The cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data s... more The cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data sample corresponding to a total luminosity of 629.4 pb −1 , collected at centre-of-mass energies ranging from 189 to 209 GeV, 9834 four-fermion events with W bosons decaying into hadrons or leptons are selected. The total cross section is measured with a precision of 1.4% and agrees with the Standard Model expectation. Assuming charged-lepton universality, the branching fraction for hadronic W-boson decays is measured to be: Br(W → hadrons) = 67.50 ± 0.42 (stat.) ± 0.30 (syst.) %, in agreement with the Standard Model. Differential cross sections as a function of the W − production angle are also measured for the semi-leptonic channels qqeν and qqµν.
... DETERMINATION OF THE LONGITUDINAL AND THE TRANSVERSE PART IN n+ ELECTROPRODUCTION H. ACKERMAN... more ... DETERMINATION OF THE LONGITUDINAL AND THE TRANSVERSE PART IN n+ ELECTROPRODUCTION H. ACKERMANN, T. AZEMOON, W. GABRIEL, HD MERTIENS ... virtual photons whose flux P is determined by the energy, the energy loss and the scattering angle of ...
Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipp... more Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipped with a TST. Using a method independent of both the neutrino flux and nuclear interaction corrections, the ratio R = On/a p has been measured. The result is R = 1.98 ± 0.19 for the ratio of total cross sections. Bjorken x distr~utions for proton and neutron targets and for u and d quarks are compared.
First observation is reported of semi-inclusive coherent diffractive charged current interactions... more First observation is reported of semi-inclusive coherent diffractive charged current interactions of antineutrinos on neon nuclei. A sharp peaking towards zero is observed in the I t I distr~ution of interactions for which the f'mal state charge is 0 and from which only one negative hadron is emitted, unaccompanied by any evidence of nuclear fragmentation or reinteraction. This peak is correlated with high momentum of the outgoing charged hadron and with small values of Q2 and x.
An event with the decay chain Ec ---,÷ A c + rr ° , AC~+ K -+ p + rr +, has been observed in an e... more An event with the decay chain Ec ---,÷ A c + rr ° , AC~+ K -+ p + rr +, has been observed in an exposure of BEBC, equipped with a track sensitive target, to the wide band neutrino beam from the SPS at CERN. The event has a unique three constraint kinematic fit to the 2xS = _A Q reaction u + p --, u-+ p + K-+ n+ + n+ + ~0 with both gammas from the ~o decay detected. The proton and other final state particles are identified. The masses are M(Ac) = 2290 ± 3 MeV/c 2, M(lCc) = 2457 ± 4 MeV/c 2 and M(Zc) -M(Ac) = 168 ± 3 MeV/c 2 . Including other data one obtainsM(Zc ~) -M(Zc) = 0 ± 4 MeV/c 2
ABSTRACT About 2000 neutral induced interactions observed inside the hydrogen filled TST in BEBC ... more ABSTRACT About 2000 neutral induced interactions observed inside the hydrogen filled TST in BEBC have been analysed. The data were obtained from an exposure to the vμ wide band beam at the CERN SPS. A separation of these events into charged current, neutral current and neutral hadron induced interactions have been achieved using a multidimensional kinematic analysis. The neutral to charged current cross section ratio for vμ interactions on free protons has been determined avoiding the drastic cuts on the data inherent in previous experiments. The result RPv = 0.47 ± 0.04 is compatible with those measurements and the prediction of the standard SU (2) × U (1) model for sin2θW = 0.18 ± 0.04.
The electroproductlon of K+Y on protons, ep ~ eK+Y, (Y =-A; ~o; 1~,o (1385), A'(1405); A'(1520)) ... more The electroproductlon of K+Y on protons, ep ~ eK+Y, (Y =-A; ~o; 1~,o (1385), A'(1405); A'(1520)) was investigated by measuring the scattered electron and the produced K + meson m coincidence. The differential cross sections were determined as functions of W, q2, t and q~K~/in the kinematical region.
