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New Spectroscopy of Heavy Mesons. Fulvia De Fazio INFN - Bari. How to ( try to ) understand the properties of recently discovered states using the heavy quark limit. Collaborators : P. Colangelo , R. Ferrandes , S. Nicotri , A. Ozpineci , M. Rizzi. Open charm/beauty states.

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New spectroscopy of heavy mesons

New SpectroscopyofHeavyMesons

Fulvia De Fazio

INFN - Bari

Howto (tryto) understand the propertiesofrecentlydiscoveredstates

using the heavy quark limit

Collaborators: P. Colangelo, R. Ferrandes, S. Nicotri, A. Ozpineci, M. Rizzi

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

Open charm/beauty states

  • D0(2308), D’1(2440)

  • Ds0*(2317), D’s1(2460)

  • D(2550), D(2600), D(2750), D(2760)

  • DsJ(2632)

  • DsJ(2860), DsJ(2710), DsJ(3040)

  • B1(5734), B*2(5738)

  • Bs1(5830), B*s2(5840)

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

Open charm/beauty states

  • D0(2308), D’1(2440)

  • Ds0*(2317), D’s1(2460)

  • D(2550), D(2600), D(2750), D(2760)

  • DsJ(2632)

  • DsJ(2860), DsJ(2710), DsJ(3040)

  • B1(5734), B*2(5738)

  • Bs1(5830), B*s2(5840)

Seenonlyby SELEX, neverconfirmed

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

Open charm/beauty states

  • D0(2308), D’1(2440)

  • Ds0*(2317), D’s1(2460)

  • D(2550), D(2600), D(2750), D(2760)

  • DsJ(2632)

  • DsJ(2860), DsJ(2710), DsJ(3040)

  • B1(5734), B*2(5738)

  • Bs1(5830), B*s2(5840)

Seenonlyby SELEX, neverconfirmed

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

Hadronscontaining a single heavy quark Q

Spinof the heavy quark and of the light degreesoffreedom

decoupled in the mQ→ ∞limit

Spinsymmetry

angularmomentum

of the light degreesoffreedom (conserved)

spin

Mesonsclassifiedasdoublets the membersofwhichhave

The heavy quark flavourbecomesirrelevantasmQ→ ∞

possibilitytorelate charm and beauty hadronproperties

Flavoursymmetry

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

HQ limitformesondoublets and strong decaysto light pseudoscalars

The twostateswithin a givendoublet are degenerate

Theyhave the same total width

The sum of the partialwidthsof a state in a doubletto a state in anotherdoublet

withemissionof a light mesonis the samefor the twostatesof a doublet

Spinsymmetrypredicts the ratiosofpartialdecaywidthsfor a given state

Partialdecaywidths are independent on the HQ flavour

Mass splittingsamong the doublets are independentof the HQ flavour

Spin

symmetry

Flavour

symmetry

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

Qqmultiplets

D-wavedoublets:

(D’(s)2,D(s)3), (B’(s)2,B(s)3)

(D*(s)1,D(s)2), (B*(s)1,B(s)2)

P-wavedoublets:

(D(s)1,D*(s)2), (B(s)1,B*(s)2)

(D*(s)0,D’(s)1), (B*(s)0,B’(s)1)

fundamentaldoublet: (D(s),D*(s)), (B(s),B*(s))

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

Qqmultiplets

Strong transitionsbetweenmultiplets

+ pseudoscalar meson

d-wave transition

mesons are expectedtobenarrow

+ pseudoscalarmeson

s-wave transition

mesons are expected to be broad

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmultiplets

Low lyingRad. Excitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lying

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lying

D*K threshold

D K threshold

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(2860)

  • DiscoveredbyBaBarCollab.

