Spectroscopy highlights from Run I and II at LHCband outlook for the upgrade

Marian StahlPhysikalisches Institut, Heidelberg University

Implications of LHCb measurements and future prospectsOctober 16th, 2018

gMot

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]2 cM

ass

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0(3050)cΩ0(3066)cΩ0(3090)cΩ0(3119)cΩ

cΩ*cΩ

(2S)cΩ*(2S)cΩ

0cΩ1cΩ 1cΩ 2cΩ

2cΩ

(2P)0cΩ (2P)1cΩ(2P)1cΩ (2P)2cΩ

(2P)2cΩ

(1D)1cΩ (1D)1cΩ (1D)2cΩ(1D)2cΩ (1D)3cΩ

(1D)3cΩ

L

qq'j

PJ

S1

+

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S1

+

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P0

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[PRL 118 182001 (sup)]

[CERN-THESIS-2018-176]

Hadron spectroscopy(Experiment)

“Bread and butter” aspect:input/background for many SM/NPmeasurements like γ, LFU tests ...

QCD Phenomenology Interpretations

m,ΓJP , B· · ·

expected spectrumformalisms . . .

vs.

Greater challenge: link QCD’s pure Yang-Mills sector to observationsHadronic spectrum is the prime observable of QCD

gHad

ron

spec

trosc

opy

atLH

Cb

2 / 15

PV

~pXb

(p/K+)

π+

K−flight di

stance

π−IPπ−

Xb decay vertexXc decay vertex

3 Excellent mass-, momentum-, vertex- and decay time resolutionHighly efficient track reconstruction at low fake rate down to low pTFast and efficient topological selection of b and c decays

3 Excellent particle identificationHigh purity hadronic final states

3 Flexible, offline quality software trigger3 Huge samples of b and c hadrons

All types of hadrons are produced, incl. b baryons and excited statesLHCb is a b baryon factory! ≈ 2M (180k) reco’d and selected Λ0

b → Λ+c µ

−νµ (Λ0

b → Λ+c π

−) per fb−1 @ 13 TeV

Large samples of exclusive decays foramplitude analyses

3 Upgrade: no hardware trigger, resolutions improve,instantaneous luminosity increases

LHCb has unique potential for spectroscopy

[CERN-THESIS-2018-176]

[LHCb-PUB-2018-009]

gD0→

K∓

π±

π±

π∓

ampl

itude

anal

ysis

3 / 15

D0 → K∓π±π±π∓ amplitudes input to γ and charm mixing measurementsSpectroscopy: light hadronic spectrum crucial for modelling non-perturbative QCDChallenges: broad states, interference, threshold effects, model complexityDouble tag method: B0 → D∗+µ−νµ with D∗+ → D0π+. Still a huge sample!

140 145 150∆m [ MeV/c2]

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RS data

D0→K−π+π+π−

Combinatorial

140 145 150∆m [ MeV/c2]

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WS data

D0→K+π−π−π+

CombinatorialMistag

Cabibbo favoured

Nsig ≈ 890k

Doubly Cabibbosuppressed

Nsig ≈ 3030

[EPJC 78 (2018) 443]

gD0→

K∓

π±

π±

π∓

ampl

itude

anal

ysis

4 / 15

Resonance structure dominated by axial resonances; fit fraction ofD0 → K0(1460)−π+ ≈ 4% with K0(1460)− → K−π+π−

Spectroscopic highlight: quasi model independent partial wave analysis (QMIPWA)of the kaons first radial excitation K0(1460)−

1 2 3sK−π+π−

[GeV2/c4

]0246810121416182022

×103

Entries/

(0.03GeV

2 /c4)

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0 0.5 1Re (A)

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)

m = 1.14 GeV/c2

m = 1.64 GeV/c2

LHCb

Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018)

K (1460) I (JP ) = 12 (0

−)

OMITTED FROM SUMMARY TABLEObserved in K ππ partial-wave analysis.

K (1460) MASSK (1460) MASSK (1460) MASSK (1460) MASS

VALUE (MeV) DOCUMENT ID TECN CHG COMMENT

• • • We do not use the following data for averages, fits, limits, etc. • • •∼ 1460 DAUM 81C CNTR − 63 K− p → K− 2πp

∼ 1400 1 BRANDENB... 76B ASPK ± 13 K± p → K+2πp

1Coupled mainly to K f0(1370). Decay into K∗(892)π seen.

K (1460) WIDTHK (1460) WIDTHK (1460) WIDTHK (1460) WIDTH

VALUE (MeV) DOCUMENT ID TECN CHG COMMENT

• • • We do not use the following data for averages, fits, limits, etc. • • •∼ 260 DAUM 81C CNTR − 63 K− p → K− 2πp

∼ 250 2 BRANDENB... 76B ASPK ± 13 K± p → K+2πp

2Coupled mainly to K f0(1370). Decay into K∗(892)π seen.

K (1460) DECAY MODESK (1460) DECAY MODESK (1460) DECAY MODESK (1460) DECAY MODES

Mode Fraction (Γi /Γ)

Γ1 K∗(892)π seen

Γ2 K ρ seen

Γ3 K∗0(1430)π seen

K (1460) PARTIAL WIDTHSK (1460) PARTIAL WIDTHSK (1460) PARTIAL WIDTHSK (1460) PARTIAL WIDTHS

Γ(K∗(892)π

)Γ1Γ

(K∗(892)π

)Γ1Γ

(K∗(892)π

)Γ1Γ

(K∗(892)π

)Γ1

VALUE (MeV) DOCUMENT ID TECN COMMENT

• • • We do not use the following data for averages, fits, limits, etc. • • •∼ 109 DAUM 81C CNTR 63 K− p → K− 2πp

Γ(K ρ

)Γ2Γ

(K ρ

)Γ2Γ

(K ρ

)Γ2Γ

(K ρ

)Γ2

VALUE (MeV) DOCUMENT ID TECN COMMENT

• • • We do not use the following data for averages, fits, limits, etc. • • •∼ 34 DAUM 81C CNTR 63 K− p → K− 2πp

Γ(K∗

0(1430)π)

Γ3Γ(K∗

0(1430)π)

Γ3Γ(K∗

0(1430)π)

Γ3Γ(K∗

0(1430)π)

Γ3VALUE (MeV) DOCUMENT ID TECN COMMENT

• • • We do not use the following data for averages, fits, limits, etc. • • •∼ 117 DAUM 81C CNTR 63 K− p → K− 2πp

HTTP://PDG.LBL.GOV Page 1 Created: 6/5/2018 18:59

Table 4: Table of fit fractions and coupling parameters for the component involving theK1(1270)−

meson, from the fit performed on the RS decay D0 → K−π+π+π−. The coupling parametersare defined with respect to the K1(1270)

− → ρ(770)0K− coupling. For each parameter, the firstuncertainty is statistical and the second systematic.