... B120 (1977) 365380 NorthHolland Publishing Company VIRTUAL PHOTOPRODUCTION OF PROTONS ON HYDR... more ... B120 (1977) 365380 NorthHolland Publishing Company VIRTUAL PHOTOPRODUCTION OF PROTONS ON HYDROGEN H. ACKERMANN, T. AZEMOON, W. GABRIEL, D. LUKE * and G ... 379 0.6 W=2.62 GeV + 60' O 60',E=0.58 f 0.5 Burfeindt et al (GeV2) Bebek et at Alder et al ...
We report measurements of kaon electroproduction from a hydrogen target carried out at DESY. The ... more We report measurements of kaon electroproduction from a hydrogen target carried out at DESY. The invariant cross section for the reaction ep --* eK + + anything is given as a function of the variables q2, W, x, p2 and q~ in the following region: -0.5 < q2 < -0.1 GeV 2 , 2.0< W<2.8GeV, 0.3<x< 1.0, p2 < 0.25 GeV 2 , 0 o < q~ < 360 ° .
Using BEBC equipped with a hydrogen-filled neon-surrounded track-sensitive target, the charged cu... more Using BEBC equipped with a hydrogen-filled neon-surrounded track-sensitive target, the charged current cross sections and structure functions of hydrogen and neon targets traversed by the same neutrinos and antineutrinos are compared directly. The measured total cross-section ratios between hydrogen and neon allow precise total cross-section values for hydrogen to be inferred. Using this normalisation, the v and ff hydrogen data are combined and the quark distributions in free nucleons, parametrised as functions of ~, are extracted.. This free-nucleon parametrisation is then compared directly with the neon data in order to measure nuclear effects such as those recently reported by the EMC collaboration. Only small effects are seen, in excellent agreement with recent SLAC data in a more similar A and q2 range.
Zeitschrift für Physik C Particles and Fields, 1984
We consider triangular arrays of Markov chains that converge weakly to a diffusion process. Edgew... more We consider triangular arrays of Markov chains that converge weakly to a diffusion process. Edgeworth type expansions of third order for transition densities are proved. This is done for time horizons that converge to 0. For this purpose we represent the transition density as a functional of densities of sums of i.i.d. variables. This will be done by application of the parametrix method. Then we apply Edgeworth expansions to the densities. The resulting series gives our Edgeworth-type expansion for the transition density of Markov chains. The research is motivated by applications to high frequency data that are available on a very fine grid but are approximated by a diffusion model on a more rough grid.
I discuss the preliminary results of the LEP experiments ALEPH, DELPHI, L3 and OPAL on the rare Z... more I discuss the preliminary results of the LEP experiments ALEPH, DELPHI, L3 and OPAL on the rare Z decays. Limits of about 10 -5 on the branching ratios are reported by most experiments. The question of excess in the ~-TV final state remains unsettled. From the analysis of the L3 data the ZZ ~ mixing angle is confined to -t-1.5 ~ for most extensions of the Standard Model of electroweak interactions.
BaBar has recently moved away from using Objectivity/DB for its event store toward a ROOT-based o... more BaBar has recently moved away from using Objectivity/DB for its event store toward a ROOT-based one. Data in the new format is produced at over two dozen institutions worldwide including SLAC. Among new challenges is the organization of data export from remote institutions, its archival at SLAC and bringing it to the users for analysis or import to their own institutions. The new system is designed to be scalable, easily configurable on a client and server side and adaptive to server load. It is integrated to work with BaBar's mass storage system (HPSS) and with xrootd service . Design, implementation, experience with the new system, as well as future developments are discussed in this article.
The BaBar database has pioneered the use of a commercial ODBMS within the HEP community. The uniq... more The BaBar database has pioneered the use of a commercial ODBMS within the HEP community. The unique object -oriented architecture of Objectivity/DB has made it possible to manage over 700 terabytes of production data generated since May'99, making the BaBar database the world's largest known database. The ongoing development includes new features, addressing the ever-increasing luminosity of the detector as well as other changin g physics requirements. Significant efforts are focused on reducing space requirements and operational costs. The paper discusses our experience with developing a large scale database system, emphasizing universal aspects which may be applied to any large scale system, independently of underlying technology used. MOKT010 ePrint cs.DB/0306020 SLAC-PUB-9889 *
The cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data s... more The cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data sample corresponding to a total luminosity of 629.4 pb −1 , collected at centre-of-mass energies ranging from 189 to 209 GeV, 9834 four-fermion events with W bosons decaying into hadrons or leptons are selected. The total cross section is measured with a precision of 1.4% and agrees with the Standard Model expectation. Assuming charged-lepton universality, the branching fraction for hadronic W-boson decays is measured to be: Br(W → hadrons) = 67.50 ± 0.42 (stat.) ± 0.30 (syst.) %, in agreement with the Standard Model. Differential cross sections as a function of the W − production angle are also measured for the semi-leptonic channels qqeν and qqµν.
