recent developments in c c , c n and c s spectroscopy:
DESCRIPTION
Recent developments in c c , c n and c s spectroscopy: X(3872), D sJ *(2317) + and D s1 *(2457) + . 1) Basic physics. How well q q worked (charmonium e.g.) 2) The X(3872), D sJ * + (2317) and D s1 * + (2457). - PowerPoint PPT PresentationTRANSCRIPT
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Recent developments in cc , cn and cs spectroscopy:
X(3872), DsJ
*(2317)+ and Ds1
*(2457)+.
1) Basic physics. How well qq worked (charmonium e.g.)
2) The X(3872), DsJ
*+(2317) and Ds1
*+(2457).
3) What we are reconsidering. (This is a story in progress…)
Ted BarnesPhysics Div. ORNLDept. of Phys. and Astro., U.Tenn.
HQL2004
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Small qq separation
Large qq separation
basic physics of QCD
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The QCD flux tube (LGT, G.Bali et al; hep-ph/010032)
LGT simulation showing
the QCD flux tube
Q Q
R = 1.2 [fm]
“funnel-shaped” VQQ(R)
Coul. (OGE)
linear conft.(str. tens. = 16
T)
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Charmonium (cc)A nice example of a QQ spectrum.
Expt. states (blue) are shown with the usual L classification.
Above 3.73 GeV:Open charm strong decays(DD, DD* …):broader statesexcept 1D
2 22
3.73 GeV
Below 3.73 GeV: Annihilation and EM decays.
, KK* , cc, , ll..):narrow states.
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s = 0.5538
b = 0.1422 [GeV2]m
c = 1.4834 [GeV]
= 1.0222 [GeV]
Fitted and predicted cc spectrumCoulomb (OGE) + linear scalar conft. potential
model blue = expt, red = theory.
3D3 (3810)
3D2 (3803)
3D1 (3787)
1D2 (3802)
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cc from LGT
exotic cc-H at 4.4 GeV
oops… cc has been withdrawn.
Small L=2 hfs.
What about LGT??? An e.g.: X.Liao and T.Manke, hep-lat/0210030 (quenched – no decay loops)Broadly consistent with the cc potential model spectrum. No radiative or strong decay predictions yet.
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J
DD*MeV
Accidental agreement?X = cc (2 or 2 or …),or a DD* molecule?
MeV
Alas the known = 3D1 cc.
If the X(3872) is 1D cc,an L-excited multiplet is split much more than expected assuming scalar confinement.
n.b.DD*MeV
MeV
Belle Collab. K.Abe et al, hep-ex/0308029;S.-K.Choi et al, hep-ex/0309032, PRL91 (2003) 262001.X(3872) from
KEK
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X(3872) confirmation (from Fermilab)
G.Bauer, QWG presentation, 20 Sept. 2003.
n.b. most recent CDF II: M = 3871.3 pm 0.7 pm 0.4 MeV
CDF II Collab. D.Acosta et al, hep-ex/0312021, PRL to appear
OK, it’s real…n.b. molecule.ne.multiquark
X(3872) also confirmed by D0 Collab. at Fermilab. Perhaps also seen by BaBar
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The trouble with multiquarks: “Fall-Apart Decay” (actually not a decay at all: no H
I)
Multiquark models found thatmost channels showed short distance repulsion:
E(cluster) > M1 + M
2.
Thus no bound states.
Only 1+2 repulsive scattering.
nuclei and hypernuclei
weak int-R attraction allows “molecules”
E(cluster) < M1 + M
2,
bag model:
u2d2s2 H-dibaryon, MH - M
= 80 MeV.
n.b.
hypernuclei exist, so this H was wrong.
Exceptions:
VNN
(R)
2mN
R R
“V
(R)”
2m
Q2q2 (Q = b, c?)
2)
1)
3) Heavy-light
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X(3872)
Belle Collab. K.Abe et al, hep-ex/0308029;S.-K.Choi et al, hep-ex/0309032, PRL91 (2003) 262001.
J
DD*MeV
Accidental agreement?X = cc 2 or 2 or …,or a molecular (DD*) state?
MeV
= 3D1 cc.
If the X(3872) is 1D cc,an L-multiplet is split much more than expected assuming scalar conft.
n.b.DD*MeV
MeV
Charm in nuclear physics???
