Spectroscopy and Interactionsof Heavy Hadrons
Makoto Oka
Tokyo Institute of Technology
Particle and nuclear physics seminar at J-PARC
Workshop on"Heavy-Quark Hadrons at J-PARC 2012"06/27/12, J-PARC Branch, KEKHeavy-Quark Hadrons at J-PARC 2012
Workshop
6/18-22 at Tokyo Tech
6/22 One-day Symposium
6/25-29 at Tokai Branch, KEK Theory Center
Organized by
A. Dote, S. Hashimoto, A. Hosaka, T. Hyodo, D. Jido,
M. Oka, K. Ozawa, M. Takizawa, S. Yasui
Sponsored by
KEK, Theory Center, JPARC Branch
JPARC Project
HPCI Strategic Program Field 5
RCNP, YITP, Tokyo Tech groups2

Heavy-Quark Hadrons at J-PARC
The 1st week: 9 Seminars + Symposium
Olsen, Spectroscopy at BES and Belle
Ozawa, Heavy quarks at J-PARC
Takeuchi, Takizawa, X(3872)
Molina, Ohkoda, D-D* D*-D* bound/resonances
Hyodo, Yamaguchi, D-N bound state
Namekawa, Takahashi, LQCD for charmed hadrons
Lee, Heavy quark and QCD correlators
Kim, QCD sum rule and diquarks
Harada, Chiral effective theories for heavy hadrons
Sudo, Kiyo, Charm production
Suzuki, Fujii, Heavy hadrons in medium
Sasaki, Koma, Heavy quark interactions
3

Contents

1. Heavy Hadron Spectra
2. New Exotic Resonances
3. Charmed Deuteron4

Heavy Hadron Spectra5Quarkonium
Hydrogen atom in QCD
charmonium

bottomium

S.N. Mukherjee, et al.,Phys. Rep. 231 (1993)

6

Quarkonium
Linear + Coulomb (Cornell) potential (Eichten et al.)Heavy quark potential from LQCD

charmonium
quark

antiquark

quenched

r0: Sommer scale

G.S. Bali / Phys. Rep. 343 (2001) 1
7

Heavy-Quark Hadrons
Heavy mesons and baryons
The SU(4) classification for the ground states works.
They follow the quark model assignments (as the light sector)

PDG
8Heavy-Quark Hadrons
Heavy mesons and baryons
The SU(4) classification for the ground states works.
They follow the quark model assignments (as the light sector)

PDG
8Heavy-Quark Hadrons
New dynamics for heavy quarks
ΛQCD(~250 MeV) < mc(~1.2 GeV) << mb(~4.5 GeV)
– Heavy quark decouples and the system is simpler.
– New symmetries are realized.

ex. HQ spin symmetry

Σ* 1385
Σav 1321
194

65

Σ*c 2518
Σc 2453200

Σ 1193
Λ 1116

K* 892

Σcav 2496

Λc 2286

D*s 2112

Dsav 2076*
Σbav 5826 Σ b 5833
Σb 581221

Λb 5620*
Bsav 5403 B s 5415

9

Heavy-Quark Hadrons
Light Baryons: qqq color singlet (color antisymmetric)
SU(6) 56 dim. L=0, (8, S=1/2) + (10, S=3/2)
Heavy Baryons:
Qqq ⇒ (3bar, J=1/2) + (6, J=1/2) + (6, J=3/2)
HQ spin symmetry
J=1/2
J=3/2
QQq
Qqq
6+3bar

QQQ
QQq
Qqq
6

10

Heavy-Quark Hadrons
New dynamics for heavy quarks
ΛQCD(~250 MeV) < mc(~1.2 GeV) ≪ mb(~4.5 GeV)
– Heavy quark decouples and the system is simpler.
– New symmetries are realized.

ex. HQ spin symmetry

New interesting dynamical contents in Heavy Baryons– Di-quark spectroscopy– Chiral partners

