the new narrow “ dfcp/papers/eps030717.pdfthe new narrow “ d s ” states – a minireview ......

The New Narrow “Ds” States – A minireview

Frank Porter

Caltech

(From the BaBar Collaboration)

Results from:

BaBar (abstract 395, PRL 90 (2003) 242001, A. Palano PIC)

Belle (abstract 570, R. Chistov & K. Trabelsi FPCP 2003)

CLEO (abstract 813, hep-ex/0305100, submitted to PRD,

J. Urheim CIPANP)

CDF (M. Shapiro FPCP 2003)

Two new narrow states (names from presumed quantum numbers, qq̄

model):D∗

sJ(2317)±

DsJ(2460)±1 Frank Porter, 17 July 2003, International Europhysics Conference on High Energy Physics

The Ds Level Scheme

Light quark angular momentum (j), combined with heavy quark spin.

P -wave multiplet

Spin-Orbit Tensor Force

= 0 ...l

= 1l

= 2 ...l

= 1/2j

= 3/2j

+ = 0PJ

+ = 1PJ

+ = 1PJ

+ = 2PJ

3× 2 ×2 states

2×2

4×2 states

1

3

3

5 states

mixing

)2M

ass

(GeV

/c

2

2.2

2.4

2.6

2.8

3

–0 –1 +0 +1 +2 –3 =PJ

DK

K*D

Godfrey/Isgur (1985)Di Pierro/Eichten (2001)ObservedNewly Discovered

Figures: Courtesy of David Williams

Conventional wisdom: P -wave j = 1/2 states heavy enough for isospin-

allowed strong decays to produce large widths. E.g., D∗±s0 → D0K±.

2 Frank Porter, 17 July 2003, International Europhysics Conference on High Energy Physics

The New Narrow State at 2317 MeV in M(Dsπ0)

Mass peak consistent with experimental resolution. Hence Γ < several MeV.

BaBarDs → φπ Ds → K∗Kπ

Ds → KKππ0

Belle preliminary

0

50

100

150

200

250

300

350

0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6

M(Ds π0) - M(Ds)GeV/c

2GeV/c

2

Eve

nts

/5M

eV

π sideband0

D sidebands

CLEO

2.10 2.20 2.30 2.40 2.50 2.60M(Dsπ

0) (GeV/c2)

0

40

80E

vent

s/5M

eV/c

2

80

Data

qq Monte Carlo

(a)


Isospin of State at M = 2317 MeV

Narrow decay width suggests isospin violating decay, I �= 1.

Not seen in D±s π∓, D±

s π±, hence I = 0.

CDF preliminary

]2

Candidates [GeV/c+

πφMass of

1.9 1.92 1.94 1.96 1.98 2 2.02

2N

umbe

r of

Can

dida

tes/

2 M

eV/c

0

500

1000

1500

2000

2500

3000

CDF Run II Preliminary

2RMS: 7.6 MeV/c

-1 ~80 pb’ss+Signal Window: 24600 D

2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3N

umbe

r of

Ent

ries

/ 10

MeV

0

50

100

150

200

250

300

-πs+

D

+πs+

D

CDF Run II Preliminary-1 ~80 pb) > 350 MeV/cπ(tp

2317

M(D ) candidate (GeV)s π

Sensitivity estimated with D∗2 → Dπ modes, relative Ds:D rates.

Working to further quantify using DsJ(2573) → DK for normalization.


D∗sJ(2317)± Spin-Parity

D∗sJ(2317) → Dsπ

0. If parity conserved, then natural JP (hence ∗).BaBar

D∗sJ(2317) → Dsπ

0 helicity angle

distribution consistent with uni-

form; consistent with 0+, or with

isotropic polarization.

