Date

Evidence of Isospin Effects in Anti-proton - Nucleus Annihilation

Balestra, F. ; Bossolasco, S. ; Bussa, M.P. ; et al.
Nucl.Phys.A 491 (1989) 572-586, 1989.
Inspire Record 264049 DOI 10.17182/hepdata.37013

Antiproton- 3 He annihilation events at rest have been detected using a self-shunted streamer chamber. The ratio of the cross section for annihilation on neutrons and on protons has been measured (0.467 ± 0.035). It is compared with other results from annihilation on free nucleons, deuterium, 3 He and 4 He. The low value of the ratio seems to indicate a strong isospin dependence of the antinucleon-nucleon P-wave amplitude.

6 data tables

No description provided.

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The Electron Spectrum From $B$ Meson Decays

The Crystal Ball collaboration Wachs, K. ; Antreasyan, D. ; Bartels, H.W. ; et al.
Z.Phys.C 42 (1989) 33, 1989.
Inspire Record 263581 DOI 10.17182/hepdata.45204

The Crystal Ball Collaboration has measured the energy spectrum of electrons from semileptonicB meson decays at thee+e− storage ring DORIS II. Branching ratios and weak mixing angles of the Kobayashi-Maskawa matrix are determined using several models for the hadronic matrix elements. We obtain the branching ratio for semileptonic.B decays to charmed states BR(B→evXc)=(11.7±0.4±1.0)%. Our result for the corresponding Kobayashi-Maskawa matrix element is |Vcb|=0.052±0.006. The model dependence of both results is included in the error. We have not observed semileptonicB decays to non-charmed mesons. Analyzing the measured electron spectrum above 2.4 GeV, where nob→c decays contribute, we find BR(B→evXu)/BR(B→evXc)<6.5% at the 90% confidence level. This corresponds to an upper limit |Vub/Vcb|<0.21.

1 data table

The errors quoted are statistical only.


Multiplicity Distributions in Pseudorapidity Intervals With $^{32}$S at 200-{GeV}/nucleon and $^{16}$O at 200-{GeV}/nucleon and 60-{GeV}/nucleon

Singh, G. ; Sengupta, K. ; Jain, P.L. ;
Phys.Rev.Lett. 61 (1988) 1073, 1988.
Inspire Record 24235 DOI 10.17182/hepdata.20129

We present results of our systematic studies of charged-shower-particle multiplicities and their dependence on pseudorapidity intervals for nearly central events produced by S32 at 200 GeV/nucleon and O16 at 200 and 60 GeV/nucleon in nuclear emulsion. An increase in the particle density with the increase of particle energy and mass is observed. We find an energy-independent linear relation between the maximum particle density (in a given pseudorapidity interval) and shower-particle multiplicity.

2 data tables

No description provided.

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Cross-section Measurement of $\pi^- p \to \pi^- \pi^+ n$ Reaction Near Threshold

The OMICRON collaboration Kernel, G. ; Korbar, D. ; Krizan, P. ; et al.
Phys.Lett.B 216 (1989) 244-248, 1989.
Inspire Record 264989 DOI 10.17182/hepdata.29858

Result of cross section measurements for the reaction π − p → π − π + n are presented. They cover a range of incident pion momenta between 295 and 450 MeV/ c . It is the first time that the cross section has been measured so close to threshold. The experiment was performed with Omicron, a large-solid-angle spectrometer, which enables a measurement of the full set of kinematic variables. In the region of overlap there is a good agreement with other experiments. The extracted value for the chiral-symmetry-breaking parameter ξ is seen to be largely extrapolition dependent but the measured value of -0.5±0.8 leaves Weinberg's prediction of ξ =0 the only remaining choice.

1 data table

No description provided.


Observation of a New $\Omega^*$- at 2.47-{GeV}/$c^2$ in $K^- p$ Interactions at 11-{GeV}/$c$

Aston, D. ; Awaji, N. ; Bienz, T. ; et al.
Phys.Lett.B 215 (1988) 799-804, 1988.
Inspire Record 264666 DOI 10.17182/hepdata.29872

Clear evidence is presented for an Ω ∗− resonance of mass 2474±12 MeV c 2 and width 72±33 MeV c 2 in K − p interactions at 11 GeV c . The state is observed in the Ω − π + π − decay mode, and the corresponding inclusive cross section, corrected for Ω − π 0 π 0 decay, is estimated to be 290±90 nb.

1 data table

Estimated inclusive production cross section in the (omega- pi+ pi-) decay mode (after correction for the omega- 2pi0 decay).


