1. |
- Abazov, V. M., et al.
(författare)
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The upgraded DO detector
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
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Tidskriftsartikel (refereegranskat)abstract
- The DO experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid -argon calorimeters and central muon detector, remaining from Run 1, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DO.
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2. |
- Aaron, F. D., et al.
(författare)
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Combined measurement and QCD analysis of the inclusive e(+/-)p scattering cross sections at HERA
- 2010
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :1
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Tidskriftsartikel (refereegranskat)abstract
- A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e(+/-)p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q(2), and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
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3. |
- Aaron, F. D., et al.
(författare)
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Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA
- 2010
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2010:3, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- A search for events containing an isolated electron or muon and missing trans verse momentum produced in e(+/-)p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb(-1). The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e(+)p data, at large hadronic transverse momentum P-T(X) > 25GeV, a total of 23 events are observed compared to a prediction of 14.0 +/- 1.9. The total single W boson production cross section is measured as 1.06 +/- 0.16 (stat.) +/- 0.07 (sys.) pb, in agreement with an Standard Model (SM) expectation of 1.26 +/- 0.19 pb.
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4. |
- Aaron, F. D., et al.
(författare)
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Multi-leptons with high transverse momentum at HERA
- 2009
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :10
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Tidskriftsartikel (refereegranskat)abstract
- Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb(-1). The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e(+)p collision data with a scalar sum of the lepton transverse momenta above 100 GeV while 1.94 +/- 0.17 events are expected. Such events are not observed in e(-)p collisions for which 1.19 +/- 0.12 are predicted. Total visible and differential di-electron and di-muon photoproduction cross sections are extracted in a restricted phase space dominated by photon-photon collisions.
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5. |
- Aaron, F. D., et al.
(författare)
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Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA
- 2012
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 72:10
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Tidskriftsartikel (refereegranskat)abstract
- A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy root s = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q(2) < 200 GeV2 in photon virtuality, 0.00035 < x(P) < 0.09 in proton fractional momentum loss, 0.09 < vertical bar t vertical bar < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/x(P), where x is the Bjorken scaling variable.
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6. |
- Abramowicz, H., et al.
(författare)
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Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA
- 2013
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 73:2
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma(c (c) over bar)(red) for charm production are obtained in the kinematic range of photon virtuality 2.5 <= Q(2) <= 2000 GeV2 and Bjorken scaling variable 3 . 10(-5) <= x <= 5 . 10(-2). The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W-+/- and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.
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7. |
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8. |
- Köhler, Th., et al.
(författare)
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Precision measurement of strong interaction isotope effects in antiprotonic 16O, 17O, and 18O atoms
- 1986
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 176:3-4, s. 327-333
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Tidskriftsartikel (refereegranskat)abstract
- The strong-interaction effects in antiprotonic 16O, 17O, and 18O atoms were measured at the CERN antiproton facility, LEAR. The shifts ε{lunate} and the widths Γ of the 3d level were determined to be -112±20 eV (16O), -140±46 eV (17O), -195±20 eV (18O), and 495±45 eV (16O), 540±150 (17O), 640±40 eV (18O), respectively. © 1986.
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9. |
- Adiels, L., et al.
(författare)
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Pi0 And Eta Spectroscopy At Lear
- 1986
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Ingår i: Tignes 1985, Proceedings, Physics With Antiprotons At Lear In The Acol Era. ; , s. 359-359
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Konferensbidrag (refereegranskat)
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10. |
- Adiels, L, et al.
(författare)
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π0 and η spectroscopy at LEAR
- 1985
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Ingår i: Physics with antiprotons at LEAR in the ACOL era. - Gif sur Yvette : Editions Frontières. - 2863320351 ; , s. 359-360
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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11. |
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12. |
- Adiels, Lars, et al.
