Heavy flavour spectroscopy at ATLAS, CMS and LHCb Mat Charles - - PowerPoint PPT Presentation

SLIDE 1

Heavy flavour spectroscopy at ATLAS, CMS and LHCb

Mat Charles (Sorbonne Université*/LPNHE)

1 * Previously Université Pierre et Marie Curie, previously Université de Paris, previously Université de France, previously Université de Paris

SLIDE 2

Topics for today

• The Ξcc++ discovery
• The ongoing X(5568) mystery
• Round-up of updates since La Thuile 2017
• Five new narrow Ωc0 → Ξc+ K− states
• Search for weakly decaying b-flavoured pentaquarks
• Excited Bc+ states
• Precise measurements of χc1 and χc2
• A promising first look at χb → 𝛷γ (𝛷 → μ+μ−)

2

No hope of covering all LHC spectroscopy results, sorry!

SLIDE 3

3

The Ξcc++ (ccu) discovery

SLIDE 4

n p

• Σ

Σ / Λ

Σ / Λ

+

Σ

+ c

Σ /

+ c

Λ

+ c

Σ /

+ c

Λ

'0 c

Ξ /

c

Ξ

'0 c

Ξ /

c

Ξ

'+ c

Ξ /

+ c

Ξ

'+ c

Ξ /

+ c

Ξ

+ cc

Ξ

++ cc

Ξ

+ cc

Ω

c

Ω

c

Σ

++ c

Σ

• Ξ

Ξ C=0 C=1 C=2

+

2 1 =

P

J

• Δ

Δ

+

Δ

++

Δ

*-

Σ

*0

Σ

*+

Σ

*-

Ξ

*0

Ξ

*0 c

Σ

*+ c

Σ

*++ c

Σ

*0 c

Ξ

*+ c

Ξ

*+ cc

Ξ

*++ cc

Ξ

• Ω

*0 c

Ω

*+ cc

Ω

++ ccc

Ω

3

I S C C=0 C=1 C=2 C=3

+

2 3 =

P

J

Ξcc++ : Quark model

• In the quark model, expect baryons with > 1 heavy quark.
• Several of them should decay weakly, including:
• ccu = Ξcc++
• ccd = Ξcc+
• ccs = Ωcc++
• ccc = Ωccc++
• At stupidly naive 0th order,
• Real calculations typically


give 3.5 < m(Ξcc) < 3.7 GeV,
 τ(Ξcc++) ~ few hundred fs,
 τ(Ξcc++)/τ(Ξcc+) ~ 3 to 4

4

m(p) = 938 MeV m(Λc) = 2286 MeV => m(Ξcc) ~ 3.6 GeV => m(Ωccc) ~ 5.0 GeV

Ξcc isospin doublet

}

See e.g. Kiselev & Likhoded [Phys. Usp. 45, 455 (2002)],
 Fleck & Richard [Prog. Theor. Phys. 82, 760 (1989)]. Full list of theory refs in backups.

SLIDE 5

Events /2.5 [MeV/c2] (c) 12 3.42 3.47 3.52 3.57 3.62 1 2 3 4 5 6 7 8 M ( Λc

+K-π+ ) [GeV/c2]

3.4 3.5 3.6 3.7 3.8

Ξcc++ : History

• Longstanding experimental puzzle: observations of Ξcc+ (ccd)

claimed by SELEX in 2002, 2005 but never reproduced by other experiments.

• Various oddities with SELEX result... but because production

environment was unique (hyperon beam on fixed target), other results didn't formally rule it out.

• Relevant points for today:


SELEX reported

• m(Ξcc+) = 3519 ± 2 MeV
• τ(Ξcc+) < 33 fs @ 90% CL

5

SELEX: PRL 89:112001 (2002) SELEX: PLB B628:18-24 (2005)

SELEX Ξcc+

SLIDE 6

Ξcc++ : Discovery

6

LHCb: PRL 119, 112001 (2017)

]

2

c ) [MeV/

++ cc

Ξ (

cand

m

3500 3600 3700

2

c Candidates per 5 MeV/ 20 40 60 80 100 120 140 160 180 Data Total Signal Background

LHCb 13 TeV

Ξ++

cc

→ Λ+

c K−π+π+

LHCb result, obtained with 2016 (Run 2) data:

Yield: 313 ± 13 Local significance > 12σ

SLIDE 7

Ξcc++ : Checks & tests

7

]

2

c ) [MeV/

++ cc

Ξ (

cand

m

3500 3600 3700

2

c Candidates per 5 MeV/ 20 40 60 80 100 120 140 160 180 Data Total Signal Background

LHCb 13 TeV ]

2

c ) [MeV/

++ cc

Ξ (

cand

m

3500 3600 3700

2

c Candidates per 5 MeV/ 10 20 30 40 50 60 70 Data Total Signal Background

LHCb 8 TeV ]

2

c ) [MeV/

++ cc

Ξ (

cand

m

3500 3600 3700

2

c Candidates per 5 MeV/ 20 40 60 80 100 120 140 Data Total Signal Background

LHCb 13 TeV > 5

t

σ t /

Significance
 >12σ Significance
 >7σ Significance
 >12σ

2016 data 2012 data With lifetime cut

• Observation confirmed with 2012 sample (crosscheck).
• Lifetime significantly different from zero: observation persists

when requiring (t / σt) > 5

• σt varies event by event, but typical resolution ~ 40-50fs

LHCb: PRL 119, 112001 (2017)

± ±

cc

e 3621.40 ± 0.72 (stat) ± 0.27 (syst) ± 0.14 (Λ+

c ) MeV

/c2, w

+

Mass: m(Ξcc++) = Differs from SELEX Ξcc+ mass by 103±2 MeV => clearly not a conventional isodoublet.

SLIDE 8

Ξcc++ : What's next?

8

• Ξcc++ lifetime measurement! Crucial to the interpretation.
• Will also give a clue about Ξcc+ lifetime.
• Ξcc++ production cross-section
• Confirmation at ATLAS & CMS? Belle-II?
• More Ξcc++ decay modes! Ratios of branching fractions.
• Constraints on spin, parity
• Ξcc+ search
• Tougher, due to shorter expected lifetime.
• LHCb failed to find Ξcc+ → Λc+ K− π+ with 0.65 fb−1 earlier... but now

have better triggers, more modes, and much more data.

• Ξcc+ properties, production relative to Ξcc++, etc
• Ωcc+ search (tougher still)
• Excited states
• Lowest expected to decay electromagnetically -- tough for LHCb
• Add pions, kaon... see what's out there!

veil of ignorance

SLIDE 9

9

The ongoing X(5568) mystery

SLIDE 10

X(5568) : The D0 observation

10

Feb 2016: D0 reported a narrow structure in the Bs0 π± spectrum (with Bs0 → J/𝜔 𝜚).
 Manifestly exotic bsqq resonance.

D0: PRL 117, 022003 (2016)

m = 5567.8 ± 2.9 (stat)+0.9

−1.9 (syst) MeV/c2

Γ = 21.9 ± 6.4 (stat)+5.0

−2.5 (syst) MeV

Yield: 133±31 events
 Significance: 6.1σ stat, or 5.1σ stat+sys (inc LEE) Eff-cor yield ratio 𝜍(X/Bs0):

10 < pT (B0

s) < 15 GeV/c : (9.1 ± 2.6 ± 1.6)%

15 < pT (B0

s) < 30 GeV/c : (8.2 ± 1.9 ± 1.4)%

average : (8.6 ± 1.9 ± 1.4)%

But then...

