Selected LHCb results

Heavy flavours and QCD Selected LHCb results

Sergey Barsuk, LAL Orsay

on behalf of the LHCb collaboration

: La nascita, la vita e la morte degli aromi pesanti a LHCb Outline

 Heavy flavour production

Onia production / Open charm and beauty production / Exotics

 Lifetime-based studies

 Heavy flavour hadron decays & CPV

Angle γ / BsBs mixing phase φ

_s

/ New results on b-baryons /

/ Radiative penguines bsγ / Search for Bsμμ

Heavy flavours – excellent place to hunt for effects beyond

Standard Model

Strategic attack on SM by LHCb : examples of where LHCb can

contribute Hot channels for the near future:

 Bs  μ μ : Is there SUSY? BR ~ tan

⁶

β / m

⁴

A .

 Bs  J/ψφ et al. : Beyond-SM CPV?

 Bd  μ μ K* : Right-handed currents?

 γ (φ3) : Is the CKM matrix sufficient?

 y _CP : Beyond-SM CPV in charm?

My goal is to show results / potential of LHCb in these areas …

 talks by Antonio Masiero and Marco Ciuchini

Introduction

 Correlated bb production, second b in acceptance once the first b is in (flavour tagging)

 LHCb covers forward region: 1.9 < η < 4.9

 optimized for forward peaked HQ production at the LHC

 only ~4% of solid angle, but ~40% of HQ production cross section

LHCb design overview

 Bunch crossings at 40 MHz, can store < 3 kHz

Aim at reducing rate, while storing as many HQ as possible, two-stage trigger:

 Hardware-based L0 trigger employs moderate pT cuts, reduces rate to 800 kHz

 Unique acceptance amongst LHC experiments:

can explore QCD in the forward region

 LHCb covers forward region: 1.9 < η < 4.9

 Busy events, O(200) particles/event

 Large cc and bb production cross section at LHC : with ALL c- and b-species produced,

e.g. 50k bb events/s

JINST 3:S08005,2008

250 mrad

10 mrad

Vertex reconstruction:

VELO

Trigger:

Muon Chambers Calorimeters RICHsPID:

Calorimeters Kinematics:

Magnet Tracker

Calorimeters

SystemMuon Tracking

RICH counters p/K/π Identification

VErtex LOcator

p p

LHCb detector – single-arm forward spectrometer 10-250 mrad (V), 10-300 mrad (H)

LHCb lifetime measurements using 36 pb^-1 of 2010 data

1.638 0.011 1.525 0.009 1.525 0.009 1.477 0.046 1.391 0.038 PDG [ps]

LHCb [ps]

Vertex Locator (VELO) provides excellent proper time resolution of ~50 fs

VErtex LOcator: precision tracking and vertexing

LHCb-CONF-2011-001

VELO sensitive area gets 8 mm to the beam axis

Charged hadron identification: Cherenkov detectors Muon detector

π⁰

X→µµ

Particle identification

photon/electron/hadron PID:

calorimeter

LHCb collected ~37 pb^-1 in 2010 and already >700 pb^-1 in 2011. Goal for 2011: 1 fb^-1

 LHC reached nominal peak luminosity of 2x10³³ cm^-2s^-1 with number of bunches ~1300 from ~2600

 LHCb recording >1pb^-1/hour running at

L~3.3x10³² cm^-2s^-1 (higher, than nominal, 2x10³² cm^-2s^-1 ) in auto-leveling mode

 LHCb tested operation up to 4x10³² cm^-2s^-1

 Visual average number of vertices now is higher µ ~1.4, compared to nominal µ =0.4

 Higher µ  higher track multiplicity, 1 PV gives 30 tracks/rapidity range,

dangerous for reconstruction

 dangerous background for D and B decay vertex reconstruction LHCb luminosity levelling

~30 pb^-1 in 29 h in a single fill.

dL/dt ~ 100 pb^-1/week possible !

LHCb operation

LHCb

(design)

ATLAS

CMS

Heavy flavour production: LHCb as a flavour factory

 Onia production: J/ψ, χ _c , ϒ(1S), χ _b

 Exotics: X(3872), X(4140)

 b-hadron production: inclusive production, B, Bs, Bc

 Exclusive charmonium production

Onia production: J/ψ and ϒ(1S)

LHCb-CONF-2011-016 Measurements getting more precise than theory, given polarisation will be measured.Mechanism of onia production: colour single model, octet model, evaporation model...?