K1(1270)− m0 = 1289.81± 0.56± 1.66MeV/c2; Γ0 = 116.11± 1.65± 2.96MeV/c2

Partial Fractions [%] |g| arg(g)[o]

ρ(770)0K− 96.30± 1.64± 6.61ρ(1450)0K− 49.09± 1.58± 11.54 2.016± 0.026± 0.211 −119.5± 0.9± 2.3K∗(892)0π− 27.08± 0.64± 2.82 0.388± 0.007± 0.033 −172.6± 1.1± 6.0

[K−π+]L=0

π− 22.90± 0.72± 1.89 0.554± 0.010± 0.037 53.2± 1.1± 1.9[K∗(892)0π−]L=2

3.47± 0.17± 0.31 0.769± 0.021± 0.048 −19.3± 1.6± 6.7ω(782) [π+π−]K− 1.65± 0.11± 0.16 0.146± 0.005± 0.009 9.0± 2.1± 5.7

Table 5: Table of fit fractions and coupling parameters for the component involving the K(1460)−

meson, from the fit performed on the RS decay D0 → K−π+π+π−. The coupling parametersare defined with respect to the K(1460)− → K∗(892)0π− coupling. For each parameter, the firstuncertainty is statistical and the second systematic.

K(1460)− m0 = 1482.40± 3.58± 15.22MeV/c2 ; Γ0 = 335.60± 6.20± 8.65MeV/c2

Partial Fractions [%] |g| arg(g)[o]

K∗(892)0π− 51.39± 1.00± 1.71

[π+π−]L=0K− 31.23± 0.83± 1.78

fKK 1.819± 0.059± 0.189 −80.8± 2.2± 6.6β1 0.813± 0.032± 0.136 112.9± 2.6± 9.5β0 0.315± 0.010± 0.022 46.7± 1.9± 3.0

18

[EPJC 78 (2018) 443]

Great potential to study light spectrum at LHCb

gDsJ

stat

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clusiv

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5 / 15

]2 invariant mass [GeV/c0SK+D

2.5 3

2C

and

idat

es /

5 M

eV/c

0

2000

4000

6000(a)LHCb

[MeV])S

0K*+m(D

2600 2800 3000 3200 3400

Can

dida

tes

/ (8

MeV

)

0

5000

10000

15000

20000 LHCb

2600 2800 3000 3200 3400

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500

]2 invariant mass [GeV/c0SK+D

2.5 3

2C

and

idat

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5 M

eV/c

0

200

400 (c)LHCb

Open charm spectroscopy probes perturbative – non-perturbative transition region;static heavy quarks (HQET) vs. dynamical resonance generationMuch discussed example: D∗sJ(2860)

Observed in inclusive reactions in the DK and D∗K channels atBaBar [PRL 97 222001],[PRD 80 092003] and LHCb [JHEP10(2012)151],[JHEP02(2016)133] respectivelyAssignment as 13D3 state preferred, but large D∗K rate measured at BaBar is puzzling[Rept.Prog.Phys. 80 076201]

gDsJ

stat

es(e

xclu

sive)

6 / 15

D∗sJ(2860)− puzzle (momentarily) solved by B0s → D0K−π+ amplitude analysis

Resolved D∗sJ (2860)− into D∗

s1(2860)− (JP = 1−) and D∗s3(2860)− (JP = 3−)

Favoured assignments Ds(13D1) and Ds(13D3)

Do Ds(13D1) and Ds(23S1) states mix to form D∗s1(2860)− and D∗

s1(2700)−?

Amplitude analysis in D∗K channel (e.g. B0s → D∗−K 0

Sπ+) and measurement

of decay rates relative to DK sensitive to mixing parameters

)−K0

D(θcos -1 -0.5 0 0.5 1

Can

dida

tes

/ 0.0

4

0

10

20

30

40

50 LHCbData

spin-1 + spin-3

spin-1

spin-3

requirements lead to a maximum efficiency variation of

about 20%, while other effects are smaller.

Projections of the data and the unbinned maximum

likelihood fit result are shown in Fig. 3. The largest

components in terms of their fit fractions, defined as the

ratio of the integrals over the Dalitz plot of a single decay

amplitude squared and the total amplitude squared, are the

Kð892Þ0 (28.6%), Ds2ð2573Þ

− (25.7%), LASS (21.4%),

and D0K− nonresonant (12.4%) terms. The fit fractions for

the Ds1ð2860Þ

− and Ds3ð2860Þ

− components are ð5.01.2 0.7 3.3Þ% and ð2.2 0.1 0.3 0.4Þ%, respec-

tively, where the uncertainties are statistical, systematic,

and from Dalitz plot model variations, as described

below. The phase difference between the Ds1ð2860Þ

−

and Ds3ð2860Þ

− amplitudes is consistent with π within a

large model uncertainty.

To assess the significance of the two states near

mðD0K−Þ ≈ 2860 MeV=c2, the fit is repeated with all

combinations of either one or two resonant amplitudes

with different spins up to and including 3. All other

combinations give values of negative log-likelihood more

than one hundred units larger than the default fit. A

comparison of the angular distributions in the region near

mðD0K−Þ ≈ 2860 MeV=c2 of the data and the best fits

with the spin-1 only, spin-3 only, and both resonances is

presented in Fig. 4. Including both spin components visibly

improves the fit. Large samples of pseudoexperiments

are generated with signal models corresponding to the best

fits with the spin-1 or spin-3 amplitude removed, and each

pseudoexperiment is fitted under both the one- and two-

resonance hypotheses. By extrapolating the tails of the

distributions of the difference in negative log-likelihood

values to the values observed in data, the statistical sig-

nificances of the spin-3 and spin-1 components are found

to be 16 and 15 standard deviations, respectively. These

significances remain in excess of 10 standard deviations in

all alternative models considered below.