4.8 5 5.2 5.4 5.6 5.8 6 500 1000 1500 2000

]

2

) [GeV/c φ ψ /

J

(

m

2

N events / 20 MeV/c

• 1

D0 Run II, 10.4 fb

Inclusive Bs0 sample (5.6k sig)

10 20 30 40 50 60 70 80 90

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

DATA Fit with background shape fixed Background Signal

(a)

15

π

5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9

]

2

) [GeV/c

±

π

S

(B

m

Bs0 π±

X(5568)

Add π± Mass and width:

This is a lot!

SLIDE 11

X(5568) : Not seen at LHCb

11 LHCb: PRL 117, 152003 (2016)

Candidates / (5 MeV)

100 200 300 400 500 600 700 800 900 Claimed X(5568) state Combinatorial

) > 5 GeV

s

B (

T

p LHCb

Pull

4 − 2 − 2 4

(MeV) )

±

π

s

m(B

5550 5600 5650 5700 5750 5800 5850 5900 5950 6000

Candidates / (5 MeV)

50 100 150 200 250 Claimed X(5568) state Combinatorial

) > 10 GeV

s

B (

T

p LHCb

Pull

4 − 2 − 2 4

(MeV) )

±

π

s

m(B

5550 5600 5650 5700 5750 5800 5850 5900 5950 6000

Candidates / (5 MeV)

10 20 30 40 50 60 70 80 90 Claimed X(5568) state Combinatorial

) > 15 GeV

s

B (

T

p LHCb

Pull

4 − 2 − 2 4

(MeV) )

±

π

s

m(B

5550 5600 5650 5700 5750 5800 5850 5900 5950 6000

(MeV) )

+

π

s

• m(D

5300 5350 5400 5450 5500 5550 5600

Candidates / (3 MeV)

1000 2000 3000 4000 5000 6000

LHCb (MeV) ) φ ψ m(J/

5200 5250 5300 5350 5400 5450 5500

Candidates / (3 MeV)

2000 4000 6000 8000 10000 12000

LHCb }

106k Bs0 Add π±, try various pT cuts... Upper limits set on (X/Bs) cor. yield ratio:

⇢LHCb

X

(pT(B0

s) > 5 GeV)

< 0.011 (0.012) , ⇢LHCb

X

(pT(B0

s) > 10 GeV)

< 0.021 (0.024) , ⇢LHCb

X

(pT(B0

s) > 15 GeV)

< 0.018 (0.020) .

... vs (8.6 ± 1.9 ± 1.4)% at D0 (but different environment) And then...

at 90% (95%) CL

Bs0 → J/𝜔 𝜚

Bs0 → Ds− π+

Aug 2016: LHCb tries to confirm peak, finds nothing despite larger Bs0 sample, extra mode.

SLIDE 12

X(5568) : Nor at CMS

12 CMS: arXiv:1712.06144 (submitted to PRL)

) [GeV]

−

K

+

K ψ M(J/

5.2 5.3 5.4 5.5

Candidates / 5 MeV

2000 4000 6000 8000 10000

278 ± 277 = 49

s B

N MeV 0.06 ± = 5366.54

s B

µ MeV 0.18 ± = 8.03

1

σ MeV 0.5 ± = 18.6

2

σ 0.02 ± = 0.47 f

Data Fit Signal Background (8 TeV)

• 1

19.7 fb

CMS

5.5 5.6 5.7 5.8 5.9

Candidates / 5 MeV

200 400 600 800

(a)

) > 10 GeV

s

(B

T

p Data Fit

(8 TeV)

• 1

19.7 fb

CMS ) [GeV]

±

π

s

(B

Δ

M

5.5 5.6 5.7 5.8 5.9

Pull

2 − 2

5.5 5.6 5.7 5.8 5.9

Candidates / 5 MeV

200 400 600

(b)

) > 15 GeV

s

(B

T

p Data Fit

(8 TeV)

• 1

19.7 fb

CMS ) [GeV]

±

π

s

(B

Δ

M

5.5 5.6 5.7 5.8 5.9

Pull

2 − 2

17 Dec 2017: CMS tries to confirm peak, also finds nothing.

49k Bs0 Add π±, try various pT cuts...

→

rX < 1.1% at 95% CL for pT(B0

s) > 10 GeV and

rX < 1.0% at 95% CL for pT(B0

s) > 15 GeV.

... vs (8.6 ± 1.9 ± 1.4)% at D0, but again different production environment. And just 10 days later...

Bs0 → J/𝜔 K+K−

SLIDE 13

2

c Candidates per 5 MeV/

2

c GeV/

)

±

π

s

M(B

5.5 5.6 5.7 5.8 5.9 20 40 60 80 100 120

signal region

s

B sideband regions

s

B

X(5568) : Nor at CDF

13

27 Dec 2017: CDF searches, finds nothing, sets UL.

2

c Candidates per 5 MeV/

2

c GeV/

) φ ψ M(J/

5.2 5.275 5.35 5.425 5.5 200 400 600 800

2

c Candidates per 5 MeV/

2

c GeV/

)

±

π

s

M(B

5.5 5.6 5.7 5.8 5.9 20 40 60 80 100 120

CDF: arXiv:1712.09620

3.6k Bs0 Add π±... Limit on corrected yield ratio: 𝜍(X/Bs) < 6.7% at 95% CL ... vs (8.6 ± 1.9 ± 1.4)% at D0.
 NB same environment And then just two days later...

Scaling D0 results to CDF...

Bs0 → J/𝜔 𝜚

SLIDE 14

X(5568) : D0 still sees it!

14

29 Dec 2017: D0 publishes second analysis with different decay mode: semileptonic
 Bs0 → Ds− μ+ X... 3.2σ signal!

D0: arXiv:1712.10176

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 50 100 150 200 (a)

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

Semileptonic Data Fit Background Signal Effect. Semileptonic Hadronic (from Ref. [15]) Cone cut No cone cut Cone cut No cone cut Fitted mass, MeV/c2 5566.4+3.4

−2.8 +1.5 −0.6

5566.7+3.6

−3.4 +1.0 −1.0

5567.8 ± 2.9+0.9

−1.9

5567.8 Fitted width, MeV/c2 2.0+9.5

−2.0 +2.8 −2.0

6.0+9.5

−6.0 +1.9 −4.6

21.9 ± 6.4+5.0

−2.5

21.9 Fitted number of signal events 121+51

−34 +9 −28

139+51

−63 +11 −32

133 ± 31 ± 15 106 ± 23 (stat) Local significance 4.3 σ 4.5 σ 6.6 σ 4.8 σ Significance with systematics 3.2 σ 3.4 σ 5.6 σ

• Significance with LEE+systematics
• 5.1 σ

3.9 σ

e obtain a production ratio f

• f

h 7.3+2.8

2.4 (stat)+0.6 1.7 (syst)

i %,

𝜍(X/Bs) = But a few weeks afterwards...

X(5568)

SLIDE 15

Events / 2 MeV 50 100 150 200 250 300 350

Data Signal (S) Background (B) Fit(S+B) D0 mass peak

) [MeV]

±

π

s

B ( m 5600 5700 5800

σ (data-fit)/

2 − 2

ATLAS

• 1

=7 TeV, 4.9 fb s

• 1

=8 TeV, 19.5 fb s )> 15 GeV

s

(B

T

p

X(5568) : But ATLAS does not

15 ATLAS: arXiv:1802.01840

) [MeV]

• K

+

K ψ J/ ( m 5200 5300 5400 5500 5600 Events / 5 MeV 1000 2000 3000 4000 5000 6000 7000 8000 9000

Data Signal (S) Background (B) Fit(S+B)

ATLAS

• 1

=7 TeV, 4.9 fb s

• 1

=8 TeV, 19.5 fb s

6 Feb 2018: ATLAS joins the fray!

53k Bs0 Add π±, try various pT cuts...

