Hadron structure: quarkmodel analysis. A. Valcarce Univ. Salamanca (Spain). Nonexotic multiquark states. Outline. QCD: Hadron physics & constituent quark model Heavy hadrons Heavy baryons: New bottom states, doubly heavy states. Heavy mesons: New opencharm and hidden charm states.
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quarkmodel analysis
A. Valcarce
Univ. Salamanca (Spain)
Hadron structure: quark model analysis
Advances (Exp.) Challenges (Theor.)
Hadron structure: quark model analysis
QCD is the correct theory of the strong interaction. It has been tested to very high accuracy in the perturbative regime. The low energy sector (“strong QCD”), i.e. hadron physics, remains challenging
N. Isgur, Overview talk at N*2000, nuclth/0007008
All roads lead to valence “constituent quarks” and effective forces inspired in the properties of QCD: asymptotic freedom, confinement and chiral symmetry Constituent quark models
Constituent quarks (appropriate degrees of freedom) behave in a remarkably simple fashion (CDF)
Effective forces: confining mechanism, a spinspin force (, ) and a longrange force
The limitations of the quark model are as obvious as its successes. Nevertheless almost all hadrons can be classified as relatively simple configurations of a few confined quarks.
Although quark models differ in their details, the qualitative aspects of their spectra are determined by features that they share in common, these ingredients can be used to project expectations for new sectors.
Hadron structure: quark model analysis
Almost all known hadrons can be described as bound states of qqq or qq:
We have the tools to deepen our understanding of “strong QCD”
Powerful numerical techniques imported from fewbody physics
Faddeev calculations in momentum space[Rept. Prog. Phys. 68, 965(2005)]
Hyperspherical harmonic expansions[Phys. Rev. D 73 054004 (2006)]
Stochastic variational methods[Lect. Not. Phys. M 54, 1 (1998)]
Increasing number of experimental data
Hadron structure: quark model analysis
nnQ
nQQ
QQQ
Hadron structure: quark model analysis
Dn=1 500 MeV
Regularities
CDF, Phys.Rev.Lett.99, 202001 (2007)
1 CLEO
2 Belle
3 BaBar
4 SELEX
5 CDF
Hadron structure: quark model analysis
Roberts et al., arXiV:0711.2492
Valcarce et al., submitted to PRD
DM (MeV)
Exp.
OGE()
OGE +OPE
s
c
Sc(3/2+) – Lc(1/2+)
232
251
217
b
Sc(3/2+) – Sc(1/2+)
64
64
67
Sb(3/2+) – Lb(1/2+)
209
246
205
Sb(3/2+) – Sb(1/2+)
22
25
22
DM (MeV)
Latt.
OGE (+ OPE)
3F (s=0)
cc(3/2+) – cc(1/2+)
75
77 (77)
cc(3/2+) – cc(1/2+)
60
72 (61)
Heavy baryons: I.a. Spin splitting
Double charm baryons no OPE
6F (s=1)
Hadron structure: quark model analysis
Heavy baryons: II. Confinement strength
Valcarce et al., submitted to PRD
[A] Fits the Roper in the light sector
[B] Fits the 1/2– in the light sector
Flavor independence of confinement
Hadron structure: quark model analysis
(1/2+) – (1/2+)6F –3Fqq
CQC Valcarce et al., submitted to PRD
[18] Roberts et al. arXiV:0711.2492
[19] Ebert et al., Phys. Lett. B659, 618 (2008)
Q(3/2+)
Hadron structure: quark model analysis
More than 30 years after the socalled November revolution, heavy meson spectrocospy is being again a challenge. The formerly comfortable world of heavy meson spectroscopy is being severely tested by new experiments
Heavylight mesons (QCD hydrogren)
Heavyheavy mesons
Y(4260) : ??
Y(4385) : 43S1,33D1
Open charm
DsJ(2632) (Selex)
DsJ*(2715) (Belle)
DsJ(2860) (Babar)
.......
X (3940)
Y (3940):23PJ=1,2,3
Z (3940)
Charmonium
Z(4433)
X(3876)
....
