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Exotic hadrons at LHCb
Anton Poluektov
University of Warwick, UKBudker Institute of Nuclear Physics, Novosibirsk, Russia
6 December 2016
On behalf of LHCb collaboration
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 1/34
Outline
LHCb experiment
Measurements of X (3872)
Z(4430) in B+ → ψ(2S)K+π−
Pentaquark states in Λ0b → J/ψpK−
Exotic states in Λ0b → J/ψpπ−
Exotic states in B+ → J/ψφK−
Search for X (5568) in B0s π− spectrum
All results presented here are based on full 3 fb−1 Run 1 data sample (2011+2012).
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 2/34
LHCb
One-arm spectrometer optimised for studies of beauty and charm decays at LHC
Angular acceptance
2 < η < 5
1η
-8 -6 -4 -2 0 2 4 6 8
2η
-8
-6
-4
-2
0
2
4
6
8LHCb acceptance
GPD acceptance
= 14 TeVsLHCb MC
Covers forward region (maximum of c and b production)
Good vertexing: measure B0 and B0s oscillations, reject prompt backgroundParticle identification: flavour tagging, misID backgroundHigh-resolution trackingCalorimetry: reconstruct neutrals (π0, γ) in the final stateEfficient trigger, including fully hadronic modes
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 3/34
LHCb
One-arm spectrometer optimised for studies of beauty and charm decays at LHC
Vertexing
B0s oscillations with B0s → Dsπ
[New J. Phys. 15 (2013) 053021]
Covers forward region (maximum of c and b production)Good vertexing: measure B0 and B0s oscillations, reject prompt background
Particle identification: flavour tagging, misID backgroundHigh-resolution trackingCalorimetry: reconstruct neutrals (π0, γ) in the final stateEfficient trigger, including fully hadronic modes
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 3/34
LHCb
One-arm spectrometer optimised for studies of beauty and charm decays at LHC
PID
K/π ID efficiency and misID rate
[EPJ C73 (2013) 2431]
Covers forward region (maximum of c and b production)Good vertexing: measure B0 and B0s oscillations, reject prompt backgroundParticle identification: flavour tagging, misID background
High-resolution trackingCalorimetry: reconstruct neutrals (π0, γ) in the final stateEfficient trigger, including fully hadronic modes
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 3/34
LHCb
One-arm spectrometer optimised for studies of beauty and charm decays at LHC
Tracking
µ+µ− mass spectrum
[PRL 111 (2013) 101805]
Covers forward region (maximum of c and b production)Good vertexing: measure B0 and B0s oscillations, reject prompt backgroundParticle identification: flavour tagging, misID backgroundHigh-resolution tracking
Calorimetry: reconstruct neutrals (π0, γ) in the final stateEfficient trigger, including fully hadronic modes
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 3/34
LHCb
One-arm spectrometer optimised for studies of beauty and charm decays at LHC
Calorimetry
B0s → χc1φ, χc1 → J/ψγ
[Nucl. Phys. B874 (2013) 663]
Covers forward region (maximum of c and b production)Good vertexing: measure B0 and B0s oscillations, reject prompt backgroundParticle identification: flavour tagging, misID backgroundHigh-resolution trackingCalorimetry: reconstruct neutrals (π0, γ) in the final state
Efficient trigger, including fully hadronic modes
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 3/34
LHCb
One-arm spectrometer optimised for studies of beauty and charm decays at LHC
Calorimetry
B0s → χc1φ, χc1 → J/ψγ
[Nucl. Phys. B874 (2013) 663]
Covers forward region (maximum of c and b production)Good vertexing: measure B0 and B0s oscillations, reject prompt backgroundParticle identification: flavour tagging, misID backgroundHigh-resolution trackingCalorimetry: reconstruct neutrals (π0, γ) in the final stateEfficient trigger, including fully hadronic modes
