1,232 research outputs found
Constraints on Neutralino masses and mixings from Cosmology and Collider Physics
Bounds on cross section measurements of chargino pair production at LEP yield
a bound on the chargino mass. If the GUT relation is assumed, the lightest
neutralino must be heavier than \approx 45 -50\GeV. If no GUT relation is
assumed, no lower bound on the neutralino mass exists. I derive mass bounds on
the lightest neutralino from relic density measurements for relativistic and
non-relativistic neutralinos and I derive bounds on the selectron mass from the
observed limits on the cross section of the neutralino pair production process
e^+e^-\to \x{1}\x{2} at LEP, if the lightest neutralino is massless. I
further discuss radiative neutralino production and its background at the
future ILC. Finally, I present a method to determine the neutralino couplings
to right and left handed selectrons and Z bosons from cross section
measurements of radiative neutralino production and neutralino pair production
at the ILC.Comment: PhD-Thesis, 101 page
Coaching Style Preferences of Division I College and Professional Softball Players
The purpose of this study was to describe the coaching style and leader behavior preferences of softball players. The Leadership Scale for Sports (LSS; Chelladurai & Saleh, 1980) was administered to Division I college softball players and professional softball players from the National Professional Fastpitch league (NPF). Sixty-four softball players completed the Leadership Scale for Sport questionnaire (preference version), 52 Division I college softball players and 12 professional softball players from the NPF. Descriptive statistics revealed that softball players prefer Training and Instruction, Democratic Behavior, and Positive Feedback; players did not prefer Autocratic Behavior or Social Support. Follow-up univariate ANOVAs indicated that Autocratic Behavior was significantly different for Division I college softball players and professional softball players. Pairwise comparisons showed professional softball players significantly preferred Autocratic Behavior to Division I softball players; however, no statistical significance was found when examining coaching style preferences with relation to age and years of experience. Two one-way ANOVAs followed the trend that professional softball players preferred autocratic coaching behavior while Division I college softball players preferred democratic coaching behavior. Thus, female softball players, overall, prefer a democratic coaching style, training and instruction, and positive feedback; however, professional softball athletes significantly prefer autocratic coaching behaviors while Division I college players do not prefer autocratic coaching styles. Age and years of experience were not statistically significant when determining coaching preference, however, a power analysis is needed to reveal the optimal sample size to establish significance
The top-quark's running mass
We discuss the direct determination of the running top-quark mass from
measurements of the total cross section of hadronic top-quark pair-production.
The theory predictions in the MSbar scheme are very stable under scale
variations and show rapid apparent convergence of the perturbative expansion.
These features are explained by studying the underlying parton dynamics.Comment: 6 pages, 2 figures; to appear in Proceedings of the 9th International
Symposium on Radiative Corrections, RADCOR 2009, Ascona, Switzerland, October
200
Accurate photonic temporal mode analysis with reduced resources
The knowledge and thus characterization of the temporal modes of quantum
light fields is important in many areas of quantum physics ranging from
experimental setup diagnosis to fundamental-physics investigations. Recent
results showed how the auto-correlation function computed from continuous-wave
homodyne measurements can be a powerful way to access the temporal mode
structure. Here, we push forward this method by providing a deeper
understanding and by showing how to extract the amplitude and phase of the
temporal mode function with reduced experimental resources. Moreover, a
quantitative analysis allows us to identify a regime of parameters where the
method provides a trustworthy reconstruction, which we illustrate
experimentally
Measurement of radiative neutralino production
We perform the first experimental study with full detector simulation for the
radiative production of neutralinos at the linear collider, at sqrt{s} = 500
GeV and realistic beam polarizations. We consider all relevant backgrounds,
like the Standard Model background from radiative neutrino production. The
longitudinal polarized beams enhance the signal and simultaneously reduce the
background, such that statistical errors are significantly reduced. We find
that the photon spectrum from the signal process can be well isolated. The
neutralino mass and the cross section can be measured at a few per-cent level,
with the largest systematic uncertainties from the measurement of the beam
polarization and the beam energy spectrum.Comment: 6 pages, 2 figures, to appear in the proceedings of the 2011
International Workshop on Future Linear Colliders (LCWS11), Sept. 26-30,
Granada, Spai
Model-independent WIMP Characterisation using ISR
The prospects of measuring the parameters of WIMP dark matter in a model
independent way at the International Linear Collider are investigated. The
signal under study is direct WIMP pair production with associated initial state
radiation. The analysis is performed in full simulation of the ILD detector
concept. With an integrated luminosity of L = 500 fb-1 and realistic beam
polarizations the helicity structure of the WIMP couplings to electrons can be
determined, and the masses and cross sections can be measured to the percent
level. The systematic uncertainties are dominated by the polarization
measurement and the luminosity spectrum.Comment: 7 pages, 4 figures, International Workshop on Future Linear Colliders
LCWS1
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