Date

Measurement of the spin-density matrix elements in exclusive electroproduction of rho0 mesons at HERA.

The ZEUS collaboration Breitweg, J. ; Chekanov, S. ; Derrick, M. ; et al.
Eur.Phys.J.C 12 (2000) 393-410, 2000.
Inspire Record 505172 DOI 10.17182/hepdata.24209

Exclusive electroproduction of rho^0 mesons has been measured using the ZEUS detector at HERA in two Q^2 ranges, 0.25<Q^2<0.85 GeV^2 and 3<Q^2<30 GeV^2. The low-Q^2 data span the range 20<W<90 GeV; the high-Q^2 data cover the 40<W<120 GeV interval. Both samples extend up to four-momentum transfers of |t|=0.6 GeV^2. The distribution in the azimuthal angle between the positron scattering plane and the rho^0 production plane shows a small but significant violation of s-channel helicity conservation, corresponding to the production of longitudinally polarised (i.e. helicity zero) rho^0 mesons from transverse photons. Measurements of the 15 combinations of spin-density matrix elements which completely define the angular distributions are presented and discussed.

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The spin-density matrix elements obtained from the BPC low Q**2 data set.

The spin-density matrix elements obtained from the DIS high Q**2 data set.

The spin-density matrix elements obtained from the low Q**2 BPC data set in two W intervals.

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Dimuon Production by Neutrinos in the {Fermilab} 15-ft. Bubble Chamber at the Tevatron

The E632 collaboration Jain, V. ; Harris, F.A. ; Aderholz, M. ; et al.
Phys.Rev.D 41 (1990) 2057, 1990.
Inspire Record 281906 DOI 10.17182/hepdata.22938

The Fermilab 15-ft bubble chamber has been exposed to a quadrupole triplet neutrino beam produced at the Tevatron. The ratio of ν to ν¯ in the beam is approximately 2.5. The mean event energy for ν-induced charged-current events is 150 GeV, and for ν¯-induced charged-current events it is 110 GeV. A total of 64 dimuon candidates (1 μ+μ+, 52 μ−μ+ and μ+μ−, and 11 μ−μ−) is observed in the data sample of approximately 13 300 charged-current events. The number and properties of the μ−μ− and μ+μ+ candidates are consistent with their being produced by background processes, the important sources being π and K decay and punchthrough. The 90%-C.L. upper limit for μ−μ−/μ− for muon momenta above 4 GeV/c is 1.2×10−3, and for momenta above 9 GeV/c this limit is 1.1×10−3. The opposite-sign-dimuon–to–single-muon ratio is (0.62±0.13)% for muon momenta above 4 GeV/c. There are eight neutral strange particles in the opposite-sign sample, leading to a rate per dimuon event of 0.65±0.29. The opposite-sign-dimuon sample is consistent with the hypothesis of charm production and decay.

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A Study of the Emc Effect Using Neutrino and Anti-neutrino Interactions in Neon and Deuterium

The WA25 & WA59 collaborations Guy, J. ; Saitta, B. ; Apeldoorn, G.Van ; et al.
Z.Phys.C 36 (1987) 337-348, 1987.
Inspire Record 236239 DOI 10.17182/hepdata.15733

Nearly 40000 neutrino and antineutrino interactions in BEBC are compared to measure the differences between neon and deuterium in the quark and antiquark distributions and in the nucleon structure functions. The ratio of Ne to D cross sections indicates some decrease betweenx∼0.2 andx∼0.6. They distributions show there is no significant increase in the neon sea, but prefer a small decrease. Taken altogether, thex andy distributions and the measured total cross-sections indicate some change in the shape of the valence distributions. No significant dependence onA is observed for either the shape of the sea or the ratio of longitudinal to transverse cross-sections.

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Total Cross-Sections for Charged Current Neutrino and anti-neutrino Interactions in BEBC in the Energy Range 20-GeV to 200-GeV

The Aachen-Bonn-CERN-London-Oxford-Saclay collaboration Bosetti, P.C. ; Deden, H. ; Deutschmann, M. ; et al.
Phys.Lett.B 70 (1977) 273, 1977.
Inspire Record 121301 DOI 10.17182/hepdata.27526

The charged-current cross sections for neutrinos and antineutrinos on nucleons in the energy range 20–200 GeV are given. Taken in conjunction with the previous Gargamelle results, they show that σ E is almost constant with energy for antineutrinos, and falls with energy for neutrinos. The value of 〈q 2 〉 E decreases with energy for both neutrinos and antineutrinos, and these deviations from exact Bjorken scaling are consistent with those observed in electron and muon inelastic scattering. We find no evidence for new heavy quark states with right-handed coupling.

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Measured charged current total cross section.

Measured charged current total cross section.


