Date

Measurement of the analyzing power and the differential cross-section of the anti-p p charge exchange reaction at LEAR

Birsa, R. ; Bradamante, F. ; Dalla Torre-Colautti, S. ; et al.
Phys.Lett.B 246 (1990) 267-272, 1990.
Inspire Record 296501 DOI 10.17182/hepdata.29676

As part of a programme to study the spin structure of the p p→ n n channel, we have measured the analysing power A 0 n and the differential cross section at an incident antiproton beam momentum of 704 MeV/ c . The analysing power exhibits a remarkable angular dependence, which is poorly reproduced by the existing potential models.

2 data tables

No description provided.

No description provided.


Experimental limits on extra Z bosons from e+ e- annihilation data with the VENUS detector at s**(1/2) = 50-GeV to approximately 64-GeV

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett.B 246 (1990) 297-305, 1990.
Inspire Record 296392 DOI 10.17182/hepdata.29664

We have tested extra Z models in the reactions e + e − → μ + μ − , τ + τ − and hadrons in the energy range 50< s <64 GeV using the VENUS detector at the TRISTAN e + e − storage ring. Our data are in good agreement with the standard model prediction ( χ 2 N Df = 2.9 31 ) ). We have obtained 90% confidence-level lower limits of 105, 125 and 231 GeV for the masses of Z Ψ , Z η and Z χ bosons which are expected from the E 6 grand unified theory. We also place a 90% confidence-level lower limit of 426 GeV for the mass of an extra-Z boson whose couplings to quarks and leptons are assumed to be the same as those for the standard Z boson. Our results exceed the previous experimental limits from the p p collider experiments, although there have been some combined analyses reporting the limits better than those obtained in the present analysis.

5 data tables

New measurements.

New measurements. Statistical and systematic errors combined in quadrature.

New measurements.

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Photoproduction of the LAMBDA(c) charmed baryon

The NA14/2 collaboration Alvarez, M.P. ; Barate, R. ; Bloch, D. ; et al.
Phys.Lett.B 246 (1990) 256-260, 1990.
Inspire Record 296476 DOI 10.17182/hepdata.29677

In a photoproduction experiment using a mean photon energy of 100 GeV we have observed 29±8 Λ c ( Λ c ) charmed-baryon and antibaryon decays in the pK − π + ( p K + π − ) final state. Quasi two-body final states do not contribite significantly to this channel. The mass of the Λ c was measured to be 2281.7±2.7±2.6 MeV/ c 2 and its lifetime 0.18±0.03±0.03 ps. The ratio of Λ c D production, measured in this experiment, is significantly greater than that predicted by photon-gluon fusion and using a Lund model to describe the hadronization. This excess cannot be completely accounted for in this model, even using a Λ c branching fraction in pK π as high as 5%.

1 data table

Result extrapolated to all lambda/c energies has large model dependent uncertainties.


Measurement of kaons in the HELIOS experiment

The HELIOS collaboration van Hecke, Hubert ;
Nucl.Phys.A 525 (1991) 227C-230C, 1991.
Inspire Record 301896 DOI 10.17182/hepdata.36791

None

5 data tables

No description provided.

No description provided.

No description provided.

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phi meson production in neutron - nucleus interactions at 30-GeV - 70-GeV

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.
JINR-E1-90-316, 1990.
Inspire Record 299080 DOI 10.17182/hepdata.39413

None

2 data tables

No description provided.

No description provided.


Factorial moments and correlations in meson - nucleus interactions at 250-GeV/c

The EHS/NA22 collaboration Botterweck, F. ; Charlet, M. ; Chliapnikov, P.V. ; et al.
Z.Phys.C 51 (1991) 37-48, 1991.
Inspire Record 302022 DOI 10.17182/hepdata.40466

A sample of 8000 interactions of 250 GeV/c π+ andK+ mesons on Al and Au nuclei, is used to search for intermittency effects by calculating the normalized factorial moments of order two to four. No significant effect is observed in the higher moments. Two-body rapidity correlations and Bose-Einstein correlations in these interactions are presented.

1 data table

No description provided.


Isospin symmetry in nuclear scattering from Li-6 and C-12 at 280-MeV

Mildenberger, Joseph L. ; Hausser, O. ; Jeppesen, R.G. ; et al.
TRI-PP-90-23, 1990.
Inspire Record 298833 DOI 10.17182/hepdata.18514

None

6 data tables

No description provided.

No description provided.

No description provided.

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First observation of the reaction gamma gamma ---> pi (2) ---> pi0 pi0 pi0

The Crystal Ball collaboration Antreasyan, D. ; Bartels, H.W. ; Besset, D. ; et al.
Z.Phys.C 48 (1990) 561-568, 1990.
Inspire Record 296523 DOI 10.17182/hepdata.15136

The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ→π0π0π0 in theπ0π0π0 invariant mass range from 850 MeV/c2 to 2600 MeV/c2. An enhancement around 1750 MeV/c2 is attributed to theπ2(1670) resonance. The observedπ0π0 invariant mass distribution and theπ0 angular distributions are consistent with those expected for the decay chainπ2→π0f2(1270)→π0π0π0. From our measurements we find the following resonance parameters: two photon partial width\(\Gamma _{\pi _2 }^{\gamma \gamma }= (1.41 \pm 0.23 \pm 0.28)keV\), massM(π2)=(1742±31±49)MeV/c2. and total width\(\Gamma _{\pi _2 }^{tot}= (236 \pm 49 \pm 36)MeV\).

2 data tables

Data read from graph.

Cross section times branching ratio to 3pi0 assuming the decay chain pi2 --> pi0f2 --> 3pi0.


Observation of cumulative isobars in p Ne-20 interactions at 300-GeV/c

Yuldashev, B.S. ; Alimov, M.A. ; Allaberdin, M.L. ; et al.
WISC-EX-90-307, 1990.
Inspire Record 296817 DOI 10.17182/hepdata.19298

None

2 data tables

No description provided.

No description provided.


Inverse Muon Decay, $\nu_\mu e \to \mu^- \nu_e$, at the Fermilab Tevatron

Mishra, S.R. ; Bachmann, K.T. ; Blair, R.E. ; et al.
Phys.Lett.B 252 (1990) 170-176, 1990.
Inspire Record 296115 DOI 10.17182/hepdata.15430

We report an improved measurement of the inverse muon decay process, ν μ +e→ μ − + ν e , at the Fermilab Tevatron. The rate of this reaction with respect to the ν μ -N charged current interaction is measured to be (0.1245±0.0057(stat.)±0.0031 (sys.)) × 10 −2 . The measurement confirms the standard model predictions for the Lorentz structure of the weak current, the helicity of the neutrino, and the energy dependence of the cross section.

4 data tables

Data from the Quadruple Triplet Neutrino beam (QTB).

Data from the Narrow Band Beam(NBB).

Weighted average of the QTB and NBB data.

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