37 research outputs found
A Method for the Precision Mass Measurement of the Stop Quark at the International Linear Collider
Many supersymmetric models predict new particles within the reach of the next
generation of colliders. For an understanding of the model structure and the
mechanism(s) of symmetry breaking, it is important to know the masses of the
new particles precisely. In this article the measurement of the mass of the
scalar partner of the top quark (stop) at an e+e- collider is studied. A
relatively light stop is motivated by attempts to explain electroweak
baryogenesis and can play an important role in dark matter relic density. A
method is presented which makes use of cross-section measurements near the
pair-production threshold as well as at higher center-of-mass energies. It is
shown that this method not only increases the statistical precision, but also
greatly reduces the systematic uncertainties, which can be important. Numerical
results are presented, based on a realistic event simulation, for two signal
selection strategies: using conventional selection cuts, and using an Iterative
Discriminant Analysis (IDA). Our studies indicate that a precision of
\Delta\mstop = 0.42 GeV can be achieved, representing a major improvement
over previous studies. While the analysis of stops is particularly challenging
due to the possibility of stop hadronization, the general procedure could be
applied to the mass measurement of other particles as well. We also comment on
the potential of the IDA to discover a stop quark in this scenario, and we
revisit the accuracy of the theoretical predictions for the neutralino relic
densityComment: 41 pages, 14 figures, in JHEP forma
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LC scintillator-based muon detector tail-catcher R&D
Preliminary analysis of test beam data from strip scintillator planes read-out with multi-anode PMTs (MAPMTs) is presented along with a description of the independent systematic measurements of relative response for all channels of several MAPMTs used in the tests. Test beam measurements for the response of a scintillator strip, read out with Si photo-sensors, is also described
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Simulation of neutral D mesons-neutral D-bar mesons mixing and preliminary analysis of CDF data
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Calculation of acceptance and efficiency for neutral D mesons decaying to electron-positrons and rates of pions and kaons faking electron signals at CDF
In the 19th century, the fundamental units of matter were believed to be atoms. Further experiments in the early 20th century demonstrated that protons and neutrons are just two examples of a class of particles called hadrons, and that hadrons are composed of quarks bound together by gluons. This has evolved to today's Standard Model of particle physics (SM) which encapsulates our knowledge of elementary particles and the fundamental forces between them
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Averages of B-Hadron Properties at the End of 2005
This article reports world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results as of at the end of 2005. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries
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Averages of B-Hadron, C-Hadron, and Tau-Lepton Properties as of Early 2012
This report talks about Averages of B-Hadron, C-Hadron, and Tau-Lepton Properties as of Early 201