Heavy flavours and QCD Selected LHCb results

SB 1LHCb results: heavy flavours and QCD Trento, 15.09.11

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 / BsBs mixing phase φs / New results on b-baryons /

/ Radiative penguines bs / Search for Bsμμ


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 ~ tan6β / m4A .

Bs J/ψφ et al. : Beyond-SM CPV?

Bd μ μ K* : Right-handed currents?

(φ3) : Is the CKM matrix sufficient?

yCP: 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 Then full event information can be used by the trigger farm (HLT)

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

CalorimetersTracker

PID:RICHs

CalorimetersMuon Chambers

Kinematics:MagnetTracker

Calorimeters

Calorimeters

MuonSystemTracking

RICH countersp/K/π Identification

VErtexLOcator

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 ± 0.0111.525 ± 0.0091.525 ± 0.0091.477 ± 0.0461.391 ± 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

0

X

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 average minimum distance between 4 PVs ~12 mm, comparable to average B travel

distance ~10 mm

LHCb luminosity levelling

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

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

LHCb operation

LHCb(design)

ATLASCMS


Heavy flavour production: LHCb as a flavour factory

Onia production: J/ψ, χc, ϒ(1S), χb

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


χc and χb production using radiative decays χcJ/ψ γ and χbϒ(1S)γLHCb-CONF-2011-020

Challenge to resolve χc1 vs. χc2

σ(χ

c2

)/σ

(χc1

)

NLONRQCD

LO colour singlet

First results for relative production of χc1 vs. χc2 are not well described by NLO

NRQCD.

χb0,1,2 can not be resolved

No sign of χb(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

M(J/Ψππ)-M(J/Ψ)

B+X(3872)K+

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

Mass calibrated by scaling track momenta and constraining ϒ(1S),ψ(2S)μμ, DoKπ and

KoS ππ masses. Control channel: ψ(2S)J/ψ ππ.

With 2011 data perform: precise mass measurements angular studies [LHCb-PUB-2010-

003] in BX(3872)K to access JPC of

X(3872)

LHCb-CONF-2011-021

LHCb-CONF-2011-043 Exotic, internal structure uncertain, possibly a DoD*o molecule.

Precise mass crucialInclusive measurement, LHCb 2010 data, 35 pb-1

for 5 GeV/c < pT < 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).2.4σ tension with CDF (using this background model)

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: σ4πbb = (288 ± 4 ± 48) μb

Dμ tags: σ2 < η < 4bb = (75 ± 5 ± 13)

μbσ4πbb = (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+, Bo, Bs, Λb ...

BsDs-π+ BoD-K+

Two complementary approaches:

1. Ratio of related hadronic decays, e.g. BoD-K+ and BsDs-π+

2. Semi-leptonic analysis with Do μX, D+ μX, Ds μX & Λc μX events and accounting for

cross-feeds [LHCb-CONF-2011-028]

[arXiv:1106.4436, sub. to PRL]

Consistent results for Bs/Bo fragmentation ratio, fs/fd, which thus can be combined:

<fs/ fd> LHCb =

0.267

Necessary input for e.g. BR(Bsμμ)

fs/fd 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 Bc+ to B+ meson production

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

in the fiducial region pT > 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 Bc

+ 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;

χc 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 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 productiondecaying to two muons.


Estimated feeddown

from χc

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 χcLHCb 2010 data

3.1 ± 0.6 pb-1

LHCb 2010 data

3.1 ± 0.6 pb-1

χc


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

wit

h

no b

ack

ward

tra

cks,

tw

o f

orw

ard

tra

cks

and n

o p

hoto

n.

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’, χc0, χc1, χc2

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

Exclusive production: χc states

LHCb 2010 data

3.1 ± 0.6 pb-1LHCb 2010 data

3.1 ± 0.6 pb-1

SB 21LHCb results: heavy flavours and QCD Trento, 15.09.11* Large theoretical uncertainties. Rescattering corrections (alters cross-section by ~20%).

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 χc0, χc1, χc2 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(ψμμ), 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’, χc0, χc1, χc2) is

seen.

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


Charm studies: LHCb as LHCcC

Mixing parameter yCP via lifetime comparison

Search for CP violation via AΓ

(Search for direct CP violation) Moved to backup


Mixing and CP violation in charm sectorCharm is abundant at LHC: 6.5 mb cross-section. However need to reconstruct low pT decays.

Φ

|q/p|

SM

D*+

D

o(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.

