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First results of the CERES electron pair spectrometer from p + Be, P + Au and S + Au collisions

The CERES/NA45 collaboration Drees, A. ; Baur, R. ; Breskin, A. ; et al.

Nucl.Phys.A 566 (1994) 87C-94C, 1994.

Inspire Record 362492 DOI 10.17182/hepdata.8728

The CERES experiment (CErenkov Ring Electron Spectrometer) studies the production of low mass e + e − pairs in proton-proton, proton-nucleus and nucleus-nucleus interactions at the CERN SPS. The CERES spectrometer, has a novel design based on two Ring Imaging Cherenkov (RICH) counters, and it operates close to its design specifications. Data were recorded with 200 GeV u sulfur beam and 450 GeV proton beam. The analysis is in progress. We have extracted first e + − -pairs samples for p+Be, p+Au and S+Au collisions. In addition other physics topics were addressed. Inclusive photon spectra were measured in S+Au interactions. No excess over known hadronic sources was found within our present systematic error of 11%. Results on high p i charged pion spectra are presented up to 4 GeV c . We also studied the production of e + e − -pairs m the strong electromagnetic fields of very peripheral S+Pt collisions. The data are well described by a first-order perturbative QED-calculation.

2 data tables

Table 1

NON-DISRUPTIVE S+PT COLLISIONS.

Table 2

No description provided.

Photoproduction and hadroproduction of phi (1020), K0 (892) and anti-K0 (892) mesons in the energy range 65-GeV to 175-GeV

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

Z.Phys.C 61 (1994) 383-398, 1994.

Inspire Record 362483 DOI 10.17182/hepdata.12881

Inclusive production of ϕ,K*0, and$\overline {K*^0 } $ mesons has been measured in γp, π±p andK± p collisions at beam energies of 65 GeV

30 data tables

Table 1

Statistical errors only.

Table 2

Statistical errors only.

Table 3

Statistical errors only.. An entry 0.00 indicates a statistical error of < 0.005.

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Scaling violations of the proton structure function f2 at small x

The H1 collaboration Abt, I. ; Ahmed, T. ; Andreev, V. ; et al.

Phys.Lett.B 321 (1994) 161-167, 1994.

Inspire Record 360235 DOI 10.17182/hepdata.45140

An analysis is presented of scaling violations of the proton structure function F 2 ( x , Q 2 ) measured with the H1 detector at HERA in the range of Bjorken x values between x = 3 × 10 −4 and 10 −2 for four-momentum transfers Q > 2 larger than 8.7 GeV 2 . The structure function F 2 ( x , Q 2 ) is observed to rise linearly with ln Q 2 . Under the assumption that the observed scaling violations at small x ⩽ 0.01 are described correctly by perturbative QCD, an estimate is obtained of the gluon distribution function G ( x , Q 0 2 ) at Q 2 2 = 20 GeV 2 .

1 data table

Table 1

No description provided.

Search for diffractive charm production in 800-GeV/c proton - silicon interactions

The Fermilab E653 collaboration Kodama, K. ; Ushida, N. ; Mokhtarani, A. ; et al.

Phys.Lett.B 316 (1993) 188-196, 1993.

Inspire Record 35969 DOI 10.17182/hepdata.28848

A search for charm production in the coherent diffractive dissociation reaction pSi→XSi was carried out for the modes D 0 → K − π + , D 0 → K − π + π + π − , and D + → K − π + π + . No charm signals were observed, and the 90% confidence level upper limit for coherent charm pair production was determined to be 26 μ b per silicon nucleus. The results are interpreted as an upper limit of 0.2% on the amount of intrinsic charm in the proton.

1 data table

Table 1

90 pct CL upper limits.

Search for excited quarks in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Albrow, Michael G. ; Amidei, Dante E. ; et al.

Phys.Rev.Lett. 72 (1994) 3004-3008, 1994.

Inspire Record 360332 DOI 10.17182/hepdata.42507

If quarks are composite particles then excited states are expected. We have searched in pp¯ collisions for excited quarks (q*) which decay to common quarks by emitting a W boson (q*→qW) or a photon (q*→qγ). The simplest model of excited quarks has been excluded for mass M*<540 GeV/c2 at 95% confidence level.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

$P_{\tau}$ and $X_F$ Dependence of the Polarization of $\Sigma^+$ Hyperons Produced by 800-GeV/c Protons

The E761 collaboration Morelos Pineda, Antonio ; Albuquerque, I.F. ; Bondar, N.F. ; et al.

Phys.Rev.D 52 (1995) 3777-3780, 1995.

Inspire Record 360549 DOI 10.17182/hepdata.42500

We utilize the angle and momentum resolution of our apparatus to study the polarization of 375 GeV/c Σ+ hyperons produced by 800 GeV/c protons incident on a Cu target. By examining in detail two of our high statistics data samples, we find evidence for structure in the pt dependence of Σ+ polarization and are able to extract the xF dependence of the Σ+ polarization and compare it with xF behavior in the Λ0 and Ξ− systems.

9 data tables

Table 1

0.9 mrad horizontal sample.

Table 2

2.9 mrad horizontal sample.

Table 3

3.3 mrad horizontal sample.

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Observation of D(s)** (2536) meson production by neutrinos in BEBC

The Big Bubble Chamber Neutrino collaboration Asratyan, A.E. ; Aderholz, M. ; Ammosov, V.V. ; et al.

Z.Phys.C 61 (1994) 563-566, 1994.

Inspire Record 363214 DOI 10.17182/hepdata.14264

Neutrino interactions in BEBC produce theDS** (2536) charmed strange meson. The mass of this state is 2534.2±1.2 MeV. The production rate is 0.011±0.005 per neutrino charged current interaction at a mean neutrino energy of 61 GeV. An earlier claim for another$c\bar s$ bound state near 2565 MeV, produced in neutrino interactions, is not supported.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

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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Measurement of the inclusive jet cross-section in photon-photon interactions at TRISTAN

The AMY collaboration Kim, B.J. ; Nozaki, T. ; Bodek, A. ; et al.

Phys.Lett.B 325 (1994) 248-256, 1994.

Inspire Record 361660 DOI 10.17182/hepdata.38388

We present cross section measurements for inclusive jet production in almost-real photon-photon interactions at TRISTAN using the AMY detector. The results are compared with leading-order QCD calculations for different parameterizations of the parton density in the photon.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.