Q-(qq)

diquark Q(qq)+ v.s. Q(qq)quark
QQq+ v.s. QQq– Appearance of the Roper-like states11

Heavy-Quark Hadrons
Heavy quark spectroscopy ⇔ Diquark spectroscopyΛQ (ΣQ) contains only the S (A) diquark.
A diquarks

Σ* 1385
Σav 1321
194

65

Σ*c 2518
Σc 2453

Σcav 2496
200

Σ 1193
Λ 1116

Λc 2286*
Σbav 5826 Σ b 5833
Σb 5812

Λb 5620

21

S diquarks

What are the roles of (other) diquarks in the excited states?
– PS diquark for the negative-parity
excited statesD*s 2112*
K* 892 diquark for the Roper-likeDsav 2076states– NovelBsav 5403 B s 5415
Kav 793

D* 2009
Ds 1968

Dav 1974

Bs 5366*
Bav 5313 B 5325
B 527912

Diquarks in QCD

Pseudoscalar
Scalar (S)VectorAxial V. (A)Color 6
only inExoticHadrons13

Baryon Spectrum
Light baryon spectrum

Ξ*(1530)

Λ*(1800)
Σ*(1750)
Λ*(1670), Ξ*(1690)
N*(1650)
Σ*(1620)
N*(1535)

Σ*(1385)

Λ*(1405)

Roper(-like) statesΣ*(1660)
Λ*(1660)
N*(1440)

Ω(1672)Δ*(1600)

Ξ*(1820)
Λ*(1690), N*(1700)
Σ*(1670)
Λ*(1520)
N*(1520)

Ξ(1318)
Σ(1193)
Λ(1116)Δ(1232)

1/2 -Negative parity

N(940)

1/2 +

3/2 -

3/2 +

Positive Parity
14

Baryon Spectrum
Heavy baryon spectrum looks simpler. They may reveal thenature of the light baryon excited states.
The higher thresholds make the heavy baryon excited states
narrower.
DN
3/2&

2700

Energy [MeV]

1500
1400
1300

3/2&
#$
1/2&
!"

1/2&

3/2+

!"c

2500

1/2+

1200

2600

3/2+
!%c

!%

1100

2800

2400

1/2+
2300
1/2+
%

1/2+
"

%c

"c

15

Diquarks in QCD
QCD predicts attraction in the channels:
PS meson q-qbar : color 1, spin-parity 0-, flavor 1+8
S diquark q-q : color 3bar, spin-parity 0+, flavor 3bar
U = [ds̄]C=3,J=0,F =3 ,D = [s̄ū]3,0,3 ,S = [ūd]3,0,3

diquark “meson” d dbar (tetra-quark)
di-diquark “baryon” d-d-q (pentaquark)
tri-diquark “dibaryon” d3 (6 quarks)
color 1, flavor 1, 0++ H dibaryon
H = [Ū D̄S̄]A = [uuddss](

diquark matter: color superconductivity
Ubar+Dbar+Sbar condensates: color-flavor locking (CFL)
Sbar: 2SC (Ubar: uSC Dbar: dSC)
16

Diquarks in QCD
Diquarks in quench lattice calculations
Hess, Karsch, Laermann, Wetzorke, PR D58, 111502 (1998)
from the correlators in the Landau gauge
mq~342 MeV, M(S)~694 MeV, M(A) ~ 810 MeV
Alexandrou, de Forcrand, Lucini, PRL 97, 222002 (2006)
gauge invariant calculation inside a Qqq system
M(A)- M(S) ~ 100-150 MeV, R(S) ~ 1 fm
M(PS)- M(S) ~ 600 MeV
Babich, et al., PR D76, 074021 (2007)
diquark correlation and effective mass in the Landau gauge
M(S)- 2mq ~ -200 MeV, M(A)-M(S) ~162 MeV
DeGrand, Liu, Schaefer, PR D77, 034505 (2008)
diquark correlation in the light baryon
S: strongly attractive, PS: attractive for small mq

17Diquarks in QCD
There are two independent local operators for the octet
baryons, i.e.
J1= (qTCγ5q)S q
J2= (qTCq)PS γ5q
It is found by both the LQCD and QCDSR calculations thatthe ground state nucleon couples mainly to J1 while J2 couples
to the negative parity nucleon.
Is the mysterious Roper resonance (the 1st excited state of thenucleon with Jπ=1/2+) related to the second baryonic current
J2?
The local operator is unique for the decuplet baryons.

