The complexity of today's experiments in High Energy Physics results in a large amount of readout channels which can count up to a million and above. The experiments in general consist of various ...subsystems which themselves comprise a large amount of detectors requiring sophisticated DAQ and readout electronics. We report here on the structured software layers to control such a data acquisition system for the case of LHCb which is one of the four experiments for LHC. Additional focus is given on the protocols in use as well as the required hardware. An abstraction layer was implemented to allow access on the different and distinct hardware types in a coherent and generic manner. The hierarchical structure which allows propagating commands down to the subsystems is explained. Via finite state machines an expert system with auto-recovery abilities can be modeled.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) The energy flow created in pp collisions at ... is studied within the pseudorapidity range 1.9<eta<4.9 with data collected ...by the LHCb experiment. The measurements are performed for inclusive minimum-bias interactions, hard scattering processes and events with an enhanced or suppressed diffractive contribution. The results are compared to predictions given by Pythia-based and cosmic-ray event generators, which provide different models of soft hadronic interactions.
The rate of gluons splitting into $c \bar{c}$ pairs in hadronic $Z$ decays is measured using the data sample collected by ALEPH from 1991 to 1995. The selection is based on the identification of ...leptons (electrons and muons) originating from semileptonic charm decays, and on the topological properties of signal events. The result derived from the selected sample is $g_{c \bar{c}}=(3.26 \pm 0.23 \rm{(stat)} \pm 0.42 \rm{(syst)}) %$
The mass of the W boson is determined from the direct reconstruction of W decays in WW→qq̄qq̄ and WW→ℓνqq̄ events in e+e- collisions at LEP. The data sample corresponds to an integrated luminosity of ...683 pb-1 collected with the ALEPH detector at centre-of-mass energies up to 209 GeV. To minimise any effect from colour reconnection a new procedure is adopted in which low energy particles are not considered in the mass determination from the qq̄qq̄ channel. The combined result from all channels is \(m_{\text{W}}=80.440 \pm0.043{\text{(stat.)}} \pm0.024{\text{(syst.)}} \pm0.009{\text{(FSI)}} \pm0.009{\text{(LEP)}} \text{GeV/}c^2, \)where FSI represents the possible effects of final state interactions in the qq̄qq̄ channel and LEP indicates the uncertainty in the beam energy. From two-parameter fits to the W mass and width, the W width is found to be \(\Gamma_{\text{W}} = 2.14 \pm0.09{\text{(stat.)}} \pm0.04{\text{(syst.)}} \pm0.05{\text{(FSI)}} \pm0.01{\text{(LEP)}} \text{GeV}. \)
Cross sections, angular distributions and forward-backward asymmetries are presented, of two-fermion events produced in e+e- collisions at centre-of-mass energies from 189 to 209 GeV at LEP, measured ...with the ALEPH detector. Results for e+e-, μ+μ-, τ+τ-, qq̄, bb̄ and cc̄ production are in agreement with the standard model predictions. Constraints are set on scenarios of new physics such as four-fermion contact interactions, leptoquarks, Z′ bosons, TeV-scale quantum gravity and R-parity violating squarks and sneutrinos.
A search has been performed for the Standard Model Higgs boson in the data sample collected with the ALEPH detector at LEP, at centre-of-mass energies up to 209
GeV. An excess of 3
σ beyond the ...background expectation is found, consistent with the production of the Higgs boson with a mass near 114
GeV/
c
2. Much of this excess is seen in the four-jet analyses, where three high purity events are selected.
Study of charm production in Z decays Barate et al, R.
The European physical journal. C, Particles and fields,
09/2000, Letnik:
16, Številka:
4
Journal Article
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The production rates of \({\mathrm{D}}^{*\pm}\), \({\mathrm{D}}_{\rm{s}}^{* \pm}\), \({\mathrm{D}}^{\pm}\), \({\mathrm{D}}^0 / \bar{{\mathrm{D}}}^0\), \({\mathrm{D}}_{\rm{s}}^{\pm}\), and ...\(\Lambda_{\rm c}^{+}/{\bar{\Lambda}}_{\rm c}^{-}\) in \({\rm Z} \rightarrow {\mathrm c} \bar{{\mathrm c}}\) decays are measured using the LEP I data sample recorded by the ALEPH detector. The fractional energy spectrum of the \({\mathrm{D}}^{*\pm}\) is well described as the sum of three contributions: charm hadronisation, b hadron decays and gluon splitting into a pair of heavy quarks. The probability for a c quark to hadronise into a \({\mathrm{D}}^{*+}\) is found to be \(f({\mathrm c} \to{\mathrm{D}}^{*+}) = 0.233 \pm 0.010 \mathrm{(stat.)} \pm 0.011\mathrm{(syst.)}\). The average fraction of the beam energy carried by \({\mathrm{D}}^{*\pm}\) mesons in \({\rm Z} \to{\rm c \bar c}\) events is measured to be \({\langle X_E ({\mathrm{D}}^{*\pm}) \rangle}_{{\mathrm c} \bar{{\mathrm c}}} =0.4878 \pm 0.0046 \mathrm{(stat.)} \pm 0.0061 \mathrm{(syst.)}.\) The \({\mathrm{D}}^{*\pm}\) energy and the hemisphere mass imbalance distributions are simultaneously used to measure the fraction of hadronic Z decays in which a gluon splits to a \({\mathrm c} \bar{{\mathrm c}}\) pair: \(\bar{n}_{\mathrm{g} \to{\mathrm c}\bar{{\mathrm c}}} = (3.23 \pm 0.48 \mathrm{(stat.)} \pm 0.53 \mathrm{(syst.)})\%.\) The ratio of the Vector/(Vector+Pseudoscalar) production rates in charmed mesons is found to be \(P_V = 0.595\pm0.045\). The fractional decay width of the Z into \({\mathrm c}\bar{{\mathrm c}}\) pairs is determined from the sum of the production rates for various weakly decaying charmed states to be \({\rm R_c} =0.1738 \pm 0.0047{\rm (stat.)} \pm 0.0116 {\rm (syst.)}.\)
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