Diffractive Triggers E   Andrew Brandt, U. Texas at Arlington Trigger Integration November 18, 2003 A1UA2U P2DP1D P Pbar LM VC

Gap+Jet Triggers JT_15TT_GAPN or S CJT(2,3)+GAP L3(1,15) Prescaled, currently.3-.4 Hz each L<40E30; <.1Hz at 40 E30 e80-l40-n30? JT_15TT_GAPSN CJT(2,3)+GAPS L3(1,15) Currently unprescaled 0.6 Hz at 40E30 expect a prescale at higher luminosity unless can improve trigger (or natural prescale from double gap takes hold) JT_45TT_GAPN or S CJT(2,5)+GAP L3(1,45) Currently prescaled by 2 at 40E30.08 Hz each would like to keep unprescaled at least to 60E30 (like highest inclusive ET trigger). Also will have natural SI prescale (note s80-u60 in prescale file!) JT_45TT_GAPSN CJT(2,5)+GAPS L3(1,45) Unprescaled at all luminosity 0.03 at 40E30 *Also have 3 zero-bias+gap triggers These triggers are used for single diffractive and double pomeron jet physics (Gaps and FPD)

J/  +Gaps J/  +Gap 2MT1_2TRK_GAPN = 2MT1_C_2L2L_2TRK + ALMNorth[v] 2MT1_2TRK_GAPS = 2MT1_C_2L2L_2TRK + ALMSouth[v] Before shutdown prescale of 4 at 30E30, 200 at 40E30 (prescale now lowered) Unprescaled rate:.25 e80-l60-n40 would be good Could be unprescaled at all lum, when low P T track match works J/  +Gaps 2MT1_2TRK_GAPSN = 2MT1_C_2L2L_2TRK + ALMSouth[v]ALMNorth[v} <.01 Hz at 20E30 <.04 at 80E30 should be unprescaled at all luminosity These triggers are being used to search for exclusive J/  and  C, a key step towards validating diffractive Higgs models

FPD DAQ

FPD L1 Trigger Modelled after CTT (central fiber tracker trigger) but with fiber detectors read out by multi-anode phototubes (MAPMT’s) instead of VLPC’s Requires a transition board (TPP) to shape signals and discard excess charge for use with AFE’s (Analog Front End boards) which receive signals, record analog values, and discriminate DFE (Digital Front End boards) receive digital signals from AFE’s and apply tracking firmware to perform hit multiplicity cut (veto events with excessive multiplicity), divide tracks in momentum and angle bins LM TDC boards used to perform timing from hits in scintillators from the Luminosity Monitor sub-detector as well as the FPD trigger scintillators FPD timing and LM information will feed into FPD trigger manager (TM) along with DFE information to form FPD AND/OR terms

Trigger Manager Inputs FPD_LM 1x96 3x96 1x96 FPD_DFE TMTM LM 1)FPD_LM Information on which detectors are hit and halo 2) LM pass through 16 LM and/or terms includes GapN GapS GAPSN SI etc. (who in LM group is doing this? ) mostly can get this info separately 3)DFE information from scintillating fiber detectors, , t, multiplicity

FPD Trigger Status All 18 FPD detectors are in readout, trigger scintillators in readout soon.(!) Currently can only trigger using special runs (NIM to generate AND/OR terms). Need LM vertex board (<6 months, according to Brendan) combined with Trigger Manager (commissioning starting in next few weeks) for scintillator based triggers. Could have DFE-based triggers through TM earlier Will need some resources, bandwidth, exposure groups, trigger bits Proposed strategery: add high rate monitor and calibration triggers (elastic, inclusive diffractive) in separate global run not to be recoed. Use TM to define an FPD exposure group (gaps 3->1 or 2). A few global run triggers for double pomeron, J/ , and dijets. Other diffractive physics symbiotically.