  • Reconstructed in

  • and in

BaBar Collab., PRL 97 (06) 222001

Quantum numberassignmentrequired in ordertoidentifyit

Possibilities: - low lying state notyetobserved

- radialexcitationofanalreadyobserved state

Onlystatesthat can decayto the observed mode DK are allowed

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

forbidden

forbidden

forbidden

forbidden

forbidden

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

allowed

forbidden

forbidden

allowed

allowed

forbidden

forbidden

allowed

allowed

forbidden

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(2710)

Belle Collab.: analysisof the mode

New resonance decaying to D0K+ with:

implies P=-1

J=0

J=1

J=2

JP=1-favoured

A broadstructure at M=2688 MeVwithG=112 MeV

wasfoundbyBaBar in the DK mass distribution

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(2860) & DsJ(2710)

predictions on alloweddecayrates can help todistinguishamong the variouspossibilities

HQ limit: the membersof the doublets are describedbyeffectivefields:

L=0

L=1

L=2

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(2860) & DsJ(2710)

Interactionswith the emissionof a light pseudoscalarmesondescribedbyeffectiveLagrangianterms

H

H p

S

H p

T

H p

X

H p

X’

H p

Analogoustermsdescribeinteractionsinvolvingradialexcitationdoublets:

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(2860) : resultsforwidthratios

P. Colangelo, S. Nicotri, FDF

PLB 642, 48

1

2

3

4

5

Would explain the observed narrowness

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(2860)

Oursupportedoption:

5

  • Signalexpected in D*K

  • Smallsignalexpectedalso in Ds 

In this case the smallwidth can beattributedto the suppression

due to the kaonmomentumfactor:

f-wave transition

Assuming the experimentally measured width would predict

in the typical range of these couplings

The spin 2 partner coulddecay in p-wave due to the effectof 1/mQcorrections

mayescape detection

Ourconclusion:

DsJ(2860) is likely to be a JP=3- state

ShoulddecaytoD*K

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

IdentifyingDsJ(2710) throughitsdecaymodes

P. Colangelo, S. Nicotri, M. Rizzi, FDF

Phys. Rev. D77, 014012

the dependence on the (unknown) couplings drops out

The D*K decay is the signal that must be investigated

in order to distinguish the two possible assignments

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

BaBarAnalysisofD*Kfinalstates

  • D*Kinvariant mass spectrum

  • (background-subtracted)

  • angularanalysis

Three peaks are visible:

The angulardistributionisconsistentwith

the expectationsforstateswithnaturalparity

(0+,1-,2+,3-,…) for Ds1(2710) and DsJ(2860)

BaBar, PRD80 (09 )092003

excludedby the observation

of the D*K mode

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

BaBarAnalysisofD*Kfinalstates

  • D*Kinvariant mass spectrum

  • (background-subtracted)

  • angularanalysis

Three peaks are visible:

The angulardistributionisconsistentwith

the expectationsforstateswithnaturalparity

(0+,1-,2+,3-,…) for Ds1(2710) and DsJ(2860)

BaBar, PRD80 (09 )092003

excludedby the observation

of the D*K mode

tobediscussedlater…

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

BaBarAnalysisofD*Kfinalstates

Branching fractions

Supports the identification of

Ds1(2710) with

23S1 (first radial excitation of Ds*)

Does not support or discard unambiguously any interpretation:

still to be understood

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmesons

BaBarobservesfournewstateswith charm and withoutstrangeness:

BaBar, PRD 82 (10) 111101

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmesons

Studyof the distribution in the helicity angle qHfor the final state D*p

BaBar, PRD 82 (10) 111101

Angle between the primaryp and the slow pfromD*decay

Godfrey & Isgur (85)

  • Consistentwithassignementsof

  • NaturalparityforD*(2600)

  • JP=0+for D(2550)

  • Comparisonwithpotentialmodel

  • Seemsto indicate that

  • (D(2750),D*(2760)) are L=2 states

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmesons

BaBarobservesfournewstateswith charm and withoutstrangeness:

BaBar, PRD 82 (10) 111101

likelytobe the radialexcitationsof

(D,D*)

likelytobe L=2 states

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmultiplets

Low lyingRad. Excitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmesons

BaBar, PRD 82 (10) 111101

Experimentalratios:

Theseratiostogetherwithmasses and widths can beusedtocheck the BaBarassignments

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmesons

Branching fractionRatio

IdentifyingD*(2600) with the first radialexcitationof D*0

weobtain:

whileBaBarfinds:

P. Colangelo & FDF, in preparation

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmultiplets: whichstates can decaybothtoDp and D*p?