The considered sources of systematic uncertainty are

divided into two main categories: experimental uncertain-

ties and model uncertainties. The experimental systematic

uncertainties arise from imperfect knowledge of: the

relative amount of signal and background in the selected

events; the distributions of each of the backgrounds across

the phase space; the variation of the efficiency across the

phase space; the possible bias induced by the fit procedure;

the momentum calibration; the fixed masses of the B0s and

D0 mesons used to define the boundaries of the Dalitz plot.

Model uncertainties occur due to: fixed parameters in the

Dalitz plot model; the treatment of marginal components in

the default fit model; the choice of models for the K−πþ S

wave, the D0K− S and P waves, and the line shapes of the

virtual resonances. The systematic uncertainties from each

source are combined in quadrature.

The masses and widths of the Ds2ð2573Þ

−, Ds1ð2860Þ

−,

and Ds3ð2860Þ

− states are determined to be

m(Ds2ð2573Þ

−)¼ 2568.39 0.29 0.19 0.18MeV=c2;

Γ(Ds2ð2573Þ

−)¼ 16.9 0.5 0.4 0.4MeV=c2;

m(Ds1ð2860Þ

−)¼ 2859 12 6 23MeV=c2;

Γ(Ds1ð2860Þ

−)¼ 159 23 27 72MeV=c2;

m(Ds3ð2860Þ

−)¼ 2860.5 2.6 2.5 6.0MeV=c2;

Γ(Ds3ð2860Þ

−)¼ 53 7 4 6MeV=c2;

where the first uncertainty is statistical, the second is due

to experimental systematic effects, and the third is due to

model variations. The largest sources of uncertainty on the

parameters of the Ds1ð2860Þ

− and Ds3ð2860Þ

− resonances

arise from varying the K−πþ S-wave description and, for

the Ds1ð2860Þ

− width, from removing the Kð1680Þ0 and

Bþv components from the model. The results for the

Ds2ð2573Þ

− mass and width are determined with signifi-

cantly better precision than previous measurements. Those

for the parameters of the Ds1ð2860Þ

− and Ds3ð2860Þ

−

resonances must be considered first measurements, since

previous measurements of the properties of theDsJð2860Þ

−

state [3,5,6] involved an unknown admixture of at least

these two particles. The results for all the complex

amplitudes determined by the Dalitz plot fit, as well as

derived quantities such as branching fractions of the

resonant contributions and detailed descriptions of the

systematic uncertainties, are given in Ref. [17].

In summary, results of the first amplitude analysis of

the B0s → D0K−πþ decay show, with significance of

more than 10 standard deviations, that a structure at

FIG. 4 (color online). Projections of the data and Dalitz plot fit

results with alternative models onto the cosine of the helicity

angle of the D0K− system, cos θðD0K−Þ, for 2.77 < mðD0K−Þ <2.91 GeV=c2, where θðD0K−Þ is the angle between the πþ and

the D0 meson momenta in the D0K− rest frame. The data are

shown as black points, with the fit results with different models as

detailed in the legend. The dip at cos θðD0K−Þ ≈ −0.6 is due to

the D0 veto. Comparisons of the data and the different fit results

in the 50 bins of this projection give χ2 values of 47.3, 214.0,

and 150.0 for the default, spin-1 only, and spin-3 only models,

respectively.

PRL 113, 162001 (2014) P HY S I CA L R EV I EW LE T T ER Sweek ending

17 OCTOBER 2014

162001-4

[PRL 113 162001] [PRD 90 072003]

Reached precision era of single open charm spectroscopy

gD0 p

ampl

itude

inΛ0 b→

D0 p

π−

7 / 15

First amplitude analysis involving open charm baryonsIs the Λc(2940)+ a D∗N molecule? ⇒ Measure JP

Kinematic separation of pπ− and D0p resonances ⇒ analyse only D0p amplitudesNear threshold region can only be described by adding new Λc(2860)+ resonance

+(2880)cΛ

+(2940)cΛ

)+(1/2p

0D

NR

)−

(1/2p

0D

NR

)−

(3/2p

0D

NR

+(2860)cΛ

)+(1/2−πpNR

Background

]2

) [GeVp0

D(2

M

10 20 30

]2

) [G

eV

−

πp(

2M

0

2

4

6

8

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12

144

1

LHCb

) [GeV]p0

D(M

2.8 2.85 2.9 2.95 3C

an

did

ate

s /

(0.0

04

GeV

)0

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100

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200

250

300

LHCb

[JHEP05(2017)030]

First observation of Λc (2860)+

gD0 p

ampl

itude

inΛ0 b→

D0 p

π−

8 / 15

JHEP05(2017)030

of the Λc(2880)+ state are found to be:

m(Λc(2880)+) = 2881.75± 0.29(stat)± 0.07(syst)+0.14

−0.20(model)MeV,

Γ(Λc(2880)+) = 5.43+0.77

−0.71(stat)± 0.29(syst)+0.75−0.00(model)MeV.

These results are consistent with and have comparable precision to the current world av-

erages (WA), which are mWA(Λc(2880)+) = 2881.53 ± 0.35MeV, and ΓWA(Λc(2880)

+) =

5.8± 1.1MeV [23].

A near-threshold enhancement in the D0p amplitude is studied. The enhancement

is consistent with being a resonant state (referred to here as the Λc(2860)+) with mass

and width

m(Λc(2860)+) = 2856.1+2.0

−1.7(stat)± 0.5(syst)+1.1−5.6(model)MeV,

Γ(Λc(2860)+) = 67.6+10.1

−8.1 (stat)± 1.4(syst)+5.9−20.0(model)MeV

and quantum numbers JP = 3/2+, with the parity measured relative to that of the

Λc(2880)+ state. The other quantum numbers are excluded with a significance of more

than 6 standard deviations. The phase motion of the 3/2+ component with respect to

the nonresonant amplitudes is obtained in a model-independent way and is consistent with

resonant behaviour. With a larger dataset, it should be possible to constrain the phase

motion of the 3/2+ partial wave using the Λc(2880)+ amplitude as a reference, without

making assumptions on the nonresonant amplitude behaviour. The mass of the Λc(2860)+

state is consistent with recent predictions for an orbital D-wave Λ+c excitation with quan-

tum numbers 3/2+ based on the nonrelativistic heavy quark-light diquark model [24] and

from QCD sum rules in the HQET framework [26].

First constraints on the spin and parity of the Λc(2940)+ state are obtained in this

analysis, and its mass and width are measured. The most likely spin-parity assignment for

Λc(2940)+ is JP = 3/2− but the other solutions with spins 1/2 to 7/2 cannot be excluded.

