Precision measurement of B0 meson oscillation frequencyPrecision measurement of B0 meson oscillation...

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Precision measurement of B 0 meson oscillation frequency Basem Khanji On behalf of the LHCb collaboration Milano-Bicocca, INFN, CERN 22-March-2016 LHC Seminar, 22 March 2016 B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) Δm d at LHCb 22-March-2016 1 / 40
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Transcript of Precision measurement of B0 meson oscillation frequencyPrecision measurement of B0 meson oscillation...

  • Precision measurement of B0 meson oscillation frequency

    Basem KhanjiOn behalf of the LHCb collaboration

    Milano-Bicocca, INFN, CERN

    22-March-2016

    LHC Seminar, 22 March 2016

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 1 / 40

  • CKM matrix

    LW±

    int = −g√2

    (uL, cL, tL)γµVCKM

    dLsLbL

    W+ + h.c

    VCKM =

    Vud Vus VubVcd Vcs VcbVtd Vts Vtb

    b cW −

    Vcb

    • |Vij |2: probability of transition from one flavour to another

    • Physics states 6= flavour states

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 2 / 40

  • CKM matrix

    VCKM =

    Vud Vus VubVcd Vcs VcbVtd Vts Vtb

    • Strength of the transition between up-type and down-type quarks

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 3 / 40

  • CP violation

    • VCKM is complex & unitary

    • Can be parametrized using 4 parameters: 3 real + 1 complex

    VCKM ∼

    1− λ2/2 λ Aλ3(ρ− iη)−λ 1− λ2/2 Aλ2Aλ3(1− ρ− iη) −Aλ2 1

    6= V ∗CKM• Nature discriminates(!) between matter and anti-matter

    • η is small → where did the anti-matter go?

    • Test the consistency of CKM picture within SM experimentally

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 4 / 40

  • Unitarity Triangle

    VudV ∗ub + VcdV ∗cb + VtdV ∗tb = 0

    • One example of unitarity triangles

    • There are six more

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 5 / 40

  • Unitarity Triangle

    VudV ∗ub + VcdV ∗cb + VtdV ∗tb = 0

    γ

    α

    α

    dm∆ Kεsm∆ & dm∆

    ubV

    βsin 2(excl. at CL > 0.95)

    < 0βsol. w/ cos 2

    α

    βγ

    ρ

    -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

    η

    0.0

    0.1

    0.2

    0.3

    0.4

    0.5

    0.6

    0.7

    exclu

    ded

    are

    a h

    as C

    L >

    0.9

    5EPS 15

    CKMf i t t e r

    • On the other hand: sides + angles are related to physics observables

    • ... most of them are accessible through b-hadron decays

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 6 / 40

  • How to fish for b-hadrons

    • 25% of bb pairs are produced forward

    0/4π

    /2π/4π3

    π

    0

    /4π

    /2π

    /4π3

    π [rad]1θ

    [rad]2θ

    b

    b

    z

    LHCb MC = 7 TeVs

    • → LHCb: forward spectrometer with unique η coverage (2 < η < 5)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 7 / 40

  • LHCb detector

    Int. J. Mod. Phys. A 30 (2015) 1530022• VELO : σ(IP) ∼ 20µm for high pT tracks• Tracking system : δ(p)/p = (0.5− 1)%, reversible magnet polarity• RICH system : �(K) ∼ 95%, 5% π → K mis-id probability• Calorimeter : Energy measurement, identify π0,γ• Muon detector : �(µ)∼ 97%, (1− 3)%, π → µ mis-id probability

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 8 / 40

  • Luminosity

    Run I(2011 + 2012): 3 fb−1 Run II (2015): 300 pb−1

    • + increase in bb cross section (7TeV→ 13 TeV)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 9 / 40

  • A precise measurement of the B0 meson oscillation frequency,LHCB-PAPER-2015-031 1

    1Paper is in preparationB. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 10 / 40