Eur.Phys.J. C71 (2011) 1645

J/ψ prompt J/ψ from b

P.Artoisenet, M.Butenschon, B.A.Kniehl

ϒ(1S)

P.Artoisenet, J.M.Campbell, J.P.Lansberg, F.Maltoni, F.Tramonato

Adequate description of J/ψ production, while still big uncertainty for ϒ(1S) 32 pb^-1

32 pb^-1

5.2 pb^-1 5.2 pb^-1

χ _c and χ _b production using radiative decays χ _c  J/ψ γ and χ _b  ϒ(1S)γ

LHCb-CONF-2011-020 Challenge to resolve χ_c1 vs. χ_c2

σ(χc2)/σ(χc1)

NLONRQCD

LO colour singlet

First results for relative production of χ_c1 vs. χ_c2 are not well described by NLO NRQCD.

 χ_b0,1,2 can not be resolved

 No sign of χ_b(2P) reported by CDF

(PRL 84 (2000) 2094), though ϒ(1S) statistics ~30 times larger.

350 59 events 35 pb^-1

35 pb^-1

37 pb^-1

LHCb preliminary 376 pb^-1

B⁺X(3872)K⁺

Exotics: X(3872), observation, mass, x-section

Mass calibrated by scaling track momenta and constraining ϒ(1S),ψ(2S)μμ, D^oKπ and K^o_S  ππ masses. Control channel: ψ(2S)J/ψ ππ.

With 2011 data perform:

 precise mass measurements

 angular studies [LHCb-PUB-2010-003]

in BX(3872)K to access J^PC of X(3872)

LHCb-CONF-2011-021 LHCb-CONF-2011-043 Exotic, internal structure uncertain, possibly a D^oD*^o molecule.

Precise mass crucial Inclusive measurement, LHCb 2010 data, 35 pb^-1

for 5 GeV/c < p

_T

< 20 GeV/c, 2.5 < η < 4.5.

35 pb^-1

LHCb preliminary 376 pb^-1 B⁺J/ΨφK⁺

~360 decays (c.f. 115 for CDF

in 6 fb^-1)

Background model is 3-body phase space convoluted with resolution

LHCb does not confirm presence of X(4140).

CDF observed a 5σ structure, X(4140),

X(4140)J/Ψ φ in B⁺J/ΨφK⁺ events [arXiv:1101.6058].

LHCb now has a large sample of these decays.

CDF ~6 fb^-1

fit: 7 5 expected signal scaled from CDF:

39 9 6

Exotics: search for the X(4140)

LHCb-CONF-2011-045

LHCb preliminary 376 pb^-1

b-hadron production studies:

b

-production with B⁺J/ΨK⁺

Measurements reasonably well described by theory (FONLL, MC@NLO)

b-hadron production

 Detached J/Ψ: σ^4π_bb = (288 4 48) μb

 Dμ tags: σ2 < η < 4

bb = (75 5 13) μb σ^4π_bb = (284 20 49) μb

 Fully reconstructed J/Ψ X states:

LHCb-CONF-2011-033 Phys. Lett. B 698 (2011) 14 Eur. Phys. J. C 71 (2011) 1645

35 pb^-1

LHCb measured fragmentation fractions: relative rates of B⁺, B^o, B_s, Λ_b ...

B_sD_s^-π⁺ B^oD^-K⁺ Two complementary approaches:

1. Ratio of related hadronic decays, e.g. B^oD^-K⁺ and B_sD_s^-π⁺

2. Semi-leptonic analysis with D^o μX, D⁺ μX, D_s μX & Λ_c μX events and accounting for cross-

feeds [LHCb-CONF-2011-028]

[arXiv:1106.4436, sub. to PRL]

Consistent results for B_s/B^o fragmentation ratio, f_s/f_d, which thus can be combined:

<f_s/ f_d> _LHCb = 0.267 f_s/f_d not a priori a ‘universal’ number,

but similar to LEP and Tevatron result.