Not seen in Dsπ+π− or Dsπ

0π0, which are forbidden for 0+:

CLEO

0.30 0.35 0.40 0.45 0.50 0.550

4

8

12

Eve

nts/

2M

eV/c

2

2317

M(D ) (GeV))-M(Ds s

+ -ππ

BaBar

π πM(D ) (GeV)00s

CDF preliminary

2.25 2.3 2.35 2.4 2.45 2.5N

umbe

r of E

ntri

es /

10

MeV

0

20

40

60

80

100

120

140

160

-π+πs+

D

-π-πs+

D

C DF R un II P reliminary-1 ~80 pb

+π+πs+

D

> 350 MeV/ct

Minimum P ion p

2317

ππ) (GeV)sM(D


D∗sJ(2317)± Spin-Parity (continued)

If D∗sJ(2317) is spin zero,

then decay to Dsγ is for-

bidden. Not seen.

Belle preliminary B → DDsγ

0

0

2.2 2.3 2.4 2.5 2.

(c)

M(Ds ) (GeV)γ

2

23172317

CLEO

0.00 0.10 0.20 0.30 0.40 0.50 0.60M(Dsγ)-M(Ds) (GeV/c2)

101

102

103

Eve

nts/

5MeV

/c2 (a)2317

BaBar

Look forward to angular analysis in B → DD∗sJ (2317) decays.


Observation of D∗sJ(2317) in Exclusive B → DDsπ

0 Decays(Belle preliminary, 124 × 106BB̄, D+

s → φπ+, K̄∗0K+, K0SK+)

0

10

20 (a)

0-0.1-0.2 0.1 0.2

Eve

nts

/10

Me

V

E (GeV)∆

0

10

20 (a)

2.2 2.3 2.4 2.5 2.6

Events

/10 M

eV

M(D ) (GeV)s

0π

B Decay channel Yield (∆E) B(10−4)

D̄0D∗sJ(2317), D∗

sJ(2317) → Dsπ0 13.7+5.1

−4.5 8.1+3.0−2.7 ± 2.4

D̄−D∗sJ(2317), D∗

sJ(2317) → Dsπ0 10.3+3.9

−3.1 8.6+3.3−2.6 ± 2.6

D̄0D∗sJ(2317), D∗

sJ(2317) → Dsγ 3.4+2.8−2.2 2.4+2.0

−1.5(< 5.7)

D̄−D∗sJ(2317), D∗

sJ(2317) → Dsγ 2.3+2.5−1.9 2.6+2.8

−2.2(< 7.1)

cf (RPP 2002): B+ → D̄0D+s = (1.3 ± 0.4)%, B0 → D−D+

s = (0.8 ± 0.3)%;

B+ → D̄0D∗+s = (0.9 ± 0.4)%, B0 → D−D∗+

s = (1.0 ± 0.5)% .


D∗sJ(2317)± Summary

Quantity BaBar Belle CLEO

Dataset (fb−1) 91 87 13.5

Ds Modes φπ, K∗K φπ φπ

Mass (MeV) 2316.8 ± 0.4 ± 3 2317.2 ± 0.5 ± 0.9 2318.5 ± 1.2 ± 1.1

M(2317) − M(Ds) (MeV) 348.4 ± 0.4 ± 3 348.7 ± 0.5 ± 0.7 350.0 ± 1.2 ± 1.0

Width (MeV, 90% C.L.) < 10 † < 7

B(Dsπ+π−)/B(Dsπ

0) (90% C.L.) < 0.019B(Dsγ)/B(Dsπ

0) (90% C.L.) < 0.05 < 0.052B(D∗

sπ0)/B(Dsπ

0) (90% C.L.) < 0.11B(D∗

sγ)/B(Dsπ0) (90% C.L.) < 0.059

σ·B(D∗sJ→Dsπ

0)σ(Ds)

(p > 3.5 GeV) (7.9 ± 1.2 ± 0.4) × 10−2

† σ = 7.6 ± 0.5 MeV consistent with resolution.

I = 0 favored (Narrow width to Dsπ0, CDF search in Dsπ

±)

JP natural, consistent with 0+


The New Narrow State at 2460 MeV in Dsπ0γ

Mass peak consistent with experimental resolution. Hence Γ < several MeV.

