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BB Effect and Early Separation Scheme Guido Sterbini CERN MCS - MA 7 December 2006

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D0 D1 TRIPLETS D0 [m] D0 4 m Early separation scheme

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Distance between the beams [ ] Distance from the IP [m] How does the early separation scheme impact on the BB effect?

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s y 50 rad 80 rad d1 d2 Trade-off between the geometrical loss factor, the BB effect and the intrusion in the detectors regions

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x y We launched the particles in the different directions in the x-y plane.

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Nominal D0a ( rad)D0b ( rad) 80 40120 20140 The beam dynamics behavior of D0 seems not to depend on the different distribution of kicks angle between D0a and D0b.

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The 45 direction seems critical. Why? The Early Separation Scheme is very sensitive to this problem: we need to deepen the BB results It would be very interesting to test different index of chaos with respect to an experimental results in order to have a hint on the maximum number of reduced LRBB interaction we can afford.

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Appendix We can consider the first two ATLAS slots: We can consider the first two ATLAS slots: Slot1 starting at 3.49 m from IP with a total length of 1.09 m Slot1 starting at 3.49 m from IP with a total length of 1.09 m Slot2 starting at 6.80 m from IP with a total length of 1.86 m Slot2 starting at 6.80 m from IP with a total length of 1.86 m We can obtain the 8 Tm splitting the dipole into two: We can obtain the 8 Tm splitting the dipole into two: a 4 T D0a in Slot1 (it should be transparent a.s.m.p.) a 4 T D0a in Slot1 (it should be transparent a.s.m.p.) a 4 T D0b in Slot2 (it should be bulky a.s.m.p.) a 4 T D0b in Slot2 (it should be bulky a.s.m.p.)