothesis that the observed state is an L =1 excited charmed meson with spin-parity 2 + .
Corrected to zero momentum using fragmentation function of Peterson et al., PR D29 (83) 105.
Data read from graph.
η production has been investigated by the Mark II collaboration at the SLAC e+e− storage ring PEP. η particles are reconstructed by their γγ decay mode. The η fragmentation function has been measured and found to be in good agreement with the Lund-model prediction. η′ production has been measured for the first time in high-energy e+e− annihilation. There is evidence at the 3σ level for Ds± decay into ηπ± and η′π±.
Numerical values supplied by G.Wormser.
Z = 0.0 point extrapolated using LUND fragmentation model.
Z = 0.0 point extrapolated using LUND fragmentation model.
We report results on the differential and total cross sections for inclusive production of the charmed particles D*+, D*0, D0, D+, Ds, and Λc in e+e− annihilations at √s=10.55 GeV. Widely used quark fragmentation models are discussed and compared with the measured charmed-particle momentum distributions. This comparison, as well as that with measurements at other center-of-mass energies, shows the need to take QCD corrections into account and their importance for a correct interpretation of the model parameters. The observed rate of D0 and D+ production is compared to the expected total charm production cross section. We measure the probability of a charmed meson being produced as a vector meson and the D*+ decay branching fraction into D0π+.
No description provided.
No description provided.
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Using the ARGUS detector at DORIS, we observe the production of D ∗+ s mesons in e + e − annihilation through their subsequent decays to a D + s and a photon. Photons which convert in the beam pipe or drift chamber inner wall are used to obtain a high precision measurement of the D ∗+ s -D + s mass difference, while photons detected in the shower counters are used to determine the production cross section, and to provide an independent measurement of the D ∗+ s -D + s mass difference. The observed D ∗+ s - D + s mass difference is 142.5±0.8±1.5 MeV/ c 2 , and σ(e + e − →D ∗+ s X)·BR(D ∗+ s →D + s γ)(·BR(D + s →φπ + ) is 4.4±1.1±1.0 pb at 10.2 GeV. The width of the D ∗+ s is less than 4.5 MeV/ c 2 at 90% confidence level.
Cross sections uncorrected for branching ratios.
Using the ARGUS detector at the DORIS II e+e− storage ring at DESY, we have obtained evidence for a new charmed resonance which decays into D*±(2010)π∓. The observed mass and width are 2420±6 MeV/c2 and 70±21 MeV/c2, respectively. The fragmentation function is found to be hard, as expected for a state containing a leading charm quark produced by nonresonant e+e− annihilation.
No description provided.
Estimated production cross section obtained by comparison with observed D*(2010) production rate.
Data from the high-resolution spectrometer at PEP have been used to study the inclusive production of φ mesons and F± mesons decaying into φπ±. Fragmentation functions and cross sections are presented and compared to existing data. The total φ cross section at 29 GeV is 40±6 pb. The observed F signal in the region z>0.4, given the assumption that R(F)[R(F)+R(D)]=0.15, corresponds to an F→φπ branching ratio of (3.3±1.1)%. The measured F mass is 1963±3±3 MeV/c2.
No description provided.
No description provided.
WITH THE FOLLOWING ANGLE CUTS ON THE DECAY REGIONS. PHI DECAY - ABS(COS(THETA)) >0.5.
Using the ARGUS detector at DORIS, we have observed the production of F ± mesons in e + e − annihilation at a centre of mass energy of 10 GeV through their subsequent decays into φπ ± and φπ + π − π ± . The values obtained for [ R (e + e − →FX). Branching Ratio] are (1.47 ± 0.32 ± 0.20)% and (1.63 ± 0.42 ± 0.41)% respectively. The observed mass is (1973.6 ± 2.6 ± 3.0) MeV c 2 . The F momentum spectrum is as expected for the fragmentation of c quarks into charmed mesons, but is somewhat softer than for fragmentation into D ∗ mesons. The relevant angular distributions are consistent with a spin-zero assignment of the F meson.
RESULTS OF FITS FOR SPECIFIED DECAY CHANNELS.
ACCEPTANCE CORRECTED FRAGMENTATION FUNCTION FOR THE TWO DECAY CHANNELS COMBINED. X IS PF/PMAX. DATA HAVE BEEN READ FROM THE GRAPH.
Evidence for a narrow state decaying into an F meson and a photon has been obtained in e+e− annihilation events at 29-GeV c.m. energy. This state lies 139.5 ± 8.3(stat.) ± 9.7(syst.) MeV above the F-meson mass and is consistent with the expected F* meson. The F mesons are identified by a peak in the K+K−Kπ± mass at 1.948±0.028±0.010 GeV.
DATA REQUESTED FROM AUTHORS.
IN (K+K-PI+) THE AUTHORS INCLUDE OTHER DECAY MODES SUCH AS (AK*0 K+),(PHI PI+),(K+ K- PI+,PI0),(K+ K- MU+ NU) WHICH CANNOT BE RESOLVED.
Using the ARGUS detector at DORIS we have observed the prediction of the charged D ∗ meson in e + e − annihilation at a center of mass energy of 10 GeV. The D ∗ fragmentation function has been measured using the decay channels D ∗+ → D 0 π + and D 0 → K − π + and K − π + π + π − .
RESULTS EXTRAPOLATED TO X>O. SYSTEMATIC ERRORS INCLUDED.
ERRORS ARE STATISTICAL ONLY.
We have observed inclusive production of D0 and D+ mesons, and their charge conjugates, in e+e− annihilation at 29 GeV on the basis of a data sample of 106 pb−1. These signals correspond to R values of R(D0+D―0)=1.8±0.5 and R(D++D−)=1.2±0.4. Taking the D+ and D0 data together, we measure a charge asymmetry of A=−0.08±0.12 for charmed quarks. A comparison of R(D+D―) with R(D*+D―*) obtained via the process D*+→D0π+ gives a DD* ratio of 1.0−0.2+0.3, indicating that direct D* production dominates over direct D production.
No description provided.
EXTRAPOLATED TO ALL Z.
No description provided.