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 3/34
LHCb in Run 1 and Run 2
3 fb−1 in 2011 and 2012 (Run 1,√s = 7, 8TeV)
2 fb−1 in 2015 and 2016 (Run 2,√s = 13TeV, higher b cross section)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 4/34
First manifestly exotic candidate: X (3872)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 5/34
X (3872)
Discovered by Belle in 2003 [PRL 91 262001 (2003)]
B+ → X (3972)K+, X (3872)→ J/ψπ+π−
Mass close to D0D∗0 [PRD 91 (2015), 011102]m(D0D∗0)−m(X (3872)) = 3± 192 keV (sic!)Small width (Γ < 1.2MeV)
Belle
M(π+π-‐J/ψ) (GeV/c2)
Even
ts/5 M
eV
a)
Hadron machines are also active in studies of X (3872) production
CDF, [PRL 93:162002,2004]
)2
(GeV/c-µ
+µ
- M-π+π-µ+µM0.6 0.7 0.8 0.9 1
2C
an
did
ate
s /
10
Me
V/c
0
200
400
600
800 DØ
(2S)ψ
X(3872)
)2
(GeV/c-µ
+µ
M
2.9 3 3.1 3.2 3.3
2C
an
did
ate
s /
10
Me
V/c
0
10000
20000
ψJ/
CMS, 7TeV [JHEP 04 (2013) 154]
) [GeV]-π+π ψm(J/3.6 3.7 3.8 3.9 4
Can
dida
tes
/ 5 M
eV
0
20
40
60
80
100
310×
datatotal fitbackgroundsignal
= 7 TeVsCMS -1L = 4.8 fb
< 50 GeVT
10 < p |y| < 1.2
) [GeV]-π+π ψm(J/3.75 3.8 3.85 3.9 3.95 4
Can
dida
tes
/ 3.1
25 M
eV
10
12
14
16
310×
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 6/34
https://arxiv.org/abs/hep-ex/0309032https://arxiv.org/abs/1501.01658https://arxiv.org/abs/hep-ex/0405004https://arxiv.org/abs/1302.3968
X (3872) results from LHCb
Observation of prompt X (3872) in pp and mass measurement:
M(X (3872)) = 3871.95± 0.48± 0.12MeV/c2 with 35 pb−1 [EPJC 72 (2012) 1972]
Quantum numbers: JPC = 1++ (> 8σ over 2−+) [PRL 110, 222001 (2013)]
) [MeV]ψ) - M(J/ψJ/-π+πM(600 800 1000 1200 1400
Num
ber
of c
andi
date
s / (
2.5
MeV
)
0
200
400
600
800
1000
1200
LHCb550 6000
200
400
600
800
1000
1200(2S)ψ
750 8000
10
20
30
40
50
60
70 X(3872)
) ]++(1L)/-+(2L = -2 ln[ t-200 -100 0 100 200
Num
ber
of e
xper
imen
ts /
bin
210
310
410
510
610
710
datat
-+=2PCSimulated J ++=1PCSimulated J
LHCb
D-wave decay could invalidate 1++, constrained < 4% [PRD 92 (2015) 011102]
Branching ratio to cc̄γ: [Nucl.Phys. B886 (2014) 665-680]
Rψγ =B(X (3872)→ ψ(2S)γ)B(X (3872)→ J/ψγ) = 2.46± 0.64± 0.29
Rules out purely molecular interpretation (Rψγ � 1)Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 7/34
https://arxiv.org/abs/1112.5310https://arxiv.org/abs/1302.6269https://arxiv.org/pdf/1504.06339.pdfhttps://arxiv.org/abs/1404.0275
Search for X (3872) → pp
[arXiv:1607.06446]
Decay B+ → ppK+
First observation of ηc(2S)→ ppMass and width of ηc(1S)
[MeV]ppM3000 3500 4000
Can
dida
tes/
(6.0
MeV
)
1
10
210
310
410
)S(1c
η
ψ/J
0cχ 1cχ )S(2
cη
)S(2ψ
LHCbX(3872) ?
B(B+ → X (3872)K+)× B(X (3872)→ pp)B(B+ → J/ψK+)× B(J/ψ → pp) < 0.25× 10
−2 @ 95% CL
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 8/34
https://arxiv.org/abs/1607.06446
Charged exotic state: Z (4430)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 9/34
Amplitude analyses
Many of LHCb exotic measurements use amplitude analysis technique.
Perform fits of the amplitude as a function of phase space variables
Three-body decays D → ABC : at least two kinematic variebles M2AB , M2BC (Dalitzplot)
Add angular variables if initial/final state not scalar
Phase space
Dynamics (line shape)
Helic
ity st
ruct
ure
Absolute phase not visible, but phases ofcomponents can be accessed thoughinterference with other structures.
Model-dependent fits: isobar model (sumof resonant/nonresonant components)
Model-independent PWA: for spin J,polynomials up to 2J order. Helicity as afunction of M2AB .
