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Sterile neutrino oscillations in MINOS and hadron production in pC collisions

Description: MINOS is a long baseline neutrino oscillation experiment, starting with a muon-neutrino beam, for the precise measurement of the atmospheric neutrino oscillation parameters |{Delta}m{sup 2}| and {theta}{sub 23}. The Near Detector measures the neutrino flux and spectra before oscillations. The beam propagates for 735 km to the Far Detector, which measures the depleted spectrum after oscillations. The depletion can be interpreted as {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillations. Subdominant {nu}{sub {mu}} {yields} {nu}{sub e} oscillations may be allowed if the mixing angle {theta}{sub 13} {ne} 0. The two detectors are functionally identical in order to cancel systematic errors when using the Near Detector data to constrain the Far Detector prediction. A crucial part of the analysis is the relative calibration between the two detectors, which is known at the 2% level. A calibration procedure to remove the time and temperature dependence of the detector response using through-going cosmic muons is presented here. Although the two-detector approach reduces the systematic uncertainties related to the neutrino flux, a cross check on the neutrino parent meson ratios is performed in this thesis. The cross sections of mesons produced in proton-carbon interactions from the NA49 experiment have been measured and the results have been compared to the MINOS expectations. A neutrino oscillation analysis allowing mixing to a sterile neutrino is performed, under the assumption that the additional mass splitting is {Omicron}(1 eV{sup 2}). The analysis uses the energy spectrum of the neutral current interaction products, as neutral current interactions are sensitive to sterile neutrino mixing but not to the active flavour neutrino mixing. The neutrino oscillation parameters have been found to be: |{Delta}m{sup 2}| = 2.43{sub -0.18}{sup +0.21} x 10{sup -3} eV{sup 2}, {theta}{sub 23} = 40.27{sup o}{sub -5.17}{sup +14.64}, {theta}{sub 24} = 0.00{sup o}{sup +5.99} and {theta}{sub 34} = 0.00{sup o}{sup +24.57} under ...
Date: July 1, 2010
Creator: Tinti, Gemma Maria & U., /Oxford
Partner: UNT Libraries Government Documents Department

A search for sterile neutrinos at the MINOS experiment

Description: MINOS is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory in Illinois, USA. The experiment was designed to study neutrino oscillation phenomena. The {nu}{sub {mu}} beam produced by the NuMI beam facility at FNAL is used along with two functionally identical detectors. The Near Detector at FNAL and a Far Detector 735 km away in the Soudan Underground Laboratory in northern Minnesota. Comparison of the observed spectra of neutrinos at the two detectors provides the evidence for neutrino oscillations. This thesis presents work on the postulated phenomena of sterile neutrinos. Oscillations between active and sterile neutrinos will lead to a deficit in the expected rate of measured Neutral Current interactions at the Far Detector. A technique for selecting Neutral Current events utilizing an Artificial Neural Network is presented with resulting overall efficiency of 91.1% and purity of 66.0%. A method of predicting the expected Charged and Neutral Current energy spectra at the Far Detector given the data recorded at the Near Detector is presented. A model to search for oscillations between sterile and active neutrinos is developed. Sources of systematic uncertainty that can effect the results of the analysis are discussed. The analysis developed is applied to a Standard Model 3 flavour oscillation model as a cross check under the scenarios with and without {nu}{sub e} appearance. The oscillation parameters measured by this model are {Delta}m{sub 32}{sup 2} = (2.39{sub -0.15}{sup +0.23}) x 10{sup -3} eV{sup 2} and {theta}{sub 23} = 0.727{sub -0.11}{sup +0.22} for the no {nu}{sub e} appearance result. An analysis of the resulting prediction reveals no evidence for active neutrino disappearance. The analysis is then performed using the 4 flavour neutrino oscillation model developed. Again this is done under the 2 scenarios of {nu}{sub e} appearance and no {nu}{sub e} appearance. The ...
Date: August 1, 2010
Creator: Pittam, Robert Neil & U., /Oxford
Partner: UNT Libraries Government Documents Department

