120839233
Search for high-energy tau-neutrino interactions
Kinematic selection criteria are developed for separating tau-neutrino charged-current interactions from a large background of muon- and electron-neutrino interactions. The criteria are designed to detect the three-prong decay mode of the $\ensuremath{\tau}$ lepton and rely on the three-particle combination's transverse momentum being anticorrelated with the tr\'ansverse momentum of the other visible particles and being correlated with the missing transverse momentum. The criteria are applied to a sample of events from an exposure of the Fermilab 15-ft bubble chamber to the quadrupole triplet neutrino beam. The average event energies for this beam are 90 GeV for neutrino and 60 GeV for antineutrino events. The $14 \ensuremath{\tau}$ candidates selected agree with the calculated background of 14.3\ifmmode\pm\else\textpm\fi{}1.2. An upper limit on the probability of muon neutrinos oscillating into tau neutrinos of 0.053 is obtained.
125826043
Study of Hadronic Systems Produced in electron-neutrino (anti-electron-neutrino) n e Interactions
124266533
Observation of mu e Events in anti-neutrino and Neutrino Interactions in the Fermilab 15-Foot Neon-H Bubble Chamber
125143796
An Exposure of the 15 foot bubble chamber with a neon - hydrogen mixture to a wideband neutrino beam from the Tevatron
123029644
Observation of short-lived particles produced in high energy neutrino interactions
Abstract Examination of a sample of 89 high-energy, neutrino-induced dilepton events produced in the Fermilab 15 ft bubble chamber has resulted in the direct observation of the production and visible semi-leptonic decay of short-lived particles. One charged decay, two neutral decays, and one decay candidate of undetermined charge are found. Assuming these events and the remaining dilepton signal result from D meson decays, we obtain τ D + = 2.5 −1.5 +3.5 × 10 −13 s and τ D 0 = 3.5 −1.7 +3.5 × 10 −13 s, using a maximum likelihood analysis.
16805647
A Detailed Monte Carlo simulation for the BELLE TOF system
We have developed a detailed Monte Carlo simulation program for the Belle time-of-flight (TOF) system. Based on GEANT simulation, it takes account of all physics processes in the TOF scintillation counters and readout electronics. The simulation reproduces very well the performance of the Belle TOF system, including the dE/dx response, the time walk effect, the time resolution, and the hit efficiency due to beam background. In this report, we will describe the Belle TOF simulation program in detail.
121508022
Multiproton final states in positive pion absorption below the Δ(1232) resonance
Inclusive cross sections for positive pion absorption leading to final states including two or more protons have been measured with a large solid angle detector for incident pion energies from 30 to 135 MeV for targets with A=2-208. The mass dependences for the inclusive ({pi}{sup +},2p), ({pi}{sup +},3p), and total absorption cross sections for multiproton final states were found to be proportional to A{sup n} with n{approx_equal}0.5. These cross sections also were observed to have an energy dependence at energies below 150 MeV reflective of the importance of the {delta}(1232) resonance, similar to that observed for {pi}d{yields}pp. The inclusive cross sections for ({pi}{sup +},4p) were found to be less than 10 mb for all targets at all energies. Estimates were also obtained for cross sections for pion absorption leading to 2p1n and 3p1n final states. Quasideuteron absorption contributions increase slowly with A, and the energy dependence of those contributions mirrors that for {pi}d{yields}pp. The data obtained here for multiproton final states indicate that a significant fraction of absorption events, increasing with A, most likely arises from final states containing fewer than two protons. (c) 2000 The American Physical Society.
198937260
Cross sections and transverse single-spin asymmetries in forward jet production from proton collisions at root s=500 GeV
117932304
Tevatron bunch length studies at CDF
A luminous interaction region can be described by the distribution in (x, y, z) over which p{bar p} interactions are observed in a detector. The spatial size of this distribution can be written in terms of expressions that involve only combinations of the proton and anti-proton bunch sizes. Hence, it is not possible to determine the sizes of the proton and anti-proton bunches independently by fitting the distribution of (x, y, z) from the recorded events. If, in addition to the coordinates (x, y, z) at which p{bar p} interactions occur, the times at which the interactions took place are also measured, then it becomes possible to measure the lengths of the proton and anti-proton bunches separately. This sensitivity is due to a correlation between z and t that arises from the fact that the proton and anti-proton bunches travel in opposite directions. The derivation presented in section 2 quantifies this correlation, resulting in an expression for the probability density as a function of z and t for p{bar p} interactions. By fitting the distributions observed at CDF using this model, we measure the lengths of the proton and anti-proton bunches at times throughout several Tevatron stores. From this analysismore » the evolution of the bunch lengths can be studied. We attempt to correlate these with other measures of the bunch length obtained using different experimental techniques.« less
117922116
Measurement of analyzing powers for the reaction p(pol.) + ch-2 at p(p) = 1.75-GeV/c - 5.3-GeV/c
Abstract We report a new measurement of analyzing powers for the reaction p ⇒ + CH 2 → one charged particle +X, at proton momenta of 1.75, 3.8, 4.5 and 5.3 GeV / c . These results extend the existing data basis, necessary for proton polarimetry at intermediate energy, and confirm the feasibility of a large acceptance polarimeter based on this process. Particular attention was devoted to the investigation of the optimal target thickness and of the useful angular range. The experiment is performed at the accelerator complex of the JINR-VBLHE (Dubna).
120304679
Nucleon form-factors using spin degrees of freedom
An overview of recent measurements of the neutron and proton electromagnetic form factors from double polarization experiments. Spin observables are sensitive to the product of nucleon form factor which allows access to the small nucleon electric form factors.