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The lambda trigger for the E704 Forward SpectrometerCranshaw, Jack Mark January 1991 (has links)
The E704 Forward Spectrometer was designed to detect the inclusive production of hyperons ($\Lambda\sp0, \Sigma\sp0$) by a 200 GeV/c polarized proton beam incident upon an unpolarized liquid hydrogen target. This measurement used a four level trigger to detect lambdas, both from direct production and from $\Sigma\sp0$ decay. This trigger used four hodoscopes and two levels of programmable logic. The correlations fed into the programmable logic (Memory Lookup Units and Programmable Logic Units) were calculated using a GEANT3 Monte Carlo program. The trigger was tested and then used during the 1990/91 fixed-target run at Fermilab. It was gradually refined during the run. We were eventually able to see lambdas, but the reconstruction rate was low due to tracking limitations, chamber inefficiencies, background processes, etc.
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Design and construction of a large area multi-wire proportional chamberEichblatt, Stephen L. January 1992 (has links)
The concepts involved in the design and operation of a multi-wire proportional chamber are reviewed. The design and construction of two chambers for the SMC (Spin Muon Collaboration) muon polarimeter are described in some detail so that one can use this thesis as an aid in the construction of a similar detector.
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Design and construction of a photon shower position detectorXu, Jianping January 1993 (has links)
The design and tests of a photon shower position detector are discussed in this thesis. Some Monte Carlo results about this detector are also discussed. It will be used to measure the shower position of photons so that single $\gamma$ QED events can be distinguished from the other kinds of events in $\gamma$p interaction. The results are encouraging. From the Monte Carlo results, the detector should do a decent job of picking up QED events. The QED event ratio will be around 40% of all events which pass our cuts. And from the offline cosmic ray test and limited online test data, the detector will function very well.
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Drift chambers for KTeVBarnes, Julius, II January 1995 (has links)
There is much potential for reliable operation of the four large drift chambers for KTeV. In time, the problem with the loss of sense wires will be solved. These chambers will have a resolution of 100 microns per plane and play a major role in measuring the direct CP violation parameter Re($\epsilon\sp\prime/\epsilon$).
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Measurement of the analyzing power in inclusive, high-x(F) charged pion production with a 200 GeV/c polarized proton beamWhite, Joseph Lasalle January 1991 (has links)
The analyzing power, A$\sb{\rm N},$ in inclusive $\pi\sp{+}$ and $\pi{-}$ production by a 200 GeV/c polarized proton beam was found to have a striking $x\sb{F}$ dependence in which the magnitude of A$\sb{\rm N}$ increases from 0 to 0.42 for the $\pi\sp{+}$ data and decreases from 0 to $-0.38$ for the $\pi\sp{-}$ data for increasing $x\sb{F}$ over the kinematic range $0.2 \le x\sb{F} \le 0.9$ and 0.2$GeV/c \le p\sb{T} \le 2.0GeV/c.$ The higher values of $x\sb{F}$ and $p\sb{T}$ in these kinematic ranges insure that the measured particle came from an interaction of the beam and target through a direct channel and that quark scattering through gluon exchange is the dominant interaction. The charged pions were identified and tracked with a large forward multi-particle spectrometer based upon a Helium gas threshold Cherenkov counter. A simple parton recombination model correctly predicts the signs of the spin parameters measured in this experiment. It also correctly predicts the magnitudes of the $\pi\sp{+}$ and $\pi\sp\circ$ analyzing power at high $x\sb{F}$ but the $\pi\sp{-}$ analyzing power is twice the predicted value. The $\pi\sp{+},$ $\pi\sp{-},$ and $\pi\sp\circ$ analyzing powers were also measured with a polarized anti-proton beam. These data and their interpretation with the simple model suggest that the transverse spin of the proton can be correlated with its quarks in certain kinematic regions, however, the details are still not well understood.
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Time-of-flight particle identification results from central silicon-silicon and silicon-tungsten collisions at 14.6 x A GeV/cChiou, Chengnan January 1992 (has links)
Momentum spectra of $\pi\sp-$, $K\sp-$, p and d have been measured from central collisions of 14.6 $\times$ A GeV/c Si beam on Si and W targets at rapidity 1.9 $<$ y $<$ 2.1. The inverse slope parameters $T\sb0$ obtained by an exponential fit with the transverse mass spectra in transverse kinetic energy are found to be $T\sb0(\pi\sp-) < T\sb0(K\sp-) < T\sb0(p) < T\sb0(d)$. This result is predicted by a radially expanding flow model. From integrated results, the $K\sp-/\pi\sp-$ ratios, (2.7 $\pm$ 0.3) % from Si and (2.4 $\pm$ 0.2) % from W, are consistent with pp collision results. The deuteron production rates can be explained by a relativistic coalescence model.
