124181456
Acceleration of Heavy Ions to Relativistic Energies and Their Use in Physics and Biomedicine
118661436
The Princeton-Pennsylvania 3 GeV Proton Accelerator as a Nuclear Tool
I would like to describe the Princeton-Pennsylvania Accelerator as a tool for nuclear research. Some people tend to think of the PPA as being too high in energy for nuclear research and, therefore, regard it as only an elementary particle research tool. While much of our work has, in fact, been related to the study of mesons, especially K-mesons, and to the study of the invariance principles, such as C, P, T, about 15% of the research has been either purely nuclear, or with strong nuclear overtones. As examples of the purely nuclear, I mention spallation reactions at 3 BeV and the study of the resulting neutron deficient nuclei. On the other side of the valley are the baryon stable, neutron rich, light fragments, 19N and 21O, which have been discovered in confirmation of Garvey’s mass formula. Negative pion scattering by twelve different complex nuclei from Be to Au over the energy range 600-1600 MeV has been used to determine optical model potentials. Neutron total cross sections over the momentum range 500-2800 MeV/c are now being studied for a wide variety of target nuclei, including the Physical Review! An especially beautiful experiment, begun as a missing mass search in the reaction p+d → He3+X° not only studied things of interest to elementary particle physics, the so-called ABC region, but simultaneously, and inadvertently, provided a hadronic probe, the proton, at correlation distances far smaller than, ever achieved before.
10342800
Acceleration of Nitrogen Ions to 7.4 Gev in the Princeton Particle Accelerator
Nitrogen ions in charge states N5+ and N6+ have been accelerated in the Princeton Particle Accelerator to 4 and 7.4 billion electron volts (Gev), respectively. An external N5+ beam of 1 x 106 particles per second has been obtained and focused to a 6-millimeter-diameter spot. The N6+ beam was about 2 x 105 particles per second. The total charge-changing collision cross section of N5+ in water vapor was determined as a function of ion energy. The improvement in vacuum necessary to increase the N5+ beam at least tenfold was calculated. The N6+ total cross section is probably smaller than that of N5+ at the higher energies.
122964093
Search for Tachyon Monopoles in Cosmic Rays
We have searched for a particle which combines the properties of a tachyon with those of a magnetic monopole. The tachyon monopole is assumed to exist in cosmic rays striking the earth and to be influenced by the extensive magnetic fringing field of Fermilab's 15-ft. bubble chamber. By hypothesizing that the tachyon monopole will either emit Cherenkov radiation in air or ionize Lexan plastic we set an upper limit of 5 x 10/sup 12/ cm/sup -2/ sec/sup -1/ on their flux.
107781576
Operating Experience And Improvements On The Princeton-Pennsylvania Accelerator
123674916
HEAVY IONS AND HIGHER PROTON CURRENTS PROPOSED FOR THE PRINCETON-- PENNSYLVANIA ACCELERATOR.
109984057
Fermilab SRF cryomodule operational experience
Fermi National Accelerator Laboratory is constructing an Advanced Accelerator Research and Development facility at New Muon Lab. The cryogenic infrastructure in support of the initial phase of the facility consists of two Tevatron style standalone refrigerators, cryogenic distribution system as well as an ambient temperature pumping system to achieve 2 K operations with supporting purification systems. During this phase of the project a single Type III plus 1.3 GHz cryomodule was installed, cooled and tested. Design constraints of the cryomodule required that the cryomodule individual circuits be cooled at predetermined rates. These constraints required special design solutions to achieve. This paper describes the initial cooldown and operational experience of a 1.3 GHz cryomodule using the New Muon Lab cryogenic system.
125390779
Proton compton scattering and neutral-pion photoproduction at large angles
The differential cross sections for ..gamma..p ..-->.. ..gamma..p and ..gamma..p ..-->.. ..pi../sup 0/p have been measured from abs. value (t) = 0.7 to 4.3 GeV/sup 2/ and for incident energies in the range 2 to 6 GeV. The energy dependence of Compton scattering is well described by parton model ideas. However, the energy dependences of ..pi../sup 0/ photoproduction and the ratio of Compton scattering to ..pi../sup 0/ photoproduction are not consistent with dimensional counting arguments.
119260064
MSSM dark matter measurements at the LHC without squarks and sleptons
We examine the case of neutralino dark matter in the focus point region of the MSSM, in which the scalar sparticles are too heavy to be produced at the LHC. Whilst it has been previously asserted that the LHC alone would fail to constrain the properties of the lightest neutralino for such a scenario, we find that one can obtain good predictions of astrophysical quantities such as the relic density, annihilation cross-section and direct search cross-sections by using the shape of the dilepton invariant mass spectrum to constrain neutralino mixing. We demonstrate our technique using a Bayesian analysis of the 24 parameter MSSM model space, and in the process introduce a novel way of improving the LHC results even without assumptions on which new sparticles are responsible for the kinematic features in the dilepton invariant mass distribution. Finally, we consider the interplay between direct search experiments and the LHC, and find that, even with a realistic estimate of the relevant astrophysical uncertainties, one could also combine current direct search exclusion limits with LHC data to constrain neutralino mixing and improve the predicition of other astrophysical quantities.
10775367
Neutralino reconstruction at the LHC from decay-frame kinematics
Decay-frame Kinematics (DK) has previously been introduced as a technique to reconstruct neutralino masses from their three-body decays to leptons. This work is an extension to the case of two-body decays through on-shell sleptons, with Monte Carlo simulation of LHC collisions demonstrating reconstruction of neutralino masses for the SPS1a benchmark point.
118552878
Natural gauge mediation with a bino NLSP at the LHC
Natural models of supersymmetry with a gravitino LSP provide distinctive signatures at the LHC. For a neutralino NLSP, sparticles can decay to two high energy photons plus missing energy. We use the ATLAS diphoton search with 4.8 fb of data to place limits in both the stop-gluino and neutralino-chargino mass planes for this scenario. If the neutralino is heavier than 50 GeV, the lightest stop must be heavier than 580 GeV, the gluino heavier than 1100 GeV and charginos must be heavier than approximately 300-470 GeV. This provides the first nontrivial constraints in natural gauge mediation models with a neutralino NLSP decaying to photons, and implies a fine tuning of at least a few percent in such models.