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Extracting longitudinal shower development information from crystal calorimetry plus tracking

Description: We present an approach to derive longitudinal shower development information from the longitudinally unsegmented BABAR electromagnetic calorimeter by using tracking information. Our algorithm takes advantage of the good three-dimensional tracking resolution of BABAR, which provides an independent geometric constraint on the shower as measured in the BABAR crystal calorimeter. We show that adding the derived longitudinal shower development information to standard particle identification algorithms significantly improves the low-momentum separation of pions from electrons and muons. We also verify that the energy dependence of the electromagnetic shower development we measure is consistent with the prediction of a standard electromagnetic shower model.
Date: November 1, 2007
Creator: Brown, David; Brown, D.N.; Ilic, J. & Mohanty, G.B.
Partner: UNT Libraries Government Documents Department

Azimuthal HBT and Transverse Momentum Fluctuations from CERES.

Description: CERES is a dilepton experiment at the CERN SPS, known for its observation of enhanced production of low mass efe- pairs in collisions between heavy nuclei [1]. The upgrade of CERES in 1997-1998 by a radial Time Projection Chamber (TPC) [2] allowed to improve the momentum resolution and the particle identification capability while retaining the cylindrical symmetry. The upgraded experiment is shown in Fig. 1. The upgrade also extended the sensitivity of CERES to hadrons and made possible results like those described below. The measurement of central Pb+Au collisions at the maximum SPS energy of 158 GeV per nucleon in the fall of 2000 was the first run of the fully upgraded CERES and at the same time the last run of this experiment. About 30 million Pb+Au collision events at 158 GeV per nucleon were collected, most of them with centrality within the top 7% of the geometrical cross section {sigma}{sub G} = 6.94 b. Small samples of the 20% and the minimum bias collisions, as well as a short run at 80 AGeV, were recorded in addition. The dilepton mass spectra from this experiment were published in [3]. In this talk I present two particular results of hadron analysis, the azimuthal dependence of two-pion correlations and a differential p{sub t} fluctuation study.
Date: July 9, 2007
Creator: Miskowiec,D.; Rehak, P. & al., et
Partner: UNT Libraries Government Documents Department

The Focusing DIRC - the First RICH Detector toCorrect the Chromatic Error by Timing, and the Development of a New TOFDetector Concept

Description: We have built and successfully tested a novel particle identification detector called Focusing DIRC. The prototype's concept is based on the BaBar DIRC with several important improvements: (a) much faster pixilated photon detectors based on Burle MCP-PMT and Hamamatsu MaPMT, (b) mirror allowing to make the photon detector smaller and less sensitive to background in future applications, (c) electronics allowing to measure the single photon resolution to better than {sigma} {approx} 100-200ps, which allows a correction of the chromatic error. While testing the timing resolution limits of a 64-pixel MCP-PMT with 10 mm MCP holes, we have achieved a timing resolution of {sigma} {approx} 30ps with single photoelectrons. In this paper we further investigate limits of the timing resolution with this particular detector.
Date: September 12, 2007
Creator: Va'vra, Jaroslav; Benitez, Jorge A.; Leith, David W.G.S.; Mazaheri, Gholamali; Ratcliff, Blair N.; Schwiening, Jochen et al.
Partner: UNT Libraries Government Documents Department

MiniBooNE Neutrino Physics at the University of Alabama

Description: This report summarizes the activities conducted by the UA group under the auspices of the DoE/EPSCoR grant number DE--FG02--04ER46112 since the date of the previous progress report, i.e., since November 2005. It also provides a final report of the accomplishments achieved during the entire period of this grant (February 2004 to January 2007). The grant has fully supported the work of Dr. Yong Liu (postdoctoral research assistant -- in residence at Fermilab) on the MiniBooNE reconstruction and particle identification (PID) algorithms.
Date: April 27, 2007
Creator: Stancu, Ion
Partner: UNT Libraries Government Documents Department

Measurements of CP asymmetries and branching fractions of two-body charmless decays of B^0 and B^0_s mesons

Description: The thesis is organized as follows: Chapter 1 describes the theoretical framework of non-leptonic B{sub (s)}{sup 0} {yields} H{sup +}h{prime}{sup -} decays, with a simple overview of the CP violation mechanism within the Standard Model and of the most used phenomenological approaches in the evaluation of strong interaction contributions. The chapter contains also a review of the theoretical expectations and the current experimental measurements along with a discussion about the importance of studying such decays. Chapter 2 contains a general description of the Tevatron collider and of the CDF II detector. Chapter 3 is devoted to the description of the data sample used for the measurement and the method used in extracting the signal from the background. Particular attention is dedicated to the on-line trigger selection, which is crucial to collect a sample enriched in B{sub (s)}{sup 0} {yields} h{sup +}h{prime}{sup -} decays. Chapter 4 shows how the information from kinematics and particle identification was used to achieve a statistical discrimination amongst modes to extract individual measurements. The available resolutions in mass or in particle identification are separately insufficient for an event-by-event separation of B{sub (s)}{sup 0} {yields} h{sup +}h{prime}{sup -} modes. The choice of observables and the technique used to combine them is an important and innovative aspect of the analysis described in this thesis. Chapter 5 is devoted to the accurate determination of the invariant mass lineshape. This is a crucial ingredient for resolving overlapping mass peaks. This chapter details all resolution effects with particular attention at the tails due to the emission of low-energy photons from charged kaons and pions in the final state (FSR). For the first time the effect of FSR has been accurately accounted for in a CDF analysis. Chapter 6 describes how kinematic and PID information, discussed in chap. 4 and chap. 5 ...
Date: December 1, 2007
Creator: Morello, Michael Joseph & /Pisa, Scuola Normale Superiore
Partner: UNT Libraries Government Documents Department

Search for third generation vector leptoquarks in 1.96 TeV proton-antiproton collisions

Description: The CDF experiment has searched for production of a third generation vector leptoquark (VLQ3) in the di-tau plus di-jet channel using 322 pb{sup -1} of Run II data. We review the production and decay theory and describe the VLQ3 model we have used as a benchmark. We study the analysis, including the data sample, triggers, particle identification, and event selection. We also discuss background estimates and systematic uncertainties. We have found no evidence for VLQ3 production and have set a 95% C.L. upper limit on the pair production cross section {sigma} to 344 fb, and exclude VLQ3 in the mass range m{sub VLQ3} > 317 GeV/c{sup 2}, assuming Yang-Mills couplings and Br(LQ3 {yields} b{tau}) = 1. If theoretical uncertainties on the cross section are taken into account, the results are {sigma} < 353 fb and m{sub VLQ3} > 303 GeV/c{sup 2}. For a VLQ3 with Minimal couplings, the upper limit on the cross section is {sigma} < 493 fb ({sigma} < 554 fb) and the lower limit on the mass is m{sub VLQ3} > 251 GeV/c{sup 2} (m{sub VLQ3} > 235 GeV/c{sup 2}) for the nominal (1{sigma} varied) theoretical expectation.
Date: February 1, 2007
Creator: Akimoto, Takashi
Partner: UNT Libraries Government Documents Department