121659740
The CDF level 2 calorimetric trigger upgrade
Abstract CDF II upgraded the calorimeter trigger to cope with the higher detector occupancy due to the increased Tevatron instantaneous luminosity ( ∼ 2.8 × 10 32 cm - 2 s - 1 ) . While the original system was implemented in custom hardware and provided to the L2 trigger a limited-quality jet clustering performed using a reduced resolution measurement of the transverse energy in the calorimeter trigger towers, the upgraded system provides offline-quality jet reconstruction of the full resolution calorimeter data. This allows to keep better under control the dependence of the trigger rates on the instantaneous luminosity and to improve the efficiency and purity of the trigger selections. The upgraded calorimeter trigger uses the general purpose VME board Pulsar, developed at CDF II and already widely used to upgrade the L2 tracking and L2 decision systems. A battery of Pulsars is used to merge and send the calorimeter data to the L2 CPUs, where software-implemented algorithms perform offline-like clustering. In this paper we review the design and the performance of the upgraded system.
38776231
Online b-jets tagging at CDF
We propose a method to identify b-quark jets at trigger level which exploits recently increased CDF trigger system capabilities. b-quark jets identification is of central interest for the CDF high-PT physics program, and the possibility to select online b-jets enriched samples can extend the physics reaches especially for light Higgs boson searches where the Hrarrbb macr decay mode is dominant. Exploiting new trigger primitives provided by two recent trigger upgrades, the Level2 XFT stereo tracking and the improved Level2 cluster-finder, in conjunction with the existing Silicon Vertex Tracker (SVT), we design an online trigger algorithm aimed at selecting good purity b-jets samples useful for many physics measurements, the most important being inclusive Hrarr bb macr searches. We discuss the performances of the proposed b-tagging algorithm which must guarantee reasonable trigger rates at luminosity greater than 2times1032 cm-2 s-1 and provide high efficiency on Hrarrbb macr events.
123031501
Triggering on Heavy Flavors at Hadron Colliders
For a number of interesting processes in the sector of heavy flavors, the quality of measurements made at hadron colliders is very similar to the quality achieved at e+e− colliders (known as B factories). The key to performing such measurements in a hadron environment is the ability to select rare processes from background in real time, that is, to trigger on them. Two distinctive features of heavy-flavor decays have been used for this purpose: the presence of leptons in the final state and secondary vertices produced by the relatively long lifetime. The selection of events based on long lifetime, although technically very challenging, is the most inclusive of all such techniques, allowing access to the widest range of channels. The focus of this review is on the innovative concepts that permitted the reconstruction of tracks produced in hadron collisions with sufficient speed and accuracy for use at trigger level to detect heavy-flavor decays.
47564335
Level-2 Calorimeter Trigger Upgrade at CDF
The CDF Run II level-2 calorimeter trigger is implemented in hardware and is based on a simple algorithm used in Run I. This system has worked well for Run II at low luminosity. However, as the Tevatron instantaneous luminosity increases, the limitation due to the simple algorithm starts to become clear. In this paper, we will present an upgrade path to the level-2 calorimeter trigger system at CDF. This upgrade approach is based on the Pulsar board, a general purpose VME board developed at CDF and used for upgrading both the level-2 tracking and the Level-2 global decision crate. This paper will describe the design, hardware and software implementation, as well as the advantages of this approach over the existing system.
119289646
A statistical prescription to estimate properly normalized distributions of different particle species
Abstract We describe a statistical method to estimate the composition of a sample of particle tracks in terms of the species of these particles. We consider the case when the particle identification information strongly depends on some kinematical variables, whose distributions are poorly known and different for each particle species. We show that the proposed procedure provides a properly normalized estimate of the unknown distributions with minimal assumption on their functional form. Moreover, we show that the method can be generalized to any kinematical distribution of the particles.
113690341
EM Design of the Low-Beta SC Cavities for the Project X Front End
56240189
CW Room Temperature Re-buncher for the PIP-II Linac Front End
At Fermilab there is a plan for improvements to the Fermilab accelerator complex aimed at providing a beam power capability of at least 1 MW on target. The essential element of the plan (the Proton Improvement Plan II – PIP-II) is a new 800 MeV superconducting linac. The PIP-II linac consists of a room temperature front-end and a high energy part that uses five types of superconducting cavities to cover the entire velocity range required for beam acceleration. The room temperature front end is composed of an ion source, low energy beam transport line (LEBT), radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT). The paper summarises design of a re-buncher cavity used in the MEBT section.