Baryons04, 25-29 Oct, Palaiseau Francesca Curbis - Università di Roma “La Sapienza” & INFN 1 Recent CDF results on heavy and exotic baryons in p-pbar collisions at s=1.96TeV Francesca Curbis, Università di Roma “La Sapienza” for CDF Collaboration Baryons 04, 25-29 Oct, Palaiseau, France
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Recent CDF results on heavy and exotic baryons in p-pbar collisions at s=1.96TeV
Recent CDF results on heavy and exotic baryons in p-pbar collisions at s=1.96TeV. Francesca Curbis, Università di Roma “La Sapienza” for CDF Collaboration. Baryons 04, 25-29 Oct, Palaiseau, France. Outline. L b mass L b lifetime L b → L c p L b → pK,p p. CDF detector - PowerPoint PPT Presentation
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Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
1
Recent CDF results on heavy and exotic baryons
in p-pbar collisions at s=1.96TeV
Francesca Curbis,
Università di Roma “La Sapienza”
for CDF Collaboration
Baryons 04, 25-29 Oct, Palaiseau, France
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
2
Outline
CDF detector
Bottom baryons
Pentaquark searches
Conclusions
b mass
b lifetime
b→cp
b→pK,p
theta plus
exotic cascade
theta c
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
3
CDF detector @Tevatron
large radius tracking wire
chamber
time of flight
High mass resolution with CDF tracking system
solenoid 1.4 T
TRACKING system:
• SILICON TRACKER
(L00+SVX+ISL)
(up to ||~2)
• DRIFT CHAMBER
(96 layers) (||<1)
→ particle ID with dE/dx
TIME OF FLIGHT→particle ID
solenoid 1.4 T
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
4
PID with TOF and dE/dx
resolution 150ps for 150cm
TOF dE/dx
Low momentum < 1.6 GeV
K/separation 1.16
high momentum > 2 GeV
complementary
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
5
Bottom baryons
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
6
B mesons masses B+ B0 B0
s b
world best
m(b)=5619±1.2±1.2 MeV/c2
compare to PDG
5624±9 MeV/c2
Measurement using several exclusive decay modes
Use J/trigger for detector calibration: Momentum scale, B-field correction and energy loss
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
7
b Lifetime in b→J/
World’s most precise measure in exclusive mode
decay asymmetrically
very soft
b only @Tevatron
Heavy Quark Expansion
prediction @NLO (b)
(B0)= 0.87±0.05
(Hep-ph 0407004)
Control sample: B0 →
J/K0s
K0s long lived like
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
8
(b)= 1.25±0.26±0.10ps
B0 → J/K0s
high statistics
(B0)= 1.38±0.10ps
compare to PDG value (b)= 1.229±0.08ps
b→ J/
b→ J/
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
9
Measurement of b → cfbaryonxBrb→+
c
fd x BrB0
→D+
=
Data: 0.30±0.05 ±0.13
MC: 1.20±0.02±0.11
PDG: 1.82±0.49
= 0.66±0.11±0.09±0.18(Br) FIRST OBSERVATION!
b x NB0 x Br+c
→pK
B0 x Nb x BrD- →K
B0 → D-
B reflections
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
10
Search for b→pK and pdecays
N(b→hh)
B x fB x Br(B0→K)=
x f x Br(b→hh)
N(B0→K)
Nb→hh<75 @90%C.L.
Brb→hh< 22 10-6
@90%C.L.
Prediction: Mohanta, Giri, Khanna 2001
Br(b→ pK)=(1.4-1.9)×10-6
Br(b→p)=(0.8-1.2)×10-6
compare to Br(B0→K)= 18×10-6
Br(b→ pK+p)<22× 10-6 @90%C.L.
Previous best limit from ALEPH
Br(b→pK+p)<50×10-6 @90%C.L.
possibility for first observation of CP
asymmetry in baryons
Fully exclusive decay
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
11
Pentaquark searches at CDF
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
12
Motivation
prediction from Chiral Soliton Model (1997 Diakonov, Petrov, Polyakov)new searches for 5-quark states
nK+ or pK0S
1530 MeV
1710 MeV
1890 MeV
2070 MeV
narrow resonances seen in several experiment
qqqqq states
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN
13
c → D*+p
m=3099±3±5MeV/c2
=12±3 MeV
Exotic cascade
m=1862±2 MeV/c2
< 18 MeV
LEPS 8 GeV Synchrotron n → K+K-n reaction
m=1540±10±5 MeV/c2
< 25 MeV
many observations, can CDF see these resonance?
NA49 pp collision at Ecm=17.2GeV
H1 e-p collision at Ecm=300GeV
→ n K+
signal was confirmed by about 10 other experiments
(CLAS, SAPHIR, ZEUS, HERMES, COSY-TOF,DIANA, SVD)
Some pentaquark claims
Baryons04, 25-29 Oct, Palaiseau
Francesca Curbis - Università di Roma “La Sapienza” & INFN