18Diquarks
The Diquark “cluster” may play major roles in thebaryon excitations.
How can we quantify the Diquark correlation in QCD?
How heavy are the Diquarks?
How large is the SU(3) breaking mass splitting?
m(U) = m(D) > m(S)What are the interaction of color-non-singlet Diquarks?
How can we measure the Diquark correlation in
hadrons?
Colored correlations in hadrons and nuclei.
=> Exotic Hadrons

19Chiral Symmetry in Heavy Hadrons
Mesons (SH Lee, Harada)

20Chiral Symmetry in Heavy Hadrons
Baryons
Chiral symmetry of
q3 = (8,1)+(1,8) , (3,3bar)+(3bar,3), . . .
Qq2 = (3bar,1)+(1,3bar) , (3,3), (6,1)+(1,6)
QQq = (3,1)+(1,3)
P-wave Heavy Baryons have two excitation modes.

L=1
L=1

<
<

L=1 (chiral)

L=1 (chiral)
21

Chiral Symmetry in Heavy Hadrons
Two excitation modes of the P-wave Heavy Baryons
Qqq baryon
quark model

Q[qq] baryon
with diquark correlations

q

q

"

q

" q
!
Q

!
Q

33"0,1,2

33"0,1,2, 61"133"0,1,2, 61"1
31!0, 63!0,1,2chiral partners

61"1

L=0
1/2-, 1/2-, 3/2-, 3/2-, 5/2P----Q
L=0
1/2-, 3/2V----Q" modesingle quark
mode
31S0, 63S1

63!0,1,2

31!1, 63!0,1,2

diquark
motion! mode31!1

spin-spin
1

3 S0, 63S1

63S1
31S0

L=1

A----Q 1/2-, 1/2-, 3/2-, 3/2-, 5/2L=1
1/2-, 3/2S----Q
L=0
A----Q 1/2+, 3/2+
L=0
1/2+
S----Q

22

New “Exotic” Resonances

23

Exotic Hadrons: Candidates
MesonsScalar meson nonets: f0, a0 vs KKbar
Baryonium-like state X(1835)
Charmonium-like resonances:X(3872)X, Y(3940), Z(3930)

Z+(4430)

Γ =45 MeV

Charged (I=1) resonances:Z+(4430), Z1(4050), Z2(4250)
Zb(10610), Zb(10650) (bbbar-like)24

S. Olsen, Heavy Quark Hadron 2012

BESIII: X(1835) confirmed + 2 new structures
J/ψ→γη′π+π−η′→ηπ+π−η′→γπ+π−X(1835)

two new ones!

X(1835)consistent with 0-+

f1(1510)
Bkg‐subtracted;
Eﬀ.‐corrected

BESIIIBESIII PRL 106, 072002 (2011)

X(1835): same mass and JPC_
as the pp peak, but larger width

ResonanceM( MeV/c2)

Γ( MeV/c2)

Stat.Sig.

X(1835)1836.5±3.0+5.6-2.1

190.1±9.0+38-36>20σ

X(2120)2122.4±6.7+4.7-2.7

X(2370)2376.3±8.7+3.2-4.3

83±16+31-11 narrow!! 7.2σ
83±17+44-6

6.4σ25

S. Olsen, Heavy Quark Hadron 2012

Charmonium & charmonium‐like mesons‐outline‐

2) New JPC=1‐ ‐ states:‐Y(4260), ‐Y(4360), ‐Y(4660)

3) Charged mesons
With hidden charm‐‐‐ ‐Z (4430)+‐‐‐ ‐Z2(4250)+‐‐‐ ‐Z1(4050)+
1) new states
below 4 GeV‐ψ2(3823)‐X(3872)‐Z(3930)‐Y(3940)‐X(3940)

Exotic Hadrons
Exotics are “Colorful” !