Events / 2 MeV 100 200 300 400 500

Data Signal (S) Background (B) Fit(S+B) D0 mass peak

) [MeV]

±

π

s

B ( m 5600 5700 5800

σ (data-fit)/

2 − 2

ATLAS

• 1

=7 TeV, 4.9 fb s

• 1

=8 TeV, 19.5 fb s )> 10 GeV

s

(B

T

p

ρ(X/B0

s) < 1.5% at 95% CL for pT (B0 s) > 10 GeV/c

ρ(X/B0

s) < 1.6% at 95% CL for pT (B0 s) > 15 GeV/c

Limit on corrected yield ratio: Wow.

Bs0 → J/𝜔 K+K−

SLIDE 16

The ongoing X(5568) mystery

• This remains a mystery.
• LHC samples have much larger Bs0 stats and disfavour D0

result assuming conventional heavy quark production.

• ... but cannot rule it out absolutely due to different

production environments.

• CDF has the same environment as D0 and does not confirm

it... but lower stats => the UL does not fully rule it out.

• But perhaps by adding more decay modes, this might be resolved.
• LHCb was quicker off the mark (data model is better
• ptimised for B physics) but ATLAS and CMS Run1 data

samples had comparable statistics in the end.

• Bodes well for future spectroscopy studies at the big

detectors!

16

SLIDE 17

17

Round-up of other updates since La Thuile 2017

• Five new narrow Ωc0 → Ξc+ K− states
• Search for weakly decaying b-flavoured pentaquarks
• Excited Bc+ states
• Precise measurements of χc1 and χc2
• A promising first look at χb → 𝛷γ (𝛷 → μ+μ−)

SLIDE 18

) [MeV]

−

K

+ c

Ξ ( m 3000 3100 3200 3300 Candidates / (1 MeV) 100 200 300 400 LHCb

−

K

+ c

Ξ Full fit Background Feed-downs sidebands

+ c

Ξ

Five new narrow Ωc0 → Ξc+ K− states

• Fit takes into account


feed-down from
 Ωc0 → Ξc′+ K−,
 Ξc′+ → Ξc+ γ
 with missing photon

• Exotic interpretations


possible for unusually
 narrow states (3050, 3119)


• Broad structure ~ 3200 MeV

18 LHCb: PRL 118, 182001 (2017) Belle: arXiv:1711.07927

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)0

fd

700 ± 40 ± 140 Ωc(3090)0

fd

220 ± 60 ± 90 Ωc(3119)0

fd

190 ± 70 ± 20

e.g. Montaña et al: arXiv:1709.08737 e.g. Debastiani et al: arXiv:1710.04231

2011, 2012, 2015.

Belle confirms 4/5 states.

SLIDE 19

Search for weakly decaying b-flavoured pentaquarks

• So far, observed pentaquarks contain charm and decay strongly.
• Skyrme: (bqqqq/bqqqq) may be tightly bound and decay weakly.
• LHCb search up to strong


threshold in suitable
 final states:

19 LHCb: arXiv:1712.08086, submitted to PRD Skyrme, Proc. Roy. Soc. Lond. A260 (1961) 127

Mode Quark content Decay mode Search window I bduud P +

B0p → J/ψK+π−p

4668–6220 MeV II buudd P −

Λ0

bπ− → J/ψK−π−p

4668–5760 MeV III bduud P +

Λ0

bπ+ → J/ψK−π+p

4668–5760 MeV IV bsuud P +

B0

sp → J/ψφp

5055–6305 MeV

[MeV] p)

• π

+

K ψ J/ m(

5000 5500 6000

Candidates/(4 MeV)

2 4 6 8 10 12

LHCb

(a)

• 5000

5500

Candidates/(4 MeV)

5 10 15 20 25

LHCb

(b)

[MeV] p)

+

π

• K

ψ J/ m(

5000 5500

Candidates/(4 MeV)

5 10 15 20 25

LHCb

(c)

) [MeV] p φ ψ J/ m(

5500 6000

Candidates/(4 MeV)

1 2 3 4 5 6

LHCb

(d)

p)

• π

K ψ J/ m( [MeV]

No signal => scan in steps and set upper limits relative to Λb0:

R = σ(pp → PBX) · B(PB → J/ψX) σ(pp → Λ0

bX) · B(Λ0 b → J/ψK−p)

I II III IV

Upper limits typically
 R < few x 10−3 (see backup)

SLIDE 20

Excited Bc+ states

20 ATLAS: PRL 113, 212004 (2014)

[MeV]

π ψ J/

m 5800 6000 6200 6400 6600 6800 Events / 40 MeV 10 20 30 40 50 60 70 ATLAS

• 1

Ldt = 4.9 fb

∫

= 7 TeV s

8 MeV ± = 6282

c

B

m 23 ± = 100

c

B

N 12 MeV ± = 49 σ

[MeV]

π ψ J/

m 5800 6000 6200 6400 6600 6800 Events / 40 MeV 20 40 60 80 100 120 140 160 ATLAS

• 1

Ldt = 19.2 fb

∫

= 8 TeV s

6 MeV ± = 6277

c

B

m 25 ± = 227

c

B

N 8 MeV ± = 50 σ

In 2014, ATLAS observes structure in (Bc+ π+ π−):

Bc+ → J/ψ π+
 (327 ± 34)

) [MeV] π )-2m(

c

)-m(B π π

c

m(B 100 200 300 400 500 600 700 Events / 20 MeV 2 4 6 8 10 12 14 16 18 20

• 1

Ldt = 4.9 fb

∫

= 7 TeV s Data Wrong-charge combinations

ATLAS ATLAS

5 MeV ± = 288

π π

c

B

Q 4 MeV ± = 18

π π

c

B

σ 6 ± = 22

π π

c

B

N

) [MeV] π )-2m(

c

)-m(B π π

c

m(B 100 200 300 400 500 600 700 Events / 20 MeV 5 10 15 20 25 30 35 40

• 1

Ldt = 19.2 fb

∫

= 8 TeV s

ATLAS ATLAS

Data Wrong-charge combinations

5 MeV ± = 288

π π

c

B

Q 4 MeV ± = 18

π π

c

B

σ 13 ± = 35

π π

c

B

N

add π+ π− Bc+(2S) → Bc+ π+ π− (57 ± 14): 5.2σ inc LEE

2011 2012 2011 2012

Bc+ Bc+

SLIDE 21

Mass (MeV)

6000 6400 6800 7200 7600

1S0

6271 6338 6855 6887 6706 7250 7272 7122 6741 6750 7145 7150 6768 7164 7572 7588 7455 7472 7475 7487 7028 7365 7036 7041 7372 7376 7045 7380 7269 7565 7271 7568 7266 7276 7563 7571

3S1 3P0 P1 3P2 3D1 D2 3D3 3F2 F3 3F4

Bc Mass Spectrum 1-

Excited Bc+ states

• Expect two structures in Bc+ π+ π−:
• Bc(21S0)+ → Bc+ π+ π−
• Bc(23S1)+ → Bc*+ π+ π−, Bc*+ → Bc+ γ
• Higher production rate of Bc(23S1)+
• Bc(21S0)+ peak at its mass,


predicted to be ~ [6830,6890] MeV

• Bc(23S1)+ peak offset from its true mass


by missing photon; separation between the two peaks is





and is predicted to be [0, 35] MeV

• So ATLAS may be seeing
• Just Bc(21S0)+
• Just Bc(23S1)+ with missing photon
• Mixture of Bc(21S0)+ and Bc(23S1)+