+0.021 -0.020 LHCb-CONF-2011-034

b-hadron production

LHCb, 35 pb^-1 LHCb, 35 pb^-1

Relative B _c ⁺ to B ⁺ meson production

Production of B_c⁺ is added by measuring it relative to B⁺,

in the fiducial region p_T > 4 GeV/c, 2.5 < η < 4.5.

LHCb 2010 data: 32.5 pb^-1

3476 62 events 43 13 events

Uncertainty is mainly statistical,

systematics dominated by the B_c⁺ lifetime measurement.

LHCb-CONF-2011-017

32.5 pb^-1 32.5 pb^-1

Usually proton collisions produce very many final state particles because the gluon is a coloured object. But if a colourless object is exchanged…..

Exclusive quarkonia production

 J/ψ and ψ’ exclusive production are interpreted as photon-pomeron fusion

or odderon-pomeron fusion;

 χ_c exclusive production is interpreted as double pomeron exchange;

 exclusive di-muons come from photon-photon fusion.

Clean signature:

 No backward tracks (gap of 2 units of rapidity)

 Precisely two forward muons

 No photons (for J/ψ and diphoton process)

 One photon (for χ_c analysis)

LHCb-CONF-2011-022

 Talk by Alain Martin

Use of backwards tracks, non-exclusive production

Backward Forward tracks

Primary vertex Muon

Backward tracks

Requiring a gap, there is evidence for central exclusive production decaying to two muons.

Estimated feeddown from χ_c

J/ψ and ψ’: number of photons ψ’ feeddown

J/ψ and ψ’: number of forward tracks

ψ’ J/ψ J/ψ

subtracted

J/ψ ψ’

Purity from forward track counting: fitting the background under the peak by using a straight line or exponential fit, yields purity estimate ~85%.

Exclusive production: signatures from J/ψ, ψ’ and χ _c

LHCb 2010 data 3.1 0.6 pb^-1

LHCb 2010 data 3.1 0.6 pb^-1

χ_c

Fit elastic and inelastic components

Estimate purity below 900 MeV : 80 3%

Exclusive production: purity from dimuon pT spectrum

J/ ψ and ψ’ signals

Clean mass peaks of J/ψ and ψ’ resonances despite looking at prompt production in pp-

collisions at 7 TeV. Contribution from non-resonant background & misidentification is small

Events with no backward tracks, two forward tracks and no photon.

J/ψ Ψ’

LHCb 2010 data 3.1 0.6 pb^-1

LHCb 2010 data 3.1 0.6 pb^-1

Require two forward tracks and one

identified photon > 200 MeV. Even cleaner!

M(μμ) GeV/c2 M(μμγ) GeV/c2

Fit M(μμγ) to MC templates

for ψ’, χ_c0, χ_c1, χ_c2

All the three χ_c states needed to describe the observed spectrum !

Exclusive production: χ _c states

LHCb 2010 data

3.1 0.6 pb^-1 LHCb 2010 data

3.1 0.6 pb^-1

Exclusive production: results

 Comparison theory-experiment requires major efforts from both parts.

 Reasonable precision for J/ψ and ψ’, systematics will be improved in 2011.

 Consistent* with Starlight, SuperChiC, Motyka & Watt [Phys. Rev. D 78, (2008) 014023] and Schaffer & Szcsurek [Phys.Rev. D76 (2007) 094014]

 Still no precise determination of individual χ_c0, χ_c1, χ_c2 production.

 Consistent* with SuperChiC, Harland-Lang et al. [arXiv:hep-ph/0909.4748].

 Does not agree to CDF 2009 [Phys. Rev. Lett. 102, (2009) 242001].

 Most clean ratio of ψ’ to J/ψ production, corrected for BR(ψμμ), 0.20 0.03.

 Consistent with HERA and Tevatron results.

 Consistent* with Starlight and Schaffer & Szcsurek [Phys.Rev. D76 (2007) 094014. arXiv:hep-ph/0811.2488]

 Contributions from all the 5 charmonium states (J/ψ, ψ’, χ_c0, χ_c1, χ_c2) is seen.

 New dedicated trigger line implemented now & statistics x 30  improvement in 2011 !