In-time hits in AU-PD detectors, no early time hits, or LM or veto counter hits A1UA2U P2D P1D P Pbar Halo Early Hits LM VC Current NIM logic allows us to form several elastic and diffractive triggers for special runs using trigger scintillators (in parallel information from scintillators is sent to TDC’s for commissioning FPD_LM system, and CAMAC scalars), veto counters, and LM. Can trivially switch from elastic to double pomeron (Aup-Pup for example) Special Run Trigger

TDCTDC TDCTDC TDCTDC VTXVTX ‘1’D‘2’+V TDC Details : Step I TDC in readout 3 TDC boards for FPD compared to 6 LM boards ‘1’ board consists of Px1, and Ax1 where x=Up,Down, In, Out pots (first quadrupole castle on either side of IP) ‘2’ board consists of Px2, and Ax2 (second quadrupole castle) 2 dipoles + 4 veto counter signals Step II Pass info to vertex board and add scalar info Allowed 80 bits from each side to vertex board Each board should set bits at two times, corresponding to in-time hits (time of flight from IP) and to early-time hits from halo (time of flight from IP earlier than interaction) Dipole 1 halo bit (T-D2<T-D1), VC none? For each TDC give in-time bit 0 or 1; 16 (6) bits For each TDC give halo bit 0 or 1; 16 (1) bits TOTAL 32 (7) bits FPD_LM

1 board should send 8 in-time and 8 halo bits to 2 board which should receive these bits and send 16 in-time bits and 16 halo bits to vertex board D+V board should send 6 in-time and 1 halo bit to Vertex board Note: cable lengths have been fixed such that 1 in-time/halo signals arrive at 1 board at a fixed time (594 nsec/438), and all 2 signals arrive at 2 board at a different fixed time (625/407), and D+V signals arrive at a 3 rd fixed time (825). Manchester group on the job, plan to have TDC’s operational soon Steps to operational FPD TDC boards? Scalar on TDC board or vertex boards? Vertex Schedule? Update next week. More TDC Details

Vertex board should receive 22 in-time bits and 17 halo bits from TDC boards. It could form 4 bit words for each of the 8 non-dipole spectrometers 0=no coincidence of 1+2 pots for that spectrometer 1=coincidence of 1+2 pots for that spectrometer 2=coincidence but either one of diagonally opposite spectrometer pots has halo bit set 3=coincidence but both of diag opposite pots has halo bit set Examples: PU1.and.PU2 no early time hits in AD1 or AD2 =1 PI1.and.PI2 with early time hits in AO1 and AO2 =3 OR it could just pass the info to TM, depending on Firmware space on Vertex or TM OR BOTH: Vertex board passes information to TM Can pass up to 96 bits to TM in 16 bit bursts (separated by 18 nsec),74 bits if send processed and raw info 1) Spec 1-8 4bit words (32 bits) 2)Spec 9 3 bit word, 2 in-time bits from spec. 9, 1 halo bit from spec. 9 (note for dipole halo bits are formed from order of dipole times D1>D2 ->halo) (3 bits) 3) 4 veto counter in-time, 4 VC halo bits? Like lm halo? (4 bits) 4) 18 in-time bits from spec 1-9 (18 bits) 5) 17 halo bits from spec 1-9 (17 bits) Vertex Board Details

Previous Plan for FPD Triggers The FPD Trigger Manager allows cuts on  =1-  p/p and t, and also incorporates information from the trigger scintillator via the LM boards. A track is defined as two detector hits in any spectrometer with a valid x and t, a trigger scint. confirm, and no halo veto set. AND-OR term definitions (13 used of 16 allowed): RTK = track in any spectrometer, (D= veto on halo) RPT = proton track RAT = anti-proton track RTK(1) x > 0.99, all t RTK(2) 0.99 > x > 0.9 all t RTK(3) x > 0.9 all t, no halo veto RTK(4) x > 0.9, |t|>1 GeV 2 RTK(5) x > 0.9, all t REL = Elastic (diagonally opposite p and ) ROV = Overconstrained track (D+Q proton tracks) REL(1) = x > 0.99, all t REL(2) = x > 0.99, |t | > 1 GeV 2 ROV(1) = x > 0.90, all t ROV(2) = x > 0.90, |t | > 1 GeV 2 ) LMO = no hits in LM; LMI(1) = Single Interaction; LMD=N+Sbar.OR. S+Nbar

New Trigger Plan Input information: Currently no global run trigger capability Vertex board is delayed DFE boards work and TM ready to be commissioned Main background not from pileup (multiple interactions) but from halo spray New strategy: Instead of calculating bin of  and t, use fiber hit patterns to demand 2 or 3 out of 3 planes of each detector are hit. Replaces trigger scintillator, simpler algo 2)Use multiplicity cut to reject halo spray, code several multiplicity levels 3)NOTE fiber ADC threshold must be high enough to avoid noise, low enough to retain efficiency and allow vetoing of halo 4)One advantage is pot positions not needed at trigger level Issues: Setting ADC threshold, need special run (and analysis) Dealing with noisy channels, variable means, could initially set threshold high, later load in mean pattern, known hot channels 3)Need to settle on bit pattern to proceed with TM logic 4)Measure efficiency with jet triggers, scint triggers from special runs 5)Little experience with DFE, none with TM

