Intermittency, as introduced into multiparticle production by Bialas and Peschanski, has become a fruitful and rapidly growing industry. The original concept of intermittency in the form of the Alpha model is discussed in detail and suggestions for extensions are made. We analyze the factorial moments measured by different experimental collaborations in terms of their nontrivial many-particle correlations, the cumulants. A large fraction of measured moments is shown to originate in two-particle correlations. The validity of the Linked Pair ansatz is tested and found to be acceptable to fourth order for hadronic collisions but uncertain for nuclear collisions. A cumulant decomposition for bin-bin correlations is derived, and a general formalism is developed for treating correlations of particle distributions consisting of several distinct populations, such as particles of different charge.

This thesis presents the detailed measurements of the tracking efficiency of the BaBar detector using T pair events. These efficiency measurements are critical for many physics analyses at BaBar. The tracking efficiency is dctcrmined both as a global valuc for the detector and in terms of the parameters on which the BaBar tracking reconstruction software depends. In addition, the charge asymmetry of the tracking efficiency as well as a detailed analysis of the systematic uncertainties related to this method are also presented. It was discovered that the sample of data conventionally used by BaBar for measuring the efficiency is contaminated by background and a ncw protocol for measuring thc cfficicncies is presented. Undcr this new protocol, the global tracking efficiency correction factor and the global tracking efficiency charge asymmetry are determined to be consistent with zero. A new method for determining the efficiency as a function of the reconstruction parameters, was also successfully demonstrated.

No description available.

The strong modification to the production of final state hadrons in heavy ion collisions is a key signature of the hot dense medium produced at energies achieved at the Relativistic Heavy Ion Collider (RHIC). Understanding the mechanisms for the parton energy loss responsible for these modifications is challenging and difficult to constrain with straightforward hadronic measurements, making it necessary to turn to more discriminating probes. One example of such a probe is photons produced by partons as they fragment, fragmentation photons, because the production mechanisms for such photons are similar to those for hadrons, but once produced, fragmentation photons will not interact directly with the medium. The challenge of distinguishing the signal for such jet-associate photons out of the large decay background motivates first making such measurements in the simple p + p environment. Combining data collected by the PHENIX detector during 2005 and 2006, the yield for fragmentation photons was measured to be on the order of several percent of all photons measured in association with a hadron with transverse momentum between 2 and 5 GeV/c. The use of two-particle correlations coupled with a sophisticated method for identifying and removing decay photons has made it possible to further study the jet properties of these fragmentation photons, in the form of pout and root mean square jT. These results will help to constrain both the underlying theoretical description of direct photon production in p + p, and modifications expected in heavy ion collisions.

Jet production in relativistic heavy ion collisions is studied using Pb+Pb collisions at a center of mass energy of 2.76 TeV per nucleon. The measurements reported here utilize data collected with the ATLAS detector at the LHC from the 2010 Pb ion run corresponding to a total integrated luminosity of 7 µ b^(-1). The results are obtained using fully reconstructed jets using the anti-k t algorithm with a per-event background subtraction procedure. A centrality-dependent modification of the dijet asymmetry distribution is observed, which indicates a higher rate of asymmetric dijet pairs in central collisions relative to periphal and pp collisions. Simultaneously the dijet angular correlations show almost no centrality dependence. These results provide the first direct observation of jet quenching. Measurements of the single inclusive jet spectrum, measured with jet radius parameters R=0.2, 0.3, 0.4 and 0.5, are also presented. The spectra are unfolded to correct for the finite energy resolution introduced by both detector effects and underlying event fluctuations. Single jet production, through the central-to-peripheral ratio R CP, is found to be suppressed in central collisions by approximately a factor of two, nearly independent of the jet p T. The R CP is found to have a small but significant increase with increasing R, which may relate directly to aspects of radiative energy loss.

Measurements at the Relativistic Heavy Ion Collider (RHIC) have provided indirect measurements of jets in a heavy ion environment using the two- particle correlation method in the presence of a high-pT particle. These measurements have offered insight into the formation of a new state of dense nuclear matter called the Quark-Gluon Plasma (QGP) through the observation of jet quenching. However, the two-particle methodology has also shown to be biased towards di-jet production near the surface of the medium being created. Here, a detailed study using the PHENIX detector is provided, in an attempt to measure a more accurate jet-induced two-particle correlation measurement than previously published and to reduce the bias observed in two-particle correlation measurements. The reduction in surface bias emission is performed via the requirement of two antipodal high-pT particles (a.k.a. "2+1" correlation) in an attempt to control the production point of the di-jet. The measurements made in Au+Au collisions when compared to p+p collisions show that the method provides additional sensitivity to the jet quenching previously observed in two-particle correlation method.

High-pT processes in proton- and deuteron-nucleus collisions at TeV energies are the best presently available way to study the partonic structure of the nucleus in a high-density regime. Jet production over a wide range of phase space can significantly constrain the current knowledge of nuclear parton distribution functions (nPDFs), which are substantially less well understood than the corresponding PDFs in protons and which have only recently begun to be treated in a spatially-dependent way. An accurate knowledge of nPDFs is crucial for a definitive control of perturbative processes in a cold nuclear environment, since high-pT probes are used to quantitatively investigate the hot QCD matter created in ultrarelativistic nucleus-nucleus collisions. Furthermore, jets from low Bjorken-x partons can probe the transition from the dilute to saturated nuclear regimes.

No description available.

Copies of author's previously published works inserted. Bibliography: p. 89-96.

<p>A series of nuclear fission experiments have been performed in the intermediate energy range. The dynamics of the fission process have been studied by means of detection of neutrons emitted from compound nuclei formed by ion beams of protons, α-particles, and ¹²C-ions, all at a beam energy of 100 MeV. The neutron emission data have been interpreted using a statistical model analysis, and the fission time scale has been found to vary between 6.4 and 170ⅹ10^-21s.</p><p>Neutron-induced fission cross section measurements have been performed on targets of ²⁰⁸Pb, ²⁰⁹Bi, and ²³⁸U. The results have been compared with other measurements as well as with model calculations and evaluations. The comparisons agreed reasonably well with previous measurements, but disagreed substantially both with calculations and evaluations. The neutron flux in the neutron-induced fission was determined relative to the <i>np</i>-scattering cross section which was measured simultaneously.</p><p>The <i>np</i>-scattering cross section has been measured with an unprecedented precision. Using a normalization procedure which takes advantage of the total <i>np</i> cross section, which has been determined with great precision, differential <i>np</i> cross sections have been presented in the angular range 74° to 180° at 96 MeV and 72° to 180° at 162 MeV. They were found to disagree with as much as 10—15 % compared with older measurements in the world data base, and with Partial Wave Analysis solutions. The data are, however, in agreement with another recent, high-quality measurement.</p>