The mass and width of the Λc(2940)+ state are measured to be

m(Λc(2940)+) = 2944.8+3.5

−2.5(stat)± 0.4(syst)+0.1−4.6(model)MeV,

Γ(Λc(2940)+) = 27.7+8.2

−6.0(stat)± 0.9(syst)+5.2−10.4(model)MeV.

The JP = 3/2− assignment for Λc(2940)+ state is consistent with its interpretations as a

D∗N molecule [16, 17, 19] or a radial 2P excitation [21].

Acknowledgments

We express our gratitude to our colleagues in the CERN accelerator departments for

the excellent performance of the LHC. We thank the technical and administrative staff

at the LHCb institutes. We acknowledge support from CERN and from the national

agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3

(France); BMBF, DFG and MPG (Germany); INFN (Italy); FOM and NWO (The Nether-

lands); MNiSW and NCN (Poland); MEN/IFA (Romania); MinES and FASO (Russia);

– 33 –

JHEP05(2017)030

of the Λc(2880)+ state are found to be:

m(Λc(2880)+) = 2881.75± 0.29(stat)± 0.07(syst)+0.14

−0.20(model)MeV,

Γ(Λc(2880)+) = 5.43+0.77

−0.71(stat)± 0.29(syst)+0.75−0.00(model)MeV.

These results are consistent with and have comparable precision to the current world av-

erages (WA), which are mWA(Λc(2880)+) = 2881.53 ± 0.35MeV, and ΓWA(Λc(2880)

+) =

5.8± 1.1MeV [23].

A near-threshold enhancement in the D0p amplitude is studied. The enhancement

is consistent with being a resonant state (referred to here as the Λc(2860)+) with mass

and width

m(Λc(2860)+) = 2856.1+2.0

−1.7(stat)± 0.5(syst)+1.1−5.6(model)MeV,

Γ(Λc(2860)+) = 67.6+10.1

−8.1 (stat)± 1.4(syst)+5.9−20.0(model)MeV

and quantum numbers JP = 3/2+, with the parity measured relative to that of the

Λc(2880)+ state. The other quantum numbers are excluded with a significance of more

than 6 standard deviations. The phase motion of the 3/2+ component with respect to

the nonresonant amplitudes is obtained in a model-independent way and is consistent with

resonant behaviour. With a larger dataset, it should be possible to constrain the phase

motion of the 3/2+ partial wave using the Λc(2880)+ amplitude as a reference, without

making assumptions on the nonresonant amplitude behaviour. The mass of the Λc(2860)+

state is consistent with recent predictions for an orbital D-wave Λ+c excitation with quan-

tum numbers 3/2+ based on the nonrelativistic heavy quark-light diquark model [24] and

from QCD sum rules in the HQET framework [26].

First constraints on the spin and parity of the Λc(2940)+ state are obtained in this

analysis, and its mass and width are measured. The most likely spin-parity assignment for

Λc(2940)+ is JP = 3/2− but the other solutions with spins 1/2 to 7/2 cannot be excluded.

The mass and width of the Λc(2940)+ state are measured to be

m(Λc(2940)+) = 2944.8+3.5

−2.5(stat)± 0.4(syst)+0.1−4.6(model)MeV,

Γ(Λc(2940)+) = 27.7+8.2

−6.0(stat)± 0.9(syst)+5.2−10.4(model)MeV.

The JP = 3/2− assignment for Λc(2940)+ state is consistent with its interpretations as a

D∗N molecule [16, 17, 19] or a radial 2P excitation [21].

Acknowledgments

We express our gratitude to our colleagues in the CERN accelerator departments for

the excellent performance of the LHC. We thank the technical and administrative staff

at the LHCb institutes. We acknowledge support from CERN and from the national

agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3

(France); BMBF, DFG and MPG (Germany); INFN (Italy); FOM and NWO (The Nether-

lands); MNiSW and NCN (Poland); MEN/IFA (Romania); MinES and FASO (Russia);

– 33 –

JHEP05(2017)030

of the Λc(2880)+ state are found to be:

m(Λc(2880)+) = 2881.75± 0.29(stat)± 0.07(syst)+0.14

−0.20(model)MeV,

Γ(Λc(2880)+) = 5.43+0.77

−0.71(stat)± 0.29(syst)+0.75−0.00(model)MeV.

These results are consistent with and have comparable precision to the current world av-

erages (WA), which are mWA(Λc(2880)+) = 2881.53 ± 0.35MeV, and ΓWA(Λc(2880)

+) =

5.8± 1.1MeV [23].

A near-threshold enhancement in the D0p amplitude is studied. The enhancement

is consistent with being a resonant state (referred to here as the Λc(2860)+) with mass

and width

m(Λc(2860)+) = 2856.1+2.0

−1.7(stat)± 0.5(syst)+1.1−5.6(model)MeV,

Γ(Λc(2860)+) = 67.6+10.1

−8.1 (stat)± 1.4(syst)+5.9−20.0(model)MeV

and quantum numbers JP = 3/2+, with the parity measured relative to that of the

Λc(2880)+ state. The other quantum numbers are excluded with a significance of more

than 6 standard deviations. The phase motion of the 3/2+ component with respect to

the nonresonant amplitudes is obtained in a model-independent way and is consistent with

resonant behaviour. With a larger dataset, it should be possible to constrain the phase

motion of the 3/2+ partial wave using the Λc(2880)+ amplitude as a reference, without

making assumptions on the nonresonant amplitude behaviour. The mass of the Λc(2860)+

state is consistent with recent predictions for an orbital D-wave Λ+c excitation with quan-

tum numbers 3/2+ based on the nonrelativistic heavy quark-light diquark model [24] and

from QCD sum rules in the HQET framework [26].

First constraints on the spin and parity of the Λc(2940)+ state are obtained in this

analysis, and its mass and width are measured. The most likely spin-parity assignment for

Λc(2940)+ is JP = 3/2− but the other solutions with spins 1/2 to 7/2 cannot be excluded.

The mass and width of the Λc(2940)+ state are measured to be

m(Λc(2940)+) = 2944.8+3.5

−2.5(stat)± 0.4(syst)+0.1−4.6(model)MeV,

Γ(Λc(2940)+) = 27.7+8.2

−6.0(stat)± 0.9(syst)+5.2−10.4(model)MeV.