TM Algorithm DFE will pass one word for each spectrometer indicating coincidence of two detectors and multiplicity level, use this to define a track (could have different multiplicity level in different spectrometers). At TM we would form terms DIFFQ=any quadrupole spectrometer track (could be false if >1 or 2 on A or P side) DIFFD=dipole track ELAS=AU-PD or AD-PU or AI-PO or AO-PI DPOM=AU-PU or AD-PD or AI-PI or AO-PO OVER=AU-DI or AD-DI or AO-DI or AI-DI (over-constrained track for alignment)

FPD Trigger List Tentative L1 FPD trigger list. V13 (mid-January) possible? 1) elastic (diag opposite spectrometers) +GAPSN 2) soft diffraction (single spectrometers)+GAPS or GAPN 3) overconstrained track (pbar in quadrupole +dipole spectrometers)+GAPN 4) double pom (up-up, dn-dn etc.)+GAPSN if needed 5) CJT(2,3) + FPD Track (DIFFQ or DIFFS) +GAPS or GAPN if needed 6) CEM(1,3)? +FPD track +GAP? 7) TTK(1,?) +FPD track +GAP? 8) MU(1,x) +FPD track +GAP? Monitors may be necessary, will need to study with special runs. Also rates are unknown. If 4 (dpom) it is not low enough to run unprescaled we would need to repeat 5-8 with two FPD tracks. We think triggers 1-3+any monitors are best done in a separate global run since they will not need general farm reconstruction.

Trigger Strategy I 1)Write out FPD, LM for every DØ event (may need to strip LM info from Raw data?) -cross section determined using standard methods x fraction that are diffractive corrected for acceptance+efficiency 2) Trigger on events that would not get written otherwise (Ex. single diffractive, elastic, double pomeron) using FPD track AND/OR terms, sometimes combined with gaps (veto on LM N or S) -high rate processes, cross sections will be measured in special run at some point (along with total cross section?) -these triggers will be in global list (or 2 nd global run) to measure  and t distributions, also be used as monitors and for alignment, calibration, and efficiency studies -double pomeron lower rate, will require extra thought for cross section, may be able to tie to elastics, or work backwards from double pomeron + object triggers

Trigger Strategy II 3) Trigger on events that would otherwise be too heavily prescaled (Ex. Jets, J/ , and then add gap(s) and/or track(s)) -cross sections determined using object trigger that does not have diffractive conditions and then bootstrapping

Different Exposure Terms FPD track(s)0 with no vetos on halo, multiplicity, veto counter, or LM -standard exposure group? Monitor (halo veto requires vertex board) FPD track(s)1 (includes FPD halo vetos+multiplicity cuts) (probably only use in special run) FPD track(s)2 (FPD track1+ a veto counter) [VCNbar or VCSbar]5.2<  <5.9 (standard inclusive SD term) [2 separate groups] (VC requires vertex board) FPD track(s)3 (FPD track1+ a veto counter+LM gap on same side) (standard inclusive SD term, gap may be necessary to control rate) [2 groups] FPD tracks4 (2 FPD tracks3) (elastic or double pomeron term) GAPN, GAPS, GAPSN Global list: FPD track0, FPD track2 or 3 (and also + object), FPD tracks4 (and also +object), LM gap +object, LM gaps+object Currently have 3 Gap exposure groups in global list out of 8 maximum. I assume 3 is limit for diffraction. Propose a single LM gap term and an FPD term. I count 10 different diffractive exposure groups, 7 needed in global list!

Trigger Work Short term trigger work: DFE algorithms: Mario, Wagner Data analysis inputs from special runs: Molina, Mike, James, Renata … DFE firmware: Ricardo, Daniel CTS tests: Daniel DFE examine? TM: Daniel, Mario… MC:? Trigger database L2 Gap: ? L3 SI, Gap, PLtot, FPDreco:? With detectors in readout, next key is maximizing useful data sample: getting L1 trigger online is vital to FPD physics success