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Search for diffractive charm production in 800-GeV/c proton - silicon interactions

The Fermilab E653 collaboration Kodama, K. ; Ushida, N. ; Mokhtarani, A. ; et al.
Phys.Lett.B 316 (1993) 188-196, 1993.
Inspire Record 35969 DOI 10.17182/hepdata.28848

A search for charm production in the coherent diffractive dissociation reaction pSi→XSi was carried out for the modes D 0 → K − π + , D 0 → K − π + π + π − , and D + → K − π + π + . No charm signals were observed, and the 90% confidence level upper limit for coherent charm pair production was determined to be 26 μ b per silicon nucleus. The results are interpreted as an upper limit of 0.2% on the amount of intrinsic charm in the proton.

1 data table
Table 1

90 pct CL upper limits.


Photoproduction and hadroproduction of phi (1020), K*0 (892) and anti-K*0 (892) mesons in the energy range 65-GeV to 175-GeV

The Omega Photon collaboration Apsimon, R.J. ; Atkinson, M. ; Baake, M. ; et al.
Z.Phys.C 61 (1994) 383-398, 1994.
Inspire Record 362483 DOI 10.17182/hepdata.12881

Inclusive production of ϕ,K*0, and\(\overline {K*^0 } \) mesons has been measured in γp, π±p andK± p collisions at beam energies of 65 GeV

30 data tables
Table 1

Statistical errors only.

Table 2

Statistical errors only.

Table 3

Statistical errors only.. An entry 0.00 indicates a statistical error of < 0.005.

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rivet Analysis
Measurement of inclusive Lambda production in electron - positron interactions at the upsilon energies

Blinov, A.E. ; Blinov, V.E. ; Bondar, A.E. ; et al.
Z.Phys.C 62 (1994) 367-370, 1994.
Inspire Record 362599 DOI 10.17182/hepdata.14205

Using the MD-1 detector at the VEPP-4e+e− strorage ring we have measured the inclusive Λ and370-1 production rates in direct Γ(1S) decays

4 data tables
Table 1

Lambda x spectrum in direct upsilon(1S) decay.

Table 2

Lambda multiplicity in direct upsilon(1S) decays.

Table 3

Lambda multiplicity in surrounding continuum.

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First results of the CERES electron pair spectrometer from p + Be, P + Au and S + Au collisions

The CERES/NA45 collaboration Drees, A. ; Baur, R. ; Breskin, A. ; et al.
Nucl.Phys.A 566 (1994) 87C-94C, 1994.
Inspire Record 362492 DOI 10.17182/hepdata.8728

The CERES experiment (CErenkov Ring Electron Spectrometer) studies the production of low mass e + e − pairs in proton-proton, proton-nucleus and nucleus-nucleus interactions at the CERN SPS. The CERES spectrometer, has a novel design based on two Ring Imaging Cherenkov (RICH) counters, and it operates close to its design specifications. Data were recorded with 200 GeV u sulfur beam and 450 GeV proton beam. The analysis is in progress. We have extracted first e + − -pairs samples for p+Be, p+Au and S+Au collisions. In addition other physics topics were addressed. Inclusive photon spectra were measured in S+Au interactions. No excess over known hadronic sources was found within our present systematic error of 11%. Results on high p i charged pion spectra are presented up to 4 GeV c . We also studied the production of e + e − -pairs m the strong electromagnetic fields of very peripheral S+Pt collisions. The data are well described by a first-order perturbative QED-calculation.

2 data tables
Table 1

NON-DISRUPTIVE S+PT COLLISIONS.

Table 2

No description provided.


Compton scattering from the proton

Hallin, E.L. ; Amendt, D. ; Bergstrom, J.C. ; et al.
Phys.Rev.C 48 (1993) 1497-1507, 1993.
Inspire Record 369337 DOI 10.17182/hepdata.26044

The proton Compton effect has been studied in the region between the threshold for pion photoproduction and the Δ(1232). The measurements were performed using bremmstrahlung from the high duty-factor electron beam available at the Saskatchewan Accelerator Laboratory. Elastically scattered photons were detected with an energy resolution of approximately 1.5% using a large NaI total absorption scintillation detector. Differential cross sections were measured for photon energies in the range 136 MeV≤Eγ≤289 MeV and for angles in the range 25°<θlab<135°. The angular distributions and the excitation functions derived from these data are in agreement with recent theoretical analyses. The results were interpreted within a formalism based in part on dispersion relations to obtain model-dependent estimates of the electric and magnetic polarizabilities, α¯ and β¯. We find, subject to the dispersion sum rule constraint α¯+β¯=(14.2±0.5)×10−4 fm3, that α¯=(9.8±0.4±1.1)×10−4 fm3 and β¯=(4.4∓0.4∓1.1)×10−4 fm3, which are consistent with the best previous measurements.

16 data tables
Table 1

Axis error includes +- 3/3 contribution (DUE TO THE CALIBRATION).

Table 2

Axis error includes +- 3/3 contribution (DUE TO THE CALIBRATION).

Table 3

Axis error includes +- 3/3 contribution (DUE TO THE CALIBRATION).