The photoproduction of $\pi^{0}$ mesons in hydrogen

Miller, D.B. ; Bellamy, E.H. ;
Proc.Phys.Soc. 81 (1963) 343-348, 1963.
Inspire Record 1393356 DOI 10.17182/hepdata.26953

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Measurement of the Neutral to Charged Current Cross-section Ratios for Neutrino and Anti-neutrino Interactions on Protons

The WA21 collaboration Jones, G.T. ; Jones, R.W.L. ; Kennedy, B.W. ; et al.
Phys.Lett.B 178 (1986) 329, 1986.
Inspire Record 18429 DOI 10.17182/hepdata.36611

The ratios R vp and R vp of the neutral current to charged current cross sections for neutrino and antineutrino interactions on protons have been measured in BEBC. The beam was the CERN SPS 400 GeV wideband beam. The bubble chamber, equipped with the standard External Muon Identifier, was surrounded with an additional plane of wire chambers (Internal Picket Fence), which was added to improve neutral current event identification. For a total transverse momentum of the charged hadrons above 0.45 GeV/ c and a charged multiplicity of at least 3, it was found that R vp = 0.384 ± 0.015 and R vp = 0.338 ± 0.014 ± 0.016, corresponding to a value of sin 2 θ w (M w MS of 0.225 ± 0.030 . Combining the results from hydrogen and an isoscalar target, the differences of the neutral current chiral coupling constants were found to be u 2 l − d 2 L = −0.080 ± 0.043 ± 0.012 and u 2 R − d 2 R = 0.021±0.055±0.028.

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Inclusive V0 Production in anti-p p Interactions at 12-GeV/c

The Brussels-CERN-London-Mons-Orsay collaboration Bertrand, D. ; Johnson, D. ; Lemonne, J. ; et al.
Nucl.Phys.B 128 (1977) 365, 1977.
Inspire Record 120622 DOI 10.17182/hepdata.36137

Results are presented on the inclusive reactions p p → K 0 X , p p → Λ X and p p → Λ X at an incident antiproton momentum of 12 GeV/ c in BEBC. The cross sections are studied as functions of the Feynman scaling variable x , the rapidity, the transverse momentum of the V 0 and the missing mass squared. The dependence of the Λ and Λ polarization on x are also studied. Comparisons with proton-proton data at 12 GeV/ c are also made. Finally, events with two detected V 0 are analyzed in order to study correlations arising from the production of two strange neutral particles.

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Production of Charmed Hadrons in Neutrino Proton and Anti-neutrino Proton Charged Current Interactions

The Birmingham-CERN-London-Munich-Oxford-London & WA21 collaborations Jones, G.T. ; Jones, R.W.L. ; Geiser, A. ; et al.
Z.Phys.C 36 (1987) 593, 1987.
Inspire Record 248865 DOI 10.17182/hepdata.41702

Usind data from avp and\(\bar v\)p experiment with BEBC at CERN, the rates for inclusive production ofD*+,Λc+ andD0 invp scattering and ofD*− in\(\bar v\)p scattering are measured. Some examples of the exclusive production ofD*+,Λc+ and∑c++ are given. The cross section for the reactionvp→μ−c++ is estimated.

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Measurement of the proton structure function F2 in e p scattering at HERA

The ZEUS collaboration Derrick, M. ; Krakauer, D. ; Magill, S. ; et al.
Phys.Lett.B 316 (1993) 412-426, 1993.
Inspire Record 357414 DOI 10.17182/hepdata.28804

This paper presents our first measurement of the F 2 structure function in neutral-current, deep inelastic scattering using the ZEUS detector at HERA, the ep colliding beam facility at DESY. The data correspond to an integrated luminosity of 24.7 nb −1 . Results are presented for data in range of Q 2 from 10 GeV 2 to 4700 GeV 2 and Bjorken x down to 3.0 × 10 −4 . The F 2 structure function increases rapidly as x decreases.

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Inclusive Production of K* (890), Sigma (1385) and S* (993) Resonances in anti-p p Interactions at 12-GeV/c Incident Momentum

Baland, J.F. ; Grard, F. ; Herquet, P. ; et al.
Nucl.Phys.B 140 (1978) 220-234, 1978.
Inspire Record 135964 DOI 10.17182/hepdata.35033

The reactions p p → K ∗ (890) X , p p →Σ ± (1385) X and p p → S ∗ (993) X at 12 GeV/ c incident momentum have been studied using 19 000 events with a visible V 0 decay in BEBC. Inclusive production cross sections of these resonances as a function of transverse momentum and rapidity are presented. The contribution of annihilation to the production of the K ∗ (890) is investigated from a comparison with the corresponding pp data.

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COMBINDED K*+ AND K*- DATA IN THIS TABLE.

COMBINDED K*+ AND K*- DATA IN THIS TABLE.

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