117842992
Quantum Number Effects in Events With a Charged Particle of Large Transverse Momentum. Part 2. Charge Correlations in Jets
Abstract Charge correlations of particles in an event with a large p T triggering particle have been investigated applying a new method, which has been developed for non-diffractive inelastic hadronic events. The correlation length for charge compensation of the fragments of the hard scattered partons and of the spectators, respectively, are equal to that one in normal inelastic events. Part of the charge of the high p T trigger particle is compensated by the soft particles of the “away jet”. These results support the idea that the rearrangement of quantum numbers in quark fragmentation shows a universal behaviour.
120405256
Direct search for light gluinos
Abstract We present the results for a direct search for light gluinos through the appearance of η →3 π 0 with high transverse momentum in the vacuum tank of the NA48 experiment at CERN. We find one event within a lifetime range of 10 −9 –10 −3 s and another one between 10 −10 –10 −9 s. Both events are consistent with the expected background from neutrons in the beam, produced by 450 GeV protons impinging on the Be targets, which interact with the residual air in the tank. From these data we give limits on the production of the hypothetical g g bound state, the R 0 hadron, and its R 0 →η γ decay in the R 0 mass range between 1 and 5 GeV.
117777970
Study of jet structure in proton-proton collisions with large transverse momentum secondaries
125139127
Proposal to measure the rare decay K+ ---> pi+ nu anti-nu at the CERN SPS
120734608
Charmed baryon production at the CERN Intersecting Storage Rings
Abstract The production of a Λ + c charmed baryon has been observed in pp collisions at the CERN ISR. A sharp peak at 2.26 GeV / c 2 was found in the decay mode Λ + c → K ∗0 p in events triggered with a forward K − meson. Also the decay mode Λ + c → K − Δ ++ seems to be present. The estimation of the total cross section for Λ + c production is given. However, the resulting value depends on the assumed form of the differential cross section. In addition, Λ + c production in events triggered by the presence of a direct electron is discussed.
116379925
RECENT RESULTS FROM THE UA1 COLLABORATION AT THE CERN PROTON - ANTI-PROTON COLLIDER
53608040
Characteristics of Magnetohydrodynamic Oscillations Observed with the Michelson Doppler Imager
We report on the spatial distribution of the magnetogram oscillatory power and the phase angles between velocity and magnetogram signals as observed with the Michelson Doppler Imager. The data set is 15125 × 15125, containing the sunspot from 1997 December 2 with a temporal sampling interval of 60 s and spatial sampling of 0605. The simultaneously observed continuum intensity and surface velocity accompany the magnetic information. We focus on three frequency regimes: 0.5-1.0, 3.0-3.5, and 5.5-6.0 mHz, corresponding roughly to timescales of magnetic evolution, p-modes, and the 3 minute resonant sunspot oscillation. Significant low-frequency magnetogram power is found in lower flux pixels, 100-300 G, in a striking ring with filamentary structure surrounding the sunspot. The 5 minute magnetogram power peaks in extended regions of flux that measure 600-800 G. The 3 minute oscillation is observed in the sunspot umbra in pixels whose flux measures 1300-1500 G. Phase angles of approximately -90° between velocity and magnetic flux in the 3.0-3.5 and 5.5-6.0 mHz regimes are found in regions of significant cross amplitude.
119279122
Recovering Joy’s Law as a Function of Solar Cycle, Hemisphere, and Longitude
Bipolar active regions in both hemispheres tend to be tilted with respect to the East–West Equator of the Sun in accordance with Joy’s law, which describes the average tilt angle as a function of latitude. Mt. Wilson Observatory data from 1917 – 1985 are used to analyze the active-region tilt angle as a function of solar cycle, hemisphere, and longitude, in addition to the more common dependence on latitude. Our main results are as follows: i) We recommend a revision of Joy’s law towards a weaker dependence on latitude (slope of 0.13 – 0.26) and without forcing the tilt to zero at the Equator. ii) We determine that the hemispheric mean tilt value of active regions varies with each solar cycle, although the noise from a stochastic process dominates and does not allow for a determination of the slope of Joy’s law on an 11-year time scale. iii) The hemispheric difference in mean tilt angles, 1.1∘±0.27, over Cycles 16 to 21 was significant to a three-σ level, with average tilt angles in the Northern and Southern hemispheres of 4.7∘±0.26 and 3.6∘±0.27, respectively. iv) Area-weighted mean tilt angles normalized by latitude for Cycles 15 to 21 anticorrelate with cycle strength for the southern hemisphere and whole-Sun data, confirming previous results by Dasi-Espuig et al. (Astron. Astrophys.518, A7, 2010). The Northern Hemispheric mean tilt angles do not show a dependence on cycle strength. v) Mean tilt angles do not show a dependence on longitude for any hemisphere or cycle. In addition, the standard deviation of the mean tilt is 29 – 31∘ for all cycles and hemispheres, indicating that the scatter is due to the same consistent process even if the mean tilt angles vary.