(författare)
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A π0 and η spectrometer of lead glass and BGO for momenta up to 1 GeV/c
- 1986
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 244:3, s. 380-390
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Tidskriftsartikel (refereegranskat)abstract
- A spectrometer consisting of two sets of bismuth germanium oxide (BGO) crystals and a lead-glass array has been used to measure the [pi]0 and [eta] momentum spectra produced from proton-antiproton annihilations at rest. We describe the test of the BGO sets in electron beams of energies from 50 to 450 MeV. We discuss the method of construction and calibration of the lead-glass array, as well as procedures to extract the energy and position resolutions for detected photons. A momentum resolution ([sigma]) for [pi]0’s and [eta]’s of 4% and 3%, respectively has been achieved at momenta below 1 GeV/c.
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13. |
- Adiels, L., et al.
(författare)
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Experimental determination of the branching ratios {Mathematical expression}, and 2γ at rest
- 1987
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Ingår i: Zeitschrift für Physik C Particles and Fields. - : Springer. - 0170-9739 .- 1431-5858. ; 35:1, s. 15-19
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Tidskriftsartikel (refereegranskat)abstract
- The branching ratios of {Mathematical expression} annihilations into the neutral final states 2π 0, π 0γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are {Mathematical expression}, {Mathematical expression}, and B γγ<1.7×10 -6 (95% c.l.).
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14. |
- Adiels, L., et al.
(författare)
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Experimental determination of the branching ratios proton-antiproton -> 2pi0, pi0γ and γγ at rest
- 1987
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Ingår i: Zeitschrift für Physik C Particles and Fields. - 0170-9739. ; 35:1, s. 15-19
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Tidskriftsartikel (refereegranskat)abstract
- The branching ratios of Mathematical expression annihilations into the neutral final states 2Ï0, Ï0γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are Mathematical expression, Mathematical expression, and Bγγ<1.7Ã10-6 (95% c.l.). © 1987 Springer-Verlag.
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15. |
- Adiels, L., et al.
(författare)
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Experimental study of the inclusive η-spectrum from p {Mathematical expression} annihilations at rest in liquid hydrogen
- 1989
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Ingår i: Zeitschrift für Physik C Particles and Fields. - : Springer. - 0170-9739 .- 1431-5858. ; 42:1, s. 49-58
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Tidskriftsartikel (refereegranskat)abstract
- The inclusive η-momentum spectrum from {Mathematical expression} annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for {Mathematical expression}, and ηη(8.1±3.1)×10 -5. An upper limit for {Mathematical expression} of 1.8×10 -4 at 95% CL was found. The ratio of the branching ratios is BR(ηρ{variant})/BR(ηω)=0.51 -0.06 +0.20. For the ratio of branching ratios into two pseudoscalar mesons, we have BR(ηπ 0)/BR(π 0π 0)=0.65±0.14, BR(ηη)/BR(π 0π 0), BR(ηη ′)/BR(π 0π 0) at 95% CL, and BR(ηη)/BR(ηπ 0). © 1989 Springer-Verlag.
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16. |
- Adiels, Lars, et al.
(författare)
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Experimental study of the inclusive η-spectrum from proton-antiproton annihilations at rest in liquid hydrogen
- 1989
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Ingår i: Zeitschrift für Physik C Particles and Fields. - 0170-9739 .- 1431-5858. ; 42, s. 49-58
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Tidskriftsartikel (refereegranskat)abstract
- The inclusive η-momentum spectrum from Mathematical expression annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for Mathematical expression, and ηη(8.1±3.1)Ã10-5. An upper limit for Mathematical expression of 1.8Ã10-4 at 95% CL was found. The ratio of the branching ratios is BR(ηÏvariant)/BR(ηÏ)=0.51-0.06+0.20. For the ratio of branching ratios into two pseudoscalar mesons, we have BR(ηÏ0)/BR(Ï0Ï0)=0.65±0.14, BR(ηη)/BR(Ï0Ï0), BR(ηηâ²)/BR(Ï0Ï0) at 95% CL, and BR(ηη)/BR(ηÏ0). © 1989 Springer-Verlag.
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17. |
- Adiels, L., et al.