CLEO(a)

(b)

M(Dsγπ0) - M(Dsγ) (GeV/c2)

Eve

nts

/ 5 M

eV/c

2

0

10

20

0

10

20

0.1 0.2 0.3 0.4 0.5 0.6

D*

D*

s

s

region

sideband region

Belle preliminary

0

20

40

60

80

100

0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6

M(Ds* π0) - M(Ds*)GeV/c

2

Eve

nts

/5M

eV D

regions*

sidebandπ0

BaBar

preliminary

D

regions

sD sideband*

*


Reflection (Cross-feed) Ambiguity

∆M(DsJ(2460)−D∗s(2112)) ∼ ∆M(D∗

sJ(2317)−Ds) ∼ 350 MeV

→ Feed-up of D∗sJ(2317) to DsJ(2460) peak possible by adding a ran-

dom photon consistent with D∗s(2112) → Dsγ.

→ Feed-down of DsJ(2460) to D∗sJ(2317) peak possible by neglecting

the photon in the D∗s(2112) → Dsγ transition.

⇒ Ambiguity in DsJ(2460) decays: Is it DsJ(2460) → D∗s(2112)π0

or DsJ(2460) → D∗sJ(2317)γ?

BaBar/Belle/CLEO all correct for cross-feeds under the DsJ(2460) → D∗s(2112)π0 hy-

pothesis.


Study of Cross-feed Ambiguity (BaBar preliminary)Dsπ

0γ: The M(Dsγ) vs M(Dsπ0) scatter plot.2460 boundary

Data Monte Carlo

Projections with linear background subtraction:Is it DsJ(2460) → D∗

s(2112)π0? Is it DsJ(2460) → D∗sJ(2317)γ?

Conclusion: Much better fit to DsJ (2460) → D∗s(2112)π0


DsJ(2460) Spin-Parity

Observed in DsJ(2460) → Dsγ, hence J �= 0.

0

5

10

15

20

25

30

35

40

45

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8M(Ds γ) - M(Ds)

GeV/c2

Eve

nts

/5M

eV

Belle preliminary; Continuum

No DsJ(2317) seen (forbidden for spin 0)

N(DsJ(2460) → Dsγ) = 152 ± 18 ± 11

Rules out J = 0

Helicity angle in DsJ(2460) → D∗s(2112)π0, D∗

s(2112)π0 → Dsγ (BaBar preliminary)Inconsistent with JP = 0−. [nb: no prediction for 1+, 2−.]

D (2460)

D (2112)*s

sJ

s

0

D

.

γθ

π


Angular analysis in B → DDsJ(2460) → DDsγ (Belle preliminary)

0

0

2.2 2.3 2.4 2.5 2.

(c)

M(Ds ) (GeV)γ

2 B → DDsγ

B(B → DDsJ(2460) → DDsγ)

=(6.7+1.3

−1.2 ± 2.0) × 10−4

B(DsJ (2460) → Dsγ)

B(DsJ (2460) → D∗sπ

0)= 0.38 ± 0.11 ± 0.04

0

2

4

6

8

10

12

-1 -0.5 0 0.5 1

cos(θDsγ)

Eve

nts

B → DDsJ (2460) → DDsγ

Data = points with errorsSpin 1 = histogram; Spin 2 = dashed line.Consistent with sin2 θ, as expected for 1+


Observation in Exclusive B Decays (Belle preliminary)

124 × 106BB̄

B → DD(∗)sJ , D → Kπ, Kππ, Kπππ, Ds → φπ, K̄∗0K+, K0

SK+

0

10

20 (a)

0

10

(b)

0

10

20

-0.2 -0.1 0 0.1 0.2

(c)

∆E (GeV)

Events/(0.01 GeV)

0

10

20 (a)

0

10

20 (b)

0

20

2.2 2.3 2.4 2.5 2.6

(c)

M(DsJ) (GeV/c2)

Events/(0.01 GeV)

M(DM(D

M(DM(D

M(DM(D

*

s )

0π

γ

s

s

π0)

)


Exclusive B Decays (Belle preliminary)

B Decay channel Yield (∆E) B(10−4)