... DETERMINATION OF THE LONGITUDINAL AND THE TRANSVERSE PART IN n+ ELECTROPRODUCTION H. ACKERMAN... more ... DETERMINATION OF THE LONGITUDINAL AND THE TRANSVERSE PART IN n+ ELECTROPRODUCTION H. ACKERMANN, T. AZEMOON, W. GABRIEL, HD MERTIENS ... virtual photons whose flux P is determined by the energy, the energy loss and the scattering angle of ...
Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipp... more Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipped with a TST. Using a method independent of both the neutrino flux and nuclear interaction corrections, the ratio R = On/a p has been measured. The result is R = 1.98 ± 0.19 for the ratio of total cross sections. Bjorken x distr~utions for proton and neutron targets and for u and d quarks are compared.
First observation is reported of semi-inclusive coherent diffractive charged current interactions... more First observation is reported of semi-inclusive coherent diffractive charged current interactions of antineutrinos on neon nuclei. A sharp peaking towards zero is observed in the I t I distr~ution of interactions for which the f'mal state charge is 0 and from which only one negative hadron is emitted, unaccompanied by any evidence of nuclear fragmentation or reinteraction. This peak is correlated with high momentum of the outgoing charged hadron and with small values of Q2 and x.
An event with the decay chain Ec ---,÷ A c + rr ° , AC~+ K -+ p + rr +, has been observed in an e... more An event with the decay chain Ec ---,÷ A c + rr ° , AC~+ K -+ p + rr +, has been observed in an exposure of BEBC, equipped with a track sensitive target, to the wide band neutrino beam from the SPS at CERN. The event has a unique three constraint kinematic fit to the 2xS = _A Q reaction u + p --, u-+ p + K-+ n+ + n+ + ~0 with both gammas from the ~o decay detected. The proton and other final state particles are identified. The masses are M(Ac) = 2290 ± 3 MeV/c 2, M(lCc) = 2457 ± 4 MeV/c 2 and M(Zc) -M(Ac) = 168 ± 3 MeV/c 2 . Including other data one obtainsM(Zc ~) -M(Zc) = 0 ± 4 MeV/c 2
ABSTRACT About 2000 neutral induced interactions observed inside the hydrogen filled TST in BEBC ... more ABSTRACT About 2000 neutral induced interactions observed inside the hydrogen filled TST in BEBC have been analysed. The data were obtained from an exposure to the vμ wide band beam at the CERN SPS. A separation of these events into charged current, neutral current and neutral hadron induced interactions have been achieved using a multidimensional kinematic analysis. The neutral to charged current cross section ratio for vμ interactions on free protons has been determined avoiding the drastic cuts on the data inherent in previous experiments. The result RPv = 0.47 ± 0.04 is compatible with those measurements and the prediction of the standard SU (2) × U (1) model for sin2θW = 0.18 ± 0.04.
The electroproductlon of K+Y on protons, ep ~ eK+Y, (Y =-A; ~o; 1~,o (1385), A'(1405); A'(1520)) ... more The electroproductlon of K+Y on protons, ep ~ eK+Y, (Y =-A; ~o; 1~,o (1385), A'(1405); A'(1520)) was investigated by measuring the scattered electron and the produced K + meson m coincidence. The differential cross sections were determined as functions of W, q2, t and q~K~/in the kinematical region.
