HEPData Search

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Measurement of the Proton - Anti-proton Elastic and Total Cross-section at a Center-of-mass Energy of 540-{GeV}

The UA4 collaboration Battiston, R. ; Bozzo, M. ; Braccini, P.L. ; et al.

Phys.Lett.B 117 (1982) 126-130, 1982.

Inspire Record 178898 DOI 10.17182/hepdata.30870

First results on the measurement of the elastic and total cross section at the CERN pp̄ Collider are presented. Combining the measurement of elastic scattering at low momentum transfer with the rate of inelastic interactions, a value of the total cross section of 66 mb with a 10% statistical error was obtained.

1 data table

Table 1

STATISTICAL ERROR ONLY.

TOTAL, ELASTIC AND INCLUSIVE SINGLE DIFFRACTIVE CROSS-SECTIONS IN ALPHA-ALPHA COLLISIONS AT THE CERN INTERSECTING STORAGE RINGS

Lloyd Owen, D. ; Paternoster, G. ; Patricelli, S. ; et al.

Nucl.Phys.B 274 (1986) 685-706, 1986.

Inspire Record 227125 DOI 10.17182/hepdata.33694

We present measurements of the total interaction cross section and of the single-diffractive dissociation cross section in αα collisions at √ s = 126 GeV. The result obtained for the total cross section, σ tot = (315±18) mb, is a substantial improvement on the precision of earlier measurements. Earlier elastic data were re-analysed, incorporating, through the optical theorem, the present σ tot measurement, resulting in improved determinations of the forward slope, b − t <0.07 = (87±4) GeV −2 , and of the integrated elastic cross section, σ el = (58±6) mb. The single-diffractive differential cross section falls exponentially with momentum transfer at small values of t with a slope b sd = (19.3 ± 0.6) GeV −2 . The integrated single-diffractive cross section is σ sd = (16.6±2.5) mb. The topology of charged tracks resulting from the disintegration of the α in single-diffractive events reveals a two-component distribution. The cross section data are compared with multiple-scattering models.

2 data tables

Table 1

Total cross section by total rate method. Systematic errors included.

Table 2

Reanalysis using data from ISR experiments R-418, and R-807.

Photon Events with Missing Energy at sqrt(s) = 183 to 189 GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Eur.Phys.J.C 17 (2000) 53-65, 2000.

Inspire Record 537913 DOI 10.17182/hepdata.32093

The production of single photons has been studied in the reaction e+e- -> gamma + invisible particles at centre-of-mass energies of 183 GeV and 189 GeV. A previously published analysis of events with multi-photon final states accompanied by missing energy has been updated with 189 GeV data. The data were collected with the DELPHI detector and correspond to integrated luminosities of about 51 pb^{-1} and 158 pb^{-1} at the two energies. The number of light neutrino families is measured to be 2.84 +/- 0.15(stat) +/- 0.14(syst). The absence of an excess of events beyond that expected from Standard Model processes is used to set limits on new physics as described by supersymmetric and composite models. A limit on the gravitational scale is also determined.

2 data tables

Table 1

No description provided.

Table 2

Combined result.

A MEASUREMENT OF ALPHA-ALPHA ELASTIC SCATTERING AT THE CERN ISR

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.

Phys.Lett.B 152 (1985) 140-144, 1985.

Inspire Record 206315 DOI 10.17182/hepdata.30430

We present measurements of the αα elastic scattering differential cross section at √ s = 126 GeV in the range 0.05 ⩽ ‖ t ‖

3 data tables

Table 1

ERRORS ARE STATISTICAL ONLY.

Table 2

EXPONENTIAL FIT TO CROSS SECTION BELOW T = 0.075 GEV**2.

Table 3

OPTICAL THEOREM CALCULATION OF THE TOTAL CROSS SECTION ASSUMING RHO IS ZERO.

Double pomeron exchange studies in p anti-p interactions at 0.63-TeV

Joyce, D. ; Kernan, A. ; Lindgren, M. ; et al.

Phys.Rev.D 48 (1993) 1943-1948, 1993.

Inspire Record 35714 DOI 10.17182/hepdata.22678

The properties of events having the topology and kinematic features of double Pomeron exchange are described. The data were taken at the CERN pp¯ collider at s=0.63 TeV in the UA1 detector. A calorimeter trigger was used to isolate events in which a central cluster of particles was separated from forward particles by large rapidity gaps. The invariant mass M of the central cluster (possibly a colliding Pomeron-Pomeron system) covers the range 10-70 GeV/c2. The M dependence of charged particle multiplicity distributions in these double Pomeron events is strikingly different from their s dependence in pp and pp¯ interactions.

6 data tables

Table 1

Pseudorapidity distribution for charged particle tracks in the DPE data.

Table 2

Pseudorapidity distribution for charged particle tracks in the MB events.

