Results from B-Physics (LHCb, BELLE) - CERN · 2014. 10. 3. · Results from B-Physics (LHCb, BELLE) Valery Pugatch Kiev Institute for Nuclear Research, NASU On behalf of the LHCb

Results from B-Physics (LHCb, BELLE)

Valery Pugatch Kiev Institute for Nuclear Research, NASU

On behalf of the LHCb Collaboration

“Prospects for Charged Higgs Discovery at Colliders”

Uppsala, Sweden, 16-18 September 2014.

V. Pugatch. “Prospects for Charged Higgs Discovery at Colliders”

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V. Pugatch. “Prospects for Charged

Higgs Discovery at Colliders” 2

OUTLINE

• Introduction

• LHCb and BELLE: B - factories

• B - spectroscopy, decays, lifetimes

• CP symmetry

• Rare decays • Search for NP (multi-quark systems, lepton number violation,

charged Higgs boson, …)

• Summary and outlook



Introduction LHC : new events at up to 1013 еV energy in 35 /fb data (Run1). Precision measurements – the way to search for New Physics.

This talk: 1. LHCb ( BELLE ) precision measurements for the NP search :

– B - spectroscopy – CP symmetry – Rare decays

2. Search for NP: - multi-quark systems, lepton number violation, - charged Higgs boson search at B-factories

3. Future studies

CERN. 4th July 2012. The first Higgs boson ! Charged Higgs bosons ? New Physics (?) - super-partners in loops, … ?

New Physics & Higgs at B-factories.

Study B-decays to predictable final states - for instance, with τ – leptons, through tree-level processes evolving via b ->sq~q, b-> sγ, … (with Higgs)

Measure & compare with SM predictions: o Differential cross-sections o branching ratios o forward-backward asymmetries, o isospin asymmetries, … -> to exclude uncertainties


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New Physics & Higgs at B-factories. Requirements to the experimental setups.

Beauty Identification at LHCb


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Flavor tagging

Bs identification

• Efficient trigger selecting B-hadrons decay products • Excellent separation of secondary vertex allows to study Bs oscillations with minimal time quantization of 40 fs. • Background suppression:

o due to high invariant mass-resolution (~14 MeV/c2) o Perfect particles identification o Magnetic field flipping up-and-down (artificial asymmetries removal)

New Physics & Higgs at B-factories. Requirements to the experimental setups.

B -> τ ν & BELLE:


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Tracks, Vertices, ID, Momentum and Energy, Triggering, Event reconstruction efficiency , Background suppression etc.,

Example:



The LHCb experiment

The LHCb detector – forward spectrometer with excellent characterisitics suitable for B-physics stuides: • Acceptance 2 < η < 5

• Momentum resolution about 0.5 %

• Track reconstruction efficiency > 96 % • Impact parameter resolution: ~ 20 μm • • Decay time resolution: ~45 fs • • Invariant mass resolution:

– ~(10-20) MeV/c2

• Ring-Imaging Cherenkov Detectors and

Muon system - particle identification (ID efficiency > 90%)

LHCb: The Large Hadron Collider Beauty

Experiment for Precise Measurements

of CP-Violation and Rare Decays

Integrated luminosity

2010: 37 pb-1

2011: 1.0 fb-1 @ 7 TeV

2012: 2 fb-1 @ 8 TeV

p p

RMS

V. Pugatch. “Prospects for Charged Higgs Discovery at Colliders” 8

LHCb . B-factory: proton-proton collisons

1011 protons per bunch collided at 7 and 8 TeV in 2011 and 2012

delivering luminosity at IP-8 (LHCb)

(2-4) times 1032 cm -2 *s-1

In each p-p collision about 1500 charged

particles are produced:

Challenging radiation load on detectors

Multi-level triggering for preselection of

Beauty and Charm events in LHCb

Integrated cross-sections

B+ ~39 µb

B0 ~38 µb

Bs ~10 µb

Uncertainty ~ 10 % LHCb-Paper-2013-004

New Physics may modify measured features

of CP-violation and

Rare decays

via its contribution in loop diagrams


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BELLE. B-factory: electron-positron collisons

KEKB. BELLE detector. (e +e - ) collisions at Y (4S) resonance. Clean samples of B-mesons.