21

∆M ≡ ⇥ M(B∗+

c ) − M(B+ c )

⇤ − ⇥ M(B∗

c(2S)+) − M(Bc(2S)+)

⇤ ,

Gershtein et al., Sov. J. Nucl. Phys. 48, 327 (1988)
 Chen & Kuang, PRD 46, 1165 (1992)
 Eichten & Quigg, PRD 49, 5845 (1994) Kiselev et al, PRD 51, 3613 (1995)
 Gupta & Johnson, PRD 53, 312 (1996) Fulcher, PRD 60, 074006 (1999) Ebert et al, PRD 67, 014027 (2003) Godfrey, PRD 70, 054017 (2004) Wei & Guo, PRD 81, 076005 (2010) Rai & Vinodkumar, Pramana 66, 953 (2006)
 Abd El-Hady et al, PRD 71, 034006 (2005) Gouz et al, Phys.Atom.Nucl. 67, 1559 (2004); Yad.Fiz. 67, 1581 (2004) Godfrey, PRD 70, 054017 (2004)

SLIDE 22

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

50 100 150 200 250 300 350

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

20 40 60 80 100 120

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

10 20 30 40 50 60

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

5 10 15 20 25 30 35 40 45

1 −

LHCb 2 fb = 8 TeV s

WS in green

Excited Bc+ states

22 LHCb: JHEP (2018) 2018: 138

add π+ π−

]

2

c ) [MeV/

+

π ψ / J ( M

6200 6300 6400 6500

)

2

c Candidates / (8 MeV/

100 200 300 400 500 600 700 800 900

Data Total fit

+

π ψ / J →

+ c

B

+

K ψ / J →

+ c

B Combinatorial

1 −

LHCb 2 fb = 8 TeV s

In 2017: LHCb doesn't confirm the observation with a larger Bc+ sample

Bc+ → J/ψ π+ (3325 ± 73)

Bins of MVA classifier output m(Bc+ π+ π−)

• UL on yield ratio (resonance/Bc+) set as function

• f mass for different hypotheses, see backups.
• LHCb & ATLAS results in mild tension but not


incompatible given uncertainties & different
 kinematics, efficiencies (low vs high pT).

• LHC experiments should be able to clear this up with Run2 data.

⟵ Increasing expected purity Bc+

SLIDE 23

) [MeV]

c2

χ ( Γ 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 CBAL SPEC LHCb E760 E835 0.13 ± Old avg: 1.95 0.11 ± New avg: 1.99

Precise measurements of χc1 and χc2

• χc1 and χc2 states well known
• Recently, BESIII observed χc(0,1,2) → J/𝜔 e+ e−
• LHCb: first observation of χc(1,2) → J/𝜔 μ+ μ−
• Competitive with world-best measurements of mass, width.

23

3.5 3.55 200 400 600 800 1000 1200 1400 1600 1800 2000

3.5 3.55 200 400 600 800 1000 1200 1400 1600 1800 2000 3.5 3.55 200 400 600 800 1000 1200 1400 1600 1800 2000

3.5 3.55

4 − 2 − 2 4

3.5 3.55 200 400 600 800 1000 1200 1400 1600 1800 2000

m(J/ψµ+µ−) [GeV] Candidates/(2 MeV) Pull LHCb

fit result χc1,c2 → J/ψµ+µ− background

Quantity LHCb Best previous [MeV] measurement measurement World average m(χc1) 3510.71 ± 0.10 3510.72 ± 0.05 3510.66 ± 0.07 m(χc2) 3556.10 ± 0.13 3556.16 ± 0.12 3556.20 ± 0.09 Γ(χc2) 2.10 ± 0.20 1.92 ± 0.19 1.93 ± 0.11

Width of χc2

2011, 2012, 2015, 2016.

E760: Nucl. Phys. B373, 35 (1992) E835: Nucl. Phys. B717, 34 (2005) BESIII: PRL 118, 221802 (2017) LHCb: PRL 119, 221801 (2017)

[E760/E835]

SLIDE 24

χb → 𝛷γ (𝛷 → μ+μ−)

• Preliminary look at 2017 data by CMS.
• Reconstruct γ from converted photons
• Possibility to improve WA with full analysis (esp. for 3P states)

24 CMS-DP-2017-029

b → (→ +-)

37

Mass[b1(1P)] = 9.890 ± 0.001 (stat.) GeV, Mass[b2(1P)] = 9.910 ± 0.001 (stat.) GeV Mass[b1(2P)] = 10.248 ± 0.001 (stat.) GeV, Mass[b2(2P)] = 10.260 ± 0.001 (stat.) GeV Mass[b1(3P)] = 10.497 ± 0.001 (stat.) GeV, Mass[b2(3P)] = 10.507 ± 0.001 (stat.) GeV

Yellow peak is misreconstructed
 χbX(2P) → 𝛷(2S)γ, 𝛷(2S) → 𝛷(1S) π+π−

SLIDE 25

Summary

• Lots and lots of spectroscopy work ongoing at LHC, in

many areas

• Things we didn't have time to talk about include
• Pentaquark discovery
• Exotic tetraquark-like states
• Charmonia X family
• More singly heavy baryon resonances
• More bottomonia
• and surely more
• Heavy flavour physics is


LHCb's bread and butter--but
 important contributions from ATLAS & CMS too.

• Look forward to more analyses with the big Run2 dataset!

25

SLIDE 26

26

˜ t

SLIDE 27

Backup stuff

• Too many references
• More on X(5568) cone cut
• Limits for weakly decaying b-flavoured PQ
• Limits for excited Bc states under different hypotheses
• More info on CMS 2017 plot
• SELEX Ξcc results
• ...

27

SLIDE 28

LHCb references: manifest exotics

• LHCb-PAPER-2017-043 : arXiv:1712.08086 : A search for weakly decaying $b$-flavored pentaquarks
• LHCb-PAPER-2017-011 : arXiv:1704.07900 : Observation of the decays $\Lambda_b^0 \to \chi_{c1} p K^-$ and $

\Lambda_b^0 \to \chi_{c2} p K^-$

• LHCb-PAPER-2016-053 : arXiv:1701.05274 : Observation of the $\varXi^{-}_{b}\to J/\psi\varLambda K^{-}$ decay
• LHCb-PAPER-2016-029 : arXiv:1608.00435 : Search for structure in the $B_s^0\pi^\pm$ invariant mass spectrum
• LHCb-PAPER-2016-019 ; arXiv:1606.07898 : Amplitude analysis of $B^+\to J/\psi \phi K^+$ decays
• LHCb-PAPER-2016-018 ; arXiv:1606.07895 : Observation of $J/\psi\phi$ structures consistent with exotic states

from amplitude analysis of $B^+\to J/\psi \phi K^+$ decays

• LHCb-PAPER-2016-015 : arXiv:1606.06999 : Evidence for exotic hadron contributions to $\Lambda_b^0 \to J/\psi p

\pi^-$ decays

• LHCb-PAPER-2016-009 : arXiv:1604.05708 : Model-independent evidence for $J/\psi p$ contributions to $

\Lambda_b^0\to J/\psi p K^-$ decays

• LHCb-PAPER-2015-038 ; arXiv:1510.01951 : Model-independent confirmation of the $Z(4430)^-$ state
• LHCb-PAPER-2015-029 : arxiv:1507.03414 : Observation of $J/\psi p$ resonances consistent with pentaquark states

in ${\Lambda_b^0\to J/\psi K^-p}$ decays

• LHCb-PAPER-2014-014 ; arXiv:1404.1903 : Observation of the resonant character of the $Z(4430)^-$ state
• LHCb-PAPER-2011-033 : arXiv:1202.5087 : Search for the $X(4140)$ state in $B^+\to J/\psi\phi K^+$ decays