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 10/34
Z (4430) in B → ψ(2S)K+π−
[PRL 112, 222002 (2014)]
Decay B0 → ψ(2S)K+π−
Signal yield: 25k events
Combinatorial background: ∼ 4%4D amplitude analysis (m2(Kπ), m2(ψ(2S)π), θψ′ , φψ′)
[MeV]-π+'Kψm5250 5300
Can
dida
tes
/ 1 M
eV
0
200
400
600
800
1000
1200
1400
1600
1800LHCb
sideband sidebandsignal
range
]2[GeV2 -π+Km0.5 1 1.5 2 2.5
]2[G
eV2
- π'ψ
m
15
16
17
18
19
20
21
22
1
10
210
LHCbK
∗(892)0
K∗(1430)0Z(4430)+
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 11/34
http://arxiv.org/abs/1404.1903
Z (4430) in B → ψ(2S)K+π−
[PRL 112, 222002 (2014)]
]2 [GeV2 −π+Km0.5 1 1.5 2 2.5
)2C
andi
date
s / (
0.0
2 G
eV
1
10
210
310 LHCbdata
total fit
excluded-Z(4430)
(892)*
K
S-wave*
K
(1430)2*
K -Z(4430)
background(1680)
*K
(1410)*
K
-total fit with no Z(4430)
]2 [GeV2 −π'ψm16 18 20 22
)2C
andi
date
s / (
0.2
GeV
0
500
1000 LHCbdata
total fit
excluded-Z(4430)
(892)*
K-Z(4430)
S-wave*
K
(1430)2*
Kbackground
(1680)*
K
(1410)*
K
-total fit with no Z(4430)
Model-dependent fit prefers resonance-like statewith JP = 1+
Quantum numbers (wrt. favoured JP = 1+)
JP LHCb Belle
0− 9.7 3.4
1− 15.8 3.7
2+ 16.1 5.1
2− 14.6 4.7
)L ln 2(-∆-200 0 200 400
Pseu
do-e
xper
imen
ts /
10.0
0
50
100
150
200
250
300
DataSimulatedexperiments
− = 0Z
PJ
Simulatedexperiments
+ = 1ZPJ
LHCb
Parameters
LHCb Belle
Mass, MeV/c2 4475± 7+15−25 4485± 22+28−11Width, MeV 172± 13+27−34 200+41−46+26−35
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 12/34
http://arxiv.org/abs/1404.1903
Z (4430): model-independent confirmation
[PRL 112, 222002 (2014)]
Model-independent test of phase rotation. Interference with K∗ states providesreference amplitude for phase motion measurement.
−ZRe A-0.6 -0.4 -0.2 0 0.2
−Z
Im A
-0.6
-0.4
-0.2
0
0.2 LHCb
Magn
itude
Phase
Breit-Wigner fit
Data
Split M(ψ′π−) (4277–4605MeV/c2)into 6 bins.
Fit magnitude and phaseindependently for each bin.
Clear phase rotation in counterclockwise direction: characteristic of aresonant behaviour.
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 13/34
http://arxiv.org/abs/1404.1903
Z (4430): model-independent confirmation
[PRD 92 (2015) 112009]
Model-independent confirmation of exotic contribution.Check that K−π+ amplitude only fails to describe the decay.K−π+ should contribute to reasonably low moments, while exotic ψ′π− contributes toall moments.
Jmax = 2lmax = 4
(K∗, K∗2 etc.)
]2 [MeV/cπ(2S)ψm3800 4000 4200 4400 4600 4800
)2Y
ield
/ (2
5 M
eV/c
0
2000
4000
6000
8000
10000
12000
14000 LHCb
Jmax = 3lmax = 6
(+K∗3 (1780) etc.)
]2 [MeV/cπ(2S)ψm3800 4000 4200 4400 4600 4800
)2Y
ield
/ (2
5 M
eV/c
0
2000
4000
6000
8000
10000
12000
14000 LHCb
Jmax = 15lmax = 30
...
]2 [MeV/cπ(2S)ψm3800 4000 4200 4400 4600 4800
)2Y
ield
/ (2
5 M
eV/c
0
2000
4000
6000
8000
10000
12000
14000 LHCb
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 14/34
http://arxiv.org/abs/1510.01951
Z (4430): model-independent confirmation
[PRD 92 (2015) 112009]
Test statistic:
−2∆NLL = −2∑i
Wi�i
logFl(m
iψπ)
F30(miψπ)
Run toys with K+π−-only model to determine distribution, compare with −2∆NLL indata.
NLL∆-20 1000 2000
Num
ber
of p
seud
oexp
erim
ents
-110
1
10
Dataσ13.3 LHCb
lmax = 4
NLL∆-2-500 0 500 1000 1500
Num
ber
of p
seud
oexp
erim
ents
-110
1
10
Dataσ8.0 LHCb
lmax = 6
NLL∆-20 1000 2000 3000
Num
ber
of p
seud
oexp
erim
ents
-110
1
10
Dataσ15.2 LHCb
lmax = 4 . . . 6 depending onm(K+π−)
Resonances with spin up to 3 cannot reproduce the features seen in data.