Charm studies: LHCb as LHCcC

 Mixing parameter y _CP via lifetime comparison

 Search for CP violation via A _Γ

 (Search for direct CP violation) Moved to backup

Mixing and CP violation in charm sector

Charm is abundant at LHC: 6.5 mb cross-section.

However need to reconstruct low pT decays.

Φ

|q/p|

SM

D*+ Do (K+ K- )π+

195 pb^-1 220 pb^-1

Ds+ K+ K- π+

D+ K+ K- π+

Large samples of charm mesons are being reconstructed.

Presently ~700 pb

^-1

collected.

D_1,2 = p |D^o

>

^{q |Do}

>

x=∆m/Γ, y=∆Γ/2Γ

 Mixing in charm sector is non-zero at >5σ by HFAG, however no single measurement excludes 0.

 CPV in mixing (SM or NP) driven by mixing parameters x,y (~1%). CPV in D mixing in SM is negligible, but can be enhanced in many models. Existing constraints are weak.

 Direct CPV best looked for in CSD, where gluonic penguins are significant.

Charm mixing parameter yCP :

Future improvement in sensitivity :

 Statistics x30 in 2011

 Improved treatment of background events

Measurement of the charm mixing parameter y

_CP LHCb-CONF-2011-054

D^oK^-π⁺ D^oK^-K⁺

D^oK^-π⁺ D^oK^-K⁺ τ_Do=410.2 0.9 fs

 Contribution from BDX to prompt charm sample

 Correct lifetime bias

on the event-by-event basis

2010 data, 28 pb^-1, flavour tagging using D^o sample from D*D^oπ decays.

LHCb preliminary 28 pb^-1

LHCb preliminary 28 pb^-1 Challenges in time-dependent

charm studies at LHC:

One of most important ways to search

CPV in charm mixing:

2010 data, 28 pb^-1, flavour tagging using D^o sample from D*D^oπ decays.

Obtained event-by-event on data

HFAG 2011 average (without LHCb):

( 0.12 0.25 ) x 10^-2

A_Γ= (-0.59 0.59 0.21) x 10^-2

Measurement of A Γ

LHCb-CONF-2011-046

Future improvement in sensitivity :

 Statistics x30 in 2011 Challenges in time-dependent charm studies

at LHC:

 Contribution from BDX to prompt charm sample

 Correct lifetime bias

on the event-by-event basis

Beauty studies: LHCb as LHCb

 Angle γ:

 Evidence of suppressed ‘ADS’ mode BDK

 Charged hadron ID and

Direct CP violation in charmless B-decays with eyes

 New results on b-baryons: Λ _b  D ^o pK ^-

 Bs mixing phase φ _s from B _s  J/Ψφ and B _s  J/Ψ f _o (980)

 Rare decays:

 Radiative penguines bsγ

 (Forward-backward asymmetry in BK*ℓℓ) Moved to backup

 Search for Bsμμ

Touch rare effects and mostly bs transitions: penguine or box diagram,

NP diagrams can compete.

B  DK decays using common mode for D^o & D^o

 γ sensitive interference

 different rates for B⁺ & B^- (CPV)

Maximize interference by using mode suppressed for D^o & favoured for D^o e.g. D^oK⁺π^- (DCS) , D^oK⁺π^- (CF) the ‘ADS’ method

[Atwood, Dunietz, Soni]

Total visible BR very small (~10^-7).

The suppressed ‘ADS’ mode is needed to access γ.

Precision CKM studies: angle γ

R_b R_t 1

 The Rt side precision limited by theory (lattice calculations), while precision of γ limited by

experiment. Improve precision of angle γ to improve CKM triangle closure check

 Search for NP by comparing tree-mediated

processes (γ, Rb) to those involving loop diagrams (γ, β, Rt)

B  (K π ) K

2010

Signal seen with 4.0σ significance & hint of asymmetry, consistent with previous results

B  (K π ) K

Ratio to favoured mode:

HFAG average (without LHCb):

(1.6 0.3) x 10^-2

B^-(K⁺π^-)K^-

343 pb^-1

Asymmetry: -0.58 0.21

B⁺(K^-π⁺)K⁺

343 pb^-1

Evidence for suppressed ADS mode

LHCb-CONF-2011-044

343 pb^-1

HFAG average (without LHCb):

‘Bhh’ (h=π,K,p) at LHCb

Inclusive spectrum, ππ hypothesis

LHCb preliminary

Deploy RICH to decript ‘hh’ !

