Do Nascimento, A.
Electron production
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First Observation of Dielectron Production at the Bevalac

The DLS collaboration Roche, G. ; Claesson, G. ; Hendrie, D. ; et al.
Phys.Rev.Lett. 61 (1988) 1069-1072, 1988.
Inspire Record 268588 DOI 10.17182/hepdata.38105

We have begun a program to measure dielectron production in p-nucleus and nucleus-nucleus collisions at the LBL Bevalac. Results are presented for the reaction p+Be at 4.9 GeV. For the first time, direct dilepton production is observed below 10 GeV incident energy. The cross sections are discussed and compared to previous data at higher energies. The observation of a structure at a mass of about 275 MeV suggests that pion annihilation may be the dominant production mechanism in this mass range.

2 data tables
Table 1

A IS TARGET ATOMIC MASS NUMBER.

Table 2

A IS TARGET ATOMIC MASS NUMBER.


rivet Analysis
Measurement of the Reaction $e^+ e^- \to \eta \pi^+ \pi^-$ in the Center-of-mass Energy Interval 1350-{MeV} to 2400-{MeV}

The DM2 collaboration Antonelli, A. ; Baldini, R. ; Calcaterra, A. ; et al.
Phys.Lett.B 212 (1988) 133-138, 1988.
Inspire Record 264144 DOI 10.17182/hepdata.29912

The e + e − → ηπ + π − reaction has been measured in the center of mass energy interval 1350–2400 MeV by the magnetic detector DM2 at the Orsay storage ring DCI. Under the hypothesis of only one large resonance the cross section is not fit in a satisfactory way. The branching ratio τ − → η − π 0 ν τ =(0.13 ± 0.02)% is deduced via CVC from the above measurement.

1 data table
Table 1

No description provided.


Measurements of Transverse Quasielastic Electron Scattering From the Deuteron at High Momentum Transfers

Arnold, R.G. ; Benton, D. ; Bosted, Peter E. ; et al.
Phys.Rev.Lett. 61 (1988) 806, 1988.
Inspire Record 261496 DOI 10.17182/hepdata.20075

Cross sections for 180° inelastic electron scattering from deuterium were measured from breakup threshold to beyond the quasielastic peak for incident-beam energies of 0.843, 1.020, 1.189, and 1.281 GeV, corresponding to 0.75≤Q2≤2.57 (GeV/c)2. The data are in reasonable agreement with nonrelativistic models that include final-state interactions and meson-exchange currents. The scaling function F(y) for these data is generally in agreement with F(y) for forward-angle data at the same Q2. Values of GMn determined from the data are in good agreement with results from previous experiments.

4 data tables
Table 1

Axis error includes +- 0.0/0.0 contribution (3.9 TO 12.0////).

Table 2

Axis error includes +- 0.0/0.0 contribution (3.9 TO 12.0////).

Table 3

Axis error includes +- 0.0/0.0 contribution (3.9 TO 12.0////).

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Study of Multi - Hadron Events With Isolated Leptons in $e^+ e^-$ Annihilation at $50\le \sqrt{s} \le 55$-{GeV}

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett.B 207 (1988) 355-360, 1988.
Inspire Record 23570 DOI 10.17182/hepdata.29946

We have studied inclusive lepton production in e + e − annihilations into multihadrons in the energy range between √ s =50 and 55 GeV using the VENUS detector at TRISTAN, KEK. Though MARK-J and JADE groups at PETRA found an excess of isolated muon events at √ s ⩾46.3 GeV, we have not observed such an anomaly in muon nor in electron production. The observed rates of isolated leptons are consistent with the production and decay of five known quarks.

4 data tables
Table 1

Observed rates for whole event sample.

Table 2

No description provided.

Table 3

No description provided.

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rivet Analysis
$\eta$ and $\eta^\prime$ Production in $e^+ e^-$ Annihilation at 29-{GeV}: Indications for the $D(s$)+- Decays Into $\eta \pi^\pm$ and $\eta^\prime \pi^\pm$

Wormser, G. ; Abrams, G.S. ; Amidei, D. ; et al.
Phys.Rev.Lett. 61 (1988) 1057, 1988.
Inspire Record 261194 DOI 10.17182/hepdata.20080

η production has been investigated by the Mark II collaboration at the SLAC e+e− storage ring PEP. η particles are reconstructed by their γγ decay mode. The η fragmentation function has been measured and found to be in good agreement with the Lund-model prediction. η′ production has been measured for the first time in high-energy e+e− annihilation. There is evidence at the 3σ level for Ds± decay into ηπ± and η′π±.

4 data tables
Table 1

Numerical values supplied by G.Wormser.

Table 2

Z = 0.0 point extrapolated using LUND fragmentation model.