The JP = 3/2− assignment for Λc(2940)+ state is consistent with its interpretations as a

D∗N molecule [16, 17, 19] or a radial 2P excitation [21].

Acknowledgments

We express our gratitude to our colleagues in the CERN accelerator departments for

the excellent performance of the LHC. We thank the technical and administrative staff

at the LHCb institutes. We acknowledge support from CERN and from the national

agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); NSFC (China); CNRS/IN2P3

(France); BMBF, DFG and MPG (Germany); INFN (Italy); FOM and NWO (The Nether-

lands); MNiSW and NCN (Poland); MEN/IFA (Romania); MinES and FASO (Russia);

– 33 –

JHEP05(2017)030

∆ lnL uncertainty for Λc(2940)+ JP

Source No Λc(2940)+ 1/2+ 1/2− 3/2+ 5/2+ 5/2− 7/2+ 7/2−

Background fraction 0.3 0.7 0.3 0.9 0.7 0.6 0.7 0.8

Efficiency profile 0.3 0.2 0.6 0.6 0.6 0.6 0.9 1.1

Background shape 3.6 3.4 3.3 2.6 1.4 2.0 2.4 4.0

Momentum resolution 0.1 0.0 0.1 0.1 0.1 0.1 0.1 0.1

Λc(2880)+ parameters 0.2 0.2 0.9 0.2 0.3 0.1 0.5 0.4

Total systematic 3.6 3.5 3.4 2.8 1.7 2.2 2.6 4.2

Breit-Wigner model 2.1 1.2 1.9 1.6 2.3 0.4 1.4 1.4

Nonresonant model 3.7 2.4 0.4 1.5 1.0 1.9 1.4 0.1

Total model 4.3 2.7 1.9 2.1 2.5 1.9 2.0 1.4

Table 10. Systematic and model uncertainties on ∆ lnL between the baseline fit with JP = 3/2−

for the Λc(2940)+ state and other fits without a Λc(2940)

+ contribution or with other spin-parity

assignments, for the exponential nonresonant model.

∆ lnL uncertainty for Λc(2940)+ JP

Source No Λc(2940)+ 1/2+ 1/2− 3/2+ 5/2+ 5/2− 7/2+ 7/2−

Background fraction 0.6 0.1 0.2 0.3 0.3 0.4 0.1 0.6

Efficiency profile 0.6 0.5 0.5 0.3 0.2 0.6 0.7 0.7

Background shape 1.2 0.5 0.6 1.4 1.6 0.7 1.5 1.3

Momentum resolution 0.5 0.2 0.1 0.1 0.1 0.1 0.1 0.1

Λc(2880)+ parameters 0.2 0.6 0.2 0.2 0.1 0.4 0.3 0.5

Total systematic 1.6 0.9 0.8 1.5 1.6 1.1 1.7 1.7

Breit-Wigner model 1.1 0.7 0.4 0.6 1.1 0.5 0.9 0.3

Nonresonant model 3.7 2.2 2.2 1.6 0.8 1.3 2.1 3.2

Total model 3.8 2.3 2.3 1.7 1.3 1.4 2.3 3.2

Table 11. Systematic and model uncertainties on ∆ lnL between the baseline fit with JP = 3/2−

for the Λc(2940)+ state and other fits without a Λc(2940)

+ contribution or with other spin-parity

assignments, for the polynomial nonresonant model.

The contributions of individual resonant components, integrated over the entire phase

space of the Λ0b→ D0pπ− decay, can be used to extract the ratios of branching fractions

B(Λ0b→ Λc(2860)

+π−)×B(Λc(2860)+ → D0p)

B(Λ0b→ Λc(2880)+π−)×B(Λc(2880)+ → D0p)

= 4.54+0.51−0.39

(stat)± 0.12(syst)+0.17−0.58

(model),

B(Λ0b→ Λc(2940)

+π−)×B(Λc(2940)+ → D0p)

B(Λ0b→ Λc(2880)+π−)×B(Λc(2880)+ → D0p)

= 0.83+0.31−0.10

(stat)± 0.06(syst)+0.17−0.43

(model),

which assumes the ratios of the branching fractions to be equal to the ratios of the fit

fractions.

The constraints on the Λc(2940)+ quantum numbers depend on the description of the

nonresonant amplitudes. If an exponential model is used for the nonresonant components,

the single best spin-parity assignment is JP = 3/2−, and the 3/2+, 5/2+ and 5/2− as-

– 31 –

)+

(3/2RRe

40− 20− 0 20 40

)+

(3/2

RIm

40−

30−

20−

10−

0

10

20

30

40

0

1

23

4

5

LHCb

[JHEP05(2017)030]

Phase motion of Λc(2860)+ [(JP)preferred = 3/2+] resembles Breit-WignerΛc(2860)+ and Λc(2880)+ [(JP)preferred = 5/2+] consistent with D-wave doubletΛc(2940)+ [(JP)preferred = 3/2−] radial 2P excitation or S-wave D∗N molecule?Need to study Σ(∗)

c π channel [arXiv:1803.00364 [hep-ph]][RevModPhys 90 015004]

Precision spectroscopy of charm baryons just begun. Many possibilities ahead

gΩ∗∗0

cst

ates

(inclu

sive

Ξ+ cK−

)

9 / 15

Before: Only ground state Ωc and Ωc(2770)0 known. More Ω∗cs expected

Observed 5 new narrow states + 1 broad (?) in inclusive Ξ+c K− spectrum

Why so many? Why so narrow? Expected only narrow Ωc2 D-wave decays in Ξ+c K−

Narrowness: ss diquark hard to separate? No decays to ΞD (kinematics)[PRD 95 114012]

]2 cM

ass

[GeV

/

2.6

2.7

2.8

2.9

3

3.1

3.2

3.3

3.4

3.5

KcΞ

' KcΞ

* KcΞ DΞ

π π 0cΩ

π π *0cΩ

π K cΞ

KK +cΛ

0π 0cΩ

0π *0cΩ

cΩ*cΩ

(2S)cΩ*(2S)cΩ

0cΩ1cΩ 1cΩ 2cΩ

2cΩ

(2P)0cΩ (2P)1cΩ(2P)1cΩ (2P)2cΩ

(2P)2cΩ

(1D)1cΩ (1D)1cΩ (1D)2cΩ(1D)2cΩ (1D)3cΩ

(1D)3cΩ

L

qq'j

PJ

S1

+

21

S1

+

23

P0

-

21

P1-

21

P1-

23

P2

-

23

P2

-

25

D1+

21

D1+

23

D2+

23

D2+

25

D3+

25

D3+

27

) [MeV]−

K+cΞ(m

3000 3100 3200 3300

Can

dida

tes

/ (1

MeV

)

