Search

21 pp. (1993)., A method is proposed for the determination of the Lorentz structure of the electroweak interaction in semi-hadronic τ decays. Spin correlations in the process$e^+e^−→τ^+τ^−→\bar v τπ^+π^0vτπ^−π^0 e^+e^−→τ^+τ^−→\bar vτπ^+π^0vτπ^−π^0$ are exploited for a measurement of the normalized product, γAV = 2Re{gAgV*}/(|gV|2 + |gV|2), of the vector (gV) and axial vector (gA) coupling of the τ lepton. The contribution of scalar (gS) or pseudo-scalar (gP) couplings is also investigated. Since in the above process the direction of flight of the τ leptons can be reconstructed up to a twofold ambiguity a likelihood method using the whole kinematic information can be employed. The matrix element entering the likelihood function has been evaluated in terms of the momenta and angles of the observed pions. The sensitivity of the derived method in ane+e− energy region around 10 GeV has been investigated for the ARGUS experiment using Monte Carlo simulations.

The reaction $e^+e^−→e^+e^−π^0π^0$ has been analyzed using 97pb$^{−1}$ of data taken with the Crystal Ball detector at the DESY $e^−e^+$ storage ring DORIS II at beam energies around 5.3 GeV. For the first time we have measured the cross section for $γγ→π^0π^0$ for π0π0 mvariant masses ranging from threshold to about 2 GeV. We measure an approximately flat cross section of about 10 nb for W=$mπ^0π^0

Evidence for the quark composition of hadrons is reviewed including deep inelastic lepton-nulceon scattering, e/sup +/e/sup -/ annihilation, and gluon fragmentation. (AIP)

28 pp. (1979).

107 pp. (1981).

120 pp. (1988).

17 pp. (1983).

(1980). doi:10.1007/BF01588839, We discuss the angular asymmetries of 3-jet events ine+e− annihilation, originating from hard gluon bremsstrahlung off quarks. Lepton beam polarization helps to disentangle the various helicity components of the bremsstrahlung cross section. They are sensitive to the spin of the radiated quantum but are otherwise parameter-free.

17 pp. (1983).

(1980). doi:10.1103/PhysRevD.21.303, The π0−π0 azimuthal-angle distributions measured at CERN ISR are described in terms of standard large-p⊥ two-jet and three-jet contributions in combination with a background obtained by superimposing two uncorrelated π0 spectra (one at high p⊥, the other at low p⊥). The main characteristics of the data can be fitted suprisingly well by a simple analytic expression. We emphasize the importance of having azimuthal-angle correlation data at higher values of the transverse-momentum cut.

64 pp. (1982).

22 pp. (1980).

28 pp. (1982).

(1982). doi:10.1051/jphyscol:1982313, Without abstract

34 pp. (1979).

(1980). doi:10.1007/BF01554399, The cross sectionsdσU,dσL,dσT anddσI fore+e−→q\(\bar q\)g are calculated for heavy quarks, and the resultant angular distribution is discussed.

21 pp. (1981).

20 pp. (1981).

146 pp. (1982).

12 pp. (1982).