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cc from the “standard” potential modelS.Godfrey and N.Isgur, PRD32, 189 (1985).
2 3( 3D
2 is a typo)2
The obvious guess, if cc, is 2 or 2 .No open-flavor strong decays: narrow states.
A more conventional possibility: X(3872) = cc?
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Charmonium Options for the X(3872) T.Barnes and S.Godfrey, hep-ph/0311169, PRD69 (2004) 054008. (n.b. Eichten, Lane and Quigg have similar results.)Our approach:
Assume all conceivable cc assignments for the X(3872):
all 8 states in the 1D and 2P cc multiplets.
Nominal Godfrey-Isgur masses were
3D3(3849) 23P
2(3979)
3D2(3838) 23P
1(3953)
3D1(3.82) [(3770)] 23P
0(3916)
1D2(3837) 21P
1(3956)
We assigned a mass of 3872 MeV to each stateand calculated the resulting strong and EM partial widths.
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Experimental R summary (2003 PDG)Very interesting open experimental question:Do strong decays use the 3P
0 model decay mechanism
or the Cornell model decay mechanism or … ?
br
vector confinement??? controversial
ee, hence 1 cc states only.
How do open-flavor strong decays happen at the QCD (q-g) level?
“Cornell” decay model:
(1980s cc papers)(cc) (cn)(nc) coupling from qq pair production by linear confining interaction.
Absolute norm of is fixed!
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The 3P0 decay model: qq pair production with vacuum quantum numbers.
L I = g
A standard for light hadron decays. It works for D/S in b1 .
The relation to QCD is obscure.
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What are the total widths of cc states above 3.73 GeV?
(These are dominated by open-flavor decays.)
< 2.3 MeV
23.6(2.7) MeV
52(10) MeV
43(15) MeV
78(20) MeV
PDG values
X(3872)
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Strong Widths: 3P0 Decay Model
1D
3D3
0.6 [MeV]
3D2
-
3D1
43 [MeV]
1D2
-
DD 23.6(2.7) [MeV]
Parameters are = 0.4 (from light meson decays), meson masses and wfns.
X(3872)
(New strong and EM decay results from Barnes, Godfrey and Swanson, in prep.)
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Strong Widths: 3P0 Decay Model
1F3F
4 9.0 [MeV]
3F3
87 [MeV]
3F2
165 [MeV]
1F3
64 [MeV]
DDDD*D*D*D
sD
s
X(3872)
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Strong Widths: 3P0 Decay Model
33S1
74 [MeV]
31S0
67 [MeV]
3S
DDDD*D*D*D
sD
s
X(3872)
52(10) MeV
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partial widths [MeV](3P
0 decay model):
DD = 0.1 DD* = 32.9 D*D* = 33.4 [multiamp. mode]D
sD
s = 7.8
Theor R from the Cornell model.Eichten et al, PRD21, 203 (1980): 4040
DD
DD*
D*D*
4159
4415
famous nodal suppression of a 33S
1 (4040) cc DD
D*D* amplitudes(3P
0 decay model):
1P1 = 0.056
5P1 = 0.251 = 1P
1
5F1
= 0
std. cc and D meson SHO wfn. length scale
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Strong Widths: 3P0 Decay Model
2D 23D3
148 [MeV]
23D2
93 [MeV]
23D1
74 [MeV]
21D2
112 [MeV]
DDDD*D*D*D
sD
s
DsD
s*
78(20) [MeV]
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partial widths [MeV](3P
0 decay model):
DD = 16.3 DD* = 0.4 D*D* = 35.3 [multiamp. mode]D
sD
s = 8.0
DsD
s* = 14.1
Theor R from the Cornell model.Eichten et al, PRD21, 203 (1980): 4040
DD
DD*
D*D*
4159
4415
std. cc SHO wfn. length scale
D*D* amplitudes:(3P
0 decay model):
1P1 = 0.081
5P1 = 0.036 1P
1
5F1 = 0.141
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E1 Radiative Partial Widths
1D -> 1P
3D3 3P
2 305 [keV]
3D2 3P
2 70 [keV]
3P1
342 [keV]
3D1 3P
2 5 [keV]
3P1
134 [keV]
3P0
443 [keV]
1D2 1P
1 376 [keV]
X(3872)
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If X = 1D cc: Total width eliminates only 3D
1.