D̄0DsJ(2460), DsJ(2460) → D∗sπ

0 7.2+3.7−3.0 11.9+6.1

−4.9 ± 3.6

D−DsJ(2460), DsJ(2460) → D∗sπ

0 11.8+3.8−3.2 22.7+7.3

−6.2 ± 6.8

D̄0DsJ(2460), DsJ(2460) → Dsγ 19.1+5.6−5.0 5.6+1.6

−1.5 ± 1.7

D−DsJ(2460), DsJ(2460) → Dsγ 18.5+5.0−4.3 8.4+2.4

−2.2 ± 2.5

D̄0DsJ(2460), DsJ(2460) → D∗sγ 4.4+3.8

−3.3 3.1+2.7−2.3(< 7.5)

D−DsJ(2460), DsJ(2460) → D∗sγ 1.1+1.8

−1.2 1.3+2.0−1.4(< 4.6)

D̄0DsJ(2460), DsJ(2460) → Dsπ0 < 2.4 < 2.2

D−DsJ(2460), DsJ(2460) → Dsπ0 < 2.4 < 2.8

D̄0DsJ(2460), DsJ(2460) → Dsπ+π− < 4.0 < 2.4

D−DsJ(2460), DsJ(2460) → Dsπ+π− < 2.5 < 2.0


DsJ(2460) Summary

Quantity BaBar Belle CLEO

Dataset (fb−1) 91 87 13.5

N(D∗sπ

0, D∗s → Dsγ) 127 ± 22 126 ± 25 ± 24 41 ± 12

Mass (MeV) 2457.0 ± 1.4 ± 3 2456.5 ± 1.3 ± 1.1 2463.6 ± 1.7 ± 1.2

M(2460) − M(D∗s) (MeV) 344.6 ± 1.2 ± 3 344.1 ± 1.3 ± 0.9 351.2 ± 1.7 ± 1.0

Width (MeV, 90% C.L.) † † < 7B(Dsπ

+π−)B(D∗

sπ0) (90% C.L.) < 0.08B(Dsγ)B(D∗

sπ0) (90% C.L.) 0.63 ± 0.15 ± 0.15 < 0.49B(D∗

sγ)B(D∗

sπ0) (90% C.L.) < 0.16B(DsJ (2317)∗γ)

B(D∗sπ0) (90% C.L.) < 0.58

† Width of mass peak is consistent with resolution.

JP �= 0±, consistent with 1+.

Not seen in Dsπ±, Dsπ

+π− modes in CDF. Not seen in Dsπ+π− in B decays in Belle.


Production Rates (pCM > 3.5 GeV)CLEOσ·B(D∗+

sJ →D+s γ)

σ(D+s )

= 0.59 ± 0.03 ± 0.01

σ·B(D∗sJ(2317)+→D+

s π0)σ(D+

s )= (7.9 ± 1.2 ± 0.4) × 10−2

σ·B(DsJ(2460)+→D∗+s π0)

σ(D+s )

= (3.5 ± 0.9 ± 0.2) × 10−2

Belle Preliminary

σ·B(DsJ(2460)+→D∗+s π0)

σ·B(D∗sJ(2317)+→D+

s π0)= 0.26 ± 0.05 ± 0.06

σ·B(DsJ(2460)+→D+s π0)

σ·B(D∗sJ(2317)+→D+

s π0)< 0.06 (90% C.L.)


Summary

Two new narrow states have been observed with cs̄ content:D∗

sJ(2317) and DsJ(2460).They are consistent with being 0+ and 1+ states, respectively.

Their masses are lower than consensus expectation in cs̄ spectroscopy.

Mass of DsJ(2460) on margin of inconsistency among experiments:

BaBar 2457.0 ± 1.4 ± 3

Belle 2456.5 ± 1.3 ± 1.1

CLEO 2463.1 ± 1.7 ± 1.2Weighted Average∗ 2459.2 ± 1.2

∗ Adding systematic and statistical uncertainties in quadrature; neglect-ing possible correlations (eg, from D∗

s mass uncertainty of 0.7 MeV).χ2 probability for consistency is 3%.

For mass difference, weighted average is 346.6± 1.2, with 2% consistency.(Removes correlated D∗

s mass uncertainty).

More results expected soon!18 Frank Porter, 17 July 2003, International Europhysics Conference on High Energy Physics

the new narrow “ dfcp/papers/eps030717.pdfthe new narrow “ d s ” states – a minireview ......

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