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 15/34
http://arxiv.org/abs/1510.01951
Pentaquarks: Pc(4380) and Pc(4450)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 16/34
Pentaquark states in Λ0b → J/ψpK−
Λ0b → J/ψpK− decay [PRL 115 (2015) 072001]
Conventional contributions only in pK−
spectrum (Λ∗ states).
[MeV]5500 5600 5700
Eve
nts
/ ( 4
MeV
)
0
1000
2000
3000
4000
5000
6000
7000LHCb
p ψ/Jm K ]2[GeVKp2m
2 3 4 5 6]2
[GeV
pψ
J/2m
16
18
20
22
24
26 LHCb
Event yield: 26007± 166 eventsLow background (5.4%)
Dalitz distribution shows an unexpectednarrow feature in J/ψp mass.
Not an experimental effect (veto B → J/ψKh, check part-rec Ξb decays, clones andghosts...)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 17/34
http://arxiv.org/abs/1507.03414
Pentaquark states in Λ0b → J/ψpK−
Λ0b → J/ψpK− decay [PRL 115 (2015) 072001]
Conventional contributions only in pK−
spectrum (Λ∗ states).
[MeV]5500 5600 5700
Eve
nts
/ ( 4
MeV
)
0
1000
2000
3000
4000
5000
6000
7000LHCb
p ψ/Jm K ]2[GeVKp2m
2 3 4 5 6]2
[GeV
pψ
J/2m
16
18
20
22
24
26 LHCb
Λ∗
reso
nan
ces
J/ψp resonance
Event yield: 26007± 166 eventsLow background (5.4%)
Dalitz distribution shows an unexpectednarrow feature in J/ψp mass.
Not an experimental effect (veto B → J/ψKh, check part-rec Ξb decays, clones andghosts...)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 17/34
http://arxiv.org/abs/1507.03414
Pentaquark states in Λ0b → J/ψpK−
PRL 115, 072001 (2015),
Full amplitude analysis of the Λ0b → J/ψpK− decay to understand its dynamics. Fit in
6D phase space: (MKp, θΛ0b, θµ, φµ, θK , φK )
[GeV]pKm1.4 1.6 1.8 2 2.2 2.4 2.6
Eve
nts/
(15
MeV
)
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
LHCb(a)
datatotal fitbackground
(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]pψ/Jm4 4.2 4.4 4.6 4.8 5
Eve
nts/
(15
MeV
)
0
100
200
300
400
500
600
700
800
LHCb(b)
Admixture of all known Λ∗ states does not reproduce the peak observed atmJ/ψ p = 4450MeV.
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 18/34
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.072001
Pentaquark states in Λ0b → J/ψpK−
PRL 115, 072001 (2015),
Full amplitude analysis of the Λ0b → J/ψpK− decay to understand its dynamics. Fit in
6D phase space: (MKp, θΛ0b, θµ, φµ, θK , φK )
[GeV]pKm1.4 1.6 1.8 2 2.2 2.4 2.6
Eve
nts/
(15
MeV
)
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
LHCb(a)
datatotal fitbackground
cP(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]pψ/Jm4 4.2 4.4 4.6 4.8 5
Eve
nts/
(15
MeV
)
0
100
200
300
400
500
600
700
800
LHCb(b)
Inclusion of the exotic J/ψp state improves the fit, best JP = 5/2±
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 18/34
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.072001
Pentaquark states in Λ0b → J/ψpK−
PRL 115, 072001 (2015),
Full amplitude analysis of the Λ0b → J/ψpK− decay to understand its dynamics. Fit in
6D phase space: (MKp, θΛ0b, θµ, φµ, θK , φK )
[GeV]pKm1.4 1.6 1.8 2 2.2 2.4 2.6
Eve
nts/
(15
MeV
)
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
LHCb(a)
datatotal fitbackground
(4450)cP(4380)cP(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]pψ/Jm4 4.2 4.4 4.6 4.8 5
Eve
nts/
(15
MeV
)
0
100
200
300
400
500
600
700
800
LHCb(b)
Two J/ψp states give the best fit, J = 3/2 and 5/2 with opposite parities
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 18/34
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.072001
Pentaquark states in Λ0b → J/ψpK−
PRL 115, 072001 (2015),
Eve
nts/
(15
MeV
)
0
200
400
(a) (b)
[GeV]pψJ/m4 4.5 5
Eve
nts/
(15
MeV
)
0
200
400 (c)
[GeV]pψJ/m4 4.5 5
(d)
LHCb
Apparent need for 2nd, wide, J/ψp state
Parameters of the pentaquark states
Pc(4380):M = 4380± 8± 29MeV,Γ = 205± 18± 86MeV
Pc(4450):M = 4449.8± 1.7± 2.5MeVΓ = 39± 5± 19MeV
Significance (stat+syst) is overwhelming:9σ and 12σ
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 19/34
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.072001
Pentaquark states in Λ0b → J/ψpK−
PRL 115, 072001 (2015),
Argand plots: model-independent confirmation of the resonant character of the exoticstates.Interference with Λ∗ states allows to extract the phase in bins of mJ/ψ p.