The Transverse Energy Distributions of $^{32}$S Nucleus Collisions at 200-{GeV} Per Nucleon

The HELIOS collaboration Akesson, T. ; Almehed, S. ; Angelis, A.L.S. ; et al.
Phys.Lett.B 214 (1988) 295-302, 1988.
Inspire Record 265090 DOI 10.17182/hepdata.29873

Transverse-energy distributions have been measured for the collisions of the 32 S nucleus with Al, Ag, W, Pt, Pb, and U target nuclei, at an incident energy of 200 GeV per nucleon. The shapes of these distribution reflect the geometry of the collisions, including the deformation effects. For central collisions, the transverse-energy production in the region −0.1< η lab <2.9 increases approximately as A 0.5 , where A is the atomic mass number of the target. This increase is accompanied by a relative depletion in the forward region η lab > 2.9. These results are compared with those obtained under similar conditions with incident 16 O nuclei. A comparison is also made with the predictions of a Monte Carlo generator based on the dual parton model. Finally, we give estimates of the energy density reached and its dependence on the atomic mass number of the projectile.

6 data tables

No description provided.

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FORWARD AND BACKWARD ANGLES DIFFERENTIAL CROSS-SECTION FOR DEUTERON PHOTODISINTEGRATION AT INTERMEDIATE-ENERGIES

Levi Sandri, P. ; Anghinolfi, M. ; Bianchi, N. ; et al.
396, 1988.
Inspire Record 268377 DOI 10.17182/hepdata.37902

None

2 data tables

No description provided.

Total cross section (4PIA0). Errors contain systematics. Calculated using data from De Sanctis et al., PR C34(86)413, combined with this work.


The Pion Electromagnetic Form-factor in the Timelike Energy Range 1.35-{GeV} $\le \sqrt{s} \le$ 2.4-{GeV}

The DM2 collaboration Bisello, D. ; Busetto, G. ; Castro, A. ; et al.
Phys.Lett.B 220 (1989) 321-327, 1989.
Inspire Record 267118 DOI 10.17182/hepdata.29829

The e + e − → π + π − cross section has been measured from about 280 events (an order of magnitude more than the previous world statistics) in the energy interval 1.35 ⩽ s ⩽ 2.4 GeV with the DM2 detector at DCI. The pion squared form factor | F π | 2 shows a deep minimum around 1.6 GeV/ c 2 and is better fit under the hypothesis of two ϱ-like resonance ⋍0.25 GeV/ c 2 wide with 1.42 and 1.77 GeV/ c 2 masses.

1 data table

Statistical errors only.


A Measurement of $\gamma \gamma \to \rho^+ \rho^-$

The ARGUS collaboration Albrecht, H. ; Bockmann, P. ; Glaser, R. ; et al.
Phys.Lett.B 217 (1989) 205-210, 1989.
Inspire Record 266416 DOI 10.17182/hepdata.29853

The reaction γγ → ϱ + ϱ − → π + π − π 0 π 0 has been studied with the ARGUS detector at the e + e − storage ring DORIS II at DESY. Near threshold, the cross section for this reaction is about four times smaller than for the reaction γγ → ϱ 0 ϱ 0 .

4 data tables

Data read from graph.

Data read from graph.

Data read from graph.

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Precise Comparison of Anti-proton - Proton and Proton Proton Forward Elastic Scattering at $\sqrt{s}=24$.3-{GeV}

The UA6 collaboration Breedon, R.E. ; Chapin, T.J. ; Cool, R.L. ; et al.
Phys.Lett.B 216 (1989) 459-465, 1989.
Inspire Record 267044 DOI 10.17182/hepdata.29854

We report results from a measurement of antiproton-proton and proton-proton small-angle elastic scattering at √ s = 24.3 GeV in the range 0.001 ⩽ | t | ⩽ 0.06 (GeV/ c ) 2 . The measurement was performed at the CERN p p Collider by using silicon detectors to observe protons recoiling from a hydrogen cluster-jet target intercepting the stored p and p beams. Fits to the measured differential cross sections yield the ratio of the real to the imaginary part of the forward nuclear scattering amplitude ρ and the nuclear slope parameter b for both p p and pp. We find that the difference Δρ = ρ ( p p ) − ρ( pp ) = 0.031 ± 0.010 agrees with conventional fits and disagrees with the “odderon” fit designed to accommodate the recent UA4 measurement of ρ( p p) at 546 GeV.

3 data tables

Data requested from authors.

No description provided.

Nuclear slopes fixed to world average.