[en] Three results are presented: (1) The semi-leptonic branching ratio of the Λ_c has been measured at SPEAR to be B(Λ_c⁺ → e⁺X) = (4.5 +- 1.7)%. (2) Properties of tau-pair production have been measured at PEP at square root S = 29 GeV: sigma^{tau tau}sigma^QED = 0.97 +- 0.05 +- 0.06; the forward-backward asymmetry is A_{tau tau} = (-3.5 +- 5.0)%; inclusive branching ratios are B(tau → 1 Prong) = (86 +- 4)%, B(tau → 3 Prongs) = (14 +- 4)%, B(tau → 5 Prongs) < 0.6% (95% C.L.). (3) A search has been performed for the pair production of charged, point-like, spin 0 particles. The existence of such particles can be ruled out at a 90% confidence level for 3 approx. < M approx. < 10 GeV/c² and branching ratio into hadrons approx. < 90%

[en] The US LHC Accelerator Research Program is a collaboration of 4 US National Laboratories (Fermilab, BNL, LBNL and SLAC) which has been formed to work with CERN on the commissioning, accelerator physics, and upgrades of the LHC. The largest single part of this program is planned to be the development of the next generation of high field superconducting magnets, made with Nb₃Sn, for a new interaction region that would be part of an LHC luminosity upgrade. The magnet research program focuses on the development of a large aperture (≥ 100 mm) quadrupole with operating gradient ≥ 200 T/m, and a larger aperture, high field (about 15 T operating field) dipole suitable for the extreme radiation environment of a dipole-first interaction regions. The goal is to develop at least one of these magnets to a production ready state by about 2012, to permit a luminosity upgrade to be implemented in the middle of next decade

[en] If the collar material has a larger coefficient of thermal contraction than the yoke and the yoke is split on the horizontal mid-plane, it may be difficult to use the yoke to provide horizontal support to the collared coil. To be inserted easily into the yoke at room temperature the collared coil must be no larger in horizontal diameter than the yoke. When the magnet is cooled to liquid helium temperature the collars will contract more than the yoke and a gap may develop between the collars and the yoke at the horizontal mid-plane. If, however, the collared coil is oversize in the vertical direction, clamping it in the yoke will tend to make its horizontal diameter grow enough to contact the yoke. Thus it may be desirable to design the collars to generate a ''vertical ovality.'' In this note I discuss a method to calculate the desired ovality of the collared coil at room temperature and the (undeflected) collar shape needed to achieve this. I then calculate the skin stress required to push the collared coil into shape. In both calculations I show the range of values resulting from plausible variations in the calculation parameters and in the coal prestress

[en] Cross-section data from the HARP experiment for pion production by protons from a tantalum target have been convoluted with the acceptance of the front-end channel for the proposed neutrino factory or muon collider and integrated over the full phase space measured by HARP, to determine the beam-energy dependence of the muon yield. This permits a determination of the optimal beam energy for the proton driver for these projects. The cross-section data are corrected for the beam-energy dependent 'amplification' due to the development of hadronic showers in a thick target. The conclusion is that, for constant beam power, the yield is maximum for a beam energy of about 7 GeV, but it is within 10% of this maximum for 4 < T_beam < 11 GeV, and within 20% of the maximum for T_beam as low as 2 GeV. This result is insensitive to which of the two HARP groups results are used, and to which pion generator is used to compute the thick target effects.

[en] An upgrade of the LHC interaction regions could potentially increase the luminosity by a factor of two or more. Several IR layouts are presented. The challenges and open questions related to the optics design, energy deposition and magnet design are discussed

[en] Results are presented from tests of the first full length prototype SSC dipole magnet. The cryogenic behavior of the magnet during a slow cooldown to 4.5K and a slow warmup to room temperature has been measured. Magnetic field quality was measured at currents up to 2000 A. Averaged over the body field all harmonics with the exception of b₂ and b₈ are at or within the tolerances specified by the SSC Central Design Group. (The values of b₂ and b₈ result from known design and construction defects which will be be corrected in later magnets.) Using an NMR probe the average body field strength is measured to be 10.283 G/A with point to point variations on the order of one part in 1000. Data are presented on quench behavior of the magnet up to 3500 A (approximately 55% of full field) including longitudinal and transverse velocities for the first 250 msec of the quench

[en] Four full scale SSC development dipole magnets have been tested for mechanical and quench behavior. Two are of a design similar to previous magnets but contain a number of improvements, including more uniform coil size, higher pre-stress and a redesigned inner-outer coil splice. One exceeds the SSC operating current on the second quench but the other appears to be limited by damaged superconductor to a lower current. The other two magnets are of alternate designs. One trains erratically and fails to reach a plateau and the other reaches plateau after four quenches. 12 refs., 4 figs

[en] This paper describes the mechanical design of the two dimensional cross-section of the base-line collider dipole magnet for the Superconducting Super Collider. The components described here are the collar laminations, the tapered keys that lock the upper and lower collars, the yoke laminations, the cold mass shell. We describe in detail the shape of the outer surface of the collars which defines the yoke-collar interface, and the shape of the collar interior, which defines the conductor placement. Other features of the collar and yoke will be described in somewhat less detail. 20 refs., 12 figs. , 6 tabs

[en] Results are presented from tests of the third full scale development dipole magnet for the Superconducting Super Collider and from a retest of a 4.5 m model magnet of the same design mounted in an SSC cryostat. The 4.5 m magnet shows consistent quench performance between its original tests in boiling liquid helium in a vertical dewar and the current tests in forced flow helium in a horizontal cryostat. Little or no retraining is observed over several thermal cycles. The full length magnet requires 12 quenches to train to its short sample limit of 6800 A and displays a reasonably stable quench plateau following training. This represents a great improvement over the performance of the first two full length magnets. Data are presented on quench behavior as a function of current and temperature and on azimuthal and longitudinal loading of the coil by the support structure. 14 refs., 7 figs

[en] The performance of the Large Hadron Collider (LHC) at collision energy is limited by the field quality of the interaction region (IR) quadrupoles and dipoles. In this paper they study the impact of the expected field errors of these magnets on the dynamic aperture (DA). Since the betatron phase advance is well defined for magnets that are located in regions of large beta functions, local corrections can be very effective and robust. They compare possible compensation schemes and propose a corrector layout to meet the required DA performance