Re A -0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.1
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
LHCb
(4450)cP
(a)
15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
(4380)cP
(b)
Pc Re APc
Im A
P c
Breit-Wigner fit Breit-Wigner fit
Data Data
Clear phase rotation for Pc(4450), direction consistent with Breit-Wigner amplitudeNot conclusive for Pc(4380), need more statistics.
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 20/34
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.072001
Model-independent approach: Λ0b → J/ψpK−
[PRL 117 (2016) 082002]
Checking that Λ∗ resonances only cannot describe the data.Use Legendre moments in cos θhel as a function of mpK .Allow lmax depending on mpK
[GeV]pKm
>U l
< P
1.5 2 2.5
0
50
100
310×
l = 1
1.5 2 2.5
0
50
100
310×
l = 2
1.5 2 2.5
0
50
100
310×
l = 3
1.5 2 2.5
0
50
100
310×
l = 4
1.5 2 2.5
0
50
100
310×
l = 5
simulation
*'s Λ
+(4450)cP, +(4380)cP
1.5 2 2.5
0
50
100
310×
l = 6
1.5 2 2.5
0
50
100
310×
l = 7
1.5 2 2.5
0
50
100
310×
l = 8
1.5 2 2.5
0
50
100
310×
l = 9
1.5 2 2.5
0
50
100
310×
l = 10
1.5 2 2.5
0
50
100
310×
l = 11
1.5 2 2.5
0
50
100
310×
l = 12
Moments from model
[GeV]Kpm
> /
(44
MeV
)U l
< P
1.5 2 2.5-500
0
500
1000 l = 1
1.5 2 2.5-500
0
500
1000 l = 2
1.5 2 2.5-500
0
500
1000 l = 3
1.5 2 2.5-500
0
500
1000 l = 4
1.5 2 2.5-500
0
500
1000 l = 5
LHCb1.5 2 2.5
-500
0
500
1000 l = 6
1.5 2 2.5-500
0
500
1000 l = 7
1.5 2 2.5-500
0
500
1000 l = 8
1.5 2 2.5-500
0
500
1000 l = 9
1.5 2 2.5-500
0
500
1000 l = 10
1.5 2 2.5-500
0
500
1000 l = 11
1.5 2 2.5-500
0
500
1000 l = 12
Moments from data
)L(-2ln∆0 50 100 150 200 250 300 350 400
Num
ber
of p
seud
oexp
erim
ents
0
20
40
60
80
100
120
140
160
180 )0
) | HL(-2ln∆( tF
*Λ
=205 MeVΓ(4380) c*,PΛ
=102 MeVΓ(4380) c*,PΛ
*, Λ=205 MeV,Γ(4380) cP=39 MeVΓ(4450) cP
*, Λ=51 MeVΓ(4380) cP
simulation
-20 0 20 40 60 80 100120140160180
1
10
210
310)
0) | HL(-2ln∆( tF
Bif. Gaussian fit
data
LHCb
10σ significance
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 21/34
http://arxiv.org/abs/1604.05708
Exotic contributions in Λ0b → J/ψpπ−
[PRL 117 (2016) 082003]
[GeV]πpψJ/m5.5 5.6 5.7
Can
dida
tes
/ ( 5
MeV
)
0
100
200
300
400
500LHCb Data
FitSignal
-pKψJ/→0bΛ
Cmb. bkg.
