Compositeness

1
Compositeness

• Ulrich Heintz

2
Signals of compositeness

• two signatures
• excited quarks and leptons
• production cross section for jets and leptons
• only considered jets here
• work done at Snowmass 2001

3
Excited quarks

• production
• q g ? q
• q q ? q q
• decay
• q ? g q
• q ? ? q
• q ? W q
• q ? Z q
• simulation pythia

4
Excited quarks

• production cross section in pb
• assume ?s200 TeV, 100 fb-1 (1 year _at_ 1035
  cm-2s-1)

m (TeV) ?s (TeV) ?s (TeV) ?s (TeV) ?s (TeV) ?s (TeV)
m (TeV) 14 28 40 100 200
0.6 3.6105 2.0106 4.7106 3.6107 1.6108
1 2.8104 1.9105 4.7105 4.1106 1.9107
6 3.310-2 6.5 40 1100 7100
60 - - - 3.110-6 5.610-3
100 - - - - 1.310-5
5
Excited quarks
2 partons with pT gt 10 TeV in 100 fb-1 at ?s200 TeV 2 partons with pT gt 10 TeV in 100 fb-1 at ?s200 TeV 2 partons with pT gt 10 TeV in 100 fb-1 at ?s200 TeV 2 partons with pT gt 10 TeV in 100 fb-1 at ?s200 TeV
m B(gq) acc N
60 TeV 76 90 510
70 TeV 76 90 100
80 TeV 76 90 23
100 TeV 76 90 1
QCD 25k
m 60 TeV
m 70 TeV
m 80 TeV
m 100 TeV
6
Excited quarks

• effect of resolution
• 5 constant term

m 60 TeV
m 70 TeV
m 80 TeV
m 100 TeV
7
Excited quarks
perfect resolution
?s m5?
40 TeV 16 TeV
100 TeV 40 TeV
200 TeV 75 TeV

assuming perfect resolution assuming perfect resolution
resolution 2
S/?B for 100 fb-1
resolution 5
resolution 10
?s 200 TeV 100 fb-1
8
Jet cross section
? 50 TeV
? 75 TeV
? 100 TeV
9
Jet cross section
?(1) events/100 fb-1 events/100 fb-1 S/?B
?(1) 30ltmjjlt70 mjjgt70 TeV S/?B
50 TeV 15000 570 43.6
75 TeV 8940 160 11.3
85 TeV 8280 120 7.2
100 TeV 7880 88 3.8
QCD 7460 55 -

1. LL isoscalar model implemented in PYTHIA Eichten,
   Hinchliffe, Lane, Quigg (Rev Mod Physics 1984)

10
Conclusions

• sensitivity to quark compositeness
• for ?s 200 TeV and 100 fb-1
• excited quarks
• m 70 TeV
• jet cross section
• ? 95 TeV