Table 3

Z = 0.0 point extrapolated using LUND fragmentation model.

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Measurement of the Difference in R = $\sigma^-$l / $\sigma^-$t and $\sigma$(a) / $\sigma(D$) in Deep Inelastic $e D$, $e$ Fe and $e$ Au Scattering

Dasu, S. ; de Barbaro, P. ; Bodek, A. ; et al.
Phys.Rev.Lett. 60 (1988) 2591, 1988.
Inspire Record 260760 DOI 10.17182/hepdata.20155

We measured the differences in R=σLσT and the cross-section ratio σAσD in deep-inelastic electron scattering from D, Fe, and Au nuclei in the kinematic range 0.2≤x≤0.5 and 1≤Q2≤5 (Gev/c)2. Our results for RA−RD are consistent with zero for all x and Q2, indicating that possible contributions to R from nuclear higher-twist effects and spin-0 constituents in nuclei are not different from those in nucleons. The European Muon Collaboration effect is reconfirmed, and the low-x data from all recent experiments, at all Q2, are now in agreement.

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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POLARIZATION MEASUREMENT IN PION NUCLEON CHARGE EXCHANGE PI+ N (POLARIZED) ---> PI0 P AT 6-GEV/C

Fujisaki, M. ; De Lesquen, A. ; Babou, M. ; et al.
Nuovo Cim.A 99 (1988) 395-404, 1988.
Inspire Record 270461 DOI 10.17182/hepdata.37515

The polarization in pion-nucleon charge exchange was measured at 6 GeV/c incident momentum for 0.1 (GeV/c)2 < |t| < 1.6 (GeV/c)2. Using the channel π+ n ↑ → π0p allowed precise measurement of the recoil proton for good rejection of inelastic events. The results are compared with previous experiments using channel π−p ↑ with or without detection of the recoil neutron.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


ELECTROPRODUCTION OF SINGLE CHARGED PIONS FROM DEUTERIUM AT Q**2 APPROXIMATELY 1-GEV**2 IN THE RESONANCE REGION

Vapenikova, O. ; Allison, John ; Dickinson, B. ; et al.
Z.Phys.C 37 (1988) 251-258, 1988.
Inspire Record 263398 DOI 10.17182/hepdata.898

We present differential cross-sections for the electro-production of single charged pions from deuterium for a virtual photon mass squared −1.0 GeV2 and for pion nucleon masses in the range 1.23–1.68 GeV (the 1st and 2nd resonance regions). The data are compared with predictions from fits to hydrogen data.

30 data tables
Table 1

FORWARD BINS.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of the Processes $e^+ e^- \to e^+ e^-$ and $e^+ e^- \to \gamma \gamma$ at $\sqrt{s}=52$-{GeV}

The TOPAZ collaboration Adachi, I. ; Aihara, H. ; Dijkstra, H.B. ; et al.
Phys.Lett.B 200 (1988) 391-396, 1988.
Inspire Record 251921 DOI 10.17182/hepdata.30010

Differential cross sections for the processes e + e − → e + e − (Bhabha scattering) and e + e − → γγ have been measured with the TOPAZ detector at s =52 GeV . The results agree with the predictions of quantum electrodynamics (QED). The lower limits for the QED cut-off parameters have been obtained to be Λ + ⩾115 GeV and Λ − ⩾236 GeV for Bhabha scattering, and Λ + ⩾94 GeV and Λ − ⩾59 GeV for the reaction e + e − → γγ .

4 data tables
Table 1

Statistical errors only.

Table 2

Statistical errors only.

Table 3

Ratio of experimental data to prediction for lowest order QED. Statistical errors only.

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Observation of the Selective Coupling of $K^*$ States to the $K^- \eta$ Channel

Aston, D. ; Awaji, N. ; Bienz, T. ; et al.
Phys.Lett.B 201 (1988) 169-175, 1988.
Inspire Record 250272 DOI 10.17182/hepdata.30009

The K − η effective mass spectrum in the reaction K − p→K − π + π − π 0 p at 11 GeV/ c has a prominent peak at ≈1.75 GeV/ c 2 , which is shown to be due to the K 3 ∗ (1780) by a spherical harmonic moments analysis and amplitude decomposition; there is no significant signal for K 2 ∗ (1430). The measured branching fractions for the leading L =1 and L =2 K ∗, s, [BF(K 2 ∗ (1430)→Kη) <0.45% at the 95% CL and BF ( K 3 ∗ (1780)→ Kη )=9.4±3.4%] confirm the SU(3) prediction that the Kη channel couples preferentially to odd spin K *, s.

2 data tables
Table 1

Numerical data of acceptance corrected spherical harmonic moments requested from authors.

Table 2

Including systematic error.