28

Blue: covered in main slides Orange: Result new since La Thuile 2017 and not covered in main slides

SLIDE 29

LHCb references: mesons

• LHCb-PAPER-2017-042 ; arXiv:1712.04094 : Search for excited Bc+ states
• LHCb-PAPER-2017-036 : arXiv:1709.04247 : Precise measurement of the $\chi_{c1}$ and $\chi_{c2}$ resonance

parameters with the decays $\chi_{c1,c2}\to J/\psi\mu^+\mu^-$

• LHCb-PAPER-2017-007 : arXiv:1706.07013 : Study of charmonium production in ${b}$-hadron decays and first

evidence for the decay ${{{B}} ^0_{{s}}} \!\rightarrow \phi \phi \phi $

• LHCb-PAPER-2016-016 : arXiv:1607.06446 : Observation of $\eta_{c}(2S) \to p \bar p$ and search for $X(3872) \to

p \bar p$ decays

• LHCb-PAPER-2015-015 : arXiv:1504.06339 : Quantum numbers of the $X(3872)$ state and orbital angular

momentum in its $\rho^0 J/\psi$ decays

• LHCb-PAPER-2013-001 : arXiv:1302.6269 : Determination of the $X(3872)$ meson quantum numbers

29

SLIDE 30

LHCb references: baryons

• LHCB-PAPER-2017-023 ; arXiv:1708.05808 : Search for baryon-number-violating Ξb0 oscillations
• LHCb-PAPER-2017-016 ; arXiv:1709.01920 : Measurement of the shape of the Λb0 → Λc+ μ− νbarμ differential decay

rate

• LHCB-PAPER-2017-018 ; arXiv:1707.01621 : Observation of the doubly charmed baryon Ξcc++
• LHCB-PAPER-2017-002 ; arXiv:1703.04639 : Observation of five new narrow Ωc0 states decaying to Ξc+ K−
• LHCB-PAPER-2016-061 ; arXiv:1701.07873 : Study of the D0 p amplitude in Λb0 → D0 p π− decays
• LHCB-PAPER-2016-010 ; arXiv:1604.03896 : Measurement of the properties of the Ξb*0 baryon
• LHCB-PAPER-2016-008 ; arXiv:1604.01412 : Measurement of the mass and lifetime of the Ωb− baryon
• LHCB-PAPER-2015-060 ; arXiv:1603.06961 : Observation of Λb0 → ψ(2S) p K− and Λb0 → J/ψ π+ π− p K− decays

and a measurement of the Λb0 baryon mass

• LHCB-PAPER-2015-047 ; arXiv:1510.03829 : Evidence for the strangeness-changing weak decay Ξb− → Λb0 π−
• LHCB-PAPER-2014-061 ; arXiv:1411.4849 : Observation of two new Ξb− baryon resonances
• LHCB-PAPER-2014-048 ; arXiv:1409.8568 : Precision measurement of the mass and lifetime of the Ξb− baryon
• LHCB-PAPER-2014-021 ; arXiv:1405.7223 : Precision measurement of the mass and lifetime of the Ξb0 baryon
• LHCb-PAPER-2014-010 ; arXiv:1405.1543 : Measurement of the Ξb− and Ωb− baryon lifetimes
• LHCB-PAPER-2014-003 ; arXiv:1402.6242 : Precision measurement of the ratio of the Λb0 to B0 lifetimes
• LHCB-PAPER-2014-002 ; arXiv:1403.3606 : Study of beauty hadron decays into pairs of charm hadrons
• LHCB-PAPER-2013-056 ; arXiv:1311.4823 : Studies of beauty baryon decays to D0 p h− and Λc+ h− final states
• LHCB-PAPER-2013-049 ; arXiv:1310.2538 : Search for the doubly charmed baryon Ξcc+
• LHCB-PAPER-2012-048 ; arXiv:1302.1072 : Measurement of the Λb0, Ξb− and Ωb− baryon masses
• LHCB-PAPER-2012-012 ; arXiv:1205.3452 : Observation of excited Λb0 baryons
• LHCB-PAPER-2011-035 ; arXiv:1112.4896 : Measurement of b-hadron masses

30

SLIDE 31

ATLAS references

• BPHY-2017-02 : arXiv:1802.01840 : Search for a Structure in the B0sπ± Invariant Mass Spectrum with the ATLAS

Experiment

• BPHY-2015-03 : arXiv:1610.09303 : Measurements of $\psi(2S)$ and $X(3872) \to J/\psi\pi^+\pi^-$ production in

$pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector

• BPHY-2013-07 : arXiv:1410.4409 : Search for the Xb and other hidden-beauty states using the π+π-ϒ(1S) channel

at ATLAS

• BPHY-2012-04 : arXiv:1407.1032 : Observation of an Excited Bc± Meson State with the ATLAS Detector
• BPHY-2013-05 : arXiv:1404.7035 : Measurement of chi_c1 and chi_c2 production with sqrt(s) = 7 TeV pp collisions

at ATLAS

• BPHY-2011-07 : arXiv:1112.5154 : Observation of a new chi_b state in radiative transitions to Upsilon(1S) and

Upsilon(2S) at ATLAS

• ATLAS-CONF-2011-136 : Observation of the χc1(1P) and χc2(1P) charmonium states in √s = 7 TeV pp collisions at

the ATLAS experiment

• See also: ATLAS B Physics and Light States publications

31

SLIDE 32

CMS references

• CMS-BPH-16-002 : arXiv:1712.06144 : Search for the X(5568) state decaying into $\mathrm{B}^{0}_{\mathrm{s}}

\pi^{\pm}$ in proton-proton collisions at $\sqrt{s} = $ 8 TeV

• CMS-BPH-13-008 : arXiv:1710.08949 : Measurement of b hadron lifetimes in pp collisions at $\sqrt{s} = $ 8 TeV
• CMS-BPH-12-001 : arXiv:1204.5955 : Observation of a New $\Xi_{b}$ Baryon
• CMS-BPH-11-026 : arXiv:1309.6920 : Observation of a peaking structure in the J/psi phi mass spectrum from B(+/-)

to J/psi phi K(+/-) decays

• CMS-BPH-11-016 : arXiv:1309.0250 : Search for a new bottomonium state decaying to Upsilon(1S) pi+ pi- in pp

collisions at sqrt(s) = 8 TeV

• CMS-BPH-11-011 : arXiv:1302.3968 : Measurement of the X(3872) production cross section via decays to J/psi pi pi

in pp collisions at sqrt(s) = 7 TeV

• CMS-DP-2017-029 : Heavy Flavour distributions from CMS with 2017 data at $\sqrt{s} = 13$ TeV
• See also: CMS B Physics and Quarkonia Publications

32

SLIDE 33

Other experimental references

• Belle : arXiv:1711.07927 : Observation of Excited Ωc Charmed Baryons in e+e− Collisions
• Belle : arXiv:1408.6457 : Observation of a new charged charmoniumlike state in B -> J/psi K pi decays
• CDF : arXiv:1712.09620 : A search for the exotic meson X(5568) with the Collider Detector at Fermilab
• CDF : arXiv:0903.2229 : Evidence for a Narrow Near-Threshold Structure in the J/ψφ Mass Spectrum in B+→J/

