13,607 research outputs found

    High Level Trigger Using ALICE ITS Detector

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    The high PTP_T trigger capabilities of the ALICE inner tracking system (ITS) as a standalone detector have been investigated. Since the high PTP_T charged particles mostly lead to the linear trajectories within this ITS sector, it is possible to select tracks of PTP_T of the order of 2 GeV and above by confining to a narrow search window in the (θ,ϕ\theta,\phi) space. Also shown that by performing a principal component transformation, it is possible to rotate from a 12 dimensional (θ\theta-ϕ\phi) space (in this space, a good ITS track has 6 pairs of hit co-ordinates) into a parametric space characterized by only two independent components when the track momentum exceeds a particular limit. This independent component analysis (ICA) has been uitilised further to reduce the false track contribution to an acceptable level particularly when the charged multiplicity is large. Finally, it is shown that with a narrow bin width of Δθ=Δϕ0.008\Delta \theta = \Delta \phi \sim 0.008 radian and with PCA or ICA cut, the ITS can be used to trigger the jet particles with PT2P_T \ge 2 GeV. Apart from triggering these high PTP_T particles, this method can also be used to estimate the initial momentum of the high PTP_T tracks for seeding which can be further prolonged into the TPC detector both for offline and online Kalman tracking or even to detect those high PTP_T tracks of rare events which might get lost in the TPC-TRD dead zone.Comment: 20 pages, 10 figure

    Matter antimatter domains: A possible solution to the CP domain wall problem in the early universe

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    An SU(5) grand unified theory model is used to show how the degeneracy between vacua with different spontaneously broken charge parity can be dynamically lifted by a condensate of heavy fermion pairs. This drives a phase transition to a unique vacuum state with definite charge parity. The transition eliminates the domain walls in a matter antimatter symmetric domain cosmology