1 / 77

Precision Measurements at LHCb

Precision Measurements at LHCb. Niels Tuning Nikhef Colloquium, 23 September 2011. Assumption. In the rest of the talk I will assume the speed of light to be constant and that particles cannot travel faster than c. “Box” diagram: Δ B=2. s. b. s. b. b. μ. s. μ. B-physics Mission.

mcclearyt
Download Presentation

Precision Measurements at LHCb

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Precision Measurementsat LHCb Niels Tuning Nikhef Colloquium, 23 September 2011 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  2. Assumption • In the rest of the talk I will assume the speed of light to be constant and that particles cannot travel faster than c. Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  3. “Box” diagram: ΔB=2 s b s b b μ s μ B-physics Mission Search for new particles or forces via their virtual loop contributions in B-decays 2) Rare Decays: Search for enhanced BR’s or decay distributions that deviate from SM 1) CP Violation: Search for CP asymmetries incom- patible with SM fits. Study of couplings of New Physics “Penguin” diagram: ΔB=1 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  4. Motivation: The ‘DNA’ of flavour models From: A.Buras, arXiv:1012.1447 “Superstars”: Today also: W. Altmannshofer, et al., Nucl. Phys. B 830 (2010) 17 “The VIP’s of Bs Physics: Bs,d →µ-µ+and Sψφ” A.Buras,, arXiv 0910.1032 “From my point of view, similar to Sψφ , precise measurements of Br(Bs →µ-µ+) … are among the most important goals in flavour physics in the coming years.” Large NP effects Small NP effects No NP effects Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  5. “Box” diagram: ΔB=2 s b s b b μ s μ B-physics Mission Search for new particles or forces via their virtual loop contributions in B decays • 2) Rare Decays: • Search for enhanced BR’s or decay • distributions that deviate from SM • Examples: • B0 →K*μμ • B0s →μμ • 1) CP Violation: • Search for CP asymmetries incom- • patible with SM fits. • Study of couplings of New Physics • Examples: • Bs0 →J/ψφ “Penguin” diagram: ΔB=1 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  6. Reminder: the “box” for discoveries s b b s • ARGUS almost discovered the top quark: • mtop> 50 GeV • Lesson: • Loop diagrams are sensitive to heavy particles ARGUS Coll, Phys.Lett.B192:245,1987 ? Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  7. Menu: LHCb “Superstars” “Box” diagram: ΔB=2 s b s b b μ s μ • B0s → J/ψφ • B0 → K*μμ • B0s → μμ “Penguin” diagram: ΔB=1 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  8. Things I will not show… Charm B0 → Kπ B0→ DK*, B+→ DK+ B0→ K*γ B0s → φφ B*(*) spectroscopy Λb Bc+ → J/ψπππ Semi-leptonic W/Z D0→ KK D0→ππ B+c→ J/ψπππ B0s→φφ B0→ K*γ Λb0→ D0p+π- Λb0→Λc+π- Z0→μμ B0s→φγ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  9. Menu: LHCb “Superstars” B0s→ J/ψφ • B0s → J/ψφ • B0 → K*μμ • B0s → μμ B0→K*μμ B0s→μμ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  10. Commonality: “FCNC” γ b s • B0s → J/ψφ • B0 → K*μμ • B0s → μμ B0s→ J/ψφ B0→K*μμ B0s→μμ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  11. Commonality: “FCNC” γ b W t s • B0s → J/ψφ • B0 → K*μμ • B0s → μμ B0s→ J/ψφ B0→K*μμ B0s→μμ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  12. Sensitive to NP: appetizer B0s→ J/ψφ • B0s → J/ψφ • B0 → K*μμ • B0s → μμ (4/3)AFB B0→K*μμ B0s→μμ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  13. Status before Summer CDF, Conf Note 10206 B0s→ J/ψφ φs • B0s → J/ψφ • Decreased 3σ→ 1σ • B0 → K*μμ • Hint for deviaton • B0s → μμ • SM p-value 1.9% BABAR: PRL 102, 091803 (2009) CDF: Note 10047 (2010) Belle: PRL 103, 171801 (2009) B0→K*μμ CDF, arXiv:1107.2304 B0s→μμ mB Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  14. The LHCb Detector 23 sep 2010 19:49:24 Run 79646 Event 143858637 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  15. The LHCb Detector B0→K*μμ B0s→μμ PID B0→K*(Kπ)μμ Lifetime, B0s → J/ψφ RICH1 T MAGNET TT VELO MUON CALO RICH2 Interaction Point Suppress background, σ(MB) B0 →K*μμ B0s→μμ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  16. LHC and LHCb performance • LHC and LHCb show excellent perfomance • Recorded 330 pb-1 for Summer conferences • 1011 bb-pairs produced! x 4.3 • Optimal use of LHC beam: • “Lumilevelling” at 3.5 1032 • (Design was 2.0 1032 !) • Max. luminosity for entire fill Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  17. Detector efficiencies • Subdetector efficiencies >98% • Mainly due to dead channels • DAQ efficiency >90% • DAQ hick-ups • Deadtime Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  18. Menu: LHCb “Superstars” “Box” diagram: ΔB=2 s b s b b μ s μ • B0s → J/ψφ • B0 → K*μμ • B0s → μμ “Penguin” diagram: ΔB=1 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  19. B0s → J/ψφ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  20. B0s → J/ψφ: Introduction B0s→J/ψφ • Interfering decay amplitudes: • B0s→J/ψφ • B0s → B0s→ J/ψφ t >0.3 ps N = 8276 ± 94 σ ~ 7 MeV L ~ 337 pb-1 eiφ A.S.Dighe, I.Dunietz, R.Fleischer Eur.Phys.J.C6:647-662,1999 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  21. B0s → J/ψφ: Analysis • Angular analysis • B0s → J/ψφ: • Pseudo-scalar →2 vectors • CP ~ (-1)L • Flavour tagging b: use this b to check if other b