ψφK+ Decays

• D0 : arXiv:1712.10176 : Study of the X±(5568) state with semileptonic decays of the B0s meson
• D0 : arXiv:1602.07588 : Evidence for a B0sπ± State
• D0 : arXiv:1508.07846 : Inclusive production of the X(4140) state in ppbar collisions at D0
• D0 : arXiv:1309.6580 : Search for the X(4140) state in B+->J/psi phi K+ decays with the D0 detector

33

SLIDE 34

Ξcc theory refs

34

[6] S. S. Gershtein, V. V. Kiselev, A. K. Likhoded, and A. I. Onishchenko, Spectroscopy

• f doubly heavy baryons, Phys. Atom. Nucl. 63 (2000) 274, arXiv:hep-ph/9811212,

[Yad. Fiz. 63, 334 (2000)]. [7] S. S. Gershtein, V. V. Kiselev, A. K. Likhoded, and A. I. Onishchenko, Spec- troscopy of doubly charmed baryons: Ξ+

cc and Ξ++ cc , Mod. Phys. Lett. A14 (1999) 135,

arXiv:hep-ph/9807375. [8] C. Itoh, T. Minamikawa, K. Miura, and T. Watanabe, Doubly charmed baryon masses and quark wave functions in baryons, Phys. Rev. D61 (2000) 057502. [9] S. S. Gershtein, V. V. Kiselev, A. K. Likhoded, and A. I. Onishchenko, Spectroscopy

• f doubly heavy baryons, Phys. Rev. D62 (2000) 054021.

[10] K. Anikeev et al., B physics at the Tevatron: Run II and beyond, in Workshop on B physics at the Tevatron: Run II and beyond, Batavia, Illinois, September 23-25, 1999, 2001. arXiv:hep-ph/0201071. [11] V. V. Kiselev and A. K. Likhoded, Baryons with two heavy quarks, Phys. Usp. 45 (2002) 455, arXiv:hep-ph/0103169. [12] D. Ebert, R. N. Faustov, V. O. Galkin, and A. P. Martynenko, Mass spectra of doubly heavy baryons in the relativistic quark model, Phys. Rev. D66 (2002) 014008, arXiv:hep-ph/0201217. [13] D.-H. He et al., Evaluation of the spectra of baryons containing two heavy quarks in a bag model, Phys. Rev. D70 (2004) 094004, arXiv:hep-ph/0403301. [14] C.-H. Chang, C.-F. Qiao, J.-X. Wang, and X.-G. Wu, Estimate of the hadronic production of the doubly charmed baryon Ξcc in the general-mass variable-flavor- number scheme, Phys. Rev. D73 (2006) 094022, arXiv:hep-ph/0601032. [15] W. Roberts and M. Pervin, Heavy baryons in a quark model, Int. J. Mod. Phys. A23 (2008) 2817, arXiv:0711.2492. [16] A. Valcarce, H. Garcilazo, and J. Vijande, Towards an understanding of heavy baryon spectroscopy, Eur. Phys. J. A37 (2008) 217, arXiv:0807.2973. [17] J.-R. Zhang and M.-Q. Huang, Doubly heavy baryons in QCD sum rules, Phys. Rev. D78 (2008) 094007, arXiv:0810.5396. [18] Z.-G. Wang, Analysis of the 1

2 + doubly heavy baryon states with QCD sum rules, Eur.

• Phys. J. A45 (2010) 267, arXiv:1001.4693.

[19] M. Karliner and J. L. Rosner, Baryons with two heavy quarks: masses, production, decays, and detection, Phys. Rev. D90 (2014) 094007, arXiv:1408.5877. [20] K.-W. Wei, B. Chen, and X.-H. Guo, Masses of doubly and triply charmed baryons,

• Phys. Rev. D92 (2015) 076008, arXiv:1503.05184.

[21] Z.-F. Sun and M. J. Vicente Vacas, Masses of doubly charmed baryons in the extended on-mass-shell renormalization scheme, Phys. Rev. D93 (2016) 094002, arXiv:1602.04714. [22] C. Alexandrou and C. Kallidonis, Low-lying baryon masses using Nf = 2 twisted mass clover-improved fermions directly at the physical pion mass, Phys. Rev. D96 (2017) 034511, arXiv:1704.02647. [23] B. O. Kerbikov, M. I. Polikarpov, and L. V. Shevchenko, Multiquark masses and wave functions through a modified Green function Monte Carlo method, Nucl. Phys. B331 (1990) 19. [24] S. Fleck and J.-M. Richard, Baryons with double charm, Prog. Theor. Phys. 82 (1989) 760. [25] S. Chernyshev, M. A. Nowak, and I. Zahed, Heavy hadrons and QCD instantons,

• Phys. Rev. D53 (1996) 5176, arXiv:hep-ph/9510326.

[26] T. M. Aliev, K. Azizi, and M. Savcı, Doubly heavy spin-1/2 baryon spectrum in QCD,

• Nucl. Phys. A895 (2012) 59, arXiv:1205.2873.

[27] Z.-F. Sun, Z.-W. Liu, X. Liu, and S.-L. Zhu, Masses and axial currents of the doubly charmed baryons, Phys. Rev. D91 (2015) 094030, arXiv:1411.2117. [28] N. Mathur, R. Lewis, and R. M. Woloshyn, Charmed and bottom baryons from lattice nonrelativistic QCD, Phys. Rev. D66 (2002) 014502, arXiv:hep-ph/0203253. [29] PACS-CS collaboration, Y. Namekawa et al., Charmed baryons at the physical point in 2+1 flavor lattice QCD, Phys. Rev. D87 (2013) 094512, arXiv:1301.4743. [30] Z. S. Brown, W. Detmold, S. Meinel, and K. Orginos, Charmed bottom baryon spectroscopy from lattice QCD, Phys. Rev. D90 (2014) 094507, arXiv:1409.0497. [31] M. Padmanath, R. G. Edwards, N. Mathur, and M. Peardon, Spectroscopy

• f doubly charmed baryons from lattice QCD, Phys. Rev. D91 (2015) 094502,

arXiv:1502.01845. [32] P. P´ erez-Rubio, S. Collins, and G. S. Bali, Charmed baryon spectroscopy and light fla- vor symmetry from lattice QCD, Phys. Rev. D92 (2015) 034504, arXiv:1503.08440. [33] Y. Liu and I. Zahed, Heavy baryons and their exotics from instantons in holographic QCD, Phys. Rev. D95 (2017) 116012, arXiv:1704.03412; Y. Liu and I. Zahed, Heavy and strange holographic baryons, arXiv:1705.01397. [34] C.-W. Hwang and C.-H. Chung, Isospin mass splittings of heavy baryons in heavy quark symmetry, Phys. Rev. D78 (2008) 073013, arXiv:0804.4044. [35] S. J. Brodsky, F.-K. Guo, C. Hanhart, and U.-G. Meißner, Isospin splittings of doubly heavy baryons, Phys. Lett. B698 (2011) 251, arXiv:1101.1983. [36] M. Karliner and J. L. Rosner, Isospin splittings in baryons with two heavy quarks,

• Phys. Rev. D96 (2017) 033004, arXiv:1706.06961.

[37] B. Guberina, B. Meli´ c, and H. ˇ Stefanˇ ci´ c, Inclusive decays and lifetimes of doubly charmed baryons, Eur. Phys. J. C9 (1999) 213, Erratum ibid. C13 (2000) 551, arXiv:hep-ph/9901323. [38] V. V. Kiselev, A. K. Likhoded, and A. I. Onishchenko, Lifetimes of doubly charmed baryons: Ξ+

cc and Ξ++ cc , Phys. Rev. D60 (1999) 014007, arXiv:hep-ph/9807354.

