T1 T2 trigger

1. T1 T2 trigger (a work in progress) Fabrizio Ferro

2. T1R T1L RPL RPR T2R T2L Inelastic trigger Total cross section: low luminosity L=1028 Double arm: (T1+T2)L && (T1+T2)R : minimum bias, double diffraction (~>80% of sin ) Single arm: (T1+T2)L || (T1+T2)R : single diffraction (~<20% of sin ) Single arm with RP: [(T1+T2)L && RPR] || [(T1+T2)R && RPL]: single diffraction Fabrizio Ferro

3. Inelastic trigger: caveat • Double arm trigger miss ~40% of DD (~2.8mb) • RP efficiency ~95% * ~82% T1+T2 SA efficiency on SD: ~78% SD efficiency • Single Arm without RP: background • sTOT studies  1kHz to be read out and written Fabrizio Ferro

4. Background What’s background in low lumi TOTEM? • Beam gas interactions: ~0.5 Hz/m at 1028 scaling with current (#bunches * Pperbunch) • Muon halo: high-E muons (E>10 GeV) at very low angle (~horizontal). 1028: T1~50Hz T2~5Hz (scaling with current) • Detector background: noise, secondary tracks. Fabrizio Ferro

5. Trigger patterns • Low background rates  concentrate on efficiency • Pointing: at least a rough pointing would be recommended to reduce bkg at higher luminosities and to reduce detector bkg. • T1: rough pointing at L1 difficult but possible (patterns under study) • T2: out of question Fabrizio Ferro

6. T1 • Major electronics modifications  reconsidering patterns • Trigger with anodes: simple pattern with anode groups under study • Preliminary: rough pointing achievable with different number of wires per group depending on the plane number and angle. Very high efficiency both with and without B field • Cathode digital readout  investigating possibility of including strips in L1 trigger  wire bands would turn into cells. Fabrizio Ferro

7. …T1 • Main beam gas rejection needs vertex reconstruction (offline) • Muon halo rejection difficult at very low angle (multiplicity trigger (?)) • Considering an alternative pattern to trigger halo muons for CMS tracker calibration Fabrizio Ferro

8. T2 Two halves • Coincidence with (5x3 pads) sectors in different plane of same half • Output: one bit per half  two bits can be combined with OR or AND logic • Two independent halves simplify logic • Muon halo is triggered (only multiplicity can may help). Beam gas (with particle in T2) are triggered. Fabrizio Ferro

9. …T2 • Real background: secondary particles generated in the BP  fake triggers (e.g. beam gas which gives DA trigger: 1 arm true, 1arm fake) • See Eric’s presentation for some numbers about simulation of trigger rates with last patterns • Giuseppe (Pisa) is investigating secondary particle generation in the simulation Fabrizio Ferro

10. Higher luminosity studies • Background rates higher: pointing and multiplicity cuts must be considered more carefully • Veto conditions on T1/T2 useful for the joint program with CMS. This is a natural rapidity gap trigger. • Obviously pile-up would destroy any possibility of using veto conditions (dets always on (see design specs)). Fabrizio Ferro

11. Work in progress • T1 – part of the studies on patterns have been reset because of new electronics  looking for the best feasible pattern. • T2 – patterns easier to be defined but investigation still needed: Eric (Helsinki) and Giuseppe (Pisa) are taking part of T2 simulation. • Luminosity: T1/T2 can operate up to which luminosity? Fabrizio Ferro