  • Theory

    • Flavour oscillation(mixing) through electroweak interaction in neutral B mesons

    �B0 B0

    W−

    u, c, t

    W+

    u, c, t

    d b

    b d

    �B0 B0

    u, c, t

    W± W±

    u, c, t

    d b

    b d

    • Physics states |BH,L〉 = p|B0〉 ∓ q|B0〉 (p2 + q2 = 1)

    • Mass difference between the two physics states: ∆md = mH −mL

    • Flavour at production is the flavour of the state at t = 0

    • Flavour at decay the flavour of the state at decay time t

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 11 / 40

  • Theory

    • Box diagram calculation leads to:

    ∆md =G2Fm2WMB0

    6π2 S0(xt)η2B|V∗tdVtb|2f 2B0 BB0

    • → ∆md constrains the side of theunitarity triangle

    • But needs theory input

    • B0-B0 system is described by Schrödinger equation

    i ddt

    (|B0(t)〉|B0(t)〉

    )=(

    M̂d − i2 Γ̂d)( |B0(t)〉

    |B0(t)〉

    )

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 12 / 40

  • Theory

    • Mixing probability for neutral B0 mesons:

    P(t) ∝ e−tτ (1 + qmixing cos(∆md t))

    • Unmixed events: qmixing = 1flavour at production = flavour atdecay

    • Mixed events: qmixing = −1flavour at production 6= flavour atdecay

    0 1 2 3 4

    Inte

    nsity

    0

    0.5

    1

    y = 0.997x = -0.946: 0K(a)

    0 1 2 3 4

    -610

    -410

    -210

    1

    y = 0.0075x = 0.0063: 0D(b)

    tΓ0 1 2 3 4

    Inte

    nsity

    0

    0.5

    1

    y = 0.005x = 0.773: 0B(c)

    tΓ0 1 2 3 40

    0.5

    1

    y = 0.046x = 25.194: sB(d)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 13 / 40

  • State of the art

    0.4 0.45 0.5 0.55

    ∆md (ps

    -1)

    World averagefor PDG 2015

    0.510 ± 0.003 ps-1

    CLEO+ARGUS(χ

    d measurements)

    0.498 ± 0.032 ps-1

    Average of aboveafter adjustments

    0.510 ± 0.003 ps-1

    LHCb *

    (3 analyses) 0.514 ± 0.005 ± 0.003 ps

    -1

    BELLE *

    (3 analyses) 0.509 ± 0.004 ± 0.005 ps

    -1

    BABAR *

    (4 analyses) 0.506 ± 0.006 ± 0.004 ps

    -1

    D0 (1 analysis)

    0.506 ± 0.020 ± 0.016 ps-1

    CDF1 *

    (4 analyses) 0.495 ± 0.033 ± 0.027 ps

    -1

    OPAL (5 analyses)

    0.479 ± 0.018 ± 0.015 ps-1

    L3 (3 analyses)

    0.444 ± 0.028 ± 0.028 ps-1

    DELPHI *

    (5 analyses) 0.519 ± 0.018 ± 0.011 ps

    -1

    ALEPH (3 analyses)

    0.446 ± 0.026 ± 0.019 ps-1

    * HFAG average

    without adjustments

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 14 / 40

  • Main components

    • Need: "flavour specific" decays with high yields• B0→ D−µ+νµ (D−→ K+π−π−): ∼ 1.6M events (full Run I data: 3 fb−1)• B0→ D∗−µ+νµ (D∗− → D0(→ K+π−)π−): ∼ 0.8M events (full Run I data: 3 fb−1)• µ charge is correlated with B0 flavour at decay

    • Need: Flavour Tagging (qmixing)• Need: Decay time reconstruction (t)

    B0 → D−µ+νµ B0 → D∗−µ+νµ

    B0

    D- π-

    K+

    μ+

    υμ

    π-

    B0D*-

    D0 π-

    K+

    μ+

    υμ

    π-

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 15 / 40

  • Background: combinatorics

    • First type of backgrounds: Combinatorics, D0 from B decays• Not sharing D(∗)− with the signal in their final state

    • Apply sPlot technique to subtract those backgrounds (Nucl. Instrum. Meth. A555 (2005) 356)• B0→ D∗−µ+νµ: mD0 , δm(= mD∗− −mD0 ) distributions• B0→ D−µ+νµ: mD− distribution

    ]2c [MeV/π πK m1800 1850 1900

    )2 cE

    vent

    s /

    ( 1.

