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Large Inclusive Charged Particle Distributions in Deep Inelastic Scattering Events at HERA

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

Z.Phys.C 70 (1996) 1-16, 1996.

Inspire Record 402646 DOI 10.17182/hepdata.44930

A measurement of inclusive charged particle distributions in deep inelastic $ep$ scattering for $\gamma~* p$ centre-of-mass energies $75< W < 175$GeV and momentum transfer squared $10< Q~2 < 160$GeV$~2$ from the ZEUS detector at HERA is presented. The differential charged particle rates in the $\gamma~* p$ centre-of-mass system as a function of the scaled longitudinal momentum, $x_F$, and of the transverse momentum, $p_t~*$ and $<\!\!p_t~{*\,2}\!\!>\,\,$ , as a function of $x_F$, $W$ and $Q~2$ are given. Separate distributions are shown for events with (LRG) and without (NRG) a rapidity gap with respect to the proton direction. The data are compared with results from experiments at lower beam energies, with the naive quark parton model and with parton models including perturbative QCD corrections. The comparison shows the importance of the higher order QCD processes. Significant differences of the inclusive charged particle rates between NRG and LRG events at the same $W$ are observed. The value of $<\!\!p_t~{*\,2}\!\!>\,\,$ for LRG events with a hadronic mass $M_X$, which excludes the forward produced baryonic system, is similar to the $<\!\!p_t~{*\,2}\!\!>\,\,$ value observed in fixed target experiments at $W \approx M_X$.

11 data tables

Table 1

Differential multiplicites for NRG events.. XL is parallel to the virtual photon axis.

Table 2

Differential multiplicites for NRG events.. PT is relative to the virtual photon axis.

Table 3

Mean PT**2 for NRG events.. PT is relative to the virtual photon axis.

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Hadron production in diffractive deep-inelastic scattering.

The H1 collaboration Adloff, C. ; Aid, S. ; Anderson, M. ; et al.

Phys.Lett.B 428 (1998) 206-220, 1998.

Inspire Record 468748 DOI 10.17182/hepdata.44324

Characteristics of hadron production in diffractive deep-inelastic positron-proton scattering are studied using data collected in 1994 by the H1 experiment at HERA. The following distributions are measured in the centre-of-mass frame of the photon dissociation system: the hadronic energy flow, the Feynman-x (x_F) variable for charged particles, the squared transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a function of x_F. These distributions are compared with results in the gamma^* p centre-of-mass frame from inclusive deep-inelastic scattering in the fixed-target experiment EMC, and also with the predictions of several Monte Carlo calculations. The data are consistent with a picture in which the partonic structure of the diffractive exchange is dominated at low Q^2 by hard gluons.

6 data tables

Table 1

Energy flow distributions in the gamma*-pomeron CM frame.. Positive etarap corresponds to the direction of the incoming photon.

Table 2

Energy flow distributions in the gamma*-pomeron CM frame.. Positive etarap corresponds to the direction of the incoming photon.

Table 3

Energy flow distributions in the gamma*-pomeron CM frame.. Positive etarap corresponds to the direction of the incoming photon.

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Strangeness production in deep-inelastic positron proton scattering at HERA.

The H1 collaboration Aid, S. ; Anderson, M. ; Andreev, V. ; et al.

Nucl.Phys.B 480 (1996) 3-34, 1996.

Inspire Record 421030 DOI 10.17182/hepdata.44711

Measurements are presented of $K~0$ meson and $\Lambda$ baryon production in deep-inelastic positron-proton scattering (DIS) in the kinematic range $10 < Q~2 < 70\,$GeV$~2$ and $10~{-4} < x < 10~{-2}$. The measurements, obtained using the H1 detector at the HERA collider, are discussed in the light of possible mechanisms for increased strangeness production at low Bjorken-$x$. Comparisons of the $x_F$ spectra, where $x_F$ is the fractional longitudinal momentum in the hadronic centre-of-mass frame, with results from electron-positron annihilation are made. The $x_F$ spectra and the $K~0$ ``seagull'' plot are compared with previous DIS results. The mean $K~0$ and $\Lambda$ multiplicities are studied as a function of the centre-of-mass energy $W$ and are observed to be consistent with a logarithmic increase with $W$ when compared with previous measurements. A comparison of the levels of strangeness production in diffractive and non-diffractive DIS is made. An upper limit of $0.9\,$nb, at the $95\%$ confidence level, is placed on the cross-section for QCD instanton induced events.

5 data tables

Table 1

The XL distribution for K0 particles.

Table 2

The XL distribution for LAMBDA particles.

Table 3

Corrected Mean PT**2 for K0 production RE = E+ P --> E+ K0 X.

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Production of neutral strange particles in muon - nucleon scattering at 490-GeV

The E665 collaboration Adams, M.R. ; Aderholz, M. ; Aïd, S. ; et al.

Z.Phys.C 61 (1994) 539-550, 1994.

Inspire Record 362429 DOI 10.17182/hepdata.42473

The production ofK0, Λ and$\bar \Lambda $ particles is studied in the E665 muon-nucleon experiment at Fermilab. The average multiplicities and squared transverse momenta are measured as a function ofxF andW2. Most features of the data can be well described by the Lund model. Within this model, the data on the K0/π± ratios and on the averageK0 multiplicity in the forward region favor a strangeness suppression factors/u in the fragmentation process near 0.20. Clear evidence for QCD effects is seen in the average squared transverse momentum ofK0 and Λ particles.

10 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Differential cross sections, charge production asymmetry, and spin-density matrix elements for D*(2010)+- produced in 500-GeV/c pi- nucleon interactions.

The Fermilab E791 collaboration Aitala, E.M ; Amato, S ; Anjos, J.C ; et al.

Phys.Lett.B 539 (2002) 218-226, 2002.

Inspire Record 587686 DOI 10.17182/hepdata.42892

We report differential cross sections for the production of D*(2010) produced in 500 GeV/c pi^- nucleon interactions from experiment E791 at Fermilab, as functions of Feynman-x (x_F) and transverse momentum squared (p_T^2). We also report the D* +/- charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are \eta= 0.01 +- 0.02 and -0.01 +- 0.02 for leading and non-leading particles, respectively.

8 data tables

Table 1

Acceptance corrected differential cross sections for D*+- production as a function of XL, Feynman X.

Table 2

Acceptance corected differential cross sections for D*+- production as a function of PT**2.

Table 3

Charge production asymmetry as a function of Feynman X.

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rivet Analysis
Inclusive production of charged pions in p p collisions at 158-GeV/c beam momentum.

The NA49 collaboration Alt, C. ; Anticic, T. ; Baatar, B. ; et al.

Eur.Phys.J.C 45 (2006) 343-381, 2006.

Inspire Record 694016 DOI 10.17182/hepdata.43114

New results on the production of charged pions in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. Pions are identified by energy loss measurement in a large TPC tracking system which covers a major fraction of the production phase space. Inclusive invariant cross sections are given on a grid of nearly 300 bins per charge over intervals from 0 to 2 GeV/c in transverse momentum and from 0 to 0.85 in Feynman x. The results are compared to existing data in overlapping energy ranges.

26 data tables

Table 1

Double differential cross sections for PI+ and PI- in P P interactions at 158 GeV.

Table 2

Double differential cross sections for PI+ and PI- in P P interactions at 158 GeV.

Table 3

Double differential cross sections for PI+ and PI- in P P interactions at 158 GeV.