Beam instrumentation for the Tevatron Collider

The Tevatron in Collider Run II (2001-present) is operating with six times more bunches and many times higher beam intensities and luminosities than in Run I (1992-1995). Beam diagnostics were crucial for the machine start-up and the never-ending luminosity upgrade campaign. We present the overall picture of the Tevatron diagnostics development for Run II, outline machine needs for new instrumentation, present several notable examples that led to Tevatron performance improvements, and discuss the lessons for future colliders

Observation of Orbitally Excited B_s Mesons

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

Diffractive production of #rho#"0(770) mesons in muon-proton interactions at 470 GeV

The diffractive production of #rho#"0(770) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV"2 < Q"3 < 20 GeV"2 and 20 GeV < #nu# < 420 GeV. The data were obtained in the Fermilab fixed-target experiment E665 with primary muons of 470 GeV energy. Results are presented on the Q"2, x and #nu# dependence of the cross section, on the shape of the #pi#"+#pi#"- mass spectrum, on the slope of the diffraction peak and on the production and decay angular distributions of the #rho#"0(770). The cross section for diffractive production of #rho#"0 by virtual photons on protons depends mainly on Q"2. At fixed Q"2, no significant dependence on x or #nu# is observed. The extrapolation to Q"2 = 0 yields a photoproduction cross section of (10.30 #+-# 0.33) #mu#b. The slope of the t' distribution has a value of (7.0#+-#0.2) GeV"-"2, with a tendency to decrease as Q"2 increases. The production and decay angular distributions of the #rho#"0 depend strongly on Q"2 and are consistent with s-channel helicity conservation. The ratio R #sigma#_L/#sigma#_T deduced from the decay angular distributions rises strongly with Q"2, passing the value of 1 at Q"2 #approx# 2 GeV"2. (orig.)SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Production of charged hadrons by positive muons on deuterium and xenon at 490 GeV

Results on the production of charged hadrons in muon-deuteron and muon-xenon interactions are presented. The data were taken with the E665 spectrometer, which was exposed to the 490 GeV muon beam of the Tevatron at Fermilab. The use of a streamer chamber as vertex detector provides nearly 4#pi# acceptance for charged particles. The #mu#D data are compared with the #mu#Xe data in terms of multiplicity distributions, average multiplicities, forward-backward multiplicity correlations, rapidity and transverse momentum distributions and of two-particle rapidity correlations of charged hadrons. The data cover a range of invariant hadronic masses W from 8 to 30 GeV. (orig.)Available from TIB Hannover: RR 2916(93-17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman