HEPData Search

A global event shape analysis of the multihadronic final states observed in neutral current deep inelastic scattering events with a large rapidity gap with respect to the proton direction is presented. The analysis is performed in the range $5 \leq Q^2 \leq 185\gev^2$ and $160 \leq W \leq 250\gev$, where $Q^2$ is the virtuality of the photon and $W$ is the virtual-photon proton centre of mass energy. Particular emphasis is placed on the dependence of the shape variables, measured in the $\gamma^*-$pomeron rest frame, on the mass of the hadronic final state, $M_X$. With increasing $M_X$ the multihadronic final state becomes more collimated and planar. The experimental results are compared with several models which attempt to describe diffractive events. The broadening effects exhibited by the data require in these models a significant gluon component of the pomeron.

21 data tables

Table 1

Measured (uncorrected) polar distribution of the sphericity axis w.r.t. thevirtual photon direction in the (gamma*-pomeron)rest frame Data are in bins of the mass of the final state hadronic system.

Table 2

Measured (uncorrected) polar distribution of the sphericity axis w.r.t. thevirtual photon direction in the (gamma*-pomeron)rest frame Data are in bins of the mass of the final state hadronic system.

Table 3

Measured (uncorrected) polar distribution of the sphericity axis w.r.t. thevirtual photon direction in the (gamma*-pomeron)rest frame Data are in bins of the mass of the final state hadronic system.

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Experimental Evidence for the Nonabelian Nature of {QCD}

The AMY collaboration Park, I.H. ; Schnetzer, S. ; Green, J. ; et al.

Phys.Rev.Lett. 62 (1989) 1713, 1989.

Inspire Record 276619 DOI 10.17182/hepdata.20045

We present evidence for the non-Abelian nature of QCD from a study of multijet events produced in e+e− annihilations from √s =50 to 57 GeV in the AMY detector at the KEK storage ring TRISTAN. A comparison of the three-jet event fraction at TRISTAN to the fraction of the DESY storage ring PETRA shows that the QCD coupling strength αs decreases with increasing Q2. In addition, measurements of the angular distributions of four-jet events show evidence for the triple-gluon vertex.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Experimental Study of Lambda p and xi0 p Interactions in the Range 1-GeV/c-10-GeV/c

Hauptman, J.M. ; Kadyk, J.A. ; Trilling, G.H. ;

Nucl.Phys.B 125 (1977) 29-51, 1977.

Inspire Record 119088 DOI 10.17182/hepdata.35369

The reactions Λ p → Λ p, → Σ ± p π ∓ , → Λ p π + π − and → Σ 0 p have been studied in the SLAC 82 inch bubble chamber for incident Λ particles in the momentum range 1–10 GeV/ c . The incident Λ flux was produced by the exposure of a platinum target mounted inside the chamber to a 12 GeV K − beam. A total of 992 events have been analyzed. The reactions are found to be qualitatively similar to corresponding nucleon-nucleon reactions. In particular, the slope parameter B in the elastic cross section d σ /d t = A e Bt has been determined as a function of incident momentum and found to be consistent with that for proton-proton elastic scattering. Angular distributions for the inelastic channels are compared with those of similar nucleon-nucleon reactions, and predictions of relevant exchange models.

13 data tables

Table 1

IN BINS OF EQUAL INCIDENT LAMBDA PATH-LENGTH.

Table 2

IN 100 MEV/C BINS.

Table 3

No description provided.

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FAST TARGET FRAGMENTS IN INTERACTIONS OF RELATIVISTIC NUCLEI WITH PHOTOEMULSION. (IN RUSSIAN)

Antonchik, V.A. ; Bakaev, V.A. ; Bogdanov, V.G. ; et al.

Yad.Fiz. 46 (1987) 1344-1352, 1987.

Inspire Record 256945 DOI 10.17182/hepdata.2434

None

38 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Hyperon production in the channel p p ---> K+ Lambda p near the reaction threshold

The COSY-TOF collaboration Abdel-Samad, S. ; Bilger, R. ; Bohm, A. ; et al.

Phys.Lett.B 632 (2006) 27-34, 2006.

Inspire Record 710561 DOI 10.17182/hepdata.26998

Hyperon production in the threshold region was studied in the reaction pp→K+Λp using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at three different beam momenta pbeam=2.59 , 2.68 and 2.85 GeV/ c (corresponding to excess energies of ɛ=85 , 115 and 171 MeV). Total cross-sections were deduced to be 7.4±0.5 μb , 8.6±0.6 μb and 16.5±0.4 μb , respectively. Differential observables including Dalitz plots were obtained. From the investigation of the Dalitz plot at pbeam=2.85 GeV/c a dominant contribution of the N∗(1650) -resonance to the reaction mechanism was found. In addition the pΛ -final-state interaction turned out to have a significant influence on the Dalitz plot distribution even 171 MeV above threshold.

7 data tables

Table 1

Measured total cross sections.

Table 2

Distribution of the invariant mass of the P-LAMBDA subsystem at beam momentum 2.85 GeV.

Table 3

Distribution of the invariant mass of the K-LAMBDA subsystem at beam momentum 2.85 GeV.