Brunini, P.L
E+ E- --> D*(2010)+ X
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Measurement of A(c) with charmed mesons at SLD.

The SLD collaboration Abe, Kenji ; Abe, Koya ; Abe, Toshinori ; et al.
Phys.Rev.D 63 (2001) 032005, 2001.
Inspire Record 533573 DOI 10.17182/hepdata.41721

We present a direct measurement of the parity-violation parameter $A_c$ in the coupling of the $Z^0$ to $c$-quarks with the SLD detector. The measurement is based on a sample of 530k hadronic $Z^0$ decays, produced with a mean electron-beam polarization of $|P_e| = 73 %$. The tagging of $c$-quark events is performed using two methods: the exclusive reconstruction of $D^{\ast+}$, $D^+$, and $D^0$ mesons, and the soft-pions ($\pi_s$) produced in the decay of $D^{\ast+}\to D^0 \pi_s^+$. The large background from $D$ mesons produced in $B$ hadron decays is separated efficiently from the signal using precision vertex information. The combination of these two methods yields $A_c = 0.688 \pm 0.041.$

1 data table
Table 1

CONST(NAME=A_C) is connected with the forward-backward asymmetry by following way: ASYM(NAME=FB) = ABS(P_e)*CONST(NAME=A_C)*2z/(1 + z**2), where z = cos(theta), theta is the polar angle of the outgoing fermion relative to the incident electron, P_e is the longitudinal polarization of the electron beam. Two values for constant A_c were obtained using two different c-quark tagging methods: exclusive charmed-meson reconstruction (C=EXCLUSIVE) and inclusive soft-pion analysis (C=SOFT_PIONS).


Properties of Charm Jets Produced in $e^+ e^-$ Annihilation Near 34-{GeV}

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Kirschfink, F.J. ; et al.
Phys.Lett.B 135 (1984) 243-249, 1984.
Inspire Record 194050 DOI 10.17182/hepdata.30600

D ∗± production via e + e − → D ∗± X was studied at CM energies near 34 GeV. The charged particles produced in the hemisphere opposite to that of the D ∗ were used to investigate the fragmentation of charm jets. All spectra studied show a close similarity between the charm jet and the average jet obtained by summing over all quark flavours. The spectra of particles produced in the D ∗ hemisphere were used to study separately first rank and higher rank fragmentation.

2 data tables
Table 1

THE C-JET IS THE JET IN THE HEMISPHERE OPPOSITE TO THAT CONTAINING THE D* MESON. DIVISION IS MADE BY A PLANE PERPENDICULAR TO THE THRUST AXIS.

Table 2

No description provided.


D*+- Production by e+ e- Annihilation Near 34.4-GeV Center-Of-Mass Energy

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Gather, K. ; et al.
Phys.Lett.B 126 (1983) 493-498, 1983.
Inspire Record 196842 DOI 10.17182/hepdata.30721

D ∗± production via e + e − →D ∗± X has been measured at an average CM energy of 34.4 GeV. The D ∗± energy spectrum is hard, with a maximum near χ = 0.6. The size of the D ∗ cross section, R D ∗ = σ( e + e − → D ∗ X ) σ μμ = 2.50 ± 0.64 ± 0.88 (assuming R D ∗0 = R D ∗+ ) indicates that a large fraction of charm quark production yields D ∗ mesons. The D ∗± angular distribution exhibits a forward—backward asymmetry, A = −0.28 ± 0.13. This is consistent with that expected in the standard theory for weak neutral currents and leads to | g A c | = 0.89 ± 0.44 for the axial vector coupling of the charm quark.

3 data tables
Table 1

ASSUMES EQUAL RATES FOR CHARGED AND NEUTRAL D*'S. ONLY CHARGED ARE DETECTED.

Table 2

DATA PEAKS AT X=0.6 TO 0.8.

Table 3

ASYMMETRY MEASUREMENT. THETA IS THE ANGLE BETWEEN THE E- AND THE D*.