    4 M

    eV/

    50

    100

    310× Data Total fit Signal Comb.

    LHCb

    ]2c [MeV/mδ140 145 150 155

    )2 cE

    vent

    s /

    ( 0.

    125

    MeV

    /

    10

    20

    30

    40

    310×

    LHCb Data Total fit

    *- D0 D

    Comb.

    LHCB-PAPER-2015-031 (preliminary)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 16 / 40

  • Background: B+ background

    • B+→ D(∗)−µ+π+νµX decays: share same characteristics of signal but do not exhibitany oscillation

    • Fraction of these B+→ D(∗)−µ+π+νµX decays correlated with ∆md• Need to fix it from somewhere

    • B of B+→ D(∗)−µ+π+νµX has 10% uncertainty → could amplify systematic effect

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 17 / 40

  • Closer look at B+ background

    • B+→ D∗−µ+π+νµX(Left), B0→ D∗−µ+νµ(Right)

    PV

    B+D*-

    D~0K+

    pi-

    pi-

    mu+

    pi+

    nu

    PV

    B0D*-

    D~0K+

    pi-

    pi-

    mu+

    nu

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 18 / 40

  • B+ background: Isolation variables

    • Conduct a search over all tracks to find if at least one of them originates from yourB candidate

    • If your candidate is signal you will find nothing• If your candidate is background you will find one

    PV

    B+D*-

    D~0K+

    pi-

    pi-

    mu+

    pi+

    nu

    PV

    B0D*-

    D~0K+

    pi-

    pi-

    mu+

    nu

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 19 / 40

  • B+ background: busted!

    iso(D)-0.5 0 0.5 1

    Ent

    ries

    (arb

    . uni

    ts)

    Signal

    Background

    iso(all)-0.5 0 0.5 1

    LHCb

    iso(B)-0.5 0 0.5 1

    iso(sum)-3 -2 -1 0

    Ent

    ries

    (arb

    . uni

    ts)

    ]2c [MeV/corrm4000 6000 8000 10000

    ) [mm]D, πIP(5 10

    LHCB-PAPER-2015-031 (preliminary)

    • Merge these quantities into one MVA classifier to maximize the separationB. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 20 / 40

  • B+ background

    • Apply a cut on the MVA classifier → reduce B+→ D(∗)−µ+π+νµX by ∼ 70%

    -1 -0.5 0 0.5 1

    Even

    ts /

    0.05

    5

    10

    310×

    LHCb (e)

    -1 -0.5 0 0.5 10

    5

    10

    15

    20

    310×

    DataTotal fit

    signal0B bkg.+B

    (g)-1 -0.5 0 0.5 1

    Even

    ts /

    0.05

    5

    10

    310×

    (f)

    BDT output-1 -0.5 0 0.5 1

    0

    5

    10

    15

    20

    310×

    (h)

    3 10×

    LHCB-PAPER-2015-031 (preliminary)

    • Bonus: use the MVA output to estimate the contribution of B+→ D(∗)−µ+π+νµX• → avoid large uncertainty(∼ 10%) from B of B+→ D(∗)−µ+π+νµX in PDG

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 21 / 40

  • Flavour tagging: qmixing

    • Mixing state qmixing: flavour at decay × flavour at production = ±1• Flavour at decay in B0→ D(∗)−µ+νµ is determined by µ charge• Flavour at production?

