Upgraded control system of scintillation counters at CDF II muon trigger

Scintillation counters are an important part of the muon detection system at CDF II (FNAL, United States). Permanently controlling and maintaining the high performance of these detectors are essential for obtaining high-quality experimental data. The first version of the control system of scintillation counters created in 2001 was completely upgraded by us due to increased requirements for the control systems of subsystems at CDF in connection with the growth of Tevatron luminosity, the introduction of new devices, and the experience of operation.     

Scintillation counters of the muon system at CDF II

The framework of scintillation counters for the CDF II muon system at the Tevatron collider at Fermilab is described. Information from the detectors of the muon system is essential for forming triggers of the first and second levels and for an “off-line” data analysis related to studies in the field of the heavy quark physics, Standard Model tests, search for phenomena beyond its limits, and for many other CDF II experiments with p \(\bar p\) collisions at the energy √s = 1.96 TeV.     

The decrease of light yield collection for scintillation counters of CDF muon trigger over time

The muon system of CDF spectrometer plays an important role in investigating processes with heavy quarks. The efficient functioning of scintillation counters, which comprise a considerable part of the CFD muon trigger, is a necessary condition for obtaining experimental data. The results of long-term measurements of the light yield, collected far from the photomultiplier end of the scintillation plate for different types of counters in order to predict the period of their effective operation in experiments, are presented.     

New results of experiments at the Tevatron

The most important results obtained by the D0 and CDF collaborations in 2011–2012 on the search for the Higgs boson, studying the properties of the t-quark, measuring the W-boson mass, studying meson and baryon states with b-quarks, and a search for a New Physics beyond the Standard Model, are discussed. A comparison with the experimental results from the LHC is given.     

Observation of the muon inner bremsstrahlung at?LEP1

Muon bremsstrahlung photons converted in front of the DELPHI main tracker (TPC) in dimuon events at LEP1 were studied in two photon kinematic ranges: 0.2<E _γ ≤1 GeV and transverse momentum with respect to the parent muon p _T <40 MeV/c, and 1<E _γ ≤10 GeV and p _T <80 MeV/c. A good agreement of the observed photon rate with predictions from QED for the muon inner bremsstrahlung was found, contrary to the anomalous soft photon excess that has been observed recently in hadronic Z ⁰ decays. The obtained ratios of the observed signal to the predicted level of the muon bremsstrahlung are 1.06±0.12±0.07 in the photon energy range 0.2<E _γ ≤1 GeV and 1.04±0.09±0.12 in the photon energy range 1<E _γ ≤10 GeV. The bremsstrahlung dead cone is observed for the first time in the direct photon production at LEP. Deceased.     

Neutrino production of same-sign dimuons at the Fermilab Tevatron

The rate of neutrino- and antineutrino-induced prompt same-sign dimuon production in steel was measured using a sample of μ^?μ^? events and 25 μ⁺μ⁺ events withP _μ>9 GeV/c, produced in 1.5 millionv _μ and 0.3 million \(\overline {v_\mu }\) induced charged-current events with energies between 30 GeV and 600 GeV. The data were obtained with the Chicago-Columbia-Fermilab-Rochester (CCFR) neutrino detector in the Fermilab Tevatron Quadrupole Triplet Neutrino Beam during experiments E 744 and E 770. After background subtraction, the prompt rate of same-sign dimuon production is (0.53±0.24)×10^?4 perv _μ charged-current event and (0.52±0.33)×10^?4 per \(\overline {v_\mu }\) charged-current event. The kinematic distributions of the same-sign dimuon events after background subtraction are consistent with those of the non-prompt background due to meson decays in the hadron shower of a charged-current event. Calculations ofc \(\bar c\) gluon bremsstrahlung, based on improved measurements of the charm mass parameter and nucleon structure functions by the CCFR collaboration, yield a prompt rate of (0.09±0.39)×10^?4 perv _μ charged-current event. In this case,c \(\bar c\) gluon bremsstrahlung is probably not an observable source of prompt same-sign dimuons.     

Sea level muon spectra at large zenith angles derived from the latest JACEE primary nucleon spectrum

Summary Sea level muon energy spectra at large zenith angles have been derived from the latest JACEE primary spectrum using the Fermilab Single-Arm Spectrometer data on charged-meson production. The role of increasing total cross-section on the final result for the energy spectra has been investigated here with special emphasis. The inclusion of the rising total cross-section at cosmic range of energies, it is seen, has come into much use in explaining the observed data at very high energies. The autors of this paper have agreed not to receive the proofs for correction.     

Cosmic ray sea level muon spectrum at large zenith angle derived from the latest JACEE primary spectrum

The sea level cosmic ray muon spectrum at 89° has been estimated from the primary nucleon spectrum estimated after the latest JACEE measurements. The p-A collision cross section has been considered for hadronic energy moments calculations. The meson atmospheric diffusion equations after Bugaev et al. have been used in this analysis. The calculated large zenith angle muon spectrum is well in accord with the latest MUTRON data for cosmic ray muons arriving at zenith angles 86° to 90°.On leave from Indian Association for the cultivation of Science, Calcutta 700032, India.     

Development of the pulsed muon facility at ISIS

The ISIS pulsed surface muon facility at RAL is presently undergoing a major expansion to provide three experimental ports with simultaneous single muon pulses at 50 Hz. This upgrade, funded by the European Community (EC), is described together with recent development results which are relevant to its future scientific programme. These new beam lines are expected to be available for experiments in June 1993.     

Production of Charged Heavy Quarkonium-Like States at the LHC and Tevatron

We study prompt hadroproduction of the charged bottomonium-like states Zb± （10610） and Zb±（10650）, and the charged eharmonium-like states Zc± （3900） and Zc± （4020）, at the Tevatron and the LHC, provided that these states are S-wave hadronic molecules. Using two Monte Carlo event generators, Herwig and Pythia, to simulate the production of heavy meson pairs, we derive an order-of-magnitude estimate of the production rates for these four particles. Our estimates yield a cross section at the nb level for the Zb（10610） and Zb（10650）. The results for the Zc（3900） and Zc （4020） are larger by a factor of 2~30. These cross sections are large enough to be observed, and measurements at hadron colliders in the future will supplement the study using electron-positron collisions, and therefore allow to explore the mysterious nature of these exotic states.     

Signatures of Neutral PG Boson P0a at the Tevatron

In topcolor-assisted technicolor scheme,we calculate the correction of the neutral color octet PG boson P0a to top quark production at the Tevatron.The result is that the PG boson P0a can significantly enhance the top quark production cross section.     

PG玻色子Pa0在Tevatron上的可能物理迹象

在Topcolor-Assisted Technicolor框架下,计算了多标度WTC模型的中性色八重态PG玻色子P0a对top夸克产生截面的修正,结果表明P0a可以增大Tevatron上top夸克的产生截面.