... B120 (1977) 365380 NorthHolland Publishing Company VIRTUAL PHOTOPRODUCTION OF PROTONS ON HYDR... more ... B120 (1977) 365380 NorthHolland Publishing Company VIRTUAL PHOTOPRODUCTION OF PROTONS ON HYDROGEN H. ACKERMANN, T. AZEMOON, W. GABRIEL, D. LUKE * and G ... 379 0.6 W=2.62 GeV + 60' O 60',E=0.58 f 0.5 Burfeindt et al (GeV2) Bebek et at Alder et al ...
We report measurements of kaon electroproduction from a hydrogen target carried out at DESY. The ... more We report measurements of kaon electroproduction from a hydrogen target carried out at DESY. The invariant cross section for the reaction ep --* eK + + anything is given as a function of the variables q2, W, x, p2 and q~ in the following region: -0.5 < q2 < -0.1 GeV 2 , 2.0< W<2.8GeV, 0.3<x< 1.0, p2 < 0.25 GeV 2 , 0 o < q~ < 360 ° .
Using BEBC equipped with a hydrogen-filled neon-surrounded track-sensitive target, the charged cu... more Using BEBC equipped with a hydrogen-filled neon-surrounded track-sensitive target, the charged current cross sections and structure functions of hydrogen and neon targets traversed by the same neutrinos and antineutrinos are compared directly. The measured total cross-section ratios between hydrogen and neon allow precise total cross-section values for hydrogen to be inferred. Using this normalisation, the v and ff hydrogen data are combined and the quark distributions in free nucleons, parametrised as functions of ~, are extracted.. This free-nucleon parametrisation is then compared directly with the neon data in order to measure nuclear effects such as those recently reported by the EMC collaboration. Only small effects are seen, in excellent agreement with recent SLAC data in a more similar A and q2 range.
Zeitschrift für Physik C Particles and Fields, 1984
We consider triangular arrays of Markov chains that converge weakly to a diffusion process. Edgew... more We consider triangular arrays of Markov chains that converge weakly to a diffusion process. Edgeworth type expansions of third order for transition densities are proved. This is done for time horizons that converge to 0. For this purpose we represent the transition density as a functional of densities of sums of i.i.d. variables. This will be done by application of the parametrix method. Then we apply Edgeworth expansions to the densities. The resulting series gives our Edgeworth-type expansion for the transition density of Markov chains. The research is motivated by applications to high frequency data that are available on a very fine grid but are approximated by a diffusion model on a more rough grid.
I discuss the preliminary results of the LEP experiments ALEPH, DELPHI, L3 and OPAL on the rare Z... more I discuss the preliminary results of the LEP experiments ALEPH, DELPHI, L3 and OPAL on the rare Z decays. Limits of about 10 -5 on the branching ratios are reported by most experiments. The question of excess in the ~-TV final state remains unsettled. From the analysis of the L3 data the ZZ ~ mixing angle is confined to -t-1.5 ~ for most extensions of the Standard Model of electroweak interactions.
BaBar has recently moved away from using Objectivity/DB for its event store toward a ROOT-based o... more BaBar has recently moved away from using Objectivity/DB for its event store toward a ROOT-based one. Data in the new format is produced at over two dozen institutions worldwide including SLAC. Among new challenges is the organization of data export from remote institutions, its archival at SLAC and bringing it to the users for analysis or import to their own institutions. The new system is designed to be scalable, easily configurable on a client and server side and adaptive to server load. It is integrated to work with BaBar's mass storage system (HPSS) and with xrootd service . Design, implementation, experience with the new system, as well as future developments are discussed in this article.
The BaBar database has pioneered the use of a commercial ODBMS within the HEP community. The uniq... more The BaBar database has pioneered the use of a commercial ODBMS within the HEP community. The unique object -oriented architecture of Objectivity/DB has made it possible to manage over 700 terabytes of production data generated since May'99, making the BaBar database the world's largest known database. The ongoing development includes new features, addressing the ever-increasing luminosity of the detector as well as other changin g physics requirements. Significant efforts are focused on reducing space requirements and operational costs. The paper discusses our experience with developing a large scale database system, emphasizing universal aspects which may be applied to any large scale system, independently of underlying technology used. MOKT010 ePrint cs.DB/0306020 SLAC-PUB-9889 *
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