    3/20 Ulrich Eitschberger | Updates on Flavour Tagging | 72nd LHCb week | June 19th, 2014

    Flavour Tagging: Determine B production flavours SS Pion SS Kaon Signal Decay

    Same Side

    Opposite Side

    OS Vertex Charge OS Muon OS Electron

    OS Kaon

    PV

    • Flavour at production (qprod : ±1, 0), Tagging efficiency (�): how often we tag andMistag probability (ω): how often we make a mistake

    • Tagging Power = �× (1− 2ω)2B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 22 / 40

  • Flavour tagging: qmixing

    • Lepton taggers are clean but rare

    • Cascade and vertex taggers are abundant but less pure

    ω

    Eur. Phys. J. C72 (2012) 2022

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 23 / 40

  • Flavour tagging: qmixing

    [%]2)ω (1-2∈0 1 2 3 4 5 6 7 8

    )d

    m∆(

    σ

    0.002

    0.004

    0.006

    0.008

    0.01

    0.012

    0.014

    0.016

    • Sensitivity scales with 1/√�× (1− 2ω)2

    • Higher tagging power is equivalent to higher luminosityB. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 24 / 40

  • Flavour tagging: qmixing

    • Mixing state qmixing: flavour at decay × flavour at production = ±1

    N±(t) ∝ e−tτ (1 + qmixing(1− 2ω) cos(∆md t))

    • Events are Grouped in 4 categories in increasing mistag probability• This increase the tagging power → increases sensitivity to ∆md• Tagging power for B0→ D(∗)−µ+νµ ∼ 2.5%

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 25 / 40

  • Determination of B0 decay time: Problem

    t = LB0 MB0pB0

    • Missing neutrino → pB0 cannot be known in data (only in simulation)• Decay time accessible in data is:

    tdata =LB0 MB0

    pDµB0 → D−µ+νµ B0 → D∗−µ+νµ

    B0

    D- π-

    K+

    μ+

    υμ

    π-

    B0D*-

    D0 π-

    K+

    μ+

    υμ

    π-

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 26 / 40

  • Determination of B0 decay time: Solution

    • To correct the decay time in data per event:• Get correction (k) from simulation:

    k =pDµpB0

    • Improve the correction of the momentum: k-factor as a function of visible mass

    tcorrected = tdata × k(MDµ)

    ]2c mass [MeV/µD*B3500 4000 4500 5000

    -facto

    rk

    0.30.40.50.60.70.80.9

    11.11.2 )2 c

    Even

    ts/(0

    .004

    )/(11

    MeV

    /

    0

    5

    10

    15

    20

    25

    30

    35LHCb

    LHCB-PAPER-2015-031 (preliminary)B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 27 / 40

  • Determination of B0 decay time: Resolution

    • Detector resolution on the flight distance of the B0 (R(L))

    • k → k(mDµ) → additional resolution function (F (k))

    • Momentum resolution introduces the largest effect in time resolution

    N±(t) ∝ e−tτ (1 + qmixing(1− 2ω) cos(∆md t))⊗ R(L)⊗ F (k)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 28 / 40

  • Tagged time-dependent fit

    • Use binned likelihood sFit (arXiv:0905.0724) to extract ∆md

    P(t, qmixing) = (1− fB+ )S(t, qmixing) + fB+B+(t, qmixing)

    • S(t, q),B+(t, q): decay rates of signal & background• fB+ : fraction of the B+→ D(∗)−µ+π+νµX in the sample

    t [ps]5 10 15

    Even

    ts / (

    0.14

    7 ps

    )

    0

    10

    20

    30

    40

    50

    310×

    DataTotal fit

    signal0B bkg.+B

    LHCb

    t [ps]5 10 15

    Even

    ts / (

    0.14

    7 ps

    )

    0

    5

    10

    15

    20

    25

    30

    35310×

    DataTotal fit

    signal0B bkg.+B

    LHCb

    B0 → D−µ+νµ B0 → D∗−µ+νµLHCB-PAPER-2015-031 (preliminary)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 29 / 40