Data set - 711 fb-1 (total 1 000 fb-1 )– (1999-2010)

Upgraded (2016) Belle II will run at 8.0 x 1035cm -2s-1 (40 times higher than at KEKB).



Spectroscopy - a perfect tool for searching “NEW”.

LHCb Spectroscopy High energy of collisions at LHC:

production rates by many orders of magnitude higher

in comparison with lepton B-factories.

All b-hadron species (but top-quark containing) were identified.



Spectroscopy - a perfect tool

for searching “NEW”.

Heavy flavour spectroscopy. Excited states of Λb

Excited states are known for the Λ and Λc .

Two excited states of Λb (at 5911.95 and 5919.76 MeV/c2 ) were

observed for the first time in the Λb0 π+π- mass- spectrum.

Uncertaintes are less than 1 MeV/2c. Discrepancies with theories reach 20 – 30 MeV/c2

Λb reconstructed

in the Λc+π- invariant mass

spectrum.

Phys.Rev.Lett.109(2012)172003

Spectroscopy - a perfect tool in searching for “NEW”. Heavy flavour spectroscopy.

χb radiative decays


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Signals: χb1 – ‘green’, χb2 – ‘magenta’

ϒ (

3S)

ϒ(2

S)

ϒ(1

S) LHCb. ( 7 & 8 ) TeV @ 3 fb-1.

Reconstruction of χb -> ϒγ : (di-muon (ϒ) + photon ) candidates

The observation of the radiative transition of χb(3P) meson to ϒ (3S)

-> the most precise value of the mass χb1 (3P)

LHCb-PAPER-2014-031

Spectroscopy and products angular distributions. A perfect tool for searching “NEW”.

Z (4430) – four-quarks resonant state

Z(3900) (BELLE, PRL 110 (2013) 252002 Z(4430) - First observed by BELLE (Phys.Rev. D88:074026)


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LHCb – Confirmed (PRL, 112, 222002 (2014) The same decay studied: B0 -> K+π-ψ (2S) JP = 1+ assigned



Measurement of Lifetime – a tool to identify “KNOWN” and “NEW”

Lifetime: B-meson and Λb- baryon

• HQE- theory [NPB, 483, 339, 1997] : Heavy b-quark determines the lifetime: equal for two b-species.

• The role of the third particle might be essential !

• Nuclear Physics – the Coulomb field of the 3d particle modifies the observed width of the two-body short-lived resonance.

LHCb result:

τ(Λb) = 1.482±0.018±0.012 ps

τ(Λb)/τ(B0) = 0.976±0.012±0.006

Confirmation of the HQE –theory.

Bs oscillation frequency



Tagged flavor evolution measurements with an accuracy of 45 fs.

Results for the Bs -mesons decays into D-sπ

+ and D+sπ- .

The extracted frequency of oscillations

Δms = 17.768 ± 0.023 ± 0.006 ps-1

Evolution of Events in Time – signature for “NEW”


B0 oscillations

observed in D+π- and J/ψK*0 decays


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The most precise measurement

of the oscillation frequency for B0 mesons.

Combined for two decay channels

Δmd = 0.5156 ± 0.0051 ± 0.0033 ps-1

LHCb-PAPER-2013-006 arXiv.1304.4741

PLB.719(2013)318

Neutral Bs and Bd mixing frequences

measured using semileptonic decays


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LHCb measures flavor evolution (mixing) with an accuracy of 45 fs due to VELO

displaced vertex reconstruction with an accuracy of few tens µm.

Characteristic features of mixing: mass difference Δm (related to the frequency of

mixing), width difference ΔГ, phase between the decay and mixing amplitudes Φs .