Large, ca. 300 – 500 keV E1 radiative partial widths to J and h
c
are predicted for 1D assignments ( 3D3, 3D
2 ) and 1D
2.
If tot
= 1 MeV these are 30% - 50% radiative b.f.s!
The pattern of final P-wave cc states you populate identifies the initial cc state.
If X = 1D2
cc, you are “forced” to discover the hc !
If X = 2P cc:23P
1 and
21P
1 are possible based on total width alone.
These assignments predict weaker but perhaps accessible radiative branches to J, ’ and
c
c’ respectively.
NOT to J states. (E1 changes parity.)
Concl: We cannot yet exclude 5 of the 8 1D and 2P cc assignments. However, we do see how to proceed.
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DD* molecule options
This possibility is suggested by the similarity in mass,
N.A.Tornqvist, PRL67, 556 (1991); hep-ph/0308277.F.E.Close and P.R.Page, hep-ph/0309253, PLB578, 119 (2004).C.Y.Wong, hep-ph/0311088. E.Braaten and M.Kusunoki, hep-ph/0311147, PRD69, 074005 (2004).E.S.Swanson, hep-ph/0311229.n.b. The suggestion of charm meson molecules dates back to 1976:(4040) as a D*D* molecule;(Voloshin and Okun; deRujula, Georgi and Glashow).
XMeV
DD*MeV
(I prefer this assignment.)
n.b.2 Could the signal simply be a cusp due to new DD* channelsopening? (A.Bacher query.) No one has considered this.
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Interesting prediction of molecule decay modes:
E.Swanson, hep-ph/0311299: 1 DoD*o molecule with additional comps. due to rescattering.
J“”J
Predicted total width ca. = expt limit (2 MeV).
Very characteristic mix of isospins: comparable J andJ“”decay modes expected.
Nothing about the X(3872) is input: this all follows from OE and C.I.
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X(3872) summary:
The X(3872) is a new state reported by Belle, CDF and DZERO.
It is seen in only one mode: J .
It is very narrow, < 2.3 MeV.
The limit on is comparable to the observed J. The mass suggests that the X is a deuteronlike DoD*o-molecule.
Naïvely, this suggests a narrow total X width of ca. 50 keV
and 3:2 bfs to DoDo and DoDo.
However, internal rescatter to (cc)(nn) may be important.
This predicts (X) = 2 MeV and remarkable, comparable “isospin violating” b.f.s to Jand J.
The bleedin’ obvious decay mode Jshould be
searched for, to test C(X) and establish whether =
Possible “wrong-mass” cc assignments to 1D and 2P levels can be tested by their (often large) E1 radiative transitions to (cc).
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Where it all started. BABAR: D*sJ
(2317)+ in Ds+
0
D.Aubert et al. (BABAR Collab.), PRL90, 242001 (2003).
M = 2317 MeV (2 Ds channels),
< 9 MeV (expt. resolution)
(Theorists expected L=1 cs states, e.g. JP=0+, but with a LARGE width and at a much higher mass.) …
“Who ordered that !?”
I.I.Rabi (about the - )
Since confirmed by CLEO, Belle and FOCUS.
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And another! CLEO: D*sJ
(2463)+ in Ds*+
0
Since confirmed by BABAR and Belle. M = 2457 MeV.
D.Besson et al. (CLEO Collab.), PRD68, 032002 (2003).
M = 2463 MeV,
< 7 MeV (expt. resolution)
A JP=1+partner of the possibly 0+ D*
sJ(2317)+ cs ?
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(Godfrey and Isgur potential model.) Prev. (narrow) expt. states in gray.
DK threshold
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Experimental D states (PDG 2002) vs Godfrey-Isgur potential model.
Is the same discrepancy evident in the cn sector?
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The new broad D states. The 1+ states are not especially low wrt QM. However the status of the 0+ is unclear. (2 expts. differ by 100 MeV.)
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Theorists’ responses to the new DsJ* states
Approx. 80 theoretical papers have been published since
the discovery. There are two general schools of thought:
1) They are cs quark model mesons, albeit at a much lower mass than expected by the usual NRQPMs. [Fermilab]
2) They are “multiquark” states.
(“DK molecules”) [UT,Oxon,Weiz.]
