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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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slide1

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

slide2

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

slide3

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

slide4

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

slide5

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

slide6

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

slide7

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

slide8

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

slide9

cqmultiplets

Low lyingRad. Excitations

F. De Fazio INFN Bari

slide10

csmultiplets

Low lying

F. De Fazio INFN Bari

slide11

csmultiplets

Low lying

D*K threshold

D K threshold

F. De Fazio INFN Bari

slide12

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

slide13

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari

slide14

csmultiplets

Low lyingRadexcitations

forbidden

forbidden

forbidden

forbidden

forbidden

F. De Fazio INFN Bari

slide15

csmultiplets

Low lyingRadexcitations

allowed

forbidden

forbidden

allowed

allowed

forbidden

forbidden

allowed

allowed

forbidden

F. De Fazio INFN Bari

slide16

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

slide17

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari

slide18

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari

slide19

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

slide20

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

slide21

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

slide22

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

slide23

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

slide24

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

slide25

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

slide26

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

slide27

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari

slide28

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari

slide29

cqmesons

BaBarobservesfournewstateswith charm and withoutstrangeness:

BaBar, PRD 82 (10) 111101

F. De Fazio INFN Bari

slide30

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

slide31

cqmesons

BaBarobservesfournewstateswith charm and withoutstrangeness:

BaBar, PRD 82 (10) 111101

likelytobe the radialexcitationsof

(D,D*)

likelytobe L=2 states

F. De Fazio INFN Bari

slide32

cqmultiplets

Low lyingRad. Excitations

F. De Fazio INFN Bari

slide33

cqmesons

BaBar, PRD 82 (10) 111101

Experimentalratios:

Theseratiostogetherwithmasses and widths can beusedtocheck the BaBarassignments

F. De Fazio INFN Bari

slide34

cqmesons

Branching fractionRatio

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

weobtain:

whileBaBarfinds:

P. Colangelo & FDF, in preparation

F. De Fazio INFN Bari

slide35

cqmultiplets: whichstates can decaybothtoDp and D*p?

Low lyingRad. Excitations

F. De Fazio INFN Bari

slide36

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

slide37

DsJ(3040)

The onlyadditional information isthatitdecays→ D*K YES

→ DK NO

JP=1+, 2-, 3+,…

F. De Fazio INFN Bari

slide38

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari

slide39

csmultiplets

Low lyingRadexcitations

F. De Fazio INFN Bari

slide40

csmultiplets

Low lyingRadexcitations

wouldimplyan (unlikely)

mass inversionifDsJ(2860)

hasbeenproperlyplaced

F. De Fazio INFN Bari

slide41

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

slide42

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

slide43

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

slide44

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

slide45

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

slide46

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

slide47

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

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