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Measurement of anti-deuteron photoproduction and a search for heavy stable charged particles at HERA.

The H1 collaboration Aktas, A. ; Andreev, V. ; Anthonis, T. ; et al.

Eur.Phys.J.C 36 (2004) 413-423, 2004.

Inspire Record 647349 DOI 10.17182/hepdata.46135

The cross section for anti-deuteron photoproduction is measured at HERA at a mean centre-of-mass energy of W_{\gamma p} = 200 GeV in the range 0.2 < p_T/M < 0.7 and |y| < 0.4, where M, p_T and y are the mass, transverse momentum and rapidity in the laboratory frame of the anti-deuteron, respectively. The numbers of anti-deuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured in photoproduction to be 0.010 \pm 0.002 \pm 0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.

2 data tables

Table 1

The measured value of the invariant DEUTBAR production cross section. The data are normalized to a total photoproduction cross section of (164 +- 11 MUB).

Table 2

The measured and weak decay corrected values of the DEUTBAR to PBAR cross sections.

Inclusive production of eta mesons in pi p, K p and gamma p collisions at energies around 100-GeV.

The Omega Photon collaboration Apsimon, R.J. ; Atkinson, M. ; Baake, M. ; et al.

Z.Phys.C 54 (1992) 185-191, 1992.

Inspire Record 339919 DOI 10.17182/hepdata.14710

Measurements are reported of inclusive production of η-mesons in the beam fragmentation region in γp, πp andKp collisions. Results include a small but significant departure from VMD, and a pronounced rise in theη/π0 ratio with increasingpT.

21 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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pi0 and eta meson production in pi+ p and K+ p collisions at 250-GeV/c

The EHS/NA22 collaboration Atayan, M.R. ; Botterweck, F. ; Charlet, M. ; et al.

Z.Phys.C 54 (1992) 247-254, 1992.

Inspire Record 322980 DOI 10.17182/hepdata.14597

We report on a study of inclusiveπ0 and η meson production inπ+p andK+p interactions at 250 GeV/c beam momentum. The Feynman-x spectrum ofπ0 is very similar in shape and normalization to that of negatively charged particles produced in the same experiment. The results are compared with data at other energies and with FRITIOF model predictions. This model overestimates the η cross section by a factor of 2.5. It reproduces theπ0 cross section correctly, but predicts a too hardπ0x distribution.

15 data tables

Table 1

Data from Gamma Detectors only.

Table 2

Data from Gamma Detectors only.

Table 3

Data from RCBC only.

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Inclusive production of $\pi^0$ mesons in $\pi$p, Kp and $\gamma$p collisions at energies around 100-GeV.

The Omega Photon collaboration Apsimon, R.J. ; Atkinson, M. ; Baake, M. ; et al.

Z.Phys.C 52 (1991) 397-405, 1991.

Inspire Record 325149 DOI 10.17182/hepdata.14858

Measurements are reported of inclusive production of π0-mesons in the beam fragmentation region in γp, πp andKp collisions. Results include the ratio of π0 production inKp and πp collisions, showing reduced production from fragmentation of theK-meson, and the ratio of π0 production in photon and hadron collisions which shows agreement with modified Vector Meson Dominance at lowPT, and departures at higherPT signalling the onset of direct photon reactions. The pattern of departure from Feynman scaling at highPT points to a contribution of hard parton-parton collisions in both γp and πp collisions.

28 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.