0

100

200

300

400 LHCb−K+

cΞFull fitBackground

Feed-downs sidebands+

cΞ

[PRL 118 182001]

(css)

(cus)(su)

(uss)(cu) or (dss)(cd)

ΞD threshold

gΩ∗∗0

cst

ates

(inclu

sive

Ξ+ cK−

)

10 / 15

Several interpretations,many implications...Study further incl. channels(e.g. Ω0

cγ/π+π−, Ξ0

cK 0S )

Measure JP (incl. or excl., e.g.Ξb → Ω∗∗0c D, Ξ−b /Ω−b → Ω∗∗0c π−)

Resonance Mass ( MeV ) Γ ( MeV ) Yield Nσ

Ωc(3000)0 3000.4 ± 0.2 ± 0.1+0.3−0.5 4.5 ± 0.6 ± 0.3 1300 ± 100 ± 80 20.4

Ωc(3050)0 3050.2 ± 0.1 ± 0.1+0.3−0.5 0.8 ± 0.2 ± 0.1 970 ± 60 ± 20 20.4

< 1.2 MeV, 95% CL

Ωc(3066)0 3065.6 ± 0.1 ± 0.3+0.3−0.5 3.5 ± 0.4 ± 0.2 1740 ± 100 ± 50 23.9

Ωc(3090)0 3090.2 ± 0.3 ± 0.5+0.3−0.5 8.7 ± 1.0 ± 0.8 2000 ± 140 ± 130 21.1

Ωc(3119)0 3119.1 ± 0.3 ± 0.9+0.3−0.5 1.1 ± 0.8 ± 0.4 480 ± 70 ± 30 10.4

< 2.6 MeV, 95% CL

Ωc(3188)0 3188 ± 5 ± 13 60 ± 15 ± 11 1670 ± 450 ± 360

Ωc(3066)0fd 700 ± 40 ± 140

Ωc(3090)0fd 220 ± 60 ± 90

Ωc(3119)0fd 190 ± 70 ± 20

empirical reasons. For instance, it was shown in

Refs. [19,35–41] that the hadronic decays of heavy-light

mesons and baryons can be reasonably described by

treating the light pseudoscalar mesons, i.e., π, K, and η,

as fundamental states in the chiral quark model. Then, the

decay patterns of those low-lying heavy-light mesons and

baryons can be described. The chiral quark model has also

been broadly applied to various processes involving light

pseudoscalar meson productions [42–59]. In this model,

the low energy quark-pseudoscalar-meson interactions in

the SU(3) flavor basis are described by the effective

Lagrangian [45–47]

Hm ¼X

j

1

fmIjψ jγ

jμγ

j5ψ j∂

μϕm; ð1Þ

where ψ j represents the jth quark field in the hadron; ϕm is

the pseudoscalar meson field, fm is the pseudoscalar meson

decay constant, and Ij is the isospin operator associated

with the pseudoscalar meson.

Meanwhile, to treat the radiative decay of a hadron we

apply the constituent quark model which has been success-

fully applied to study the radiative decays of cc and bbsystems [60,61]. In this model, the quark-photon EM

coupling at the tree level is adopted as [62]

He ¼ −

X

j

ejψ jγjμAμðk; rjÞψ j; ð2Þ

where Aμ represents the photon field with three-momentum

k. ej and rj stand for the charge and coordinate of the

constituent quark ψ j, respectively.

To match the nonrelativistic harmonic oscillator wave

functions adopted in our calculations, we should provide

the quark-pseudoscalar and quark-photon EM couplings in

a nonrelativistic form. In the initial-hadron-rest system, the

nonrelativistic form of the quark-photon EM coupling can

be written as [45–47,60–62]

TABLE I. The spectrum of 1P- and 2S-wave Ωc states in the constituent quark model. The total wave function of a Ωc state is

denoted by jN2Sþ1LσJPi. The Clebsch-Gordan series for the spin and angular-momentum addition jN2Sþ1LσJ

Pi ¼P

LzþSz¼JzhLLz; SSzjJJziNΨσ

LLzχSzϕΩc

has been omitted. The details of the wave functions can be found in our previous work

[19]. The unit of mass is MeV in the table.

State

jN2Sþ1LσJPi Wave function

Predicted

mass [7]

Predicted

mass [8]

Predicted

mass [9]

Predicted

mass [13]

Predicted

mass [15]

Predicted

mass [14] Observed state

j02S12

þi 0Ψ

S00χλSzϕΩc

2698 2745 2718 2695 2731 2648(28) Ωcð2695Þj04S3

2

þi 0Ψ

S00χsSzϕΩc

2768 2805 2776 2767 2779 2709(32) Ωcð2770Þj12Pλ

1

2

−i 1Ψ

λ1Lz

χλSzϕΩc3055 3015 2977 3011 3030 2995(46)

j12Pλ3

2

−i 3029 3030 2986 2976 3033 3016(69) Ωcð3066Þ?j14Pλ

1

2

−i 1Ψ

λ1Lz

χsSzϕΩc2966 3040 2990 3028 3048

j14Pλ3

2

−i 3054 3065 2994 2993 3056 Ωcð3050Þ?j14Pλ

5

2

−i 3051 3050 3014 2947 3057 Ωcð3090Þ?j22Sλλ12þi 2

Ψλλ00χλSzϕΩc

3088 3020 3152 3100 Ωcð3119Þ?j24Sλλ32þi 2

Ψλλ00χsSzϕΩc

3123 3090 3190 3126 Ωcð3119Þ?

TABLE II. Spin-parity (JP) numbers of the newly observed Ωc states suggested in various works.