oscillated Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  22. B0s → J/ψφ: Analysis • Angular analysis • B0s → J/ψφ: • Pseudo-scalar →2 vectors • CP ~ (-1)L • Flavour tagging • ω = 36% • εD2 = 2.08±0.41% • PDG: Δms=17.77 ±0.120 ps-1 • LHCb: Δms=17.725±0.041±0.025 ps-1 CP + CP - B0s→ J/ψφ Bs0→Ds-π+ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  23. B0s → J/ψφ: Angular Analysis Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  24. B0s → J/ψφ: Results LHCb-CONF-2011-049 • Most precise value of φs! φs=0.13 ± 0.18(stat) ± 0.07(sys) rad • Consistent with SM: φs=-0.03 ΔΓs=0.123 ± 0.029(stat) ± 0.008(sys) ps-1 = SM CDF:Γs=0.076 ± 0.059(stat) ± 0.006(sys) ps-1 D0:Γs=0.19 ± 0.07 (stat) ± 0.015(sys) ps-1 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  25. B0s → J/ψφ: Comparison Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  26. S.Stone, L.Zhang, Phys.Rev. D79 (2009) 074024 Intermezzo: B0s → J/ψf0 R.Fleischer, R.Knegjens, G.Ricciardi arXiv:1109.1112 • 2010: First observation at LHCb • f0is spin-0 • J/ψf0 is CP-odd eigenstate! • φs: no need for angular analysis LHCb, Phys.Lett.B698:115-122,2011. LHCb-CONF-2011-051 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  27. B0s → J/ψφ and f0: Combination • φs=0.13 ± 0.18(stat) ± 0.07(sys) rad • φs=-0.45+0.48-0.51rad Combination: • φs=0.03 ± 0.16(stat) ± 0.07(sys) rad B0s→ J/ψφ B0s→ J/ψf0 LHCb-CONF-2011-051 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  28. Intermezzo: B0s → J/ψKs K.de Bruyn, R.Fleischer, P.Koppenburg Eur.Phys.J. C70 (2010) 1025-1035 • Control subtle effects • like DCS Penguin contributions to sin2β • MeasuredBR(B0s → J/ψKs) : LHCb-CONF-2011-049 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  29. Sub-Summary • B0s → J/ψφ • B0 → K*μμ • B0s → μμ • Most precise measurement of φs • Combined with B0s → J/ψf0 • φs=0.03 ± 0.16(stat) ± 0.07(sys) rad • Measured DCS: BR(B0s → J/ψKs) Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  30. B0 → K*μμ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  31. B0→K*μμ: Motivation A.Ali, Th.Mannel, T.Morozumi Phys.Lett. B273 (1991) 505-512 • Hadronic uncertainties largely cancel in angular asymmetries • Forward-backward asymmetry AFB easiest μ+ θl K* μ- Example: (4/3)AFB • Zero-crossing point • particularly interesting: • Small hadronic uncertainties • Directly sensitive to C7 and C9 W.Altmannshofer et al., JHEP 0901:019,2009 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  32. B0→K*μμ: Status Belle, 657M BB PRL 103, 171801 (2009) • AFB measured at B-factories and CDF • All opposite sign for AFB? • Hint of deviation? Babar, 465M BB PRD 79, 031102 (2009) SM CDF 6.8 fb-1 arXiv:1108.0695 SM Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  33. B0→K*μμ: at LHCb ψ' • Reject J/ψandψ’ resonances • Veto peaking backgrounds • Select with boosted decision tree • B, J/ψ, K*vtx, FD, IP • N(B0→K*μμ) = 302 ± 20 • Babar: 60 • Belle: 247 • CDF: 164 J/ψ B0 LHCb-CONF-2011-038 N = 302 ± 20 L ~ 309 pb-1 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  34. B0→K*μμ: at LHCb ψ' • Reject J/ψandψ’ resonances • Veto peaking backgrounds • Select with boosted decision tree • B, J/ψ, K*vtx, FD, IP • N(B0→K*μμ) = 302 ± 20 • Babar: 60 • Belle: 247 • CDF: 164 J/ψ B0 LHCb-CONF-2011-038 1<q2<6 GeV2 N = 70 ± 10 L ~ 309 pb-1 N = 302 ± 20 L ~ 309 pb-1 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  35. B0→K*J/ψ: Asymmetry μ+ • Validate analysis on B0→K*J/ψ: • FL = 0.556±0.015 (Babar: 0.556±0.009±0.010) • AFB = -0.006±0.008 θl K* μ- NB: q2 = mJ/2 = 9.6 GeV2 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  36. B0→K*μμ: Asymmetry Ch.Bobeth,G.Hiller,D.van Dyk JHEP 1107:067,2011 • Validate analysis on B0→K*J/ψ: • FL = 0.556±0.015 (Babar: 0.556±0.009±0.010) • AFB = -0.006±0.008 • Measure AFB and FL in bins of q2 • Event-by-event acceptance correction LHCb-CONF-2011-038 m2μμ= Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  37. B0→K*μμ: Comparison J/ψ ψ' Belle, PRL 103, 171801 (2009) Babar, PRD 79, 031102 (2009) CDF, PRL 106, (2011) Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  38. B0→K*μμ: Asymmetry Ch.Bobeth,G.Hiller,D.van Dyk JHEP 1107:067,2011 • Still limited statistics • Good agreement with SM Example: LHCb-CONF-2011-038 (4/3)AFB W.Altmannshofer et al., JHEP 0901:019,2009 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  39. B0→K*μμ: Comparison Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  40. Sub-Summary • B0s → J/ψφ • B0 → K*μμ • B0s → μμ • Most precise measurement of AFB • Still limited statistical precision • More angular observables available Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  41. B0s → μμ Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  42. B0s→μμ: Motivation • Branching Ratio very sensitive to NP models • BR strongly enhanced in MSSM at large tanβ:  tan6/mA4 • Example: 10x higher BR for tan=50(20), mH+=800(200) GeV A.Buras, G.Isidori, P.Paradisi Phys.Lett.B694:402-409,2011 Allowed parameter space from fit in constrained MSSM: 1-CL tanβ=50 mH+=200 GeV Mt1=500 GeV, Mt2=850 GeV 5σ discov. CMS @30/60 fb-1: H,A → τ+τ− 10x SM 10x SM → tan  → MH+ (GeV) A.Buras et al., Nucl.Phys.B659:3,2003 O.Buchmueller et al. Eur.Phys.J.C64:391-415,2009 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium (Direct limits at CMS: Gennai et al. Eur.Phys.J.C52:383-395,2007)

