We report measurements of the two-photon processes e+e−→e+e−π+π− and e+e−→e+e−K+K−, at an e+e− center-of-mass energy of 29 GeV. In the π+π− data a high-statistics analysis of the f(1270) results in a γγ width Γ(γγ→f)=3.2±0.4 keV. The π+π− continuum below the f mass is well described by a QED Born approximation, whereas above the f mass it is consistent with a QCD-model calculation if a large contribution from the f is assumed. For the K+K− data we find agreement of the high-mass continuum with the QCD prediction; limits on f′(1520) and θ(1720) formation are presented.
Data read from graph. Additional overall systematic error 20% not included.
Data read from graph.. Additional overall systematic error 20% not included.
Data read from graph.. Additional overall systematic error 20% not included.. The Q**2 dependence is normalized to unity for the bin centred on Q**2 = 0.
We present evidence for inclusive F-meson production in B-meson decay. The product branching fraction B(B→FX)B(F+→φπ+) is measured to be 0.0038±0.010. The F momentum spectrum indicates the presence of a large component of two-body final states in the decay B→FX.
No description provided.
DATA SAMPLE CONSISTED OF 77 1/PB. DATA TAKEN ON THE PEAK OF THE UPSI(10575).
CONTINUUM DATA SAMPLE CONSISTED OF 36 1/PB. ENERGY JUST BELOW THE UPSI(10575).
None
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
None
Axis error includes +- 0.0/0.0 contribution (?////NO DECLAIRED SE.DECAY-BR(BRN=K*(892)+ --> K0 PI+,C=PDG 84)//DECAY-BR(BRN=K2*(1430) --> KAON PION,C=PDG 84)//RES-DEF(RES=K*(892)+,BACK=CORRECTED,DEF=0.72 < M(K0 PI+) < 1.20 GEV,C=M AND W FROM PDG 84)//RES-DEF(RES=K2*(1430)+,BACK=CORRECTED,DEF=1.30 < M(K0 PI+) < 1.68 GEV,C=M AND W FROM PDG 84)//RES-DEF(RES=DEL++,BACK=CORRECTED,DEF= M(P PI+) < 1.6 GEV,C=M AND W FROM PDG 84)).
Axis error includes +- 0.0/0.0 contribution (?////NO DECLAIRED SE.DECAY-BR(BRN=K*(892)+ --> K0 PI+,C=PDG 84)//DECAY-BR(BRN=K2*(1430) --> KAON PION,C=PDG 84)//RES-DEF(RES=K*(892)+,BACK=CORRECTED,DEF=0.72 < M(K0 PI+) < 1.20 GEV,C=M AND W FROM PDG 84)//RES-DEF(RES=K2*(1430)+,BACK=CORRECTED,DEF=1.30 < M(K0 PI+) < 1.68 GEV,C=M AND W FROM PDG 84)//RES-DEF(RES=DEL++,BACK=CORRECTED,DEF= M(P PI+) < 1.6 GEV,C=M AND W FROM PDG 84)).
No description provided.
We present results on the production of hadrons in collisions of 400-GeV/c protons with beryllium, copper, and tungsten nuclei. The data cover the region from 5.6 to 8.0 GeV/c in the transverse momentum of the final-state hadron and from 73° to 102° in the proton-nucleon center-of-momentum frame production angle theta*. The restriction of the data to values of xT (xT=2pT/ √s ) greater than 0.4 enriches the sample with hard collisions of valence quarks. Asymmetries about theta*=90° reflect the presence of neutrons in the target nuclei. The variation of the atomic-weight dependence parameter α with production angle is discussed in the context of the phenomenology of nucleonic structure within nuclei. We also extrapolate our measurements to a ‘‘deuteron’’ target to minimize nuclear effects and compare the result to QCD calculations.
No description provided.
No description provided.
We have searched for exclusive hadronic J/ψ production by looking for narrow resonances in the e+e− mass spectrum of the reaction π−p→e+e−n. No events were observed in the region around 3.1 GeV/c2. The cross section for the reaction π−p→J/ψ n at 13 GeV/c is no more than 103 pb at the 90% confidence level.
Corrected cross section based on 7.4 pct branching ratio.
Data read off graph.
Data read off graph.
No description provided.
BEBC filled in turn with hydrogen, and with a neon-hydrogen mixture, was exposed to the CERN SPS wide band neutrino and antineutrino beams. The ratios of the charged-current cross sections per nucleon, σ(νH 2 ) σ(ν Ne ) and σ( ν H 2 ) σ( ν Ne ) , between 20 and 300 GeV were found to be 0.656 ± 0.020 and 1.425 ± 0.052, respectively. Multiplying these ratios by the revised cross sections in neon, σ(ν Ne ) E = (0.723 ± 0.038) × 10 −38 cm 2 / GeV per nucleon and σ( ν Ne ) E = (0.351 ± 0.019) × 10 −38 cm 2 / GeV per nucleon, and their ratio, σ( ν Ne ) σ(ν Ne ) = 0.485 ± 0.020 ,, yields values for the total charged-current cross sections on protons, σ(νp)/ E and σ( ν p ) E , of (0.474 ± 0.029) × 10 −38 cm 2 /GeV and (0.500 ± 0.032) × 10 −38 cm 2 /GeV. respectively, and a value for the ratio σ( ν p ) σ(ν p ) of 1.053 ± 0.066.
No description provided.
The pion form factor has been measured in the space-like q 2 region 0.014 to 0.26 (GeV/ c ) 2 by scattering 300 GeV pions from the electrons of a liquid hydrogen target. A detailed description is given of the apparatus, data analysis and corrections to the data. The mean square charge radius extracted from the data is model-dependent. We find that a form which includes a realistic description of the form factor phase gives a similar results to the naive pole form, and conclude 〈r 2 π 〉 = 0.438±0.008 fm 2 .
No description provided.