Total cross-section of the reaction p p ---> p K+ Lambda close to threshold

Balewski, J.T. ; Budzanowski, A. ; Dombrowski, H. ; et al.
Phys.Lett.B 420 (1998) 211-216, 1998.
Inspire Record 467810 DOI 10.17182/hepdata.42045

The energy dependence of the total cross section for the pp \to pK^+\Lambda reaction was measured in the threshold region covering the excess energy range up to 7MeV. Existing model calculations describe the slope of the measured cross sections well, but are too low by a factor of two to three in rate. The data were used for a precise determination of the beam momentum of the COSY-synchrotron.

1 data table match query

Only statistical errors are presented in the table.


Eta-prime production in proton proton scattering close to threshold

Moskal, P. ; Balewski, J.T. ; Budzanowski, A. ; et al.
Phys.Rev.Lett. 80 (1998) 3202-3205, 1998.
Inspire Record 467809 DOI 10.17182/hepdata.42086

The $pp \to pp \eta^{\prime}$ (958) reaction has been measured at COSY using the internal beam and the COSY-11 facility. The total cross sections at the four different excess energies \mbox{$ Q = ~1.5 ~MeV, ~1.7 ~MeV, ~2.9 ~MeV,$ and $ ~4.1 MeV$} have been evaluated to be \mbox{$ \sigma = 2.5 \pm 0.5~nb$, $~~~ 2.9 \pm 1.1~nb$, $~~~ 12.7 \pm 3.2~nb$, ~ and $~~~ 25.2 \pm 3.6 ~nb $}, respectively. In this region of excess energy the $\eta^{\prime}$ (958) cross sections are much lower compared to those of the $\pi ^0$ and $\eta$ production.

1 data table match query

Only statistical errors are presented in the table.


Measurement of $\pi^- p \to \pi^- p \pi^0$ Reaction Near Threshold and Breaking of Chiral Symmetry

The OMICRON collaboration Kernel, G. ; Korbar, D. ; Krizan, P. ; et al.
Phys.Lett.B 225 (1989) 198-202, 1989.
Inspire Record 278272 DOI 10.17182/hepdata.29804

A full-kinematics measurement of the π − p→ π − p π 0 reaction in the incident π − momentum region from 295 to 450 MeV/ c is presented. The measurement was performed with the OMICRON spectrometer at the CERN synchrocyclotron.

1 data table match query

Integrated cross section.


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 match query

Statistical errors only.


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 match query

No description provided.


Pion Pair Production From $\gamma \gamma$ Interactions at {PEP} and the Radiative Width of the F0 Meson

The DELCO collaboration Courau, A. ; Johnson, R.P. ; Sherman, S.S. ; et al.
Phys.Lett.B 147 (1984) 227-231, 1984.
Inspire Record 202552 DOI 10.17182/hepdata.30498

Results are presented of an untagged e + e − → e + e − + π + π − experiment performed at PEP with the DELCO detector. In the invariant-mass range 0.7 ⩽ W ππ < 2.0 GeV/ c 2 , the QED e + e − background is identified and eliminated, and both the π + π − predictions and the μ + μ − and K + K − background substractions are normalized to the measurement of the e e + e − events. The results agree with a simple model of superposition and interference of the f 0 (1270) resonance, produced with helicity 2, with a Born-term continuum. From a fit of the model to the data, the radiative width of the f 0 is determined to be Γ f 0 → γγ = 2.70 ± 0.21 keV.

1 data table match query

Data read from graph.


Production of $K \bar{K}$ Pairs in Photon-photon Collisions and the Excitation of the Tensor Meson F-prime (1515)

The TASSO collaboration Althoff, M. ; Brandelik, R. ; Braunschweig, W. ; et al.
Phys.Lett.B 121 (1983) 216-222, 1983.
Inspire Record 181468 DOI 10.17182/hepdata.30814

We have observed exclusive production of K + K − and K S O K S O pairs and the excitation of the f′(1515) tensor meson in photon-photon collisions. Assuming the f′ to be production in a helicity 2 state, we determine Λ( f ′ → γγ) B( f ′ → K K ) = 0.11 ± 0.02 ± 0.04 keV . The non-strange quark of the f′ is found to be less than 3% (95% CL). For the θ(1640) we derive an upper limit for the product Λ(θ rarr; γγ K K ) < 0.03 keV (95% CL ) .

2 data tables match query

Data read from graph.. Errors are the square roots of the number of events.

Data read from graph.. Errors are the square roots of the number of events.


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 match query

No description provided.


A Measurement of the electric form-factor of the neutron through polarized-d (polarized-e, e-prime n)p at Q**2 = 0.5-(GeV/c)**2

The E93026 collaboration Zhu, H. ; Ahmidouch, A. ; Anklin, H. ; et al.
Phys.Rev.Lett. 87 (2001) 081801, 2001.
Inspire Record 556212 DOI 10.17182/hepdata.31418

We report the first measurement of the neutron electric form factor $G_E^n$ via $\vec{d}(\vec{e},e'n)p$ using a solid polarized target. $G_E^n$ was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia, $^{15}$ND$_3$. The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility (TJNAF) in quasi free kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find $G_E^n = 0.04632\pm0.00616 (stat.) \pm0.00341 (syst.)$ at $Q^2 = 0.495$ (GeV/c)$^2$.

1 data table match query

No description provided.


Asymmetry ratios in the photoproduction of π + by linearly polarized γ-rays in the energy range 200–400 MeV

Gorenstein, P. ; Grilli, M. ; Soso, F. ; et al.
Phys.Lett. 23 (1966) 394-396, 1966.
Inspire Record 1392866 DOI 10.17182/hepdata.30179

The asymmetry ratio for the process γ + p → n + π + by linearly polarized γ rays are reported for E γ = 200 − 400 MeV and for θ (production angle of π in the c.m. system) = 90°. The experimental results are compared with some recent theoretical predictions.

1 data table match query

No description provided.