Phys. Lett. B 723 (2013) 33-43


http://cds.cern.ch/ejournals.py?publication=Phys.+Lett.+B&volume=723&year=2013&page=33http://cds.cern.ch/ejournals.py?publication=Phys.+Lett.+B&volume=723&year=2013&page=33http://cds.cern.ch/ejournals.py?publication=Phys.+Lett.+B&volume=723&year=2013&page=33http://cds.cern.ch/ejournals.py?publication=Phys.+Lett.+B&volume=723&year=2013&page=33http://cds.cern.ch/ejournals.py?publication=Phys.+Lett.+B&volume=723&year=2013&page=33http://cds.cern.ch/ejournals.py?publication=Phys.+Lett.+B&volume=723&year=2013&page=33http://cds.cern.ch/ejournals.py?publication=Phys.+Lett.+B&volume=723&year=2013&page=33

Measuring asymmetries - restrict the systematic errors in search for “NEW”

CP symmetry violation

CP Violation (CPV) – potential source of New Physics – SM expectations are significantly lower than needed to explain baryon asymmetry in the Universe.

Three ways for CP violation:

Direct - in decay

Indirect - in mixing

Interference of the above two processes.

B – mesons

mixing (oscillations)

Mixing may proceed also via loop diagrams

involving heavy particles – New Physics.


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CP Violation in Beauty Direct Decays


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Asymmetries were derived from measured data for decays of neutral Bd as well as Bs mesons (to get rid out of systematic errors)

Within SM expectations

First observation of CP violation

in the decays of B0s mesons

ACP(B0s→K

-π+) = +0.27 ± 0.04 ± 0.01

ACP(B0→K+π-) = -0.080 ± 0.007 ± 0.003

The most precise measurement.

Phys. Rev. Lett. 110 (2013) 221601

http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=110&year=2013&page=221601http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=110&year=2013&page=221601http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=110&year=2013&page=221601http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=110&year=2013&page=221601http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=110&year=2013&page=221601


CP Violation in Bs Mixing


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Time dependent decay studies for measuring CP violating parameters in Bs mixing: Bs J/Ψ Κ

+Κ – and Bs J/Ψ π

+π-

CP violating phase Φs may include new physics …

Combined for two

processes results are

compatible with SM. (Phys.Lett. B736 (2014) 186) – Update for 3 fb-1

Фs = (70 +/- 68 +/- 8 ) mrad


CP Violation in Bs Mixing


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CKM2014 Vienna, 8 -12th September 2014


CP Violation

in three-body charmless B decays.


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The first evidence of inclusive CP asymmetry in charmless three-body B± decays.

ACP = +0.025 ± 0.004 ± 0.004 ± 0.007,

2.8 σ

B±→K±π+π- B±→K±K+K-

ACP = -0.036 ± 0.004 ± 0.002 ± 0.007,

4.3 σ

Phys. Rev. Lett. 111 (2013) 101801

LHCb-Paper-2014-044:

From 1 to 3 fb-1 asymmetries are confirmed.

http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=111&year=2013&page=101801http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=111&year=2013&page=101801http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=111&year=2013&page=101801http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=111&year=2013&page=101801http://cds.cern.ch/ejournals.py?publication=Phys.+Rev.+Lett.&volume=111&year=2013&page=101801

The B±→DK and B±→Dπ decays were analyzed :

D decays: KK, ππ, K0Sππ, K0SKK or Kπππ.


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Example: γ = (71.1+16.6-15.7)° for

B±→DK decay (68% CL).

LHCB-PAPER-2013-020.

PLB, 726, 151 (2013)

LHCb (CKM2014, Vienna). LHCb-CONF-2014-004 Updated LHCb combined measurements

γ = (72.9 +9.2 – 9.9 )0

CKM angles in the Unitarity Triangle.

φ3 (γ) from B±→Dh± decays


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CKM angles in the Unitarity Triangle. Angle φ1 (β)

BELLE

CKM angles in the Unitarity Triangle.