Signal yield: 1885± 50 eventsBackground: ∼ 20%
N∗ states in pπ−
Possible exotic contributions:
Pc in J/ψp
Zc in J/ψπ− [Belle, PRD 90, 112009 (2014)]
M = 4196+ 31−29+ 17−13 MeV/c
2
Γ = 370± 70+ 70−132 MeV
]2[GeVπp2m2 4 6
]2[G
eVp
ψJ/2
m
16
18
20
22
24
26
28
30(a) LHCb
N∗
Pc(4450)
]2[GeVπp2m2 4 6
]2[G
eVπ
ψJ/2
m
10
12
14
16
18
20
22(b) LHCb
N∗
Zc(4200)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 22/34
http://arxiv.org/abs/1606.06999https://arxiv.org/abs/1408.6457
Exotic contributions in Λ0b → J/ψpπ−
[GeV]πpm1 1.5 2 2.5
Yie
lds/
(25
MeV
)
1
10
210
N(1440)N(1520)N(1535)N(1650)N(1675)N(1720)NR
Data
c+2PcRM N*+ZEM N*
(4450)cP(4380)cP(4200)cZ
LHCb
[GeV]pψJ/m4.5 5
Yie
lds/
(50
MeV
)
0
5
10
15
20
25
30
35
40 (b) LHCb
[PRL 117 (2016) 082003]
N∗ → pπ− contributions:Basline: isobar pπ− with 7-14 states.
Tried BW and Flatté for N(1535) (opening of nηthreshold)
Cross-check: K -matrix for 1/2− usingBonn-Gatchina parametrisation
Exotic contributions:
Considered Pc(4380), Pc(4450) (in J/ψp) andZc(4200) (in J/ψπ
−).
Total significance of exotic contributions: 3.1σ.
Individual contributions are not significant
Fit fractions:F(Pc (4380)) = (5.1± 1.5+2.6−1.6)%F(Pc (4450)) = (1.6+0.8−0.6
+0.6−0.5)%
F(Zc (4200)) = (7.7± 2.8+3.4−4.0)%
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 23/34
http://arxiv.org/abs/1606.06999
X (4140) and J/ψφ family
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 24/34
Exotic states in B+ → J/ψφK+
Peaks in J/ψφ around 4140 and 4274MeV/c2 are found by CDFand confirmed by D0 and CMS
[CDF, PRL 102, 242002 (2009)]
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7
]2) [GeV/c-µ+µ)-m(-K+K-µ+µm(1 1.1 1.2 1.3 1.4 1.5
2C
andi
date
s pe
r 10
MeV
/c
0
2
4
6
8
10 [D0, PRD 89, 012004 (2014)]
) (GeV)-
K+
KψM(J/4.2 4.3 4.4 4.5
) / 30 M
eV
+N
(B0
20
40
60Data
Full Fit
X(4140)
X(4330)
PHSP
-1DØ Run II, 10.4 fb (c)
[CMS, PLB 734 (2014) 261]
m [GeV]∆1.1 1.2 1.3 1.4 1.5
) / 2
0 M
eV+
N(B
0
50
100
150
200
250
300-1 = 7 TeV, L=5.2 fbsCMS,
Data
Three-body PS (global fit)
)+, Kφ,ψEvent-mixing (J/ )+ Kφ,ψEvent-mixing (J/
Global fit
1D fit
uncertainty bandσ1±
Belle [PRL 104:112004 (2010)]:no X (4140), but X (4350) in γγ → J/ψφ
no evidence from:BaBar [PRD 91, 012003 (2015)],LHCb (0.37 fb−1) [PRD 85, 091103(R) (2012)]
LHCb
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 25/34
https://arxiv.org/abs/1101.6058https://arxiv.org/abs/1101.6058https://arxiv.org/abs/1309.6920https://arxiv.org/abs/0912.2383https://arxiv.org/abs/1407.7244https://arxiv.org/abs/1202.5087
Exotic states in B+ → J/ψφK+
[arXiv:1606.07895]
[MeV]KφψJ/m5250 5300 5350
Can
dida
tes/
(1 M
eV)
0
50
100
150
200
250
300
350
400
LHCb
Signal yield: 4289± 151 eventsBackground: ∼ 20% ]2 [GeV2 Kφm
2.5 3 3.5 4 4.5 5
]2 [
GeV
2φ
ψJ/
m
17
18
19
20
21
22
23
0
2
4
6
8
10
12
14
16
LHCb
Full 6D amplitude analysis
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 26/34
https://arxiv.org/abs/1606.07895
Exotic states in B+ → J/ψφK+
[arXiv:1606.07895]
[MeV]KφψJ/m5250 5300 5350
Can
dida
tes/
(1 M
eV)
0
50
100
150
200
250
300
350
400
LHCb
Signal yield: 4289± 151 eventsBackground: ∼ 20% ]2[GeV2 Kφm
2.5 3 3.5 4 4.5 5
]2[G
eV2
φψ
J/m
17
18
19
20
21
22
23
0
2
4
6
8
10
12
14
16
LHCb
K∗ X (4140) ?
X (4274) ?
???
???
