A study of jet energy measurement at CDF Metadata

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Title

  • Main Title A study of jet energy measurement at CDF

Contributor

  • Sponsor: United States. Department of Energy.
    Contributor Type: Organization
    Contributor Info: USDOE, Washington, DC (United States)

Publisher

  • Name: Fermi National Accelerator Laboratory
    Place of Publication: Batavia, Illinois
    Additional Info: Fermi National Accelerator Lab., Batavia, IL (United States)

Date

  • Creation: 1998-09-01

Language

  • English

Description

  • Content Description: This thesis describes the effort being made to improve the Jet Energy Reconstruction as performed by the CDF international collaboration at the Tevatron collider. This experiment studies proton-antiproton interactions at a center of mass energy of 1.8 TeV. During the three years data taking period Run 1, from 1992 to 1995 the CDF experiment collected an amount of data corresponding to a total integrated luminosity of 110 pb{sup -1}. One of the major results obtained analyzing this data sample is the discovery of the top quark. In the year 2000 a new period of data taking, Run 11, will start with a higher luminosity and a slightly higher center of mass energy giving us the chance to explore high energy physics even deeper. In preparation of this new run several upgrades are being made to adapt the CDF detector to the high luminosity foreseen and to improve its capabilities. Many signatures requested to trigger the detector aim at signaling a quark or a gluon in the final state. Unfortunately we are not able to measure quarks as free particles because they undergo a fragmentation process when turning into jets of particles. Thus it is of key importance to build up algorithms which reconstruct the energy of the initial parton starting from the jet informations. The description of the algorithm adopted till now will be given as an introduction to the new method being developed, that will be the main subject of this thesis. In Chapter I we will give a theoretical introduction on strong interactions to describe the mechanism to produce hadronic jets. In Chapter 2 we will describe some results from the experiment where the reconstruction of hadronic jets was important. Here we will also mention some important results which we think we can obtain during new the data taking period. We will give particular emphasis to those processes where an improved jet energy measured would bring to better results. In Chapter 3 we will give a description of the CDF detector including some more details on the elements which are relevant for jet energy reconstruction. The way of defining jets which has been used by CDF so far, will be the subject of chapter 4. Starting from the present CDF algorithm we studied the various problems which arise with jet reconstruction. Those problems can be grouped into two categories, the one including effects coming from physics and a second one including the effects due to a non-perfect resolution of our detector. In Chapter 5 the physics effects limiting jet energy reconstruction will be addressed. We will discuss the radiation of hard gluons both from initial state and final state partons and we will show how these problems are connected with jet definition algorithms. In Chapter 6 we will describe a new method to define jet energy making use of some detector informations which are not used in the present algorithm. The energy of each single calorimeter tower will be re-defined taking into account not only the energy released in the calorimeters, but also the informations on the shower development through it and the tracking informations coming from the Central Tracking Chamber. Finally, in Chapter 7 we apply the studies described above on photon+jet events collected during the run 1. The use of data is of key importance to claim that our corrections are working fine. We will show how a 30 % improvement in jet energy resolution, a major step towards better jet physics in Run 11, is obtained.
  • Physical Description: 124 p.; Other: FDE: POSTSCRIPT; PL:

Subject

  • Keyword: Energy
  • Keyword: Algorithms
  • Keyword: Fermilab Collider Detector
  • Keyword: Jets
  • Keyword: Resolution
  • STI Subject Categories: 66 Physics

Source

  • Other Information: PBD: Sep 1998

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Report

Format

  • Text

Identifier

  • Other: DE98058982
  • Report No.: FNAL--98058982
  • Grant Number: AC02-76CH03000
  • DOI: 10.2172/665739
  • Office of Scientific & Technical Information Report Number: 665739
  • Archival Resource Key: ark:/67531/metadc707419

Note

  • Display Note: INIS; OSTI as DE98058982
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