State [20] [21] [22] [24] [30] [26] [28] [29] [33] [27] This work

Ωcð3000Þ 1=2− 1=2− (3=2−) 1=2− 1=2− 1=2− 1=2− 1=2þ or 3=2þ 1=2− 1=2−

Ωcð3050Þ 1=2− 1=2− (3=2−) 1=2− 5=2− 3=2− 1=2− 5=2þ or 7=2þ 3=2− 3=2−

Ωcð3066Þ 1=2þ 1=2þ or 1=2− 3=2− (5=2−) 3=2− 3=2− 5=2− 3=2− 3=2− 1=2þ 3=2−

Ωcð3090Þ 3=2− (1=2þ) 3=2− 1=2− 1=2þ 3=2− 5=2− 1=2þ 5=2−

Ωcð3119Þ 3=2þ 3=2þ 5=2− (3=2þ) 5=2− 3=2− 3=2þ 5=2− 5=2þ or 7=2þ 3=2þ 1=2− 1=2þ or 3=2þ

FIG. 1. ssc system with λ- or ρ-mode excitations. ρ and λ are

the Jacobi coordinates defined as ρ ¼ 1ffiffi

2p ðr1 − r2Þ and

λ ¼ 1ffiffi

6p ðr1 þ r2 − 2r3Þ. q1 and q2 stand for the light s quarks,

and Q3 stands for the heavy c quark.

WANG, XIAO, ZHONG, and ZHAO PHYSICAL REVIEW D 95, 116010 (2017)

116010-2

[PRL 118 182001]

[PRD 95 11610]

Anticipate rich Ω∗∗−b spectrumAre some Ω∗∗0c s molecules/multiquarks?

gΞ+

+cc

obse

rvat

ion

11 / 15

The quark model predicts three JP = 1/2+ doubly charmed ground state baryons:Ξ+

cc (ccd) Ξ++cc (ccu) and Ω+

cc (ccs)Experimental evidence for Ξ+

cc in Λ+c K−π+ and pD+K− @ ≈ 3520 MeV from SELEX,

measuring an short lifetime and large production rate (< 33 fs @ 90 % CL, ≈ 20 % of Λ+c come from Ξ+

cc )

Null results from FOCUS, BaBar, Belle and LHCb (2011 1 fb−1 at√

s = 7 TeV)[Nucl. Phys. B Proc. Suppl. 115 33][PRD 74 011103][PRL 97 162001][JHEP 12(2013)090]

LHCb observed Ξ++cc in Λ+

c K−π+π+ using2016 data (1.7 fb−1 at

√s = 13 TeV)

Expected 3–4 times longer lifetime w.r.t.Ξ+

cc higher sensitivityFull event reconstruction in software triggerConfirmed with 2012 data(2 fb−1 at

√s = 8 TeV)

]2c) [MeV/++ccΞ(candm

3500 3600 3700

2 cC

andi

date

s pe

r 5

MeV

/

0

20

40

60

80

100

120

140

160

180

DataTotalSignalBackground

LHCb 13 TeV

[PRL 121 052002]

[PRL 89 112001][PLB 628 18]

m(Ξ++cc ) = 3621.40± 0.72(stat)± 0.27(syst)± 0.14(Λ+

c ) MeV

gΞ+

+cc

lifet

ime

and

Ξ++

cc→

Ξ+ ccπ

+

12 / 15

0.5 1 1.5 2Decay time [ps]

0.00

0.05

0.10

0.15

0.20

Arb

itrar

y sc

ale

LHCb++ccΞ0bΛ

3500 3550 3600 3650 37000

20

40

60

80

100

Can

dida

tes

/(5

MeV/c

2)

m(Ξ+c π+)

[MeV/c2

]

LHCb DataTotalSignalBackground

Lifetime of Ξ++cc expected to be enhanced by destructive Pauli interference

(valence u with u from weak c decay), and Ξ+cc shortened by W capture

τ(Ξ++cc ) = 0.256+0.024

−0.022(stat)± 0.014(syst) ps somewhat lower than expectationsInterfering c decay amplitudes can change dynamics of weak decay⇒ study further decay channels like Ξ++

cc → Ξ+ccπ

+

[PRL 121 052002] [arXiv:1807.01919]

Renewed interest in doubly heavy exotics (talks by Anthony Francis and Ahmed Ali)Search for doubly heavy ground state and excited baryons

gΞb(

6227

)−ob

serv

atio

n

13 / 15

Observed new Ξb(6227)− resonance in Λ0bK− and Ξ0

bπ− decays

Measured m and Γ in excl. hadronic Λ0b → Λ+

c π− decays; exploited high statistics

semileptonic (SL) Λ0b/Ξ0

b → Λ+c /Ξ+

c µ−νµ decays for production ratio measurements

SL: Infer νµ momentum from Λ0b/Ξ0

b mass constraint ≈ 20 MeV FWHM resolution

m(Ξb(6227)−) = 6226.9± 2.0(stat)± 0.3(syst)± 0.2(Λ0b) MeV

Γ(Ξb(6227)−) = 18.1± 5.4(stat)± 1.8(syst) MeVMeasured production ratios imply that B(Ξb(6227)− → Λ0

bK−) ≈ B(Ξb(6227)− → Ξ0bπ−)

]2c) [MeV/0bΛ(M −)

−K0

bΛ(M500 600 700 800 900

)2 cC

andi

date

s / (

8 M

eV/

100

200

300

400 Full fit−

K)−π+cΛ→(0

bΛ →−(6227)bΞ

Combinatorial

LHCb=13 TeVs

]2c) [MeV/0bΛ*(M −)

−K0

bΛ*(M500 600 700 800 900

)2 cC

andi

date

s / (

4 M

eV/

1000

2000

Full fit−

K)X−µ+cΛ→(0

bΛ →−(6227)bΞ

Combinatorial

LHCb=13 TeVs

]2c) [MeV/0bΞ*(M − )−π0

bΞ*(M400 600 800

)2 cC

andi

date

s / (

10 M

eV/

100

200

300

400 Full fit−π)X−µ+

cΞ→(0bΞ →−

(6227)bΞCombinatorial

LHCb=13 TeVs

[PRL 121 072002]

hadronic semileptonic Λ0b semileptonic Ξ0

b

gExc

ited

Ξ bsp

ectru

m

14 / 15

Interpretation of Ξb(6227)− as 1P orbital excitation of Ξb(5955)−(JP = 3/2− or 5/2−) preferred over 2S stateFuture: Search isospin partner; decays via Ξ′b and Ξ∗b could help to determine JP

the mass of the Ξbð6227Þ− under the 2S and 1P assign-

ments. To give further constraints on its quantum number,

we will investigate the strong decays in the following.