D1,2 = p |Do> ± q |Do>

x=m/, y=/2

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

yCP= (5.5 ± 6.3 ± 4.1) x 10-3

Measurement of the charm mixing parameter yCPLHCb-CONF-2011-054

DoK-π+ DoK-K+

DoK-π+ DoK-K+τDo=410.2±0.9 fs

Contribution from BDX to prompt charm sample Correct lifetime bias on the event-by-event basis

HFAG 2011 average (without LHCb): (11.1 ± 2.2) x 10-3

2010 data, 28 pb-1, flavour tagging using Do sample from D*Doπ 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 Do sample from D*Doπ decays.

Obtained event-by-event on data

HFAG 2011 average (without LHCb): ( 0.12 ± 0.25 ) x 10-2

AΓ= (-0.59 ± 0.59 ± 0.21) x 10-2

Measurement of AΓ LHCb-CONF-2011-046

Future improvement in sensitivity : Statistics x30 in 2011 Improved treatment of background events

Challenges in time-dependent charm studies at LHC:

Contribution from BDX to prompt charm sample

Correct lifetime bias on the event-by-event basis


Beauty studies: LHCb as LHCb

Angle : Evidence of suppressed ‘ADS’ mode BDK Charged hadron ID and

Direct CP violation in charmless B-decays with eyes

New results on b-baryons: ΛbDopK-

Bs mixing phase φs from BsJ/Ψφ and BsJ/Ψ fo(980)

Rare decays: Radiative penguines bs (Forward-backward asymmetry in BK*ℓℓ) Moved to

backup

Search for Bsμμ

Touch rare effects and mostly bs transitions: penguine or box diagram, NP diagrams can

compete.


B± DK± decays using common mode for Do &

Do γ sensitive interference different rates for B+ & B- (CPV)

Maximize interference by using mode suppressed for Do & favoured for Do

e.g. DoK+π- (DCS) , DoK+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

Rb Rt

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):


‘Bhh’ (h=π,K,p) at LHCb

Inclusive spectrum,ππ hypothesis

LHCb preliminary

Deploy RICH to decript ‘hh’ !

BoKπ Rely on good performance of trigger and RICH

Λbpπ

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

Boππ

BsKKΛbpK


BoK+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:

Bd,sKπ: direct CPV LHCb-CONF-2011-042

In future perform time dependent study, particularly of BsKK: New Physics sensitive measurement of γ [e.g. Fleischer, PLB

459 (1999) 306]

BoK-π+

BsK+π-BsK-π+

320 pb-1 320 pb-1

320 pb-1320 pb-1


ΛbDopπ-

ΛbDopK-

New measurements with b -baryons LHCb-CONF-2011-036

ΞobDopK-

Cabibbo-suppressed decay ΛbDopK-, potentially powerful mode for measuring CKM

angle γ.

Normalization channel: ΛbDopπ-.

A signal with (stat+syst) significance of 2.6σ, consistent with decay.

ΞobDopK

-Relative production rate x BR: Mass relative to Λb:

Ξob [Ξ+

cπ-, Ξ+

cΞ-π+π-, Ξ-Λπ-, Λpπ-] recently observed by CDF

[arXiv:1107.4015].

Consistent masses from two experiments: MLHCb(Ξob) - MCDF(Ξ

ob) = -14.2 ± 7.7

MeV/c2

M(Dopπ-) MeV/c2 M(DopK-) MeV/c2

First observation of with significance of 6.3σ:

ΛbDopK-


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 φs from BsJ/Ψφ

Time dependent analysis Time resolution measured using prompt J/Ψ background: στ = 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 νμ

Dilution Dtag = 0.277 ± 0.011 ± 0.025 Tagging power εD2 = (2.08 ± 0.41)%

Angular analysis PVV decay: needs an angular analysis to resolve CP-even and CP-odd components Angular acceptance determined from MC Maximum deviation from uniform: 5%


φs from BsJ/ΨφΔ

Γs [

rad]

Φs [rad]

~770 decays

SM

Φs [rad]

First evidence (4σ) of ΔΓs > 0 !

φsJ/Ψφ = 0.13 ± 0.18 (stat) ± 0.07 (sys) rad

Γs = 0.656 ± 0.009 (stat) ± 0.008 (sys)

ps-1

ΔΓs = 0.123 ± 0.029 (stat) ± 0.008 (sys)

ps-1

337 pb-136 pb-1


φs from BsJ/Ψ fo(980)

First observation of BsJ/Ψ fo(980) (fo(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 extractsφs.