Full 6D amplitude analysis
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 26/34
https://arxiv.org/abs/1606.07895
Exotic states in B+ → J/ψφK+
[arXiv:1606.07895]
[MeV]φψJ/m4100 4200 4300 4400 4500 4600 4700 4800
Can
dida
tes/
(10
MeV
)
0
20
40
60
80
100
120 data
s)*Ktotal fit (
background
LHCb
K∗ states only
[MeV]φψJ/m4100 4200 4300 4400 4500 4600 4700 4800
Can
dida
tes/
(10
MeV
)
0
20
40
60
80
100
120 LHCb
K∗ plus 4(!) exotic states in J/ψφ
Contribution JPC Significance M0 [ MeV ] Γ0 [ MeV ] FF %
X (4140) 1++ 8.4σ 4146.5±4.5 +4.6−2.8 83±21 +21−14 13±3.2 +4.8−2.0X (4274) 1++ 6.0σ 4273.3±8.3 +17.2− 3.6 56±11 + 8−11 7.1±2.5 +3.5−2.4X (4500) 0++ 6.1σ 4506±11 +12−15 92±21 +21−20 6.6±2.4 +3.5−2.3X (4700) 0++ 5.6σ 4704±10 +14−24 120±31 +42−33 12± 5 + 9− 5
Masses for X (4140) and X (4274) are consistent with previous measurements, butwidths significantly larger.
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 27/34
https://arxiv.org/abs/1606.07895
Exotic states in B+ → J/ψφK+
[arXiv:1606.07895]
)Z(I Re -0.4− 0.2− 0 0.2 0.4 0.6 0.8 1
)Z(I
Im
-
0.4−
0.2−
0
0.2
0.4
0.6
0.8
1
cusp
Breit-Wigner
[MeV]φψJ/m4100 4200 4300 4400 4500 4600 4700 4800
Can
dida
tes/
(10
MeV
)
0
20
40
60
80
100
120 LHCbD+s D
∗−s
cusp
JP = 1+ assignment rules out interpretation of X (4140) as a D∗+s D∗−s molecule.
X (4140) could be a D+s D∗−s state, below threshold ⇒ not a Breit-Wigner line shape.
“Cusp” model by [E.S.Swanson, Phys. Rev. D91 034009, 2015]Preferred by 3σ over Breit-Wigner fit.
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 28/34
https://arxiv.org/abs/1606.07895https://arxiv.org/abs/1504.07952
bsud candidate: X (5568)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 29/34
Search for exotic states in B0s π+ spectrum
B0s → J/ψφ, J/ψ → µ+µ−, φ→ K+K− [DZero, PRL 117, 022003 (2016)]
4.8 5 5.2 5.4 5.6 5.8 60
500
1000
1500
2000
]2 ) [GeV/cφ ψ/ J (m
2N
eve
nts
/ 2
0 M
eV
/c
-1 D0 Run II, 10.4 fb
5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.90
20
40
60
80
100
120
2N
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
05
1015
20
]2 ) [GeV/c± π S0
(Bm
Re
sid
ua
ls (
Da
ta-F
it)
5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.90
10
20
30
40
50
60
70
80
90
2N
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
0
5
10
15
]2 ) [GeV/c± π S0
(Bm
Re
sid
ua
ls (
Da
ta-F
it)
B0s → J/ψφ, J/ψ → µ+µ−Yield: ∼ 5500 events
B0s combined with π+,
pT(B0s ) > 10GeV,
pT(π+) > 500MeV
After “cone cut”,∆R =
√∆η2 + ∆φ2 < 0.3
M(X (5568)) = 5567.8± 2.9+0.9−1.9 MeV/c2Γ(X (5568)) = 21.9± 6.4+5.0−2.5 MeV
Very large fraction of B0s from X decays: ρX = (8.6± 1.9± 1.4)%
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 30/34
https://arxiv.org/abs/1602.07588
Search for exotic states in B0s π+ spectrum
[PRL 117, 152003 (2016)]
LHCb has B0s sample ∼ 20 times larger:pp environment of course
B0s → D−s π+ and B0s → J/ψφpT(Bs) > 5MeV/c and pT(Bs) > 10MeV/c (to be consistent with DZero)
(MeV))+πs-m(D5300 5350 5400 5450 5500 5550 5600
Can
dida
tes
/ (3
MeV
)
0
1000
2000
3000
4000
5000
6000 LHCb
B0s → D−s π+Signal yield: 65× 103 events
Background: ∼ 10%
(MeV))φψm(J/5200 5250 5300 5350 5400 5450 5500
Can
dida
tes
/ (3
MeV
)0
2000
4000
6000
8000
10000
12000LHCb
B0s → J/ψφSignal yield: 45× 103 events
Background: ∼ 2%
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 31/34
https://arxiv.org/abs/1608.00435
Search for exotic states in B0s π+ spectrum
[PRL 117, 152003 (2016)]
B0s → D−s π+ and B0s → J/ψφ modes, combined. No cone cut applied.