–
–
Hadron structure: quark model analysis
2007 Close: “I have always felt that this is an example of where naive quarks models are too naive”
When a qq state occurs in L=1 but can couple to hadron pairs in S waves,
the latter will distort the qq picture. The cs states 0+ and 1+ predicted above the DK (D*K) thresholds couple to the continuum what mixes DK (D*K) components in the wave function
UNQUENCHING THE NAIVE QUARK MODEL
Hadron structure: quark model analysis
Ds1
(2458)
DsJ*
(2317)
2600
2400
2200
Chiral gap
2000
{
jq=3/2
{
1800
jq=1/2
–
–
0
+
2
+
+
0
1
1
Phys. Rev. D73, 034002 (2006)
Bardeen et al.,Phys. Rev. D68, 054024 (2003)
DsJmesons: quarkantiquark pairs ?
Ds1
(2460)
DsJ*
(2317)
D*K
D0K
)
V
e
M
(
E
Ok!
0
2
–
–
+
+
+
0
1
1
Hadron structure: quark model analysis
The effect of the admixture of hidden flavor components in the baryon sector has also been studied. With a 30% of 5q components a larger decay width of the Roper resonance has been obtained. 10% of 5q components improves the agreement of the quark model predictions for the octet and decuplet baryon magnetic moments. The admixture is for positive parity states and it is postulated. Riska et al. Nucl.Phys.A791, 406421 (2007)
From the spectroscopic point of view one would expect the effect of 5q components being much more important for low energy negative parity states (5q S wave)
Takeuchi et al., Phys. Rev. C76, 035204 (2007)
OGE
Dynamically generated resonances UPT
Oset et al., Phys. Rev. Lett. 95, 052301(2005)
Hadron structure: quark model analysis
2200
2100
2100
2000
2000
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1900
1900
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V
V
e
e
1800
1800
M
M
Mesonbaryon Swave thresholds
Capstick and Isgur, Phys. Rev. D34, 2809 (1986)
Mixing of 3q plus MB (5q) a=85 MeV
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N
N
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1700
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4
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4
4
6
6
7
7
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9
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7
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/
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3
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1
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D
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5
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D
D
1
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D
D
D
D
5
5
3
3
L
L
D
D
D
D
N
N
Mesonbaryon threshold effects in the lightquark baryon spectrum
P. González et al., IFICUSAL submitted to PRC
Hadron structure: quark model analysis
–
ccnn
Vijande et al., in progress
Janc et al., Few Body Syst. 35, 175 (2004)
Hadron structure: quark model analysis
Solving the Schrödinger equation forcncn : HH
3
1
3
1
2
4
2
1,2 c
3,4 n
!
Cparity is a good symmetry of the system
Good symmetry states
Cparity=1234
Hadron structure: quark model analysis
Compact fourquark structure cncn (I=0)
Phys. Rev. D76, 094022 (2007)
Hadron structure: quark model analysis
–
–
c
c
c
–
–
–
–
–
–
–
c
n
n
n
n
n
n
n
n
c
n
J/
w
–
–
c
cncn
—
D
n
D
–
–
ccnn
c
c
c
c
D
D
Difference between the two physical systems
Hadron structure: quark model analysis
Many body forces do not give binding in this case
Phys. Rev. D76, 114013 (2007)
Hadron structure: quark model analysis
Hadron structure: quark model analysis
Let me thank the people I collaborated with in the different subjects I covered in this talk
Thanks!
Hadron structure: quark model analysis
See you in the 2010 European FewBody Conference in Salamanca
Hadron structure: quark model analysis
Charmonium: playground of new models
Central potential:
Spinspin interaction:
Barnes et al., Phys. Rev. D72, 054026 (2005)
Spinorbit interaction:
Hadron structure: quark model analysis
3872
DD
cc state ?
cc mass spectrum
Belle, Phys. Rev. Lett. 91, 262001 (2003)
B+ K+ X(3872) K++J/
PDG, M = 3871.2 ± 0.5 MeV; < 2.3 MeV
mD + mD* = (3870.3 ± 2.0)MeV M = (+0.9 ± 2.0)MeV
Production properties very similar to ’(23S1)
Seen in J/ C = +
Belle rules out 0++ and 0–+, favors 1++
CDF only allows for 1++ or 2–+
2–+: is a spinsinglet D wave while J/ is a spintriplet S wave, so in the NR limit the E1 transition
2–+ J/ is forbidden. D and S radial wave functions are orthogonal what prohibits also M1
1++: Expected larger mass and width ( rJ/ violates isospin).
Hadron structure: quark model analysis
Wave function:
–
–
Interaction:
Model predictions:
Hadron structure: quark model analysis