[39] C.-H. Chang, T. Li, X.-Q. Li, and Y.-M. Wang, Lifetime of doubly charmed baryons,

• Commun. Theor. Phys. 49 (2008) 993, arXiv:0704.0016.

[40] A. V. Berezhnoy and A. K. Likhoded, Doubly heavy baryons, Phys. Atom. Nucl. 79 (2016) 260, [Yad. Fiz. 79, 151 (2016)].

SLIDE 35

D0 X(5568): Cone cut

35 D0: PRL 117, 022003 (2016)

5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 10 20 30 40 50 60 70 80 90

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

DATA Fit with background shape fixed Background Signal

(a)

5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9

• 10
• 5

5 10 15

]

2

) [GeV/c

±

π

S

(B

m

Residuals (Data-Fit) 5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 20 40 60 80 100 120

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

DATA Fit with background shape fixed Background Signal

(b)

5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9

• 25
• 20
• 15
• 10
• 5

5 10 15 20

]

2

) [GeV/c

±

π

S

(B

m

Residuals (Data-Fit)

• FIG. 3: The m(B0

sπ±) distribution together with the back-

ground distribution and the fit results (a) after applying the ∆R < 0.3 cone cut and (b) without the cone cut.

5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 100 200 300 400 500 600 700

]

2

) [GeV/c

±

π

S

(B

m

N events / 8 MeV

Background model w/o cone cut Background model with cone cut Fits to background function

• FIG. 2: The combined background for the m(B0

sπ±) distri-

bution described in the text and the fit to that distribution with the ∆R < 0.3 cone cut and without the cone cut.

SLIDE 36

D0 X(5568): Cone cut

36 D0: arXiv:1712.10176

π φ

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 50 100 150 200 250

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

Data Data with Cone Cut

• FIG. 3. The m(B0

sπ±) distribution for the semileptonic data

with (red upward triangles) and without (black downward triangles) the cone cut (color online). Below 5.56 GeV/c2 the red and black points have the same values.

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 20 40 60 80 100 120 (a)

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

Same Sign Data Fit with smoothed MC

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 10 20 30 40 50 60 70 80 (b)

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

Same Sign Data Fit with smoothed MC

• FIG. 6. The comparison of the m(B0

sπ±) background only distributions a) without the cone cut and b) with the cone cut,

• btained using the weighted MC (histogram) and from the same sign data samples (points with error bars). The fluctuations

in the number of MC events with the cone cut are due to the weighting procedure and the size of the sample.

5.6 5.7 5.8 5.9 500 1000 1500

2

N events / 8 MeV/c ]

2

) [GeV/c

±

π

S

(B m D0 Background Model

(a) 5.6 5.7 5.8 5.9 1000 2000 3000

2

N events / 8 MeV/c ]

2

) [GeV/c

±

π

S

(B m D0 Background Model

(b)

• FIG. 7. The background model produced according to the procedure described in the text is showm along with background

function (1) (a) with and (b) without the cone cut. The grey band shows the systematic uncertainties on the background model (see Section VI D).

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 50 100 150 200 (a)

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

Semileptonic Data Fit Background Signal

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 50 100 150 200 250 (b)

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

Semileptonic Data Fit Background Signal

• FIG. 9. The m(B0

sπ±) distribution (a) with and (b) without the cone cut. The fitting function is superimposed (see text for

details).

SLIDE 37

D0 X(5568): Cone cut

37

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 50 100 150 200 250

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

(a)

• 1

D0 Run II, 10.4 fb

Semileptonic Data Hadronic Data 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 50 100 150 200 250 300

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

(b)

• 1

D0 Run II, 10.4 fb

Semileptonic Data Hadronic Data

• FIG. 11. The m(B0

sπ±) distribution for the hadronic (red squares) and semileptonic (black circles) data with the combined

fitting function superimposed (a) with and (b) without the cone cut. (see text for details, the resulting fit parameters are given in Table VIII). The background parametrization function is taken from Eq. 1.

D0: arXiv:1712.10176

SLIDE 38

Search for weakly decaying b-flavoured pentaquarks

38

) [MeV] p

• π

+

K ψ J/ m(

b

Λ

B) × σ /(

B

P

B) × σ UL( ) [MeV] p π K ψ J/ m(

b

Λ

B) × σ /(

B

P

B) × σ UL( ) [MeV] p

+

π K ψ J/ m(

b

Λ

B) × σ /(

B

P

B) × σ UL( ) [MeV] p φ ψ J/ m(

b

Λ

B) × σ /(

B

P

B) × σ UL(

5000 5500 6000

3 −

10

LHCb

(a)

• 5000

5500

3 −

10

2 −

10

LHCb

(b)

• 5000

5500

3 −

10

2 −

10

LHCb

(c)

5500 6000

3 −

10

2 −

10

LHCb

(d)

R = σ(pp → PBX) · B(PB → J/ψX) σ(pp → Λ0

bX) · B(Λ0 b → J/ψK−p)

Upper limits at 90% CL

LHCb: arXiv:1712.08086, submitted to PRD

SLIDE 39

Excited Bc+ states

39 LHCb: JHEP (2018) 2018: 138

]

2

c ) [MeV/

+

) S

1

(2

c

B ( M

6830 6840 6850 6860 6870 6880 6890

R upper limit on

0.05 0.1 0.15 0.2

CL 90%

+

)

1

S

3

(2

c

B +

+

) S

1

(2

c

B CL 95%

+

)

1

S

3

(2

c

B +

+

) S

1

(2

c

B

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

+

)

1

S

3

(2

c

B ( M Reconstructed

6830 6840 6850 6860 6870 6880 6890

(a) ∆M = 0 MeV

/c2 ]

2

c ) [MeV/

+

) S

1

(2

c

B ( M

6830 6840 6850 6860 6870 6880 6890

R upper limit on

0.05 0.1 0.15 0.2

CL 90%

+

) S

1

(2

c

B CL 95%

+

) S

1

(2

c

B CL 90%

+

)

1

S

3

(2

c

B CL 95%

+

)

1

S

3

(2

c

B

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

+

)

1

S

3

(2

c

B ( M Reconstructed

6810 6820 6830 6840 6850 6860 6870 6880

(b) ∆M = 15 MeV

/c2 ]

2

c ) [MeV/

+

) S

1

(2

c

B ( M

6830 6840 6850 6860 6870 6880 6890

R upper limit on

0.05 0.1 0.15 0.2

CL 90%

+

) S

1

(2

c

B CL 95%

+

) S

1

(2

c

B CL 90%

+

)

1

S

3

(2

c

B CL 95%

+

)

1

S

3

(2

c

B

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

+

)

1

S

3

(2

c

B ( M Reconstructed

6800 6810 6820 6830 6840 6850 6860 6870

(c) ∆M = 25 MeV

/c2 ]

2

c ) [MeV/

+

) S

1

(2

c

B ( M

6830 6840 6850 6860 6870 6880 6890

R upper limit on

0.05 0.1 0.15 0.2

CL 90%

+

) S

1

(2

c

B CL 95%

+

) S

1

(2

c

B CL 90%

+

)

1

S

3

(2

c

B CL 95%

+

)

1

S

3

(2

c

B

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

+

)

1

S

3

(2

c

B ( M Reconstructed

6790 6800 6810 6820 6830 6840 6850 6860

(d) ∆M = 35 MeV

/c2

Figure 4: The upper limits on the ratio R(B(∗)

c (2S)+) at 95% and 90% confidence levels under

different mass splitting ∆M hypotheses.

