Results 1 - 10 of 2573
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[en] The threshold of the transverse mode coupling instability is calculated in framework of the square well model at arbitrary value of space charge tune shift. A new method of calculation is developed beyond the traditional expansion technique. The square, resistive, and exponential wakes are investigated. It is shown that the instability threshold goes up indefinitely when the tune shift increases. Finally, a comparison with conventional case of the parabolic potential well is performed.
[en] The transverse decoherence of the kicked beam due to amplitude dependent tune shift and the linear and the second order chromaticity are studied. For the kicked beam the closed analytical expression for the beam centroid evolution in subsequent turns is obtained. Analysis of the kicked beam centroid signal on the machine optical characteristics is given.
[en] The higher order transverse perturbations for modulated wave packets in a dusty plasma are investigated. A Davey-Stewartson equation is obtained for this system. The instability for small amplitude linear transverse perturbations are investigated
[en] We propose a new search strategy for directly-produced sbottoms at the LHC with a small mass splitting between the sbottom and its decayed stable neutralino. Our search strategy is based on boosting sbottoms through an energetic initial state radiation jet. In the final state, we require a large missing transverse energy and one or two b-jets besides the initial state radiation jet. We also define a few kinematic variables to further increase the discovery reach. For the case that the sbottom mainly decays into the bottom quark and the stable neutralino, we have found that even for a mass splitting as small as 10 GeV sbottoms with masses up to around 400 GeV can be excluded at the 95% confidence level with 20 inverse femtobarn data at the 8 TeV LHC.
[en] The relations between the parameter of the transverse damping system, the damping speed, and the accelerator parameters are discussed. Formulas for determining the damping system parameters are given. The constant voltage damping system is proposed and discussed. For the same damping speed, the damping voltage and damping power needed by this system is much less than those needed by the traditional proportional damping system. This idea can also be applied to the longitudinal damping system and the stochastic cooling system
[en] The almost hermetic coverage of the CMS detector is used to measure the distribution of transverse energy, Eτ, over 13.2 units of pseudorapidity η for pPb collisions at a center-of-mass energy per nucleon pair of √sNN=5.02 TeV. The huge angular acceptance exploits the fact that the CASTOR calorimeter at -6.6 < η < -5.2 is effectively present on both sides of the colliding system because of a switch in the proton-going and lead-goingbeam directions. This wide acceptance enables the study of correlations between well-separated angular regionsand makes the measurement a particularly powerful test of event generators. For minimum biaspPb collisionsthe maximum value of dEτ/dη is 22 GeV, which implies an Eτ per participant nucleon pair comparable to thatof peripheral PbPb collisions at √sNN=2.76 TeV. The increase of dEτ/dη with centrality is much stronger forthe lead-going side than for the proton-going side. The η dependence of dEτ/dη is sensitive to the η range inwhich the centrality variable is defined. Several modern generators are compared to these results but none isable to capture all aspects of the η and centrality dependence of the data and the correlations observed between different η regions. © 2019 CERN.
[en] We report the observation of laser oscillation in whispering-gallery mode (WGM) of a microcylinder with laser gain molecules present only in the evanescent field region of WGM. We show that the observe signal was originated from the evanescent-wave coupled gain of WGM. This novel concept of evanescent-wave WGM lasing offers potential applications in ultralow threshold photonic devices. (author)
[en] Based on kinetic theory of ideal gas, the present work gives an indirect measurement on relativistic temperature transformation by using transverse momentum distribution of particles. Our result shows that Planck–Einstein relation is right. A moving system which has no energy current exchange with external surroundings becomes cool. (author)
[en] Lindhard proposed his classical equation for the critical channeling angle from consideration of conservation of transverse energy. We generalize those ideas via consideration of conservation of transverse momentum, and propose an improved equation. A dimensional analysis of the problem is also presented, and that analysis puts our arguments and results on a firm footing.