CMS Level 1 Calorimeter Trigger Performance on Technical Proposal Physics
We examine the eeciency and rates of the CMS Calorimeter Level 1 Trigger as presented in the CMS Technical Proposal for selecting the events needed for use in the CMS physics program described in the Proposal. Speciic signals investigated include top decays to electrons, Standard Model Higgs decays to electrons and photons, signals from SUSY Higgs, and Gluino production. A variety of masses and SUSY parameters are investigated. The eeciencies are studied at the luminosity 10 33 cm ?2 s ?1 or 10 34 cm ?2 s ?1 depending on the expected rate of events as assumed in the CMS Technical proposal. A single set of Level 1 Calorimeter energy thresholds for electrons, jets and missing energy is selected to provide a 15 kHz rate at each of the two luminosity settings considered. It is shown that this set of cuts provides suuciently high eeciency and satisses CMS physics goals as stated in the Technical Proposal. We also explore the rate of B Physics signals that pass this high p t trigger.
Study of calorimeter calibration with ’ s in CMS
We propose to calibrate in situ the CMS calorimetry using the single, isolated pions from ! in W ! andZ; ! processes applying the p=E method. In case of pions non-interacting in the ECAL the method is straightforward, but for pions interactin g i the ECAL care is needed to suppress and keep under control + 0’s from ’s or QCS jets, which could vitiate the method. This can be achieved exploiting the ECAL granularity and tracker-calorimet y special matching. The momentum of the isolated high pt pion can be directly compared to the calorimeter measurement. Triggering of theW ! events is envisaged with a special -jet trigger combined with a missing transverse energy trigger. The Z; ! events could be triggered by lepton + -jet and double -jet trigger. The event rate for p t > 15 GeV is enough to calibrate each HCAL cell at a 1% precision after collection of104pb 1 of data. a) On leave from ITEP, Moscow, Russia
Pioneer 10 Observations of the Ultraviolet Glow in the Vicinity of Jupiter
A two-channel ultraviolet photometer aboard Pioneer 10 has made several observations of the ultraviolet glow in the wavelength range from 170 to 1400 angstroms in the vicinity of Jupiter. Preliminary results indicate a Jovian hydrogen (1216 angstrom) glow with a brightness of about 1000 rayleighs and a helium (584 angstrom) glow with a brightness of about 10 to 20 rayleighs. In addition, Jupiter appears to have an extensive hydrogen torus surrounding it in the orbital plane of Io. The mean diameter of the torus is about equal to the diameter of the orbit of Io. Several observations of the Galilean satellites have also occurred but only a rather striking Io observation has been analyzed to date. If the observed Io glow is predominantly that of Lyman-α, the surface brightness is about 10,000 rayleighs.