  • Time dependent asymmetries

    5 10

    -0.5

    0

    0.5 LHCb

    (a)

    5 10

    -0.5

    0

    0.5

    (c)

    5 10

    -0.5

    0

    0.5

    (b)

    5 10

    -0.5

    0

    0.5

    (d)

    )t(A

    [ps]t

    5 10

    -0.5

    0

    0.5 LHCb

    (e)

    5 10

    -0.5

    0

    0.5

    (g)

    5 10

    -0.5

    0

    0.5

    (f)

    5 10

    -0.5

    0

    0.5

    (h)

    )t(A

    [ps]t

    B0 → D−µ+νµ B0 → D∗−µ+νµLHCB-PAPER-2015-031 (preliminary)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 30 / 40

  • Systematic uncertainties

    • Several sources of systematic uncertainties• k-factor method, B+ and other background sources & Other sources (time acceptance,

    detector resolution, momentum and length scale)

    • Large number of parameterized simulation to evaluate systematic uncertainties

    Source of uncertaintyB0→ D−µ+νµ [ns−1] B0→ D∗−µ+νµ [ns−1]

    Uncorrelated Correlated Uncorrelated CorrelatedB+ background 0.4 0.1 0.4 –Other backgrounds – 0.5 – –k-factor distribution 0.4 0.5 0.3 0.6Other fit-related 0.5 0.4 0.3 0.5Total 0.8 0.8 0.6 0.8

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 31 / 40

  • ... and ∆md is

    • Fits performed separately for per channel and per year

    • Combination across the two channel using weighted average

    • Results per decay channel (LHCB-PAPER-2015-031):

    Mode 2011 sample 2012 sample Total sample∆md [ ns−1] ∆md [ns−1] ∆md [ns−1]

    B0→ D−µ+νµ 506.2± 5.1stat 505.2± 3.1stat 505.5± 2.7stat ± 1.1systB0→ D∗−µ+νµ 497.5± 6.1stat 508.3± 4.0stat 504.4± 3.4stat ± 1.0syst

    • Combination of ∆md measurement across the two channels using Run I data:

    ∆md = 505.0± 2.1 (stat)± 1.0 (syst) ns−1(preliminary)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 32 / 40

  • Theory catching up

    ∆md =G2Fm2WMB0

    6π2 S0(xt)η2B|V∗tdVtb|2f 2B0 BB0

    • arXiv:1602.03560: Fermilab Lattice and MILC Collaborations

    • Improvements on uncertainties related to hadronic matrix elements:

    f 2B0 BB0 = 0.0526± 0.0042GeV/c2

    ∆md (Theory) = 0.639(50)(36)(5)(13) ps−1

    ∆md/∆ms(Theory) = 0.0323(9)(9)(0)(3)

    • PDG 2015: ∆md = (0.510± 0.003) ps−1, ∆ms = (17.757± 0.021) ps−1

    • Theory prediction for:∆md , ∆md/∆ms are 2.1, 2.9σ away from experiment

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 33 / 40

  • Conclusion

    • LHCb measure ∆md inB0→ D(∗)−µ+νµ channels using 3 fb−1

    ∆md = 505.0± 2.1 (stat)± 1.0 (syst) ns−1

    (preliminary)

    • LHCb provides the most precisemeasurement of ∆md

    • Better than the world average:(510± 3) ns−1(PDG 2015)

    • Recent development from the lattice:∆md prediction is 2.1σ away fromworld average

    ]-1 [nsdm∆450 500 550

    ALEPH (3 analyses) 19± 6 ±446

    DELPHI (5 analyses) 11± 18 ±519

    L3 (3 analyses) 28± 28 ±444

    OPAL (5 analyses) 15± 18 ±479

    CDF1 (4 analyses) 27± 33 ±495

    D0 (1 analysis) 16± 20 ±506

    BABAR (4 analyses) 4± 6 ±506

    BELLE (3 analyses) 5± 4 ±509

    LHCb (3 analyses) 3± 5 ±514

    1.3GeV) 0.27 + 0.19 - 0.21±4.32

    Average (w/o this meas.) 3±510

    HFAGSummer 2014

    Bosch, Lange, Neubert and Paz (BLNP)Phys.Rev.D72:073006,2005

    /dof = 9.2/11 (CL = 61.00 %)2χ

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 34 / 40

  • Backups

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 35 / 40

  • Time projections in 2012 data

    t [ps]5 10 15

    Eve

    nts

    / (0.