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Observation of jet photoproduction and comparison to Monte Carlo simulationLincoln, Donald W. January 1994 (has links)
The photon is the carrier of the electromagnetic force. However in addition to its well known nature, the theories of QCD and quantum mechanics would indicate that the photon can also for brief periods of time split into a $q\overline{q}$ pair (an extended photon). How these constituents share energy and momentum is an interesting question and such a measurement was investigated by scattering photons off protons. The post collision kinematics should reveal pre-collision information. Unfortunately, when these constituents exit the collision point, they undergo subsequent interactions (gluon radiation, fragmentation, etc.) which scramble their kinematics. An algorithm was explored which was shown via Monte Carlo techniques to partially disentangle these post collision interactions and reveal the collision kinematics. The presence or absence of large transverse momenta internal ($k\sb\bot$) to the photon has a significant impact on the ability to reconstruct the kinematics of the leading order calculation hard scatter system. Reconstruction of the next to leading order high $E\sb\bot$ partons is more straightforward.
Since the photon exhibits this unusual behavior only part of the time, many of the collisions recorded will be with a non-extended (or direct) photon. Unless a method for culling only the extended photons out can be invented, this contamination of direct photons must be accounted for. No such culling method is currently known, and so any measurement will necessarily contain both photon types.
Theoretical predictions using Monte Carlo methods are compared with the data and are found to reproduce many experimentally measured distributions quite well. Overall the LUND Monte Carlo reproduces the data better than the HERWIG Monte Carlo. As expected at low jet $E\sb\bot$, the data set seems to be dominated by extended photons, with the mix becoming nearly equal at Jet $E\sb\bot$ $>$ 4 GeV. The existence of a large photon $k\sb\bot$ appears to be favored.
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Identification of the tau lepton through its hadronic decay modes at the DO collider detectorSen, Naresh January 2000 (has links)
This thesis focuses on tau identification efficiencies in Monte Carlo simulations of various processes by implementing optimization techniques to determine optimal values for selection cuts on discriminant variables. Two sets of discriminants were studied: the first set consisted of only the Fisher discriminant, and the second set comprised the jet width and profile. Results obtained for the two sets are comparable for the central region (|eta| < 1.1) of the DO detector. For the forward region (|eta| ≥ 1.1), the optimization procedure did not yield optimal values for the set of variables used, suggesting that the signatures of the tau decay products in the forward regions is different from that in the central region, so that it appears that a different approach is required to identify the tau in the forward region. Given that the tau is to be identified through a reconstruction of its decay products, the complex interplay of the multitude of variables that need to be taken into account make the task of tau identification an ideal candidate for a multivariate analysis.
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Measurement of the gamma W boson decaying to muon-neutrino-photon cross section, limits on anomalous trilinear vector boson couplings, and the radiation amplitude zero in proton-antiproton collisions at center of mass energy = 1.96 TeVAskew, Andrew W. January 2005 (has links)
This thesis details the measurement of the pp¯ → W gamma + X → munugamma + X cross section at s = 1.96 TeV using the DO detector at Fermilab, in 134.5 pb -1 of integrated luminosity. From the photon E T spectrum limits on anomalous couplings of the photon to the W are obtained. At 95% confidence level, limits of -1.05 < Deltakappa < 1.04 for lambda = 0 and -0.28 <lambda < 0.27 for Deltakappa = 0 are obtained on the anomalous coupling parameters. The charge signed rapidity difference from the data is displayed, and its significance discussed.
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Neutral strange particle spectra with direct daughter particle identification in 11.6A GeV/c Au+Au collisionsKainz, Kristofer Keith January 2002 (has links)
The BNL-AGS Experiment 896 intended to measure neutral strange particles, including the Λ hyperon and Ks meson, by recognizing and reconstructing their charged decay daughters. As designed, E896 had no means of directly identifying the species of these daughters, which is a powerful tool for the rejection of certain background processes that can mimic the signatures of such decays. A Time-Of-Flight (TOF) detector system was thus added to this experiment to provide a means for direct particle identification of the charged decay products. The detectors were constructed and installed in the E896 apparatus, and experimental data was collected with these new detectors during several runs of the experiment both with single hadron beams and central collisions of gold nuclei at a beam momentum of 11.6 GeV/c/N. Software was written to calibrate the raw TOF detector information, to make the crucial association of tracks in the experiment to hits in the TOF system, and to optimize the timing performance and particle identification capabilities. This software was then used to form samples of reconstructed neutral strange particles under the more stringent criteria possible with the addition of the TOF information to the E896 data. The transverse mass distributions of Λ hyperons and Ks mesons from central 11.6 GeV/c/N Au+Au collisions, obtained from the analyses including direct daughter particle identification, will be presented and compared with other experiments and a theoretical model.
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