Low lyingRad. Excitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

cqmultiplets: whichstates can decaybothtoDp and D*p?

Branching fractionratiosfor the otherthreepossibilities:vs the mass of the decayingmeson

No assignmentto a mesonof mass 2600 MeV

wouldreproduce the expresult:

Either HQ symmetryisstronglyviolated

or a revisionof the experimentalanalysis

isrequired

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(3040)

The onlyadditional information isthatitdecays→ D*K YES

→ DK NO

JP=1+, 2-, 3+,…

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

csmultiplets

Low lyingRadexcitations

wouldimplyan (unlikely)

mass inversionifDsJ(2860)

hasbeenproperlyplaced

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(3040): howto discriminate among the fourpossibilities?

  • info fromRelativistic Quark Model (RQM)

  • Allowed strong decays:

  • - toD*(s) + light pseudoscalarmeson

  • D*K, D*s

  • - tomembersofhigherdoublets + a light pseudoscalarmeson

  • D*0K, D*s0 , D’1K

  • D1K, D*2K

  • - to D(s) + a light vectormeson

  • DK*, Ds

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(3040): howto discriminate among the fourpossibilities?

  • decays in s-wavetoD*K, Ds* (broader), has the largest R1 ,

  • the largestwidthto light vectormesons

P. Colangelo , FDF

PRD81, 094001

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(3040): howto discriminate among the fourpossibilities?

  • decays in s-wavetoD*K, Ds* (broader), has the largest R1 ,

  • the largestwidthto light vectormesons

P. Colangelo , FDF

PRD81, 094001

  • the two 2-statesshouldnotbeobserved in the decayto light vectormesons

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(3040): howto discriminate among the fourpossibilities?

  • decays in s-wavetoD*K, Ds* (broader), has the largest R1 ,

  • the largestwidthto light vectormesons

P. Colangelo , FDF

PRD81, 094001

  • the two 2-statesshouldnotbeobserved in the decayto light vectormesons

  • Ds2 cannotdecayto D1K butshouldhave the largestwidthto D2*K

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(3040): howto discriminate among the fourpossibilities?

  • decays in s-wavetoD*K, Ds* (broader), has the largest R1 ,

  • the largestwidthto light vectormesons

P. Colangelo , FDF

PRD81, 094001

  • the two 2-statesshouldnotbeobserved in the decayto light vectormesons

  • Ds2 cannotdecayto D1K butshouldhave the largestwidthto D2*K

  • look at the featuresof the spin partner

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

DsJ(3040): howto discriminate among the fourpossibilities?

  • decays in s-wavetoD*K, Ds* (broader), has the largest R1 ,

  • the largestwidthto light vectormesons

P. Colangelo , FDF

PRD81, 094001

  • the two 2-statesshouldnotbeobserved in the decayto light vectormesons

  • Ds2 cannotdecayto D1K butshouldhave the largestwidthto D2*K

  • look at the featuresof the spin partner

F. De Fazio INFN Bari


New spectroscopy of heavy mesons

Concludingremarks

  • - all the observedcsstatesclassifiedasordinarymesons

  • DsJ(2700)identifiedwith D*’s

  • DJ(2600)mostlikelyits non strange partner: BR ratiotobereconsidered

  • Stilltobeunderstood: DsJ(2860) (JP = 3- ?)

  • DsJ(3040) variousalloweddecaymodesmay help in the classification

  • D(2750) and D(2760) : probably L=2 states

F. De Fazio INFN Bari