Date

First Observation of $\gamma \gamma \to \omega \omega$

The ARGUS collaboration Albrecht, H. ; Andam, A.A. ; Binder, U. ; et al.
Phys.Lett.B 198 (1987) 577-582, 1987.
Inspire Record 247566 DOI 10.17182/hepdata.30070

The reaction γγ → 2 π + 2 π − 2 π 0 has been studied using the ARGUS detector at the e + e − storage ring DORIS II at DESY. Production of ω mesons is observed and, in particular, the reaction γγ → ωω is seen for the first time. The cross section for γγ → ωω has an enhancement at ∼ 1.9 GeV/ c 2 of about 10 nb. The cross sections for γγ → 2 π + 2 π − 2 π 0 and γγ → ωπ + π − π 0 are also given.

3 data tables

Topological cross section. 14 pct systematic uncertainty not included.

Cross section for (omega omega) production. Additional 25 pct systematic error not included.

Cross section for (omega pi+ pi- pi0) where (omega omega) events have been removed. Additional 15 pct systematic error not included.


No description provided.

No description provided.

No description provided.

More…

Production of W's wiith Large Transverse Momentum at the CERN Proton - Antiproton Collider

The UA1 collaboration Albajar, C. ; Albrow, M.G. ; Allkofer, O.C. ; et al.
Phys.Lett.B 193 (1987) 389-398, 1987.
Inspire Record 246169 DOI 10.17182/hepdata.30164

We have measured the W transverse momentum distribution ( p T W ) using a sample of 323 W → eν and W → μν events produced in proton-antiproton collisions at the CERN collider. In the present letter we extend the study of the distribution up to p T W ∼- m W and compare to leading and higher order QCD. This comparison is a precise test of QCD with hadron colliders and the inclusive spectrum gives good agreement over a large range of p T W . However we observed two events at very large p T W (∼- 100 GeV/ c ) in which the W candidate recoils against an energetic di-jet system. Both events have a very large missing transverse energy and a jet-jet mass compatible with the W mass. In a separate analysis, a topologically similar event has been observed in which a high-mass di-jet system is balanced by a large missing transverse energy which could be interpreted as Z 0 → ν ν decay. We cannot easily explain these three events in terms of explicit second-order QCD calculations. However we cannot exclude at this stage the possibility that they are the result of non-gaussian fluctuations in the response of UA1 calorimetry or a statistical fluctuation in the data.

1 data table

THESE NUMBERS WRE READ OFF FIG 1A.


Measurements of the Nucleon Structure Functions F(2)N in Deep Inelastic Muon Scattering from Deuterium and Comparison with Those from Hydrogen and Iron

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Nucl.Phys.B 293 (1987) 740-786, 1987.
Inspire Record 245537 DOI 10.17182/hepdata.33529

None

12 data tables

No description provided.

No description provided.

No description provided.

More…

Multiparticle Production in Proton - Nucleus Collisions at 360-{GeV}/$c$ Using the European Hybrid Spectrometer

The EHS-RCBC collaboration Bailly, J.L. ; Banerjee, S. ; Bartl, W. ; et al.
Z.Phys.C 35 (1987) 301, 1987.
Inspire Record 245414 DOI 10.17182/hepdata.15776

360 GeV/c proton interactions with aluminium (Al) and gold (Au) targets are studied using the European Hybrid Spectrometer (EHS) equipped with the Rapid Cycling Bubble Chamber (RCBC). Multiplicities, rapidity distributions and correlations between leading and other produced particles are presented and compared with Monte Carlo calculations based on the multi-chain and Lund models.

1 data table

No description provided.


Investigation of the polarization of Lambda hyperons produced in C-12 C and C-12 Ta interactions at 4.2-GeV/c per nucleon.

Iovchev, K. ; Kladnitskaya, E.N. ; Boldea, V. ; et al.
Sov.J.Nucl.Phys. 47 (1988) 285-286, 1988.
Inspire Record 247551 DOI 10.17182/hepdata.39463

None

2 data tables

No description provided.