Can
dida
tes
/ (5
MeV
)
0
50
100
150
200
250
Claimed X(5568) state
Combinatorial
) > 10 GeVs0B(
TpLHCb
Pul
l
4−2−024
(MeV))±πs0m(B
5550 5600 5650 5700 5750 5800 5850 5900 5950 6000 (MeV)m(X)
5550 5600 5650 5700 5750 5800 5850 5900 5950 6000
XLHC
bρ
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07 = 10 MeVΓ90% CL UL ; = 20 MeVΓ90% CL UL ; = 30 MeVΓ90% CL UL ;
= 40 MeVΓ90% CL UL ; = 50 MeVΓ90% CL UL ;
) > 10 GeVs0B(
TpLHCb
ρX Upper limit, 90(95) % CL
pT(B0s ) > 5GeV/c < 0.011(0.012)
pT(B0s ) > 10GeV/c < 0.021(0.024)
pT(B0s ) > 15GeV/c < 0.018(0.020)
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 32/34
https://arxiv.org/abs/1608.00435
Search for exotic states in B0s π+ spectrum
[PRL 117, 152003 (2016)]
B0s → D−s π+ and B0s → J/ψφ modes, combined. No cone cut applied.
Can
dida
tes
/ (5
MeV
)
0
50
100
150
200
250
300 Claimed X(5568) state
Combinatorial
) > 10 GeVs0B(
TpLHCb
(MeV))±πs0m(B
5550 5600 5650 5700 5750 5800 5850 5900 5950 6000 (MeV)m(X)5550 5600 5650 5700 5750 5800 5850 5900 5950 6000
XLHC
bρ
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07 = 10 MeVΓ90% CL UL ; = 20 MeVΓ90% CL UL ; = 30 MeVΓ90% CL UL ;
= 40 MeVΓ90% CL UL ; = 50 MeVΓ90% CL UL ;
) > 10 GeVs0B(
TpLHCb
ρX Upper limit, 90(95) % CL
pT(B0s ) > 5GeV/c < 0.011(0.012)
pT(B0s ) > 10GeV/c < 0.021(0.024)
pT(B0s ) > 15GeV/c < 0.018(0.020)
DZero: ρX = (8.6± 1.9± 1.4)% in pp collisions
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 32/34
https://arxiv.org/abs/1608.00435
Search for exotic states in B0s π+ spectrum
Two preliminary results shown at ICHEP
[GeV]PDG
)s0)+M(B±π
s0M(B∆
5.5 5.6 5.7 5.8 5.9
Can
dida
tes
/ 8 M
eV
0
200
400
600
800
1000
1200
1400(a)
(8 TeV)-119.7 fbCMS Preliminary
CMS confirms no evidence[CMS-PAS-BPH-16-002]
]2) [MeV/c�πs
0M(B
5600 5700 5800 5900
2E
vents
/8 M
eV
/c
0
50
100
150
200
250
-1D0 Preliminary 10.4 fb
m(X)m(X)DataMC Background SimulationExpected Signal
DZero with semileptonic B0s → D−s µ+νµ[DZero Note 6488]
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 33/34
https://cds.cern.ch/record/2204918?ln=enhttps://www-d0.fnal.gov/Run2Physics/WWW/results/prelim/B/B67/
Summary
Exotic spectroscopy is an essential part of LHCb physics programme
Many important results with 3 fb−1:X (3872) measurementsConfirmation and quantum numbers of Z(4430)Discovery of hidden-charm pentaquarksExotic states in J/ψφ
New results still to come with Run 1 sample, and many more expected with addedsample of Run 2:
Updates of present analyses with higher stats, precision measurementsPentaquark searches with open-charm statesPrompt production of exotic statesFinal states with neutrals (χc , Λ0, K0S , ω)
New initial states (B0s , B+c , b-baryons)
More amplitude analyses
Data taking plans:Run 2 (2015-2018): 8 fb−1
Phase-1 upgradeRun 3 (2021-2024): 23 fb−1
Phase-1b upgrade (?), HL-LHCRun 4 (2027-2030): 46 fb−1
Anton Poluektov Exotic hadrons at LHCb HINT2016, J-PARC, Japan, 5-9 December 2016 34/34
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