Hagopian, V.
SLAC Hybrid Facility Photon
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CHARM PHOTOPRODUCTION AT 20-GeV

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.D 30 (1984) 1, 1984.
Inspire Record 194546 DOI 10.17182/hepdata.23639

Sixty-two charm events have been observed in an exposure of the SLAC Hybrid Facility toa backward sacttered laser beam. Based on 22 neutral and 21 charged decays we have measured the charmed-meson lifetimes to be τD0=(6.8−1.8+2.3)×10−13 sec, τD±=(7.4−2.0+2.3)×10−13 sec and their ratio τD±τD0=1.1−0.3+0.6. The inclusive charm cross section at a photon energy of 20 GeV has been measured to be 56−23+24 nb. Evidence is presented for a non-DD¯ component to charm production, consistent with (35±20)% Λc+ production and some D*± production. We have found no unambiguous F decays.

1 data table match query
Table 1

No description provided.


Lifetimes, Cross-sections and Production Mechanisms of Charmed Particles Produced by 20-{GeV} Photons

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Armenteros, R. ; Bacon, T.C. ; et al.
Phys.Rev.D 33 (1986) 1, 1986.
Inspire Record 214735 DOI 10.17182/hepdata.23544

Seventy-one events containing charmed-particle decays have been observed in an experiment using the SLAC Hybrid Facility exposed to a backward-scattered photon beam. Several improvements were made to the apparatus since the previous experiment on charm photoproduction. Results for the charmed-meson lifetimes are consistent with the published results from the previous experiment and the two data samples have been combined yielding a total sample of 136 charm events. After imposing rigorous cuts, 50 neutral, 48 charged, and 2 charged/neutral ambiguous decays remain. From these, the charmed-meson lifetimes are measured to be &=(8.6±1.3−0.3+0 .7)×10−13 sec, &=(6.1±0.9±0.3)×10 −13 sec, and their ratio &=1.4±0.3− 0.1+0.2. The total charm cross section at a photon energy of 20 GeV has been measured to be (62±8−10+15) nb. There is evidence for both DD¯X and D¯Λc+X production with σD¯Λc+X/σcharm=(71± 11±6)%.

1 data table match query
Table 1

No description provided.


Search for a Threshold Enhancement in the $\gamma (p) \to$ Charmed Baryon + Charmed Meson Cross-section

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Bingham, H.H. ; et al.
Phys.Rev.D 30 (1984) 694, 1984.
Inspire Record 200010 DOI 10.17182/hepdata.23592

Results of a search for a predicted enhancement of several microbarns in the charm-photoproduction cross section just above threshold are reported. No charm decays were detected, from which an upper limit to the charm cross section of 94 nb (90% C.L.) at Eγ≃10 GeV was obtained. Upper limits in the range 270 to 450 nb were also obtained for the peak cross sections for threshold enhancements in γp→D−Σc++ and similar channels.

2 data tables match query
Table 1

UPPER LIMIT TO AVERAGE CHARM CROSS SECTION.

Table 2

UPPER LIMITS TO INDIVIDUAL CHANNELS.