B^oKπ Rely on good performance of trigger and RICH

Λ_bpπ Two-body charmless B decays: significant contribution of penguin diagrams, important for NP searches

B^oππ

BsKK Λ_bpK

B^oK⁺π^-

HFAG average (without LHCb):

Most precise single measurement and first 5σ observation of CPV at hadron machine:

CDF result:

0.17 First evidence of CPV in Bs decays:

B _d,s  Kπ: direct CPV

LHCb-CONF-2011-042

In future perform time dependent study, particularly of BsKK:

B^oK^-π⁺

B_sK⁺π^- B_sK^-π⁺

320 pb^-1 320 pb^-1

320 pb^-1 320 pb^-1

Λ_bD^opπ^-

Λ_bD^opK^-

New measurements with b -baryons

LHCb-CONF-2011-036

Ξ^o_bD^opK^-

Cabibbo-suppressed decay Λ_bD^opK^-, potentially powerful mode for measuring CKM angle γ.

Normalization channel: Λ_bD^opπ^-.

 A signal with (stat+syst) significance of 2.6σ, consistent with Ξ^o_bD^opK^- decay.

Relative production rate x BR: Mass relative to Λb:

Ξ^o_b [Ξ⁺_cπ^-, Ξ⁺_cΞ^-π⁺π^-, Ξ^-Λπ^-, Λpπ^-] recently observed by CDF [arXiv:1107.4015].

M(D^opπ^-) MeV/c² M(D^opK^-) MeV/c²

 First observation of

with significance of 6.3σ:

Λ_bD^opK^-

 Phase is small in SM (box diagram) : 0.0363 0.0017 rad [CKMFitter]

 Deviations due to NP could be large

Precision CKM studies: Bs mixing phase φ _s from B _s  J/Ψφ

Time dependent analysis

 Time resolution measured using prompt J/Ψ background: σ_τ = 50 fs

 LHCb measurement with 2010 data: 37 pb^-1, 757 28 signal candidates

[LHCb-CONF-2011-006]

Tagging

 Need to tag initial flavour of the Bs

 Per event mistag calibrated on B+  J/Ψ K and Bd  D* μ ν_μ

 Dilution D_tag = 0.277 0.011 0.025

 Tagging power εD² = (2.08 0.41)%

Angular analysis

 PVV decay: needs an angular analysis to resolve CP-even and CP-odd components

 Angular acceptance determined from MC

 Maximum deviation from uniform: 5%

φ _s from B _s  J/Ψφ

ΔΓs [rad]

Φs [rad]

~770 decays

SM

Φs [rad]

First evidence (4σ) of ΔΓs > 0 !

φ _s ^J/Ψφ = 0.13 0.18 (stat) 0.07 (sys) rad

Γ _s = 0.656 0.009 (stat) 0.008 (sys) ps ^-1 ΔΓ _s = 0.123 0.029 (stat) 0.008 (sys) ps ^-1

337 pb^-1 36 pb^-1

φ _s from B _s  J/Ψ f _o (980)

 First observation of BsJ/Ψ f_o(980) (f_o(980)ππ) by LHCb with 30 pb^-1

[Phys. Letters B 698 (2011) 115]

confirmed by

Belle [Phys.Rev.Lett.106:121802,2011] and CDF [arXiv:http://arxiv.org/abs/1106.3682]

 With 330 pb^-1 LHCb extractsφ_s.

 The f_o(980) looks pure scalar

 no angular analysis needed.

330 pb^-1

LHCb preliminary 330 pb^-1 LHCb preliminary 330 pb^-1

Bs J/ψ fo(980) B^oJ/ψK*B^oJ/ψπ⁺π^-

φ _s from B _s  J/Ψ f _o (980) and B _s  J/Ψφ

φ

_s^J/Ψfo(980)

= -0.44 0.44 0.02 rad

φ

_s^{J/Ψφ+J/Ψfo}

= 0.03 0.16 0.07 rad

Or, combining, B_sJ/Ψφ and B_sJ/Ψ f_o(980) :

SM fit: 0.0363 0.0017 rad

B_sJ/Ψφ B_sJ/Ψ f_o(980)

LHCb with 0.3 fb^-1

already more sensitive, than CDF and D0 330 pb^-1

Measure ratio of the branching fractions for BK*γ and Bsφγ

Expect: 1.0 0.2 from SM.

Radiative penguines: bsγ

Ali, Pecjak, Greub [Eur.Phys.J.C 55 (2008) 577]

LHCb-CONF-2011-055

 Test for NNLO QCD predictions

 Photons  Broader signal peak than typical B decay

 More work on backgrounds (B  Kππ^o etc)

 However, largest Bsφγ sample

Bsφγ BK*γ 340 pb^-1

340 pb^-1

 Next: study time evolution and CP asymmetries

In SM, Bsμμ occurs only via loop diagrams, and is helicity suppressed:

BR(Bsμμ)_SM = (3.2 0.2) x 10^-9

[A.J.Buras, arXiv:1012.1447]

Can be strongly enhanced in NP models,

especially those with extended Higgs sector.

E.g. MSSM:

NUHM (= generalised version of CMSSM) [O. Buchmuller et al, arXiv:0907.5568]

BR(Bsμμ) - highly discriminatory

Recent CDF result with 7 fb^-1:

[arXiv:1107.2304]

Search for Bsμμ

BR(Bsμμ) = (1.8 ) x 10^-8

or < 4.0 x 10^-8 @ 95% CL +1.1-0.9

LHCb 2010 data, 0.037 fb^-1:

[PLB 699 (2011) 330]

BR(Bsμμ) < 5.6 x 10^-8 @ 95% CL

Many previous measurements

 Talk by M.Kraemer

 Similar to 2010 analysis [PLB 699 (2011) 330]

 Select Bsμμ, using Boosted Decision Tree out of 9 kinematical and topological variables

 BDT tuned on MC, but calibrated on data:

Bhh, triggered on ‘other B’, and sidebands

 Calibrate invariant mass resolution (~25 MeV) on data (dimuon resonances & Bhh)

 Look on 6 x 4 grid of μ+μ- invariant mass vs. BDT output

 Normalize to: B⁺J/ΨK⁺, B_sJ/Ψφ and B^oKπ^–

 all give consistent results

Search for Bsμμ, LHCb 2011 data, 300 pb ^-1

LHCb-CONF-2011-037

300 pb^-1

300 pb^-1 300 pb^-1

300 pb^-1

Combinatorial background

Data

Bhh misid background 0.1 0.1

events in each of 4 BDT bins

Signal with SM BR

Search for B _s  μμ, LHCb 2011 data, 300 pb ^-1

LHCb preliminary 300 pb^-1 LHCb preliminary

300 pb^-1 LHCb preliminary

300 pb^-1

LHCb preliminary 300 pb^-1

Compute limits using frequentist CLs method and LHCb combined result for fs/fd

expected: background only 1σ

observed 1σ

observed

Search for B _s  μμ, LHCb limits

Expected limit assuming bkg only (95% CL) 1.0x10^-8 3.1x10^-9 Expected limit assuming bkg + SM signal (95% CL) 1.5x10^-8

Observed limit (95% CL) 1.6x10^-8 5.1x10^-9

p-value of background only hypothesis 14% 79%

Observed limit, 2010+2011 (95% CL) 1.5x10^-8

BR(B_sμ⁺μ^-) BR(B_dμ⁺μ^-) LHCb preliminary

300 pb^-1 LHCb preliminary

300 pb^-1 expected:

background and signal SM BR

A preliminary CMS (1.14 fb^-1)-LHCb (0.34 fb^-1) combination on BR(B_sμ⁺μ^-) has been performed, again using the CLs approach,

& taking LHCb value of f_s/f_d as common input

CMS + LHCb preliminary

1σ

observed

Observed candidates in both experiments are consistent with the sum of backgrounds and SM signal  BR < 1.1 x 10^-8 @ 95% CL.

This limit is 3.4 times the expected SM value.

-8

Search for B _s  μμ, combining LHCb and CMS results

LHCb (0.34 fb^-1) + CMS (1.14 fb^-1) preliminary expected: background only

LHCb-CONF-2011-047 CMS PAS BPH 11-019

Hunting for physics Beyond Standard Model (“New Physics”) continues and

either we discover it within our lifetime scale

or …

… and New New Physics ==

Beyond New Physics discover on our own.

... or we have to ask for

help this time ...

Summary

 LHCb is proving to be a heavy flavour factory

 Production of quarkonia and open heavy flavour hadrons is being systematically studied

 Charm cross section is large, huge D-meson samples collected, and first CPV studies with 2010 data look promising

 Precision CKM angle γ studies are launched, hint on the ‘ADS’ asymmetry in BDK is observed

 Most precise measurement of the direct CPV in BKπ

 First evidence of the direct CPV in BsKπ

 New data on the b-baryons

 LHCb and CMS do not confirm the hint seen by TEVATRON for B

_s

 μμ, and set the limit, which is x 3.4 SM value

 2011 data being analysed, many analyses still on 2010 data

 Expect 1 fb

^-1

in 2011, more in 2012, setting the scene for precision

rare effects studies

Backup

37 pb^-1

2010

370k decays

 Compare with 43k events in BABAR, 80 fb^-1 [PRD 71 (2005) 091101 (R)]

 Normalize D⁺ vs. D^- to remove production asymmetries

 Use resonance motivated binning & uniform binning

 Look for statistically significant difference in D⁺ vs.

D^- bin contents (based on PRD 80 (2009) 096006)

 Look for fake CPV in sidebands and control modes

Cabibbo favoured control modes (no CPV expected)

 No fake CPV seen: data & method robust against biases

Same topology D_s⁺K⁺K^-π⁺

10x more abundant D⁺K^-π⁺π⁺

Direct CPV search

Paper in preparation Perform model independent binned CPV search

in singly Cabibbo suppressed D⁺K^-K⁺π^- events

BK*μμ

 b  l l s, very rare in the SM BR (B  l l K*) = (3.3 1.0) x 10^-6

 Sensitive to Supersymmetry, any 2HDM, Fourth generation, Extra dimensions, Axions . . .

 Ideal place to look for new physics

b  l l s

Angular Distributions & A

_FB

Many observables depending on q

²

= m

²_μμ

c

⁴

[Krüger & Matias]

[Egede et al.] [Ali et al.]

Models probed

by A

_FB

(q2) dependence

LHCb presents a result with 300 events with 309 pb-1: Largest sample in the world

[LHCb-CONF-2011-038]

 Select events B0K*μ+μ- using Boosted Decision Tree from sample of 309 pb-1

 Veto decays in J/Ψ and Ψ(2S) (used as control of angular fits)

 Weight events according to η^-1(θ_l,φ,θ_K,q²)

B0K*μ+μ-

Measure in 6 q² bins:

extract dГ/dq2

SM: Bobeth et al., [arXiv:1105.0376]

Fit for θ

_K

and θ

_l

AFB in B0→K*μ+μ-in LHCb with 309 pb-1

Systematic uncertainties are small, and generally themselves statistics limited.

LHCb-CONF-2011-038

Data are consistent with SM at present sensitivity.

 Add other observables, e.g. AT(2), sensitive to RH currents

φ _s from B _s  J/Ψφ

φ _s from B _s  J/Ψφ

Tagging

Need to tag initial flavour of the Bs

Per event mistag calibrated on B+  J/Ψ K and Bd  D* μ ν_μ Dilution D_tag = 0.277 0.011 0.025

Tagging power εD² = (2.08 0.41)%

Angular analysis

PVV decay: needs an angular analysis to resolve CP-even and CP-odd components

Angular acceptance determined from MC Maximum deviation from uniform: 5%

φ _s from B _s  J/Ψφ: fit projections

Miscellaneous

LHCb also measures the double J/ψ cross section:

[LHCb-CONF-2011-009], submitted to Phys.Lett.B 5.1 1.0 1.1 nb-1

Model: [hep-ph/0603175]

37.5 pb^-1

Sensitivity to tetraquarks, built of c-quarks

Only statistical errors shown.

LHCb operation: luminosity limitations

J/ψ  μμ ψ(2S)  μμ

ψ(2S) / J/ψ

15% theo. uncertainty assumed

15% theo. uncertainty assumed

Deviation significance, [σ]

Exclusive production: results