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The Anti-proton - nuclei annihilation cross-section at the momentum range from 0.70-GeV/c to 2.5-GeV/c

Kuzichev, V.F. ; Lepikhin, Yu.B. ; Smirnitsky, V.A. ;
Nucl.Phys.A 576 (1994) 581-602, 1994.
Inspire Record 363976 DOI 10.17182/hepdata.39981

The results of the measurements of antiproton-nuclei annihilation cross-sections at the momentum range from 0.70 to 2.50 GeV/ c are presented. The A -dependence of the cross-sections is described by the formula σ 0 A α . The behavior of the parameters σ 0 and α indicates the possibility of Coulomb influence on the annihilation processes at low momenta. Comparison with the Glauber theory is carried out. The Coulomb corrections to the Glauber formula for the absorption cross-sections of hadrons by nuclei are calculated. The influence of the real part of the nuclear potential is taken into account. Calculations are made in the frame of the high-energy approach. A comparison with data of annihilation cross-sections of antiprotons on nuclei is made.

9 data tables
Table 1

DETECTOR OF ANNIHILATION COLLECTS 75 PCT OF GENERATED PARTICLES. THE PION BACKGROUND IN THE BEAM WAS NOT GREATER THEN 3-4 PCT (FOR 1.76 GEVABOUT 2 PCT).

Table 2

DETECTOR OF ANNIHILATION COLLECTS 75 PCT OF GENERATED PARTICLES. THE PION BACKGROUND IN THE BEAM WAS NOT GREATER THEN 3-4 PCT (FOR 1.76 GEVABOUT 2 PCT).

Table 3

DETECTOR OF ANNIHILATION COLLECTS 75 PCT OF GENERATED PARTICLES. THE PION BACKGROUND IN THE BEAM WAS NOT GREATER THEN 3-4 PCT (FOR 1.76 GEVABOUT 2 PCT).

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Scaling violations of the proton structure function f2 at small x

The H1 collaboration Abt, I. ; Ahmed, T. ; Andreev, V. ; et al.
Phys.Lett.B 321 (1994) 161-167, 1994.
Inspire Record 360235 DOI 10.17182/hepdata.45140

An analysis is presented of scaling violations of the proton structure function F 2 ( x , Q 2 ) measured with the H1 detector at HERA in the range of Bjorken x values between x = 3 × 10 −4 and 10 −2 for four-momentum transfers Q > 2 larger than 8.7 GeV 2 . The structure function F 2 ( x , Q 2 ) is observed to rise linearly with ln Q 2 . Under the assumption that the observed scaling violations at small x ⩽ 0.01 are described correctly by perturbative QCD, an estimate is obtained of the gluon distribution function G ( x , Q 0 2 ) at Q 2 2 = 20 GeV 2 .

1 data table
Table 1

No description provided.


Production of J / psi at large x(F) in 800-GeV/c p copper and p beryllium collisions

Kowitt, M.S. ; Gidal, G. ; Ho, P.M. ; et al.
Phys.Rev.Lett. 72 (1994) 1318-1321, 1994.
Inspire Record 361036 DOI 10.17182/hepdata.42472

The differential cross sections dσ/dxF for J/ψ produced inclusively in 800 GeV/c p-Cu and p-Be collisions have been measured in the kinematic range 0.30≤xF≤0.95 through the decay mode J/ψ→μ+μ−. They are compared with the predictions of the semilocal duality model for several sets of parton density functions. No evidence for a suggested intrinsic charm contribution to the cross section is observed. The ratio of the differential cross sections for Cu and Be targets confirms the suppression of J/ψ production in heavy nuclei at large xF.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Enhanced leading production of D+- and D*+- in 250-GeV pi+- - nucleon interactions

The E769 collaboration Alves, G.A. ; Amato, S. ; Anjos, J.C. ; et al.
Phys.Rev.Lett. 72 (1994) 812-815, 1994.
Inspire Record 361344 DOI 10.17182/hepdata.42499

A leading charm meson is one with longitudinal momentum fraction, xF>0, whose light quark (or antiquark) is of the same type as one of the quarks in the beam particles. We report on the production asymmetry, A=[σ(leading-σ(nonleading)]/[σ(leading)+σ(nonleading)] as a function of xF. The data consist of 1500 fully reconstructed D± and D*± decays in Fermilab experiment E 769. We find a significant asymmetry for the production of charm quarks is not expected in perturbative quantum chromodynamics.

2 data tables
Table 1

Asymmetry as function of XL.

Table 2

Asymmetry as function of PT**2.


Measurements of polarized-neutron-polarized-proton scattering: Implications for the triton binding energy

Wilburn, W.S. ; Gould, C.R. ; Haase, D.G. ; et al.
Phys.Rev.Lett. 71 (1993) 1982-1985, 1993.
Inspire Record 370854 DOI 10.17182/hepdata.19731

Measurements have been made of ΔσT for polarized neutrons incident on a polarized-proton target from 3.65 to 11.60 MeV. In the energy range near 10 MeV, ΔσT is very sensitive to the nucleon-nucleon tensor interaction. Comparison of the data to potential-model predictions indicate that the tensor interaction is weak, resulting in values of the 3S1−3D1 mixing parameter ε1 which are smaller than predicted by any nucleon-nucleon potential model. A smaller tensor force will bring the predictions of local potential models for the triton binding energy into closer agreement with the experimental value.

1 data table
Table 1

The measured cross section is the total cross section with the spins antiparallel minus the total cross section with the spins parallel.