(Lipkin@YKIS07)(qq)8 or (qq)6 are allowed only in the multi-quarks.
q

q

q

8

q

q
6

q

q

q

27

Scalar mesons
The lowest lying scalar nonets, f0(600, 980), a0(980), K0(800),
have wrong ordering and do not fit the qqbar spectrum.
f0(1710)a0(1450)

M (MeV)a1(1230)f0(1370)a2(1320)a0(980)q-qbar 3P0 + glueballf0(1500)
K0*(1430)

f0(980)K0*(800)"(770)

Tetra-quark q2-qbar 2
nonets?

!(600)

Two sets of the 0++ meson nonets!(137)
0! !(1)

JPG(I))
1+ !(1)
1!+(1)

2+ !(1)0+ !(1)0++(0)

0+ (1/2)

28

Scalar mesons
Tetra-quark conjecture (Jaffe, Shechter)¯
f0 (600) ∼ S S̄ = (ud)(ūd)¯ − (su)(s̄ū)
U Ū − DD̄(ds)(ds̄)√√a0 (980) ∼=22¯ + (su)(s̄ū)
U Ū + DD̄
(ds)(ds̄)√√f0 (980) ∼=2
2

no strange quark}

two strange quarks

composed of Di(anti-)quarks in flavor 3
U = (d s ) S=0,C=3 D = (s u ) S=0,C=3 S = (u d ) S=0,C=3
Now the observed mass ordering can be explainedby the numbers of the strange quarks.
All the quarks are€in S-wave, so that no€€ extra excitation energy
is necessary.

29

Λ(1405)
Why is Λ(1405) the lowest negative-parity baryon?

Σ*(1660)
Λ*(1660)

Ξ*(1530)

Λ*(1800)
Σ*(1750)
Λ*(1670), Ξ*(1690)
N*(1650)
Σ*(1620)
N*(1535)

Σ*(1385)

Λ*(1405)Ω(1672)Δ*(1600)

N*(1440)
Ξ(1318)

Ξ*(1820)
Λ*(1690), N*(1700)
Σ*(1670)
Λ*(1520)
N*(1520)ΔLS ~-15~+50 MeV

ΔLS (Λ*)= 115 MeV

Δ(1232)

Σ(1193)
Λ(1116)Δs ~ 300 MeV

N(940)

Δm = 150 ~175 MeV

1/2 +1/2 3/2 P-wave

3/2 +S-wave30Λ(1405)

1.6

3

Masses for negative−parity ! 24 x 48

Lattice QCD calculation by T. Takahashi
Two Lambda states are observed, whose masses are muchhigher than Λ(1405).
The result indicates that Λ(1405) may not be a 3-quark state.

1.4

T.T. Takahashi, M.O.
PRD81, 034505 (2010)

1.2
1
1670
0.8
0.6

1405

0

0−th state
1−st state

0.1
0.2
0.3
0.4
pionmass squared [lattice unit]

0.5

31

Λ(1405)
Penta-quark picture of Λ*(1405)
1¯ = √1 uds(uū + dd)¯
Λ∗ = √ (S̄ D̄ū + S̄ Ū d)2
2
The orbital angular momenta are all zero : Jπ=1/2Need no spin 3/2- partner
Flavor 1+8, ideal mixing
New Σ* partner?

(B.S. Zou, Σ*(1385) (1/2-))

1
1¯¯ S̄ D̄d,¯ S̄ Ū ū√√Σ =(S̄ D̄ū − S̄ Ū d) =uds(uū − dd),2
2∗

Are many of the “P-wave” hadrons all in S-wave?
ΔM (qqbar-pair) v.s. ΔM (L=1)

32

However, . . .