95% CL UL on R

R = σB(∗)

c

(2S)+

σB+

c

· B(B(∗)

c (2S)+ → B(∗)+ c

π+π−) = NB(∗)

c

(2S)+

NB+

c

· εB+

c

εB(∗)

c

(2S)+

,

√s = 7 TeV √s = 8 TeV ATLAS (0.22 ± 0.08 (stat))/ε7 (0.15 ± 0.06 (stat))/ε8 LHCb – < [0.04, 0.09]

∆M ≡ ⇥ M(B∗+

c ) − M(B+ c )

⇤ − ⇥ M(B∗

c(2S)+) − M(Bc(2S)+)

⇤

R is ratio of excited vs ground-state Bc+ yields, corrected for effic:

SLIDE 40

χb → 𝛷γ (𝛷 → μ+μ−)

40 CMS-DP-2017-029

b → (→ +-)

• Trigger conditions: opposite-sign muon pair with invariant mass in range 8.5-11.5

GeV, pT > 12 GeV, single muons || < 1.5 and vertex-fit probability > 0.5%

• The has pT > 12 GeV
• The is a converted photon
• The distance between the and the vertices along the beam direction is < 1 mm
• The system has a vertex-fit probability > 1%
• Fit method: unbinned extended maximum likelihood

○ Signal: double side Crystal Ball for each peak with common n, ■ m(b2) - m(b1) fixed to previous CMS results ■ first peak corresponds to the misreconstructed decay b(2P) → (2S) (→ (1S)+-) ○ Background: exponential times power law

36

SLIDE 41

χb → 𝛷γ (𝛷 → μ+μ−)

41 CMS-DP-2017-029

b → (→ +-)

37

Mass[b1(1P)] = 9.890 ± 0.001 (stat.) GeV, Mass[b2(1P)] = 9.910 ± 0.001 (stat.) GeV Mass[b1(2P)] = 10.248 ± 0.001 (stat.) GeV, Mass[b2(2P)] = 10.260 ± 0.001 (stat.) GeV Mass[b1(3P)] = 10.497 ± 0.001 (stat.) GeV, Mass[b2(3P)] = 10.507 ± 0.001 (stat.) GeV

SLIDE 42

SELEX Ξcc results

42

1 2 3 4 5 6 7 8 3.46 3.48 3.5 3.52 3.54 3.56 3.58

!

+ c K- "+ and D+ p K-

fitted masses: 3518(3) and 3519(2) MeV/c2

M(ccd) Events/2.5 MeV/c2

SELEX

PRL 89:112001 (2002) and PLB 628:18 (2005)

• In 2002 and 2004, SELEX published results on a weakly-

decaying Ξcc+ at 3518 MeV/c2

• Ξcc+ → Λc+ K− π+: 15.9 events over background of 6.1 ± 0.5 => 6.3σ
• Ξcc+ → p D+ K−: 5.62 events over background of 1.38 ± 0.13 => 4.8σ
• ... and also unpublished results on 4 other claimed Ξcc states
• These observations were not been confirmed.
• Searches by BABAR, Belle, FOCUS, LHCb-(0.65/fb)
• SELEX used O(1600) Λc+, FOCUS O(20k), BaBar+Belle O(1M)

2 4 6 8 10 12 3.3 3.35 3.4 3.45 3.5 3.55 3.6

!

+ c K- "+

Mass 3520 MeV/c2 Sigma 3 MeV/c2 signal/!(back) 16/!(6) = 6.5# Poisson Prob < 10-6

M(! + c K- "+) GeV/c2 Events/5 MeV/c2

3425 3450 3475 3500 3525 3550 3443 MeV 3460 MeV 17 MeV L=0 3520 MeV 3541 MeV 21 MeV L>0 78 MeV

!

+ cK-"+

!

+ cK-"+"+

ccd+ ccu++

0.5 1 1.5 2 2.5 3 3.3 3.35 3.4 3.45 3.5 3.55 3.6

!

+ c K- "+ "+

Mass 3541 MeV/c2 Data Wrong-sign events L/# > .25 cos$K*cos$! < -.25 Poisson Prob < 5 x 10-5 signal/bkg 7.4/1.6

M(! + c K- "+ "+) GeV/c2 Events/5 MeV/c2 0.5 1 1.5 2 2.5 3 3.5 4 3.3 3.35 3.4 3.45 3.5 3.55 3.6

Mass 3443 MeV/c2 !

+ c K- "+

Data cos$

* K>-.6

sig/bkg 7.4/1.6 Poisson Prob < 3.8 x 10-5 L/# >1

M(! + c K- "+) GeV/c2 Events/2.5 MeV/c 2 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 3.3 3.35 3.4 3.45 3.5 3.55 3.6

Mass 3460 MeV/c2 !

+ c K- "+ "+

RIGHT-SIGN cos($K*) > -.6 signal/!(back) 7.1/!(.9) = 7.5# Poisson Prob < 10-5

M(! + c K- "+ "+) GeV/c2 Events/5 MeV/c 2

Fermilab - Joint Experimental and Theoretical Physics Seminar - June 13, 2003

SELEX (unpublished)

See also: hep-ex/0212029

SLIDE 43

Pentaquark recap: Λb → J/ψ p K−

43

[GeV]

p K

m

1.4 1.6 1.8 2 2.2 2.4 2.6

Events/(15 MeV)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200

LHCb

(a)

data total fit background (4450)

c

P (4380)

c

P (1405) Λ (1520) Λ (1600) Λ (1670) Λ (1690) Λ (1800) Λ (1810) Λ (1820) Λ (1830) Λ (1890) Λ (2100) Λ (2110) Λ

[GeV]

p ψ / J

m

4 4.2 4.4 4.6 4.8 5

Events/(15 MeV)

100 200 300 400 500 600 700 800

LHCb

(b)

PRL 115 (2015) 072001 [LHCb-PAPER-2015-029]

[GeV]

p K

m

1.4 1.6 1.8 2 2.2 2.4 2.6

Events/(15 MeV)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200

LHCb

(a)

data total fit background (1405) Λ (1520) Λ (1600) Λ (1670) Λ (1690) Λ (1800) Λ (1810) Λ (1820) Λ (1830) Λ (1890) Λ (2100) Λ (2110) Λ (2350) Λ (2385) Λ

[GeV]

p ψ / J

m

4 4.2 4.4 4.6 4.8 5

Events/(15 MeV)

100 200 300 400 500 600 700 800

LHCb

(b)

Fit with PQ Fit sans PQ

[MeV] 5500 5600 5700 Events / ( 4 MeV) 1000 2000 3000 4000 5000 6000 7000 LHCb

p ψ / J

m

K

SLIDE 44

Pentaquark recap: Λb → J/ψ p K−

• Combined significance (vs no Pc) ~ 15σ
• Pc(4380)+: m=4380±8±29 MeV, Γ=205±18±86 MeV, ~9σ
• Pc(4450)+: m=4449.8±1.7±2.5 MeV, Γ=39±5±19 MeV, ~12σ
• Preferred JP: 3/2− and 5/2+ for lower and heavier
• Also compatible with reversed parity: 3/2+ and 5/2−

44

Re A

• 0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05

0.05 0.1 0.1

• 0.35
• 0.3
• 0.25
• 0.2
• 0.15
• 0.1
• 0.05

0.05 0.1 0.15

LHCb

(4450)

c

P

(a)

15 -0.1 -0.05 0.05 0.1 0.15 0.2 0.25 0.3 0.35

(4380)

c

P

(b)

P

c

Re AP

c

Im A P

c