L1Cal Trigger Terms: Run IIb

updated: 03-May-06

Index

Run IIa: And/or term usage
Run IIa: L1Cal and/or terms
Run IIb: Primitives for constructing and/or terms (TAB ouput)
Run IIb: L1Cal and/or terms (example)
Run IIb: L1Cal topological triggers (examples)
Run IIb: L1Cal EM-Isolation triggers
Run IIb: Definition of N,S,C eta regions
Run IIb: COOR parameters

Marco's Proposed List

L1Cal And/Or Terms in Run IIb (24-Aug-05 ver.)

Previous versions

Hal's talk at the Vancouver workshop
15-Mar-05
22-Oct-04
Hal's talk at the 13-Feb-03 Collab Meeting

Current Proposal

Name	n	N(Thresh's)	Regions	Trig Terms
CSWJT(n,t,eta*) Jets	1,2 3,4	4 2	C,all all	16 4
CSWTA(n,t,ratio,eta*) Taus	1,2	1	C,all	4
CSWEM(n,t,eta*) EM	1,2	4	C,all	16
CSWEI(n,t,emi,emf,eta*) Isolated EM	1,2	1	C,all	4
CSWMET(t,cut,eta_sum,icr*) Missing Et	1	4	all	4
CSWTET(t,cut,eta_sum,icr*) Total Et	1	2	all	2
CSWAJT(t_a,t_v,contig*) Acoplanar Jet	1	2	all	2
CSWBBEM(t,contig*) Back-to-Back EM	2	2	all	2
Total				54

Downloadable Parameters

These parameters are downloaded to the GAB(TABs) to define the triggers.

t = thresholds used in these triggers
- 6 thresholds are available in data from the TABs that is used to construct these triggers
t_a,t_v = threshold for the found jet and for a jet to be counted in the jet-free region
ratio = tau isolation ratio
emi = power of 2 for EM-Isolation definition
emf = power of 2 for EM/HAD definition
- Note: only a single pair (emi,emf) can be downloaded to the TABs.

Fixed Parameters

These parameters are fixed in the firmware. They can be changed, but only with a new firmware version

n = number of objects in trigger
eta* = eta region over which trigger is constructed
- Possibilities are C=central, all=all-eta. See below for region definitions.
- Currently (28-Jun-05) only triggers using all are implemented, but it should be simple to put in the C requirement since these counts exist in the code.
eta_sum* = eta region over which Et sums are constructed
cut* = cut on Et of TT to enter sum
- currently (28-Jun-05) not used
icr* = use ICR TTs in constructing sums are constructed
contig* = number of contiguous TTs used in topological triggers.
- can be different for each trigger

Example L1Cal Topological Triggers for Run IIb

Name	Definition	Combine w/	Other Info
JET_FREE(n,t)	A contiguous phi-region of the calorimeter is free of jets. n = number of contiguous positions to define free region. t = threshold that jet must pass to be counted in free region Useful for ZH --> vvbb	AND w/ CJT(1,t)	figure
ACOP_JET(t_a,t_v,contig)	Require 2 jets that are not back-to-back in phi. t_a,t_v = threshold for the found jet and for a jet to be counted in the jet-free region contig = number of contiguous positions to define the jet-free region 180^o from a found jet. Useful for ZH --> vvbb	AND w/ CJT(2,t)	figure
DIEM_B2B(n,t)	Require 2 EM objects that are back-to-back in phi. n = number of contiguous positions to define the where the opposite EM object must be found. t = threshold for the EM objects Useful for Z --> e+e-	AND w/ CEM(2,t)	figure

Triggers using EM Isolation for Run IIb

Isolated EM objects are identified using Isolation Bits defined in detail here. Because of limitations on the number of bits per event that can be transmitted between the TABs and the GAB (detailed here) an isolation bit cannot be associated with each possible EM object. There are thus a total of 96 isolation bits, which, when set, indicate that there is at least one EM object that passes the isolation criteria in the region defined by:

eta = S,C,N (see region definitions)
phi = 0,1,2,...,31

Constructing Isolated EM Object Triggers

For a specified threshold, t, consider all phi's (0-31) and eta regions (S,C,N).

At each position (phi,eta-region) increment the isolated object count (by 1) if there is at least one EM object at this position with
- Et-threshold >= t
- and the Isolation Bit = 1 for this position
Isolated Single-EM triggers, CEI(1,t), require: count >= 1
Isolated Di-EM triggers, CEI(2,t), require: count >= 2

Limitations of Isolation Triggers

If there are two isolated EM objects at, e.g. phi=1 and eta=C, they will only be counted as one by the above algorithm.

Topological Triggers with Isolation

This is probably overkill. We won't construct any of these unless the physics demonstrably requires it.

Definitions of phi and eta Regions used in And/Or Terms

Translations between L1Cal eta,phi numbering conventions and detector eta,phi are given here.

Eta Regions

Region	eta	ieta(TT)	ieta(TAB)
S	-3.4 / -1.0	-16 / -5	4 / 15
C	-1.0 / +1.0	-4 / +5	16 / 24
N	+1.0 / +3.0	+6 / +15	25 / 34

Note - the eta regions currently (28-Jun-05) implemented in the TAB firmware are: S(4-13), C(14-23), N(24-34). These will be changed soon to match the above.

Phi Quadrants

Qdrnt	iphi(TT)	iphi(TAB)
0	1 / 8	0 / 7
1	9 / 16	8 / 15
2	17 / 24	16 / 23
3	25 / 32	24 / 31