Probing low-x QCD with cosmic neutrinos at the Pierre Auger Observatory

Description: The sources of the observed ultra-high energy cosmic rays must also generate ultra-high energy neutrinos. Deep inelastic scattering of these neutrinos with nucleons on Earth probe center-of-mass energies {radical}s {approx} 100 TeV, well beyond those attainable at terrestrial colliders. By comparing the rates for two classes of observable events, any departure from the benchmark (unscreened perturbative QCD) neutrino-nucleon cross-section can be constrained. Using the projected sensitivity of the Pierre Auger Observatory to quasi-horizontal showers and Earth-skimming tau neutrinos, we show that a ''Super-Auger'' detector can thus provide an unique probe of strong interaction dynamics.
Date: May 1, 2006
Creator: Anchordoqui, Luis A.; /Northeastern U. /Wisconsin U., Milwaukee; Cooper-Sarkar, Amanda M.; U., /Oxford; Hooper, Dan; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Multiple Scattering Measurements in the MICE Experiment

Description: The international Muon Ionization Cooling Experiment (MICE), under construction at RAL, will test a prototype cooling channel for a future Neutrino Factory or Muon Collider. The cooling channel aims to achieve, using liquid hydrogen absorbers, a 10% reduction in transverse emittance. The change in 4D emittance will be determined with an accuracy of 1% by measuring muons individually. Step IV of MICE will make the first precise emittance-reduction measurements of the experiment. Simulation studies using G4MICE, based on GEANT4, find a significant difference in multiple scattering in low Z materials, compared with the standard expression quoted by the Particle Data Group. Direct measurement of multiple scattering using the scintillating-fibre trackers is found to be possible, but requires the measurement resolution to be unfolded from the data.
Date: May 1, 2012
Creator: Carlisle, T.; Cobb, J.; U., /Oxford; Neuffer, D. & /Fermilab
Partner: UNT Libraries Government Documents Department

Determining Supersymmetric Parameters With Dark Matter Experiments

Description: In this article, we explore the ability of direct and indirect dark matter experiments to not only detect neutralino dark matter, but to constrain and measure the parameters of supersymmetry. In particular, we explore the relationship between the phenomenological quantities relevant to dark matter experiments, such as the neutralino annihilation and elastic scattering cross sections, and the underlying characteristics of the supersymmetric model, such as the values of {mu} (and the composition of the lightest neutralino), m{sub A} and tan {beta}. We explore a broad range of supersymmetric models and then focus on a smaller set of benchmark models. We find that by combining astrophysical observations with collider measurements, {mu} can often be constrained far more tightly than it can be from LHC data alone. In models in the A-funnel region of parameter space, we find that dark matter experiments can potentially determine m{sub A} to roughly {+-}100 GeV, even when heavy neutral MSSM Higgs bosons (A, H{sub 1}) cannot be observed at the LHC. The information provided by astrophysical experiments is often highly complementary to the information most easily ascertained at colliders.
Date: July 1, 2006
Creator: Hooper, Dan; /Fermilab; Taylor, Andrew M. & U., /Oxford
Partner: UNT Libraries Government Documents Department

Top Quark Anomalous Couplings at the International Linear Collider

Description: We present a study of the experimental determination of the forward-backward asymmetry in the process e{sup +}e{sup -} {yields} t{bar t} and in the subsequent t {yields} Wb decay, studied in the context of the International Linear Collider. This process probes the elementary couplings of the top quark to the photon, the Z and the W bosons at a level of precision that is difficult to achieve at hadron colliders. Measurement of the forward-backward asymmetry requires excellent b quark identification and determination of the quark charge. The study reported here is performed in the most challenging all-hadronic channel e{sup +}e{sup -} {yields} b{bar b}q{bar q}q{bar q}. It includes realistic details of the experimental environment, a full Monte Carlo simulation of the detector, based on the Silicon Detector concept, and realistic event reconstruction. The forward-backward asymmetries are determined to a precision of approximately 1% for each of two choices of beam polarization. We analyze the implications for the determination of the t{bar t}Z and Wt{bar b} couplings.
Date: August 15, 2011
Creator: Devetak, Erik; Nomerotski, Andrei; U., /Oxford; Peskin, Michael & /SLAC
Partner: UNT Libraries Government Documents Department

