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.
A Proposal for Update of CMS Level-1 Calorimeter Regional Trigger Implementation
Implementation of the fine-grain EM ID and EM isolation algorithms within the constraints of the conceptual design proposed for the CMS level-1 calorimeter trigger is discussed. Some minor modifications to the algorithms are needed for this implentation and are checked with fast simulation program to cause no degradation in performance. The modifications suggested, not only simplify some of the neighbor data sharing in the system, but also provide primitives for tau trigger implementation. However, changes to the hardware are significant and warrant a closer study. This note only indicates variations on the the conceptual design that might be possible with various hardware changes. The aim of this document is to obtain an approval on the specifications outlined here so that an engineering investigation can be made.
VLA stereoscopy of solar active regions. 2: Altitude, relative motion, and center-to-limb darkening of 20 centimeter emission
A newly developed method of stereoscopic correlation is applied to solar radio maps at a wavelength of 20 cm. On the basis of stereoscopic correlations between radio maps obtained on 6 different days we establish the presence of 66 radio source components associated with 22 active regions. We find the following statistical results for active region source structures at 20 cm: 1. The observed lifetime is consistent with an exponential distribution having an e-folding time scale of greater than 18 days. 2. The average altitude of 20 cm sources is 25 +/- 15 Mm; 90% of the sources are found in heights less than 40 Mm. 3. The average diameter of discrete source structures is 48 +/- 15 Mm, implying a vertical/horizontal aspect ratio of q(sub A) approx. = 0.5. 4. No significant source motion has been found with respect to the standard differential rotation rate of Omega = 13.45 deg - ((3 deg (sin(exp 2)B)). 5. We find a statistical limb darkening, which can be described by the relation (T(sub B)(alpha))/T(sub B)(0)) = 0.4 + ((0.6(cos(exp 2) alpha)) for sources with T(sub B) greater than 0.5 MK. 6. The degree of source polarization is 15% +/- 10% and is independent of source location. 7. Bright sources (greater than or approximately equal to 0.5 MK), or equivalently, long-lived sources (greater than or approximately equal to 5 days) show a systematic variation of their altitude as function of the center-limb distance.