The Response of CMS Combined Calorimeters to Single Hadrons, Electrons and Muons

We report on the response of the combined CMS electromagnetic (EB) and hadronic barrel (HB) calorimeters to hadrons, electrons and muons in a wide momentum range from 1 to 350 GeV/c. To our knowledge, this is the widest range of momenta in which any calorimeter system is studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. We analyze in detail the differences in total calorimeter response to charged pions, kaons, protons and antiprotons and discuss the underlying phenomena. These data will play a crucial role in the thorough understanding of jets in CMS

Design, Performance, and Calibration of the CMS Hadron-Outer Calorimeter

The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with an outer calorimeter to ensure high energy shower containment in the calorimeter. Fabrication, testing and calibration of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing \et measurements at LHC energies. The outer hadron calorimeter will also be used for the muon trigger in coincidence with other muon chambers in CMS

Studies of Heavy Baryons in DELPHI and Radiation Monitoring in DØ

Between the years 1992 and 1995 about 3.5 million hadronic Z decays were collected by the DELPHI detector at CERN. This data has been used to measure the production and lifetime of the beauty strange baryon Ξb, in the inclusive decay channel Ξb →Ξ-ℓ- X. The Ξ- baryon was reconstructed through the decay Ξ- → Λ π-, using a constrained fit method for cascade decays. An iterative discriminant analysis was used for the Ξb selection. A search for the Ξb baryon was also performed using an alternative method of reconstructing the Ξ- baryon. A measurement of the production of the charmed strange baryon Ξc in the decay channel Ξc → Ξ-π+ using the same data is also presented. The radiation monitoring system of the Silicon Microstrip Tracker in the DØ detector is studied and used to estimate the radiation dose received by the Silicon detector during normal running conditions of the TeVatron accelerator

Production of Xi_c^0 and Xi_b in Z decays and lifetime measurement of Xi_b

The charmed strange baryon Ξ 0 c was searched for in the decay channel Ξ 0 c → Ξ −π +, and the beauty strange baryon Ξb in the inclusive channel Ξb → Ξ −` −ν¯X, using the 3.5 million hadronic Z events collected by the DELPHI experiment in the years 1992–1995. The Ξ − was reconstructed through the decay Ξ − → Λπ −, using a constrained fit method for cascade decays. An iterative discriminant analysis was used for the Ξ 0 c and Ξb selection. The production rates were measured to be fΞ0 c ×BR(Ξ 0 c → Ξ −π +) = (4.7±1.4(stat.)±1.1(syst.))×10−4 per hadronic Z decay, and BR(b → Ξb)×BR(Ξb → Ξ −` −X) = (3.0±1.0(stat.)±0.3(syst.))×10−4 for each lepton species (electron or muon). The lifetime of the Ξb baryon was measured to be τΞb = 1.45+0.55 −0.43(stat.)± 0.13(syst.) ps. A combination with the previous DELPHI lifetime measurement gives τΞb = 1.48+0.40 −0.31(stat.)±0.12(syst.) ps

The CMS Barrel Calorimeter Response to Particle Beams from 2 to 350 GeV/c

The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. The analysis of the differences in calorimeter response to charged pions, kaons, protons and antiprotons and a detailed discussion of the underlying phenomena are presented. We also show techniques that apply corrections to the signals from the considerably different electromagnetic (EB) and hadronic (HB) barrel calorimeters in reconstructing the energies of hadrons. Above 5 GeV/c, these corrections improve the energy resolution of the combined system where the stochastic term equals 84.7$\pm$1.6$\%$ and the constant term is 7.4$\pm$0.8$\%$. The corrected mean response remains constant within 1.3$\%$ rms