    147

    ps)

    0

    10

    20

    30

    40

    50

    310×

    DataTotal fit

    signal0B bkg.+B

    LHCb

    t [ps]5 10 15

    Eve

    nts

    / (0.

    147

    ps)

    0

    5

    10

    15

    20

    25

    30

    35310×

    DataTotal fit

    signal0B bkg.+B

    LHCb

    LHCB-PAPER-2015-031 (preliminary)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 36 / 40

  • D0 mass distributions for 2012

    ]2c [MeV/πK m1840 1860 1880 1900

    )2 cE

    vent

    s / (

    0.8

    MeV

    /

    0

    2

    4

    6

    8

    10

    310×

    LHCb Data Total fit

    *- D0 D

    Comb.

    ]2c [MeV/πK m1840 1860 1880 1900

    )2 cE

    vent

    s / (

    0.8

    MeV

    /

    0

    5

    10

    15

    20

    25

    310×

    LHCb Data Total fit

    *- D0 D

    Comb.

    LHCB-PAPER-2015-031 (preliminary)

    • D0 mass fits in B0→ D∗−µ+νµ decay

    • Components with D∗−D0π can be only distinguished using δm(= mD∗− −mD0 )

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 37 / 40

  • Asymmetries in 2011

    5 10

    -0.5

    0

    0.5 LHCb

    (a)

    5 10

    -0.5

    0

    0.5

    (c)

    5 10

    -0.5

    0

    0.5

    (b)

    5 10

    -0.5

    0

    0.5

    (d)

    )t(A

    [ps]t

    5 10

    -0.5

    0

    0.5 LHCb

    (a)

    5 10

    -0.5

    0

    0.5

    (c)

    5 10

    -0.5

    0

    0.5

    (b)

    5 10

    -0.5

    0

    0.5

    (d)

    )t(A

    [ps]t

    LHCB-PAPER-2015-031 (preliminary)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 38 / 40

  • MVA classifier

    -1 -0.5 0 0.5 1

    Even

    ts /

    0.0

    33

    5

    10

    15

    20

    310×

    LHCb (a)

    -1 -0.5 0 0.5 10

    50

    100

    310×

    DataTotal fit

    signal0B bkg.+B

    (c)-1 -0.5 0 0.5 1

    Even

    ts /

    0.0

    33

    5

    10

    15

    20

    310×

    (b)

    BDT output-1 -0.5 0 0.5 1

    0

    50

    100

    310×

    (d)

    3 10×

    -1 -0.5 0 0.5 1

    Even

    ts /

    0.0

    5

    5

    10

    310×

    LHCb (e)

    -1 -0.5 0 0.5 10

    5

    10

    15

    20

    310×

    DataTotal fit

    signal0B bkg.+B

    (g)-1 -0.5 0 0.5 1

    Even

    ts /

    0.0

    5

    5

    10

    310×

    (f)

    BDT output-1 -0.5 0 0.5 1

    0

    5

    10

    15

    20

    310×

    (h)

    3 10×

    B0→ D−µ+νµ B0→ D∗−µ+νµLHCB-PAPER-2015-031 (preliminary)

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 39 / 40

  • 0.35 0.4 0.45 0.5 0.55 0.6 0.65

    ∆md (ps

    -1)

    World averageSummer 2015

    0.5055 ±0.0020 ps-1

    CLEO+ARGUS(χ

    d measurements)

