121023736
PHASE-SPACE INTEGRALS FOR MULTIPARTICLE SYSTEMS
The total phase-space integrals, occurring in the Fermi statistical theory of meson production, for 2-, 3-, 4-, and 5-body final states are reduced to forms suitable for numerical evaluation by hand computation. In addition, the momentum spectrum of any one particle, as derived from the statistical factor, is evaluated. For the 3- and 4-body systems, the $Q$ distribution for any two of the particles (effective mass minus the rest masses of the 2-particle subsystem) is derived. Numerical results are presented for nucleon-nucleon collisions at 0.8-, 1.5-, and 2.7-Bev bombarding kinetic energies.
119621682
Ultra-high Energy Predictions of proton-air Cross Sections from Accelerator Data
M. M. Block Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 We predict σ p−air, the proton–air inelastic production cross section, at pp center-of-mass energies 2 ≤ √ s ≤ 100000 TeV, using high energy predictions from a saturated Froissart bound parameterization of accelerator data on forward p̄p and pp scattering amplitudes, together with Glauber theory. The parameterization of the p̄p and pp cross sections incorporates analyticity constraints and unitarity, allowing accurate extrapolations to ultra-high energies. Our predictions are in excellent agreement with cosmic ray extensive air shower measurements, both in magnitude and in energy dependence.
27952461
Are we really measuring the phase of the nuclear scattering amplitude?
The interference at small {vert_bar}{ital t}{vert_bar} of the Coulomb scattering amplitude {ital f}{sub {ital c}} and the nuclear amplitude {ital f}{sub {ital n}} is used to measure the phase of the nuclear scattering amplitude, and, hence, the {rho} value, where {rho}{equivalent_to}(Re{ital f}{sub {ital n}}/Im{ital f}{sub {ital n}}){sub {ital t}=0}. The {open_quote}{open_quote}normal{close_quote}{close_quote} analysis of {ital {bar p}}{ital p} and {ital pp} elastic scattering uses a {open_quote}{open_quote}spinless{close_quote}{close_quote} Coulomb amplitude, i.e.,a Rutherford amplitude (2{radical}{pi}{alpha}/{ital t}) multiplied by a Coulomb form factor {ital G}{sup 2}({ital t}), an ansatz that pretends that the nucleon does not have any magnetic scattering. In this article, we investigate the role of the anomalous magnetic moment of the nucleon, {kappa}{approx_equal}1.79. Given the method of analysis currently used by most published experiments, we conclude that the current experimentally inferred values of {rho} for {ital {bar p}}{ital p} should be {ital systematically} {ital lowered} by {approx_equal}0.005{endash}0.0100 and, correspondingly, the {rho} values for {ital pp} should be {ital systematically} {ital raised} by the same amount. We discuss the theoretical uncertainties and a method of experimentally minimizing them. {copyright} {ital 1996 The American Physical Society.}
121620095
Experimental observation of a copious yield of electrons with small transverse momenta in pp collisions at high energies
Abstract Inclusive electron and positron emission have been observed for θ cm = 30° and s = 2800 GeV 2 at the CERN Intersecting Storage Rings (ISR). Over the transverse momentum interval 0.2 GeV/ c p T c , electrons and positrons, which are equal in number within the experimental accuracies, appear to grow with respect to other particles (pions) approximately like 1/ p T . We are unable to explain their number and p T -dependence in terms of “conventional” mechanisms.
95016103
A Liquid Helium Bubble Chamber
1) To provide an efficient dewar with large windows on two sides which allow for illuminating and photo­ graphing the bubble chamber tracks without the difficulty of any intervening liquid nitrogen or helium baths in the light path between the bubble chamber and the room temperature photographic system. At the same time heat losses due to room temperature radiation must be reduced several hundred times below that expected from two such room temperature windows.
124887738
NEUTRINO EXPERIMENTS IN THE 25-FOOT BUBBLE CHAMBER.
10030510
DUST PRODUCTION AND MASS LOSS IN THE GALACTIC GLOBULAR CLUSTER NGC 362
We investigate dust production and stellar mass loss in the Galactic globular cluster NGC 362. Due to its close proximity to the Small Magellanic Cloud (SMC), NGC 362 was imaged with the Infrared Array Camera and Multiband Imaging Photometer cameras onboard the Spitzer Space Telescope as part of the Surveying the Agents of Galaxy Evolution (SAGE-SMC) Spitzer Legacy program. We detect several cluster members near the tip of the red giant branch (RGB) that exhibit infrared excesses indicative of circumstellar dust and find that dust is not present in measurable quantities in stars below the tip of the RGB. We modeled the spectral energy distribution (SED) of the stars with the strongest IR excess and find a total cluster dust mass-loss rate of 3.0{sup +2.0}{sub -1.2} x 10{sup -9} M{sub sun} yr{sup -1}, corresponding to a gas mass-loss rate of 8.6{sup +5.6}{sub -3.4} x 10{sup -6} M{sub sun} yr{sup -1}, assuming [Fe/H] =-1.16. This mass loss is in addition to any dustless mass loss that is certainly occurring within the cluster. The two most extreme stars, variables V2 and V16, contribute up to 45% of the total cluster dust-traced mass loss. The SEDs of the more moderate stars indicate themore » presence of silicate dust, as expected for low-mass, low-metallicity stars. Surprisingly, the SED shapes of the stars with the strongest mass-loss rates appear to require the presence of amorphous carbon dust, possibly in combination with silicate dust, despite their oxygen-rich nature. These results corroborate our previous findings in omega Centauri.« less