33

Quark core v.s. Hadron molecule
Most of these multi-quark-like resonances lie close to twohadron threshold(s)f0(980) and a0(980) v.s. KKbar
Λ(1405) v.s. NKbar
X(3872) v.s. DD*bar
Couplings of the “core” quark state with two hadron boundand/or continuum states are important.
Some resonances are dominated by two-hadron components
with significant fraction (sometimes 100%).
“Hadron Molecules” or color-singlet “Hadron Cluster” states“Clustering” is strongly developed at the hadronic thresholds.
Are there Λ(1405)-like baryons with heavy quark(s)?
34Λ(1405) as a moleculeΛ(1405) as a Kbar N “bound” state.

Chiral unitary approaches predict two resonance poles forΛ(1405). (Jido et al., 2003)
They are “generated” by a KbarN bound state and a πΣresonance. (Hyodo, Weise)35

Heavy Exotic Hadrons
New quarkonium-like resonances v.s. open charm thresholds
Coincidences of the newquarkonium-like resonances
and the open charm(bottom) thresholds motivateinterpretations of thosestates as hadronic molecules.
Belle (KEK)

BB*

B*B*

36

Exotic Hadrons - Mesons
X(3872) Takeuchi, Takizawa

37

Exotic Hadrons - Mesons
X(3872) Takeuchi, Takizawa

37

Exotic Hadrons - Mesons
X(3872) Takeuchi, Takizawa

37

A few questions on Heavy exotics
Many mesonic “exotic” resonances have been found at Belleand the other heavy-quark factories.
What can J-PARC do? Different production processes areimportant to reveal exotic natures of resonances.
Are there Λ(1405)-like baryons with heavy quark(s)?
How can we distinguish “exotic” hadrons from the “ordinary”
hadrons?

38

Charmed Deuteron

39

Charm in Medium
Di-baryon and Nuclei with Heavy Quark(s)ΛcN, ΣcN, . . , (charmed deuteron)ΞcN, ΛcΛc, ΛcΣc, . . (doubly charmed deuteron)Charmed hypernucleus (super-nucleus??)
D(*), B(*), J/ψ bound states in nucleus
HQ version of the Kbar-nucleus
Not a new ideaΣc

PRL 39, 1506 (1977)

Ξ’c

Λc
40

Charmed deuteron
H. Bando, S. Nagata, PTP 69, 557 (1983), H. Bando, PTP S81,
197 (1984)

SU(4) extension of the Nijmegen D (HC) model potential is employed.
No K, K* exchanges are allowed for the ΛcN, which results in a weakerYcN potential compared with ΛN.
No 2-body bound state is found.
41

Charmed deuteron
We reexamine the possibility of the YcN and YcYc bound states fromthe modern view points of the heavy quark symmetry and chiralsymmetry.
Advantages of the heavy baryon systems:- The large mass of Yc suppresses the kinetic energy.
- Strong Yc - Y*c channel couplings give extra attractions.
We emphasize the importance of the Σc - Σc* degeneracy under theheavy quark spin symmetry and the couplings of the ΣcN, Σc*N
virtual states to the ΛcN states through the central and tensor forces.
NN (1S0, I=1)

×

NN (3S1-3D1, I=0)

deuteronΛN-ΣN (1S0)×ΛN-ΣN (3S1-3D1)

×ΛΛ-NΞ-ΣΣ (1S0)

H dibaryon

ΛcN-ΣcN-Σ*cN (1S0-5D0)?
?

ΛcN-ΣcN-Σ*cN (3S1-3,5D1)?