No description provided.


Pion Pair Production in Photon-photon Collisions at Dci

The DM1-DM2 collaboration Ajaltouni, Z. ; Falvard, A. ; Jousset, J. ; et al.
Phys.Lett.B 194 (1987) 573, 1987.
Inspire Record 248992 DOI 10.17182/hepdata.30109

This paper presents experimental results on π + π − production threshold from the collision of quasi-real photons. The data, obtained at the e + e − collider DCI, are a combination of the results from the DM1 and DM2 experiments. Using the e + e − and π + π − production for normalization and cross-checks, we observe a pion pair yield at low invariant mass ( W < 500 MeV/ c 2 ) which is approximately twice the one expected from Born terms.

2 data tables

Data read from graph.

Data read from graph.


Analysis of Transverse Momentum Distributions for $p p$ Interactions at 360-{GeV}/$c$ in the Framework of a Quark - Diquark Fragmentation Model

The EHS-RCBC collaboration Bailly, J.L. ; Bruyant, F. ; Buschbeck, B. ; et al.
Z.Phys.C 35 (1987) 295, 1987.
Inspire Record 245106 DOI 10.17182/hepdata.15802

Using a quark-diquark fragmentation model, in which either the Field-Feynman or the Lund model is coupled with a quark-diquark distribution function, we study transverse momentum distributions,pT, for the inclusive reactionspp→hadron +anything at 360 GeV/c. We find that a primordial mean transverse momentum 〈kT〉≃0.4 GeV/c can well reproduce thepT2 distributions of charged hadrons, π0,Ks0, Λ0,K* and Σ* and the Feynmanx−pT correlations. We confirm that a diquark in a proton plays an important rôle in reproducing thex−pT correlation of Λ0.

1 data table

No description provided.


Measurement of the Structure Functions F2 and Xf3 and Comparison With {QCD} Predictions Including Kinematical and Dynamical Higher Twist Effects

The BEBC WA59 collaboration Varvell, K. ; Cooper-Sarkar, A.M. ; Parker, M.A. ; et al.
Z.Phys.C 36 (1987) 1, 1987.
Inspire Record 245094 DOI 10.17182/hepdata.15775

The isoscalar nucleon structure functionsF2(x, Q2) andxF3(x, Q2) are measured in the range 0<Q2<64 GeV2, 1.7<W2<250 GeV2,x<0.7 using ν and\(\bar v\) interactions on neon in BEBC. The data are used to evaluate possible higher twist contributions and to determine their impact on the evaluation of the QCD parameter Λ. In contrast to previous analyses reaching to such lowW2 values, it is found that a low\(\Lambda _{\overline {MS} } \) value in the neighbourhood of 100 MeV describes the data adequately and that the contribution of dynamical higher twist effects is small and negative.

9 data tables

No description provided.

No description provided.

No description provided.

More…

Observation of $e^+ e^- \to D(s$)+- $D^*(s$)-+ at $\sqrt{s}=4$.14-{GeV}

The MARK-III collaboration Blaylock, G. ; Bolton, T. ; Brown, J.S. ; et al.
Phys.Rev.Lett. 58 (1987) 2171, 1987.
Inspire Record 244856 DOI 10.17182/hepdata.20170

We present evidence for the exclusive reaction e+e−→Ds±Ds*∓, observed with the Mark III detector at the SLAC storage ring SPEAR. The Ds± is reconstructed in the φπ± decay mode, while the Ds*∓ is detected as a narrow peak in the recoil-mass distribution. The mass of the Ds* is found to be 2109.3±2.1±3.1 MeV/c2, yielding a Ds*−Ds mass difference of 137.9±2.1±4.3 MeV/c2. The width of the Ds* is <22 MeV/c2 at the 90%-confidence level. The observed signal corresponds to σ(e+e−→Ds+Ds*−+Ds−Ds*+)B(Ds+→φπ+)=30±6±11 pb at s=4.14 GeV.

1 data table

No description provided.