(författare)
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Investigations on baryonium and other rare pmacrp annihilation modes using high resolution pi0 spectrometers (PS 182)
- 1985
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Ingår i: Antiproton 1984. Proceedings of the VII European Symposium on Antiproton Interactions. - : Institution of Electrical Engineers (IEE). ; , s. 297-304
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Konferensbidrag (refereegranskat)abstract
- In the search for heavy, narrow exotic states such as baryonium or glueballs, carried out so far, various methods of high- and low-energy production, low-energy formation, and e+e- reactions were used. In particular, a search for baryonium states below threshold (mxlsimmppmacr) has shown some evidence [Richter et al., 1983, Brando et al., 1984] for a few states. However, the results of these measurements suffer from poor statistics. Among the possible methods which can be applied in the baryonium bound state research at LEAR, the authors consider the study of the reaction ppmacrrarrX+pi0 as the most promising. They have performed an experiment to study this reaction by means of an experimental set-up especially tailored for measuring monoenergetic pi0,s, allowing for both angular distribution measurements and high-resolution spectroscopy. They report on the preliminary results from our actual measurements of the inclusive pi0 and eta spectra following the antiproton annihilation at rest.
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18. |
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19. |
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20. |
- Adiels, L., et al.
(författare)
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Pi0 and eta spectra from proton-antiproton annihilations at rest
- 1984
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Ingår i: Zeitschrift für Physik. C, Particles and fields. - 0170-9739. ; 21:4, s. 315-319
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Tidskriftsartikel (refereegranskat)abstract
- The low-energy part of the Ï0 spectrum associated with Mathematical expression annihilation at rest was measured in order to search for bound baryonium-like states. The upper limit for reaching such states via the emission of monochromatic Ï0’s was found to be 8% per annihilation in the mass region of 1650 MeV. The low-energy part of the η spectrum from Mathematical expression annihilations at rest was also observed.
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21. |
- Adiels, L., et al.
(författare)
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Search for narrow exotic states in annihilations on 4He
- 1984
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 138:1-3, s. 235-240
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Tidskriftsartikel (refereegranskat)abstract
- After having found evidence for narrow exotic states in p annihilation, the production of such states on a nuclear target was studied with similar techniques. The γ spectrum associated with annihilation on 4He at rest was measured. The spectrum shows two peaks, at energies of 161.9 and 203.0 MeV, corresponding to intermediate narrow states of masses which seem to be related to states found in p annihilations. The confidence is better than 4 σ.
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22. |
- Adiels, L., et al.
(författare)
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Search for narrow signals in the [gamma]-spectrum from [Proton-antiproton] annihilation at rest
- 1986
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 182:3-4, s. 405-408
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Tidskriftsartikel (refereegranskat)abstract
- The [gamma]-spectrum originating from pp[combining macron] annihilations at rest in liquid hydrogen was measured with two BGO spectrometers. A total of 24 ï¿œ 106[gamma]’s were accumulated. No narrow peaks indicating exotic states such as baryonium were observed. The upper limit for the branching ratio with 1040 [less-than-or-equals, slant] mx [less-than-or-equals, slant] 1770 MeV/c2 and with [lambda]x [less-than-or-equals, slant] 25 MeV/c2 is less than 10-3 with more than 99.96% confidence.
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23. |
- Adiels, L., et al.
(författare)
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Search for narrow signals in the γ-spectrum from pp̄ annihilation at rest
- 1986
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 182:3-4, s. 405-408
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Tidskriftsartikel (refereegranskat)abstract
- The γ-spectrum originating from pp̄ annihilations at rest in liquid hydrogen was measured with two BGO spectrometers. A total of 24 × 10 6 γ's were accumulated. No narrow peaks indicating exotic states such as baryonium were observed. The upper limit for the branching ratio p p ̄ → γ + X with 1040 ≤ m x ≤ 1770 MeV/c 2 and with λ x ≤ 25 MeV/c 2 is less than 10 -3 with more than 99.96% confidence. © 1986.
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24. |
- Adiels, L, et al.
(författare)
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Some results of experiment PS182 at LEAR
- 1986
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Ingår i: Antiproton 86. - Singspore : World Scientific Publishing. - 9971503131 ; , s. 199-204, s. 199-204
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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25. |
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