ΛcΛc-ΣcΣc-Σ*cΣ*c (0+)

42Charmed deuteron

Our framework:
The Yc-N and Yc-Yc interactions are composed of one-pion or oneboson (π, σ, ρ, ω) exchange potentials.
Heavy-quark spin symmetry, chiral symmetry, and hidden local
symmetry are used to determine the meson-baryon couplings.
The OPE tensor force induces strong mixings of the D-wave ΣcN (S=1)
and Σ*cN (S=1, 2) states, whose thresholds are degenerate in the large
mQ limit.
Tensor coupling

43

Heavy quark symmetry
The heavy quark (c, b) is “inactive” in the heavy-light hadronΣ 1385systems.
Σ c 2518*!
"
S=1 J=1/2
ΣQ = Q ⊕ {ud}f =6!
"∗
S=1 J=3/2
ΣQ = Q ⊕ {ud}f =6!
"
S=0 J=1/2
ΛQ = Q ⊕ [ ud ]f =3̄

(S, f ) = (1/2 3bar)*

Σ*b 5833
Σb 5812Σc 2453Σ 1193
Λ 1116

Λc 2286

Λb 5620(1/2 6)(3/2 6)
S=3/2

S=1/2

44

Heavy quark symmetry
Physics of heavy quark systems is simplified for mQ ≫ ΛQCD
Light quarks do not feel the mass and spin of the heavy quarkin the mQ → ∞ limit.
- asymptotic freedom- suppressed magnetic-gluon coupling
Effective field theory based on the 1/mQ expansion, whichleads to a super-selection rule of the heavy quark velocity.
p µ = mQ v µ + k µ

For small kµ = O(ΛQCD ) ! mQ vµ , the velocity of the heavy quark ispreserved. Then, we can remove the large momentum component
by defining a new effective heavy quark field Qv (x) = eimQ v·x Q(x).

This is a symmetry of QCD in the large mQ regime.
The heavy quark spin is conserved at each velocity. (HQ spinsymmetry)45

Heavy quark symmetry
Effective Lagrangian with the heavy-baryon and light mesons
Heavy baryon Q(qq): qq (di-quark) (S, f )= (0+, 3bar) or (1+, 6)→ (S, f ) = (1/2, 3bar) ⊕ [(1/2, 6) ⊕ (3/2, 6)] degenerate in the HQ limit(S, f ) = (1/2 3bar)(1/2 6)(3/2 6)

Pseudoscalar and vector nonet mesons
Pseudoscalar nonet mesons√

2fGeorgi

Vector nonet mesons
gV
i√
2

46

Heavy quark symmetry
Chiral and Hidden-Gauge symmetries for light quarks/
hadrons
ChiraliΠ(x)transform
SU(3)L×SU(3)R for NG bosons2Σ=e= ξ (x)

Hidden Local Gauge Symmetry: h(x) ∈ SU(3)Light Vector mesons

gV2
47

Heavy quark symmetry
Heavy-Quark-Chiral Effective Lagrangian

Pseudoscalar (π)
Vector (ρ, ω)σA flavor singlet (I=0) scalar σ meson (mσ = 600 MeV) is
introduced. It “simulates” exchanges of two pions correlated in
the I=0, J=0 channel. We assume that the σ meson couples to u
and d quarks, but not to charm.
48

linear sigma model

The mesons couple to the light quarks only.

Σc → Λc + π

OBEPThe Λc-N, Σc-N and Σ*c-N diagonal and transition potentials
are composed of one-pion and/or one-boson (π, σ, ρ, ω)
exchange model.
Note that the Λc (in general the 3bar baryon) does not couple tothe pion (pseudoscalar meson) directly. The other possible
mesons, η and φ, are neglected because they give little
contribution.
Short range part of the potential is implemented by the cutoff
parameters in the form factors.
The monopole form factor for each vertex is taken into
account. F (q) = Λ2 − m2
Λ2 − q 2

The cutoff parameters are chosen in two ways:(1) The universal cutoff for all the mesons(2) The scaled cutoff Λ = m + α ΛQCD (ΛQCD=220 MeV)
50

OBEP
Standard meson exchange potential with monopole form
factors
Neglect O(1/MQ) corrections and the contact terms.

and so on51Λc N: 0+Λc N (1 S0 ) − Σc N (1 S0 ) − Σ∗c N (5 D0 )Diagonal potentials with Λπ = Λσ = Λvec = 1 GeV