Modeling Free Convection Flow of Liquid Hydrogen within a Cylindrical Heat Exchanger Cooled to 14 K

Description: A liquid hydrogen in a absorber for muon cooling requires that up to 300 W be removed from 20 liters of liquid hydrogen. The wall of the container is a heat exchanger between the hydrogen and 14 K helium gas in channels within the wall. The warm liquid hydrogen is circulated down the cylindrical walls of the absorber by free convection. The flow of the hydrogen is studied using FEA methods for two cases and the heat transfer coefficient to the wall is calculated. The first case is when the wall is bare. The second case is when there is a duct some distance inside the cooled wall.
Date: May 8, 2004
Creator: Green, Michael A.; U., Oxford; Yang, S.W.; Green, M.A. & Lau, W.
Partner: UNT Libraries Government Documents Department

The intergalactic propagation of ultrahigh energy cosmic ray nuclei

Description: We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).
Date: August 1, 2006
Creator: Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M. & U., /Oxford
Partner: UNT Libraries Government Documents Department

Search for excited and exotic muons at CDF

Description: The authors present a search for the production of excited or exotic muons ({mu}*) via the reaction {bar p} + p {yields} {mu}* + {mu} {yields} {mu}{gamma}+{mu} using 371 pb{sup -1} of data collected with the Run II CDF detector. In this signature-based search, we look for a resonance in the {mu}{gamma} mass spectrum. The data are compared to standard model and detector background expectations, and with predictions of excited muon production. We use these comparisons to set limits on the {mu}* mass and compositeness scale {Lambda} in contact interaction and gauge-mediated models.
Date: May 1, 2006
Creator: Gerberich, Heather; /Illinois U., Urbana; Hays, Christopher; U., /Oxford; Kotwal, Ashutosh & U., /Duke
Partner: UNT Libraries Government Documents Department

Comparisons of the MINOS Near and Far Detector Readout Systems at a Test Beam

Description: MINOS is a long baseline neutrino oscillation experiment that uses two detectors separated by 734 km. The readout systems used for the two detectors are different and have to be independently calibrated. To verify and make a direct comparison of the calibrated response of the two readout systems, test beam data were acquired using a smaller calibration detector. This detector was simultaneously instrumented with both readout systems and exposed to the CERN PS T7 test beam. Differences in the calibrated response of the two systems are shown to arise from differences in response non-linearity, photomultiplier tube crosstalk, and threshold effects at the few percent level. These differences are reproduced by the Monte Carlo (MC) simulation to better than 1% and a scheme that corrects for these differences by calibrating the MC to match the data in each detector separately is presented. The overall difference in calorimetric response between the two readout systems is shown to be consistent with zero to a precision of 1.3% in data and 0.3% in MC with no significant energy dependence.
Date: February 1, 2009
Creator: Cabrera, A.; U., /Oxford; Adamson, P.; London, /University Coll.; Barker, M.; U., /Oxford et al.
Partner: UNT Libraries Government Documents Department

Luminosity Function of Faint Globular Clusters in M87

Description: We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit Hubble Space Telescope (HST) WFPC2 imaging program. The very deep images and corresponding improved false source rejection allow us to probe the mass function further beyond the turnover than has been done before. We compare our luminosity function to those that have been observed in the past, and confirm the similarity of the turnover luminosity between M87 and the Milky Way. We also find with high statistical significance that the M87 luminosity function is broader than that of the Milky Way. We discuss how determining the mass function of the cluster system to low masses can constrain theoretical models of the dynamical evolution of globular cluster systems. Our mass function is consistent with the dependence of mass loss on the initial cluster mass given by classical evaporation, and somewhat inconsistent with newer proposals that have a shallower mass dependence. In addition, the rate of mass loss is consistent with standard evaporation models, and not with the much higher rates proposed by some recent studies of very young cluster systems. We also find that the mass-size relation has very little slope, indicating that there is almost no increase in the size of a cluster with increasing mass.
Date: July 14, 2006
Creator: Waters, Christopher Z.; Zepf, Stephen E.; U., /Michigan State; Lauer, Tod R.; /NOAO, Tucson; Baltz, Edward A. et al.
Partner: UNT Libraries Government Documents Department

