Blocker, C.A.
[6.0, 7.0]
Max results
Sort by Reverse order

Showing 10 of 39 results

Date

Measurement of the isolated prompt photon cross-sections in anti-p p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Amidei, Dante E. ; Apollinari, G. ; et al.
Phys.Rev.Lett. 68 (1992) 2734-2738, 1992.
Inspire Record 333081 DOI 10.17182/hepdata.19869

We present a measurement of the cross section for production of isolated prompt photons in p¯p collisions at √s =1.8 TeV. The cross section, measured as a function of transverse momentum (PT), agrees qualitatively with QCD calculations but has a steeper slope at low PT.

1 data table
Table 1

Additional normalization systematic uncertainty of 27 pct for first eleven entries, and +32 pct(-46 pct) for last four entries.


Charge exchange photoproduction of the a2- (1320) in association with Delta++ at 19.3-GeV/c

The SLAC Hybrid Facility Photon collaboration Condo, G.T. ; Handler, T. ; Shimony, J. ; et al.
Phys.Rev.D 41 (1990) 3317-3323, 1990.
Inspire Record 306086 DOI 10.17182/hepdata.22925

We examine the negative 3π final state produced in association with Δ++(1232) in the reaction γp→Δ++π+π−π− at an incident photon energy of 19.3 GeV. The most prominent enhancement in the 3π spectrum occurs at a mass and with a width consistent with the parameters of the a2(1320). This identification is confirmed by the various angular distributions. The a2 production cross section, corrected for efficiencies and alternate a2 decay modes, is 0.45±0.05 μb.

1 data table
Table 1

No description provided.


High precision measurement of A in large P(T)**2 spin polarized 24-GeV/c proton proton elastic scattering

Crabb, D.G. ; Kaufman, W.A. ; Krisch, A.D. ; et al.
Phys.Rev.Lett. 65 (1990) 3241-3244, 1990.
Inspire Record 299843 DOI 10.17182/hepdata.19939

We measured the analyzing power A out to P⊥2=7.1 (GeV/c)2 with high precision by scattering a 24-GeV/c unpolarized proton beam from the new University of Michigan polarized proton target; the target’s 1-W cooling power allowed a beam intensity of more than 2×1011 protons per pulse. This high beam intensity together with the unexpectedly high average target polarization of about 85% allowed unusually accurate measurements of A at large P⊥2. These precise data confirmed that the one-spin parameter A is nonzero and indeed quite large at high P⊥2; most theoretical models predict that A should go to zero.

1 data table
Table 1

Errors quoted contain both statistical and systematic uncertainties.


Jet fragmentation properties of anti-p p collisions at S**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Amidei, D. ; Apollinari, G. ; et al.
Phys.Rev.Lett. 65 (1990) 968-971, 1990.
Inspire Record 297585 DOI 10.17182/hepdata.19919

The charged-particle fractional momentum distribution within jets, D(z), has been measured in dijet events from 1.8-TeV p¯p collisions in the Collider Detector at Fermilab. As expected from scale breaking in quantum chromodynamics, the fragmentation function D(z) falls more steeply as dijet invariant mass increases from 60 to 200 GeV/c2. The average fraction of the jet momentum carried by charged particles is 0.65±0.02(stat)±0.08(syst).

1 data table
Table 1

No description provided.


Two Jet Differential Cross-Section in anti-p p Collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Amidei, D. ; Apollinari, G. ; et al.
Phys.Rev.Lett. 64 (1990) 157, 1990.
Inspire Record 283353 DOI 10.17182/hepdata.19998

The two-jet differential cross section d3σ(p¯p→jet 1+jet 2+X)/dEtdη1dη2, averaged over -0.6≤η1≤0.6, at √s =1.8 TeV, has been measured in the Collider Detector at Fermilab. The predictions of leading-order quantum chromodynamics for most choices of structure functions show agreement with the data.

6 data tables
Table 1

Systematic error contains all known systematic uncertainties, including the effect of uncertainties in the energy scale.

Table 2

Systematic error contains all known systematic uncertainties, including the effect of uncertainties in the energy scale.

Table 3

Systematic error contains all known systematic uncertainties, including the effect of uncertainties in the energy scale.

More…

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
Table 1

No description provided.


Test of S Channel Helicity Conservation in Inelastic $\rho^0$ Diffraction in 20-{GeV} Photoproduction

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.D 32 (1985) 2288, 1985.
Inspire Record 209692 DOI 10.17182/hepdata.23546

The reaction γp→ρfast0pπ+π− has been studied with the linearly polarized 20-GeV monochromatic photon beam at the SLAC Hybrid Facility to test the prediction of s-channel helicity conservation in inelastic diffraction for t’<0.4 (GeV/c)2. In a sample of 1934 events from this reaction, the ρ0 decay-angular distributions and spin-density-matrix elements are consistent with s-channel helicity conservation, the π+π− mass shape displays the same skewing as seen in the reaction γp→pπ+π−, and the pπ+π− mass distribution compares well and scales according to the vector dominance model with that produced in π±p→πfast±pπ+π−.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

SPIN DENSITY MATRIX ELEMENTS FOR THE DIFFRACTIVE RHO0 MESON FROM STUDY OF THE ANGULAR DISTRIBUTIONS. CORRECTION HAS BEEN MADE FOR THE (20 +- 5) PCT NON DIFFRACTIVE BACKGROUND IN THE FINAL DATA SAMPLE, ASSUMING IT TO HAVE AN ISOTOPIC ANGULAR DISTRIBUTION.


Study of the $\rho^\prime$ (1600) Mass Region Using $\gamma p \to \pi^+ \pi^- p$ at 20-{GeV}

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.Lett. 53 (1984) 751, 1984.
Inspire Record 201710 DOI 10.17182/hepdata.20387

We have observed the π+π− decay of the ρ′(1600) in the production reaction γp→ρ′p at 20 GeV. Using a calculation which takes into account the interference of the ρ′ with the ρ(770) and a Drell background, we find good evidence that this resonance is a radial excitation of the ρ(770). The background interference strongly distorts the angular distributions predicted by a purely s-channel helicity-conserving production mechanism. We measure m0=(1.55±0.07) GeV/c2 and Γ0=(0.28−0.08+0.03) GeV/c2.

4 data tables
Table 1

SLOPE VARIATION WITH M(PI+ PI-) IN THE RANGE 0.4 TO 2.5 GEV.

Table 2

No description provided.

Table 3

No description provided.

More…

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
Table 1

No description provided.


Inclusive Photoproduction of Neutral Strange Particles at 20-{GeV}

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.D 29 (1984) 1877, 1984.
Inspire Record 190724 DOI 10.17182/hepdata.23774

We have studied inclusive production of KS0, Λ, and Λ¯ particles in 20-GeV γp interactions and have found features similar to those observed in both hadronic and leptonic interactions. The production cross sections, charged-particle multiplicities, and average Λ polarization are reported. Inclusive distributions of x and pT are shown and discussed in terms of quark fragmentation models. Production cross sections for K*(890) and Σ*(1385) are also reported.

9 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…