Exotic hadrons at LHCb...Model-independent test of phase rotation. Interference with K states...

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Exotic hadrons at LHCb Anton Poluektov University of Warwick, UK Budker 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

Transcript of Exotic hadrons at LHCb...Model-independent test of phase rotation. Interference with K states...

  • 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

    -8 -6 -4 -2 0 2 4 6 8

    -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

    - 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

    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

    )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

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    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

    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

    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

    =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

    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

    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

    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