Table 3

Mean charged particle multiplicity as function of the invariant mass of the charged particles in DPE events.

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First measurement of the neutron electromagnetic form-factor in the timelike region

Antonelli, A. ; Baldini, R. ; Bertani, M. ; et al.

Phys.Lett.B 313 (1993) 283-287, 1993.

Inspire Record 359376 DOI 10.17182/hepdata.28867

The first measurement of the neutron form factor in the time-like region has been performed by the FENICE experiment at the ADONE e + e − storage ring. Results at q 2 = 4.0 and 4.4 (GeV/ c ) 2 , together with a new measurement of the proton form factor are presented here.

2 data tables

Table 1

Neutron form factor and cross section.

Table 2

Preliminary analysis of proton form factor and cross section.

Diffractive Photoproduction of D*+/-(2010) at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.

Eur.Phys.J.C 51 (2007) 301-315, 2007.

Inspire Record 747652 DOI 10.17182/hepdata.45627

Diffractive photoproduction of D*+/-(2010) mesons was measured with the ZEUS detector at the ep collider HERA, using an integrated luminosity of 78.6 pb^{-1}. The D* mesons were reconstructed in the kinematic range: transverse momentum p_T(D*) > 1.9 GeV and pseudorapidity |eta(D*)| < 1.6, using the decay D*+ -> D0 pi+_s followed by D0 -> K- pi+ (+c.c.). Diffractive events were identified by a large gap in pseudorapidity between the produced hadronic state and the outgoing proton. Cross sections are reported for photon-proton centre-of-mass energies in the range 130 < W < 300 GeV and for photon virtualities Q^2 < 1 GeV^2, in two ranges of the Pomeron fractional momentum x_pom < 0.035 and x_pom < 0.01. The relative contribution of diffractive events to the inclusive D*+/-(2010) photoproduction cross section is about 6%. The data are in agreement with perturbative QCD calculations based on various parameterisations of diffractive parton distribution functions. The results are consistent with diffractive QCD factorisation.

12 data tables

Table 1

Total cross section integrated over the given kinematic range.

Table 2

Ratio of diffractive to inclusive D* cross section.

Table 3

Differential cross sections for diffractive photoproduction of D*+- mesons as a function of X(NAME=POMERON).

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A Study of inclusive double pomeron exchange in p anti-p ---> p X anti-p at s**(1/2) = 630-GeV

The UA8 collaboration Brandt, A. ; Erhan, S. ; Kuzucu, A. ; et al.

Eur.Phys.J.C 25 (2002) 361-377, 2002.

Inspire Record 586770 DOI 10.17182/hepdata.43241

We report measurements of the inclusive reaction, p pbar -> p X pbar, in events where either or both the beam-like final-state baryons were detected in Roman-pot spectrometers and the central system was detected in the UA2 calorimeter. A Double-Pomeron-Exchange (DPE) analysis of these data and single diffractive data from the same experiment demonstrates that, for central masses of a few GeV, the extracted Pomeron-Pomeron total cross section exhibits an enhancement which exceeds factorization expectations by an order-of-magnitude. This may be a signature for glueball production. The enhancement is shown to be independent of uncertainties connected with possible non-universality of the Pomeron flux factor. Based on our analysis, we present DPE cross section predictions, for unit (1 mb) Pomeron-Pomeron total cross section, at the Tevatron, LHC and the 920 GeV fixed-target experiment, HERA-B.

2 data tables

Table 1

The corrected differential cross section as a function of the mass of the central system X for the 'AND' and 'OR' data sets.

Table 2

Mass dependence of the Pomeron-Pomeron total cross section derived from the'AND' and 'OR' data sets.

Exclusive electroproduction of Phi mesons at HERA.

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.

Nucl.Phys.B 718 (2005) 3-31, 2005.

Inspire Record 679957 DOI 10.17182/hepdata.45894

Exclusive electroproduction of $\phi$ mesons has been studied in $e^\pm p$ collisions at $\sqrt{s}=318 \gev$ with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb$^{-1}$. The $\gamma^*p$ cross section is presented in the kinematic range $2<Q^2<70 \gev^2$, $35<W<145 \gev$ and ${|t|}<0.6 \gev^2$. The cross sections as functions of $Q^2$, $W$, $t$ and helicity angle $\theta_h$ are compared to cross sections for other vector mesons. The ratios $R$ of the cross sections for longitudinally and transversely polarized virtual photons are presented as functions of $Q^2$ and $W$. The data are also compared to predictions from theoretical models.

23 data tables

Table 1

Exclusive GAMMA* P --> PHI P cross section in the Q**2 range 2 to 3 GeV**2.

Table 2

Exclusive GAMMA* P --> PHI P cross section in the Q**2 range 3 to 5 GeV**2.

Table 3

Exclusive GAMMA* P --> PHI P cross section in the Q**2 range 5 to 9 GeV**2.