in heavy baryons Atsushi Hosaka RCNP Osaka U 91013 2013 Charmed baryons 1 Practical questions of hadron physics How ground and excited states are described Are there simple language for it ID: 148034
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Slide1
Diquarks in heavy baryons
Atsushi Hosaka (RCNP, Osaka U.)
9/10-13, 2013
Charmed baryons
1
Practical questions of hadron physics
• How ground and excited states are described?
• Are there simple language for it
when quarks and gluons interact strongly
• Are there kinds of quasi-particles interacting weakly
• Constituent quarks:
Mere
useful tool of symmetry realization or
Dynamically realistic
and active object
•
How can
diquarks
be
be identified in
multi-quark systems
Baryons, nuclei, nuclear matter, quark matterSlide2
Quark-diquark baryon
Selem-Wilczek:
e-Print: hep-ph/0602128
•
ee has repulsive force, BUT
• qq has attractive force
SU(3)
c
: half of qqbar attraction SU(2)c : Same as qqbar Pauli-Gursey symmetry ~ several hundred MeV• Diquark can be seen better in heavy baryons than in light
Color magnetic int.
Good
BadSlide3
Some evidences
9/10-13, 2013Charmed baryons
3
• Σ-Λ (80 MeV),
Σc
-Λc (215 MeV) mass difference
• Production rate of
Λ
,
Σ (e+e-@10 GeV) Λ : Σ = 0.08:0.023, Λc : Σc = 0.074:0.014• ΔI = ½ rule • F2n/F2p
¼• Lack of exotics Repulsive between g
ood diquarks?Slide4
In QCD
9/10-13, 2013Charmed baryons4
• How
diquarks
are defined? -- correlation function
ud
-diquark
Heavy quark
t
= 0
2
t
t
• How are they observed
in charmed baryons?
Spectrum, decay rate, production
•
A
re there other opportunities to hunt
diquarks
?
qq interaction in a baryon (colored environment)Slide5
Density correlations
9/10-13, 2013Charmed baryons5
Alexandrou
,
deForcrand
, LuciniPRL 97, 222002 (2006)
cos
θ
1.0
r
θ
r
= 0.69
fm
r
= 0.47
fm
r
= 0.35
fmGood
diquarkBad
diquarkIndicates significant attraction between quarks in good diquark pairSlide6
Baryon spectrum
S=1/2
S=3/2
qqq
qq
c
q
cc
c
I
Light flavor baryons (
uds
)
Ground 8 + 10
and excited
~
80
states
9/10-13, 2013
Charmed baryons
6
udsSlide7
S=3/2
S=1/2
Charmed baryons
14
c
+
1
cc
<< 80
uds
(6
excited)
1/2
+
1/2
–
1/2
+
3
/2
+
1/2
–
1/2
+
3
/2
+
3/2
–
5/2
+
?
Ξ
C
[
GeV
]
?
1/2
+
3
/2
+
Ω
C
cqq
cqq
csq
css
Ξ
C
Ξ’
C
1
hω
?
1
Ξ
+
cc
9/10-13, 2013
Charmed baryons
7Slide8
Advantage of heavy quark
• Discriminate of modes
Light baryon
One HQ baryon
Two HQ baryon
•
Spectrum, productions and decays
9/10-13, 2013
Charmed baryons
8Slide9
λ and
ρ motions split known as isotope shift
s
q
s
q
, SO
Σ
c
(1/2-,3/2-)
Λ
c
(
1/2-
,1/2-
3/2-,3/2-,
5/2-)
Λc(1/2-,3/2-)
Σ
c
(1/2-,1/2- 3/2-,3/2-,
5/2-)
Σc(1/2+,3/2+
)Λ
c(1/2+)
“Q” may isolate “qq”
q
q
q
Q
λ
q-q
Q
ρ
q-q
λ
mode
ρ
mode
G.S.
9/10-13, 2013
Charmed baryons
9Slide10
Decays
Ratio:
9/10-13, 2013
Charmed baryons
10
ρ
-mode
λ
-mode
ρ
-mode
バリオンは軽い中間子と重いバリオンに
λ
-mode
重い 軽い に崩壊Slide11
9/10-13, 2013
Charmed baryons11
1/2–
1/2
+ E1 transition
λ
mode
Good
diquark
0+
l
λ = 1
3P0
diquark
0
–
lρ
= 1
ρ
mode
0
–
0
+
is
forbidden
Good
diquark
0
+Slide12
9/10-13, 2013
Charmed baryons12
5/2–
1/2
+ M2, E3 transition
λ
mode
3
S
1 diquark
1
+
lλ
= 1
3
P
2
diquark
2
–
lρ
= 1
ρ mode
2
–
0
+
is
M2
Good
diquark
0
+
Both M2 E3Slide13
Role of a heavy quark
9/10-13, 2013Charmed baryons13
• Filter out 2
-body correlations
• Excitation spectru,
λ-ρ modes, Good
vs
bad
diquark
• Decay pattern, selection rules• Diquark densitiesEstablish diquarks from QCD Phenomena