    0.498 ±0.032 ps-1

    Average of 32 above 0.5055 ±0.0020 ps-1

    LHCb D(*)

    µ/OST(3 fb

    -1, prel)

    0.5036 ±0.0020 ±0.0013 ps-1

    LHCb Dµ/OST,SST(1 fb

    -1)

    0.503 ±0.011 ±0.013 ps-1

    LHCb B0d(full)/OST,SST

    (1 fb-1

    )0.516 ±0.005 ±0.003 ps

    -1

    LHCb B0d(full)/OST(0.036 fb

    -1)

    0.499 ±0.032 ±0.003 ps-1

    BABAR D*lν/l,K,NN(23M BB

    −)

    0.492 ±0.018 ±0.013 ps-1

    BABAR D*lν(part)/l

    (88M BB−

    )0.511 ±0.007 ±0.007 ps

    -1

    BELLE B0d(full)+D

    *lν/comb

    (152M BB−

    )0.511 ±0.005 ±0.006 ps

    -1

    BELLE l/l(32M BB

    −)

    0.503 ±0.008 ±0.010 ps-1

    BELLE D*π(part)/l

    (31M BB−

    )0.509 ±0.017 ±0.020 ps

    -1

    BABAR l/l(23M BB

    −)

    0.493 ±0.012 ±0.009 ps-1

    BABAR B0d(full)/l,K,NN

    (32M BB−

    )0.516 ±0.016 ±0.010 ps

    -1

    D0 D(*)

    µ/OST(02-05)

    0.506 ±0.020 ±0.016 ps-1

    CDF1 D*l/l

    (92-95)0.516 ±0.099

    +0.029 ps

    -10.516 ±0.099

    -0.035

    CDF1 l/l,Qjet(94-95)

    0.500 ±0.052 ±0.043 ps-1

    CDF1 µ/µ(92-95)

    0.503 ±0.064 ±0.071 ps-1

    CDF1 Dl/SST(92-95)

    0.471 +0.078

    ±0.034 ps-1

    0.471 -0.068

    OPAL π*l/Qjet

    (91-00)0.497 ±0.024 ±0.025 ps

    -1

    OPAL D*/l

    (90-94)0.567 ±0.089

    +0.029 ps

    -10.567 ±0.089

    -0.023

    OPAL D*l/Qjet

    (90-94)0.539 ±0.060 ±0.024 ps

    -1

    OPAL l/Qjet(91-94)

    0.444 ±0.029 +0.020

    ps-1

    0.444 ±0.029 -0.017

    OPAL l/l(91-94)

    0.430 ±0.043 +0.028

    ps-1

    0.430 ±0.043 -0.030

    L3 l/l(IP)(94-95)

    0.472 ±0.049 ±0.053 ps-1

    L3 l/Qjet(94-95)

    0.437 ±0.043 ±0.044 ps-1

    L3 l/l(94-95)

    0.458 ±0.046 ±0.032 ps-1

    DELPHI vtx(94-00)

    0.531 ±0.025 ±0.007 ps-1

    DELPHI D*/Qjet

    (91-94)0.523 ±0.072 ±0.043 ps

    -1

    DELPHI l/l(91-94)

    0.480 ±0.040 ±0.051 ps-1

    DELPHI π*l/Qjet

    (91-94)0.499 ±0.053 ±0.015 ps

    -1

    DELPHI l/Qjet(91-94)

    0.493 ±0.042 ±0.027 ps-1

    ALEPH l/l(91-94)

    0.452 ±0.039 ±0.044 ps-1

    ALEPH l/Qjet(91-94)

    0.404 ±0.045 ±0.027 ps-1

    ALEPH D*/l,Qjet

    (91-94)0.482 ±0.044 ±0.024 ps

    -1

    Heavy FlavourAveraging Group

    ∆md (world average 2015) = 505.5± 2.0 ns−1

    B. Khanji, LHCb (Milano-Bicocca, INFN, CERN) ∆md at LHCb 22-March-2016 40 / 40