The fo(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)

BoJ/ψK*BoJ/ψπ+π-


φs from BsJ/Ψ fo(980) and BsJ/Ψφ

φsJ/Ψfo(980) = -0.44 ± 0.44 ± 0.02

rad

φsJ/Ψφ+J/Ψfo= 0.03 ± 0.16 ± 0.07 rad

Or, combining, BsJ/Ψφ and BsJ/Ψ

fo(980) :

SM fit: 0.0363 ± 0.0017 rad

BsJ/Ψφ

BsJ/Ψ fo(980)

LHCb with 0.3 fb-1 already more sensitive, than CDF and D0

330 pb-1


Measure ratio of the branching fractions for BK* and Bsφ

Expect: 1.0 ± 0.2 from SM.

Radiative penguines: bs

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 Kππo

etc) However, largest Bsφ sample

Bsφ

BK*340 pb-1

340 pb-1

Next: study time evolution and CP asymmetries


In SM, Bsμμ occurs only via loop diagrams, and is helicity suppressed:

BR(Bsμμ)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(Bsμμ) - highly discriminatory

Recent CDF result with 7 fb-1:

[arXiv:1107.2304]

Search for Bsμμ

BR(Bsμμ) = (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(Bsμμ) < 5.6 x 10-8 @ 95% CL

Many previous measurements

Talk by M.Kraemer


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

Select Bsμμ, using Boosted Decision Tree out of 9 kinematical and topological variables

BDT tuned on MC, but calibrated on data:

Bhh, triggered on ‘other B’, and sidebands Calibrate invariant mass resolution (~25 MeV) on data (dimuon resonances & Bhh)

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

BDT output

Normalize to: B+J/ΨK+, BsJ/Ψφ

and

BoKπ– all give

consistent results

Search for Bsμμ, 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

Bhh misid background

0.1±0.1events ineach of 4BDT bins

Signal with SM BR

Search for Bsμμ, 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±1σobserved

±1σobserved

Search for Bsμμ, 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(Bsμ+μ-

)

BR(Bdμ+μ-)

LHCb preliminary

300 pb-1

LHCb preliminary

300 pb-1expected: background and signal SM BR


A preliminary CMS (1.14 fb-1)-LHCb (0.34 fb-1) combination on

BR(Bsμ+μ-) has been performed, again using the CLs approach,

& taking LHCb value of fs/fd as common input

CMS + LHCb preliminary

±1σobserved

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. A BR of 1.8 x 10-8 has a CLs value of ~0.3%

Search for Bsμμ, combining LHCb and CMS results

LHCb (0.34 fb-1) + CMS (1.14 fb-

1) preliminaryexpected: 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 studies are launched, hint on the ‘ADS’ asymmetry in BDK is observed

Most precise measurement of the direct CPV in BKπ

First evidence of the direct CPV in BsKπ

New data on the b-baryons

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

Bsμμ, 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

No evidence of CPV for signal in any binning

Cabibbo favoured control modes (no CPV

expected)

No fake CPV seen: data & method robust against biases

Same topology Ds+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


BK*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, any2HDM, Fourth generation, Extradimensions, Axions . . .

Ideal place to look for new physics

b l l s


Angular Distributions & AFB

Many observables depending on q2 = m2μμ c4


[Krüger & Matias][Egede et al.] [Ali et al.]

Models probed by AFB(q2)

dependence


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

2011-038]

Select events B0K*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(θl,φ,θK,q2)


B0K*μ+μ-Measure in 6 q2 bins:

extract dГ/dq2

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


Fit for θK and θl


AFB in B0→K*μ+μ-in LHCb with 309 pb-1

Systematic uncertainties are small, and generally themselves statistics limited.

LHC

b-C

ON

F-20

11

-03

8

Data are consistent with SM at present sensitivity.

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



φs from BsJ/Ψφ


φs from BsJ/Ψφ

Tagging Need to tag initial flavour of the Bs Per event mistag calibrated on B+ J/Ψ K and Bd D* μ νμ

Dilution Dtag = 0.277 ± 0.011 ± 0.025

Tagging power εD2 = (2.08 ± 0.41)%

Angular analysis PVV decay: needs an angular analysis to resolve CP-even and CP-odd components Angular acceptance determined from MCMaximum deviation from uniform: 5%


φs from BsJ/Ψφ: fit projections


Miscellaneous


LHCb also measures the double J/ψ cross section: [LHCb-CONF-2011-009], submitted to

Phys.Lett.B5.1 ± 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

Documents

Heavy flavours and QCD Selected LHCb results