Angle φ2 (α) . B0 -> π +π_


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Global fit: φ2 (α), φ2 (γ)



Rare decays B0s→µ

+µ- and B0→µ+µ- Standard Model - FCNC and helicity suppressed processes with pure leptonic final states , PRL 112 101801 (2014) :

Br (B0s→µ+µ-) = (3.65 ± 0.23) × 10-9

Br (B0→µ+µ-) = (1.1 ± 0.10) × 10-10

-> If in experiment different – evidence for New Physics.

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Results: 1. B0s → µ+µ-

First observation LHCb (PRL 111, 101805 (2013)) Combined LHCb & CMS (2014)

(preliminary) (2.9 +/- 0.7) x 10-9

2. B0 → µ+µ-

New Physics - the next digit of data accuracy ?

Results consistent with the SM

CMS PAS BPH-13-007 LHCb-CONF-2013-012

Rare decays. Angular Distributions

B0→K+ π-μ+μ- .


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B0→K+ π-μ+μ- - FCNC process via

loop diagram in SM. - Possibility of modification of angular

distributions due to contribution of new

particles.

In total, P1-8 parameters determining

angular distribution of final state

products have been measured.

The P5' observable is shown as a function

of the μ+μ- invariant mass squared q2.

3.7σ deviation of data above

the Standard Model prediction

is observed at 4.3 < q2 < 8.68 GeV2/c4.

JHEP 08 (2013) 131

http://cds.cern.ch/ejournals.py?publication=J.+High+Energy+Phys.&volume=08&year=2013&page=131http://cds.cern.ch/ejournals.py?publication=J.+High+Energy+Phys.&volume=08&year=2013&page=131http://cds.cern.ch/ejournals.py?publication=J.+High+Energy+Phys.&volume=08&year=2013&page=131

Higgs boson searches at B-factories.

Some ways how it might proceed with Higgs-bosons to observable final states.


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B -> τν (BELLE & BABAR) B-decays with heavy τ–lepton in final state may evolve with additional decay modes not present with light leptons : NP contribution might occur through tree processes

Branching ratios change

• Predicition: Minimal extension of the SM with two Higgs doublet – 2HDM

Br(B->τν) = (1.11 +/- 0.28) X 10-4 • Experimental results : BELLE (PRL 110, 131801 (2013) BaBaR (arXiv:1207.0698 (2012)

averaged over hadronic and semileptonic tagging: Br(B->τν) = (1.15 +/- 0.23) X 10-4

Consistent with Standard Model


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B -> D*τν Ratios (R) are considered : R = Br(B->D*τν) /Br(D->D*lν) – to exclude experimental and theoretical uncertainties R (D) = Br(B->Dτν) /Br(D->Dlν) =

0.430 +/- 0.091 R (D*) = Br(B->D*τν) /Br(D*->Dlν) =

0.405 +/- 0.047 (BELLE – KEK–FF2013)

Deviations from the SM theory:

R (D) : 1.4 σ; R (D*) – 3.0 σ

(S. Feiter et al., PRD 85 094025 (2012)

R- dependence on the SM parameters Y. Sakai, R. Watanabe, M. Tanaka. PRD 87, 034028 (2013)


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Search for NP.

Lepton Flavor Violation

τ --> µ - µ + µ - (LHCb)

LHCb result (1 fb-1 @ 7 TeV, 2 fb-1 @ 8 TeV )

branching fraction of the τ --> µ - µ + µ - :

< 4.6 x 10-8 (90 % confidence level) – consistent with the SM expectation

BELLE: < 2.1 x 10-8 (90 % confidence level)

PLB 687, 139 (2010)

LHCb-PAPER-2014-052

Dashed line – SM; Solid line – observed. Yellow - 68 % CL, Green – 95 % CL


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Search for NP. Lepton Flavor Violation

and Baryon Number Violation

LHCb


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LHCb Search for Majorana neutrinos in B- -> π+μ-μ- BR < 4 x 10 -9 (95 % CL) (LHCb data, 3 fb-1) PRL 112, 131802 (2014)

Search for NP. Asymmetries.

Backward – Forward asymmetry in Inclusive B -> Xs l+ l- (BELLE)


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Experimental data (BELLE) – The Forward-Backward Asymmetry (AFB) for the sum of 10 exclusive states (B0 , B+ ) dependence on the momentum transferred q2 . SM calculation – Red band AFB 10.2 GeV/c2

Deviation from the SM : 1.8 σ for the q2

Search for NP. Asymmetries.

• Isospin Asymmetries (AI). arXiv 1403.8044. LHCb (3 fb-1)

B -> K (*) µ+µ-


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Limits on the Higgs production. LHCb

Cross-section for the production of Higgs – like boson

does not exceed 32 pb @ 95 % CL The specific model BV48:

mSUGRA with baryon number violation and parameters:

114 GeV/c2 – h0,

48 Gev/c2 – anti-X0 ,

10 ps - τ (X0)

Data analyzed: 35.8 pb-1 (LHCb –CONF-2012-014) . Further studies continue.


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Limits on Higgs → ττ production. LHCb

JHEP05(2013)132 –> (1 fb-1 @ √s = 7 TeV) LHCb Limit on MSSM Higgs boson production

0.7 pb < σ x BF < 8.6 pb for 90

Limits on Higgs production. LHCb

W/Z (leptons) + H → b anti-b (jets)

-> LHCb acceptance for the 2 b’s inside the detector ≈ 5% -> LHCb acceptance for single lepton inside the detector ≈ 5% Determine limits on H → bb from the observed vs expected events

- Tools developed: jets and B-jet tagging

- Benchmark analysis made – Measurement of the central forward bb asymmetry (LHCb-

CONF-2013-001)

– Measurement of σ(bb) with inclusive final states (LHCb-CONF-2013-002)

for 2.5

Conclusions and Outlook

• Beauty Physics studies have been successfully carried out at the leptonic and hadronic B-factories. Substantial data sets with B-matter samples were accumulated and analyzed at the LHCb and BELLE experiments.

• Measurements of physics observables (new range of energy for collisions up to 8 TeV at LHC) have been performed with unprecedented accuracy (CP violation, rare decays) or for the first time (Bs->µ

+µ- , CPV in B0s , new resonances). Efforts to establish signals beyond Standard Model are being undertaken.

• Most of results obtained were in agreement with the Standard Model predictions. Some disagreements in the data space sensitive to New Physics are under studies (P5 in B

0→K*0μ+μ-, Lepton universality in B+ -> K+ l+l- , …).


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Conclusions and Outlook

• LHCb will continue data taking in 2015-2017 planning the upgrade for running in 2019 at luminosity up to 2 times 1033 cm-2s -1 . BELLE II after upgrade aims to accumulate 50 000 fb-1 data set .

• New Physics must exist! It might require new tools and methods to be developed for its observation. New huge energy valley opened at LHC is certainly rich by new phenomena. There are observables which have to be discovered to study New Physics !


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There ... New Physics ! THANK YOU FOR YOUR ATTENTION !

There are new directions for HEP studies. Energy: from 1013 еV (at LHC) to 1021 еV. Space: from 10-18 m to 1025 m (Universe) Time: from 10-24 s to 1017 s New Physics ?! It might require new tools and methods to be developed for its observation. New huge energy valley opened at LHC is certainly rich for new phenomena. There might be observables which have to be discovered to study New Physics !

Distribution of Galaxies visible in cosmic rays with E >10 19 eV). Scale: 10 24 m. The Earth diameter - ~107 m, The LHC diameter – ~104 m

Documents

Results from B-Physics (LHCb, BELLE) - CERN · 2014. 10. 3. · Results from B-Physics (LHCb, BELLE) Valery Pugatch Kiev Institute for Nuclear Research, NASU On behalf of the LHCb