Hadronic Final States and QCD: Summary

Description: A summary of new experimental results and recent theoretical developments discussed in the 'Hadronic Final States and QCD' working group is presented.
Date: August 1, 2008
Creator: Gehrmann, Thomas; U., /Zurich; Grindhammer, Guenter; /Munich, Max Planck Inst.; O'Dell, Vivian; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

First Measurements of the Longitudinal Bunch Profile at SLAC Using Coherent Smith-Purcell Radiation at 28GeV

Description: Coherent Smith-Purcell radiation has been demonstrated as a technique for measuring the longitudinal profile of charged particles bunches in the low to intermediate energy range. However, with the advent of the International Linear Collider, the need has arisen for a non-invasive method of measuring the bunch profile at extremely high energies. Smith-Purcell radiation has been used for the first time in the multi-GeV regime to measure the longitudinal profile of the 28GeV SLAC beam. The experiment has both successfully determined the bunch length, and has also demonstrated its sensitivity to bunch profile changes. The challenges associated with this technique, and its prospects as a diagnostic tool are reported here.
Date: November 2, 2011
Creator: Blackmore, V.; Doucas, G.; Ottewell, B.; Perry, C.; U., /Oxford; Kimmitt, M.F. et al.
Partner: UNT Libraries Government Documents Department

Boosted Objects: A Probe of Beyond the Standard Model Physics

Description: We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.
Date: June 12, 2012
Creator: Abdesselam, A.; U., /Oxford; Kuutmann, E.Bergeaas; /DESY; Bitenc, U.; U., /Freiburg et al.
Partner: UNT Libraries Government Documents Department

Search for muon-neutrino to electron-neutrino transitions in MINOS

Description: This letter reports on a search for {nu}{sub {mu}} {yields} {nu}{sub e} transitions by the MINOS experiment based on a 3.14 x 10{sup 20} protons-on-target exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of 27 {+-} 5(stat.) {+-} 2(syst.) events predicted by the measurements in the Near Detector. If interpreted in terms of {nu}{sub {mu}} {yields} {nu}{sub e} oscillations, this 1.5 {sigma} excess of events is consistent with sin{sup 2}(2{theta}{sub 13}) comparable to the CHOOZ limit when |{Delta}m{sup 2}| = 2.43 x 10{sup -3} eV{sup 2} and sin{sup 2} (2{theta}{sub 23}) = 1.0 are assumed.
Date: September 1, 2009
Creator: Adamson, P.; /Fermilab; Andreopoulos, C.; /Rutherford; Arms, K.E.; U., /Minnesota et al.
Partner: UNT Libraries Government Documents Department

Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

Description: The shadowing of cosmic ray primaries by the the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 {sigma} level and the shadow of the sun at the 3.8 {sigma} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 {+-} 0.12{sup o}. Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.
Date: August 1, 2010
Creator: Adamson, P.; /Fermilab; Andreopoulos, C.; U., /Rutherford /Athens; Ayres, D.S.; /Argonne et al.
Partner: UNT Libraries Government Documents Department

New constraints on muon-neutrino to electron-neutrino transitions in MINOS

Description: This letter reports results from a search for {nu}{sub {mu}}{yields}{nu}{sub {mu}} transitions by the MINOS experiment based on a 7 x 1020 protons-on-target exposure. Our observation of 54 candidate e events in the Far Detector with a background of 49.1 {+-} 7.0(stat.) {+-} 2.7(syst.) events predicted by the measurements in the Near Detector requires 2 sin2(2{theta}13) sin2{theta}23 < 0.12 (0.20) at the 90% C.L. for the normal (inverted) mass hierarchy at {delta}CP = 0. The experiment sets the tightest limits to date on the value of {theta}13 for nearly all values of {delta}CP for the normal neutrino mass hierarchy and maximal sin2(2{theta}23).
Date: June 1, 2010
Creator: Adamson, P.; /Fermilab; Andreopoulos, C.; /Rutherford; Auty, D.J.; U., /Sussex et al.
Partner: UNT Libraries Government Documents Department

A Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector

Description: We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the Standard-Model Extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found using the MINOS near detector.
Date: July 1, 2010
Creator: Adamson, P.; /Fermilab; Auty, D.J.; U., /Sussex; Ayres, D.S.; /Argonne et al.
Partner: UNT Libraries Government Documents Department

Search for charmed particles

Description: We propose to use the CCM spectrometer to carry out a sensitive search for charmed particles produced in strong interactions at a nominal beam energy of 150 GeV/c. We limit ourselves to production in the beam diffraction region for reasons of acceptance and reconstruction. We present results of a test run undertaken in April 1975 to demonstrate the feasibility of K{sub S}{sup 0} trigger, which we incorporate in the present proposal. Results of the test are combined with new insights which increase our sensitivity to charmed particle production by a large factor. We request a total of 2 x 10{sup 11} negative pions at a rate of 10{sup 6} per pulse. With this illumination we estimate that we can measure a large number of hadronic decay modes. We make estimates of enhancements in mass spectra from charmed particle production and decay and calculate expected backgrounds using data from existing experiments. With conservative assumptions about the charmed particle model, we calculate effects corresponding to ten or more standard deviations in our most favorable channels.
Date: October 1, 1975
Creator: Ascoli, G.; Cooper, J.; Francis, W.; Holloway, L.; Kirk, T.; Koester, L. et al.
Partner: UNT Libraries Government Documents Department

Picosecond Bunch length and Energy-z correlation measurements at SLAC's A-Line and End Station A

Description: We report on measurements of picosecond bunch lengths and the energy-z correlation of the bunch with a high energy electron test beam to the A-line and End Station A (ESA) facilities at SLAC. The bunch length and the energy-z correlation of the bunch are measured at the end of the linac using a synchrotron light monitor diagnostic at a high dispersion point in the A-line and a transverse RF deflecting cavity at the end of the linac. Measurements of the bunch length in ESA were made using high frequency diodes (up to 100 GHz) and pyroelectric detectors at a ceramic gap in the beamline. Modeling of the beam's longitudinal phase space through the linac and A-line to ESA is done using the 2-dimensional tracking program LiTrack, and LiTrack simulation results are compared with data. High frequency diode and pyroelectric detectors are planned to be used as part of a bunch length feedback system for the LCLS FEL at SLAC. The LCLS also plans precise bunch length and energy-z correlation measurements using transverse RF deflecting cavities.
Date: June 27, 2007
Creator: Molloy, Stephen; Emma, P.; Frisch, J.C.; Iverson, R.H.; Ross, M.; McCormick, D.J. et al.
Partner: UNT Libraries Government Documents Department

Electron Bunch Profile Diagnostics in the Few FS Regime Using Coherent Smith-Purcell Radiation

Description: The rapid developments in the field of laser-driven particle acceleration hold the prospect of intense, highly relativistic electron bunches that are only a few fs long. The determination of the temporal profile of such bunches presents new challenges. The use of a radiative process such as Smith-Purcell radiation (SPR), is particularly promising in this respect. In this technique the beam is made to radiate a small amount of e/m radiation and the temporal profile is reconstructed from the measured spectral distribution of the radiation. We summarise the advantages of SPR and present the design parameters and preliminary results of the experiments at the FACET facility at SLAC. We also discuss a new approach to the problem of the recovery of the 'missing phase', which is essential for the accurate reconstruction of the temporal bunch profile.
Date: December 13, 2011
Creator: Bartolini, R.; Source, /Oxford U. /Diamond Light; Clarke, C.; /SLAC; Delerue, N.; /Orsay, LAL et al.
Partner: UNT Libraries Government Documents Department