For carrying out the study of strong decay behaviors of the

discussed bottom-strange baryons, we employ the quark pair

creation (QPC) model [23–25] to calculate their two-body

OZI-allowed decays. The QPC model has been extensively

used to study the strong decays of different kinds of

hadrons. For a decay process of an excited bsq baryon state

(q designates a u or d quark), Aðqð1Þsð2Þbð3ÞÞ →Bðqð5Þsð2Þbð3ÞÞ þ Cðqð1Þqð4ÞÞ, the transition matrix

element in the QPC model is written as hBCjT jAi ¼δ3ðKB þKCÞMjA;jB;jCðpÞ, where the transition operator

T reads as

T ¼ −3γX

m

h1; m; 1;−mj0; 0iZZ

d3k4d3k5δ

3ðk4 þ k5Þ

× Ym1

k4 − k5

2

ωð4;5Þφð4;5Þ0 χ

ð4;5Þ1;−md

†

4ðk4Þd†5ðk5Þ ð2Þ

in a nonrelativistic limit. Here, the ωð4;5Þ0 and φ

ð4;5Þ0 are the

color and flavor wave functions of the q4q5 pair created from

the vacuum, respectively. Therefore, ωð4;5Þ ¼ ðRRþGGþBBÞ=

ffiffiffi

3p

and φð4;5Þ0 ¼ ðuuþ ddþ ssÞ=

ffiffiffi

3p

are color and

flavor singlets. The χð4;5Þ1;−m represents the pair production in a

spin triplet state. The solid harmonic polynomial Ym1 ðkÞ≡

jkjYm1 ðθk;ϕkÞ reflects the momentum-space distribution

of the q4q5. The dimensionless parameter γ describes the

strengthof the quark-antiquarkpair created from thevacuum.

The useful partial wave amplitude is related to the

helicity amplitude MjA;jB;jCðpÞ by

MA→BþCLS ðpÞ ¼

ffiffiffiffiffiffiffiffiffiffiffiffiffiffi

2Lþ 1p

2JA þ 1

X

jB;jC

hL0JjAjJAjAi

× hJBjB; JCjCjJjAiMjA;jB;jCðpÞ; ð3Þ

where the Ji and ji (i ¼ A, B, and C) denote the total

angular momentum and their projection of initial and final

hadron states, respectively. L denotes the orbital angular

momenta between the final states B and C. Finally, thepartial width of A → BC is written in terms of the partial

wave amplitudes as

ΓðA → BCÞ ¼ 2πEBEC

MA

pX

L;S

jMLSðpÞj2 ð4Þ

in the A rest frame. To obtain the concrete expressions of

MjA;jB;jCðpÞ, an integral IlA;mlB;lC

ðpÞ should be performed,

which describes the overlap of the spatial functions of the

initial state (A), the created pair from the vacuum, and two

final states (B andC). Usually, the simple harmonic oscillator

(SHO) wave function ψmnrL

ðkÞ ¼ RnrLðβ;kÞYm

nrLðkÞ is

taken to construct the spatial wave function of a hadron

state. In this way, the analytical IlA;mlB;lC

ðpÞ can be extracted.

In our calculations, all values of the SHO wave function

scale (denoted as “β”), which reflect the distances between

the light diquark and the b quark in the bottomed baryons,

are obtained by reproducing the realistic root mean square

radius via Eq. (1). The results are collected in Table II. The

values of βs for the light diquark and other related hadrons

are taken from our previous work [19]. In this work, the

value of γ is taken as 1.296 since the measured widths

of 2S and 1P states of charmed and charmed-strange baryons

have been reproduced in Ref. [19].

With the preparation above, we first test our method by

calculating the partial widths of these observed 1S bottom

baryon states. At present, only the 1S bottomed baryons

have been reported by experiments in their OZI-allowed

decay channels. In Table III, wemake a comparison between

theoretical and experimental results of partial decay widths,

b

b

b

bK

bKbK

B

b 6227

b 5795

b 5935

b 5955

1S

2S

3S

1P

2P

1D

1S

2S

3S

1P

2P

1D

b b

5.8

6.0

6.2

6.4

6.6

6.8

5.8

6.0

6.2

6.4

6.6

6.8

Mass

inG

eV

FIG. 2. The obtained masses for the bottom-strange baryons.

The red solid lines (left) correspond to the predicted masses of Ξb

states which are composed of a good diquark and a bottom quark,

while the blue solid lines (right) correspond to the Ξ0b states which

contain a bad diquark. Here, we also listed the measured masses

of the ground states [1] and the Ξbð6227Þ− [9], which are marked

by “filled circle”.

TABLE II. The effective β values for the different bottomed

baryon states (in GeV).

States Λb Ξb Σb Ξ0b Ωb

1Sð1=2þÞ 0.288 0.341 0.345 0.367 0.404

1Sð3=2þÞ 0.334 0.355 0.390

2S 0.157 0.181 0.181 0.191 0.206

3S 0.115 0.131 0.132 0.139 0.148

1P 0.198 0.227 0.228 0.241 0.258

2P 0.131 0.149 0.150 0.158 0.169

1D 0.157 0.178 0.179 0.189 0.201

ROLE OF NEWLY DISCOVERED Ξbð6227Þ− FOR … PHYS. REV. D 98, 031502 (2018)

031502-3

] 2cm [MeV/δ0 10 20 30 40

2 cE

ntri

es p

er 0

.45

MeV

/

0

20

40

60

80

100

120

140

−π0bΞ

+π0bΞ

] 2cm [MeV/δ2 3 4 5

2 cE

ntri

es p

er 0

.1 M

eV/

05

101520253035

LHCb

[PRD 98 031502][PRL 114 062004]

Sensitivity boost from adding high statistics semileptonic channels

Ξ′b(5935)−Ξb(5955)∗−

gSum

mar

yan

dO

utlo

ok

15 / 15

Pattern in (non-exotic) spectroscopy: Search for 1. ground state and 2. excited states ininclusive decays. 3. Precision spectroscopy of excited states in amplitude analyses

Prospects and challenges in light hadron spectroscopyLarge statistics; large dynamical/non-perturbative effects challenging parametrisation of amplitude models

Prospects and challenges in (single) open charm spectroscopyEntering and laying foundation for precision charm spectroscopy

Prospects and challenges in beauty and double charm spectroscopyWe are at steps 1. and 2.; Step 3. requires much more data

Anticipate rich excited doubly charmed and Ωb spectrum

Bright future for spectroscopy at LHCb