3) They are somewhere between 1) and 2). [reality]
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M.A.Nowak, M.Rho and I.Zahed,PRD48, 4370 (1993).W.A.Bardeen and C.T.Hill,PRD49, 409 (1994)BEH, PRD68, 054024 (2003).
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2. Multiquark states (DK molecules) [UT,Oxon,Weiz.] T.Barnes, F.E.Close and H.J.Lipkin,
hep-ph/0305025, PRD68, 054006 (2003).
3. reality
Reminiscent of Weinstein and Isgur’s “KK molecules”.
(loop effects now being evaluated)
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L’oops
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Future: “Unquenching the quark model”
Virtual meson decay loop effects,qq <-> M1 M2 mixing.
DsJ
* states (mixed cs <-> DK …, how large is the mixing?)
Are the states close to |cs> or |DK>, or are both basis states important?
A perennial question: accuracy of the valence approximation.
Also LGT-relevant (they are usually quenched too).
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S.Godfrey and R.Kokoski,PRD43, 1679 (1991).
Decays of S- and P-wave D Ds B and Bs flavor mesons.
3P0 “flux tube” decay model.
The L=1 0+ and 1+ cs “Ds” mesons are predicted to Have rather large total widths, 140 - 990 MeV. (= broad tounobservably broad).
Charmed meson decays (God91)
How large are decay loop mixing effects?
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JP = 1+ (2457 channel)
JP = 0+ (2317 channel)
The 0+ and 1+ channels are predicted to have very largeDK and D*K decay couplings.This supports the picture of strongly mixed
|DsJ
*+(2317,2457)> = |cs> + |(cn)(ns)> states.
Evaluation of mixing in progress. Initial estimates for cc …
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L’oops
[ J/ - M1M
2 - J/
3P0 decay model,
std. params. and SHO wfns.
M1M
2 M [J/] P
M1M
2 [J/]
DD
- 30. MeV 0.027
DD*
- 108. MeV 0.086
D*D*
- 173. MeV 0.123
DsD
s - 17. MeV 0.012
DsD
s*
- 60. MeV 0.041
Ds*D
s*
- 97. MeV 0.060
famous 1 : 4 : 7 ratio DD : DD* : D*D*
Sum = - 485. MeV Pcc
= 65.% VERY LARGE mass shift and large non-cc component!
Can the QM really accommodate such large mass shifts??? Other “cc” states?
1/2 : 2 : 7/2 DsD
s : D
sD
s* : D
s*D
s*
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L’oops
[ cc - M1M
2 - cc
3P0 decay model,
std. params. and SHO wfns.
Init.
Sum M P
cc
J/ - 485. MeV 0.65
c - 447. MeV 0.71
2 - 537. MeV 0.43
1
- 511. MeV 0.46
0- 471. MeV
0.53 hc
- 516. MeV 0.46
Aha? The large mass shifts are all similar; the relative shifts are “moderate”.
Continuum components are large; transitions (e.g. E1 radiative) will have to berecalculated, including transitions within the continuum.
Apparently we CAN expect DsJ
-sized (100 MeV) relative mass shifts due to decay
loops in extreme cases. cs system to be considered. Beware quenched LGT!
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Summary and conclusions:1) Three new narrow mesons containing at least cc and cs have been reported:
X(3872) D*sJ(2317)+ D*
sJ(2457)+
2) Theorists expected similar (?) states but at rather different masses. The cs states were expected to have very broad strong decay widths.The interpretation of the new states (qq / two-meson molecules / lin.comb.) is being discussed. Decay loops determine mixing.
Radiative transitions should allow definitive tests of qq assignments.
There are E1 rate predictions for D*sJ Ds
+ andDs* + assuming cs,
analogous to the X(3872) rates we discussed.(e.g. S.Godfrey, hep-ph/0305122, PLB568, 254 (2003).)D*
sJ(2457)+ Ds+ reported recently by Belle; strongly favors J=1, as expected.
3) Useful future measurements: A. Precise E1 cc (CLEO; ’ , (3770) and ) and D*
sJ radiative rates;
B. Strong decay model checks (4040, 4159 DD, DD*; D*D* PWA) (BES,CLEO).
n.b(4415 + ) (at ca. 4440 MeV) a D*sJ source?
(expect few % BFs to D*s0(2317) D*
s and D*s1(2457) Ds)