ρ

ω
total

σ

(11): Λc N (1 S0 ) ↔ Λc N (1 S0 )

π

ω
total

σ

(22): Σc N (1 S0 ) ↔ Σc N (1 S0 )⇐ (33): Σ∗c N (5 D0 ) ↔ Σ∗c N (5 D0 )18 / 38

π
π

ρ
total

total

ρ

total

Strong tensor mixings due to the pionexchange potentialπωρΛc N (1 S0 ) − Σc N (1 S0 ) − Σ∗c N (5 D0 )One Pion Exchange Only

Λc N (1S0)Σc N (1S0)Σ*c N (5D0)Λc N (1 S0 ) − Σc N (1 S0 ) − Σ∗c N (5 D0 )

Λc N (1 S0 ) − Σc N (1 S0 ) − Σ∗c N (5 D0 )
Λ = m(meson) + α ΛQCD

Λc N (3 S1 − 3 D1 ) − Σc N (3 S1 − 3 D1 ) − Σ∗c N (3 S1 − 3 D1 − 5 D1 )For the ΛcΛc systems, we takeonly the one-pion exchangeinteraction.
Note that there is no πΛcΛccoupling, and thus the bindingcomes only from the channel
coupling effect.
Again the tensor couplingstrength is very strong so that theΣ*cΣ*c channel contribution islarge.

ΛcΛc 1S0

Σ*cΣ*c 5D0Σ*cΣc 5D0

Summary for Charmed DeuteronPossibility of bound Charmed deuteron (ΛcN, or ΛcΛc boundstates) has been studied in the one-boson exchange potential
approach.
The effective Lagrangian is derived from the heavy-quark spinsymmetry for charm quarks as well as chiral symmetry andhidden local symmetry for the light quark sector in order todetermine the couplings of pseudo-scalar and vector mesons to
the heavy baryons.
The short-range part of the potential is parameterized by the
cut-off parameters. The results are sensitive to the choice ofthe cutoff. It is an important and interesting future problem toevaluate the short range part of the BB interaction.
The couplings of the ΣcN and Σc*N (ΣcΣc, Σc*Σc and Σc*Σc*)channels are taken into account and we have found that thetensor couplings to the D wave Σc*N (5D0 etc) states are very
important.
60

Short-range repulsion
Microscopic view of the short-range B-B interactions can beprovided by the quark substructure of the baryons.
The quark Pauli effects for Λc-N, Σc-N, Λc-Λc, do not produce strong
repulsion at short distances.
On the other hand, the color-magnetic interaction (CMI) will givesome repulsion to these channels. A simple evaluation of the CMI
assuming the heavy-quark limit (charm spin decoupled) gives
V(Λc-N) ~ 300 MeV at R=0
V(Σc-N) ~ 100 MeV
V(Λc-Λc) ~ 220 MeV
compared with
V(N-N; 1S0) ~ 450 MeV
V(Λ-N; 1S0) ~ 400 MeV
Work in progress
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Further interests
Other predictions of heavy-quark bound states
DN bound state → Λ*c (1/2-) by Mizutani, Ramos.
DNN may also be bound (Dote, Hyodo, MO).
Dbar N: exotic (pentaquark) bound state by Yamaguchi,
Yasui et al.
J/ψ, ηc bound nuclei:
Weak attraction to N with a (J/ψ, ηc - N) ~ 0.2-0.4 fm
in lattice QCD calculation by Kawanai, Sasaki.
Such an attraction may produce a bound (J/ψ, ηc ) - 4He
nuclei. (Yokota, Hiyama, MO)62

Goals of the Workshop
Questions to be answered
What are the most valuable observables in HQ physics?
@ J-PARC?
What new information does HQ physics give to QCD?
How are HQs different from q?

Personal answer
Heavy baryon spectroscopy → excited states
Exotic heavy meson/baryon states → molecules
Heavy quark in medium → heavy quark/hadron bound nuclei

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