  43. Intermezzo 2: Allowed MSSM parameter space • constraints. These include precision electroweak data, the anomalous magnetic moment of the muon, • (g − 2)μ, • B-physics observables (the rates for • BR(b → sγ) and • BR(Bu → τντ ), • Bs mixing, • and the upper limit on • BR(Bs → μ+μ−)), • the bound on the lightest MSSM Higgs boson mass, Mh, and the cold dark matter (CDM) density inferred from • astrophysical and cosmological data, assuming that this is dominated by the relic density of the lightest neutralino, χh2. Allowed parameter space from fit in constrained MSSM: CMS, Gennai et al. Eur.Phys.J. C52:383-395,2007 shown are the 5-σ discovery contours for observing the heavy MSSM Higgs bosons H,A in the three decay channels H,A → τ+τ− → jets (solid line), jet+μ (dashed line), jet+e (dotted line) at the LHC. The discovery contours have been obtained using an analysis that assumed 30 or 60 fb−1 collected with the CMS detector. O.Buchmueller et al. Eur.Phys.J.C64:391-415,2009 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  44. B0s→μμ: Motivation • Branching Ratio very sensitive to NP models • BR strongly enhanced in MSSM at large tanβ:  tan6/mA4 • Example: 10x higher BR for tan=50(20), mH+=800(200) GeV A.Buras, G.Isidori, P.Paradisi Phys.Lett.B694:402-409,2011 Allowed parameter space from fit in non-univ Higgs mass (NUHM): 1-CL tanβ=50 mH+=200 GeV Mt1=500 GeV, Mt2=850 GeV 10x SM 10x SM → tan  → MH+ (GeV) A.Buras et al., Nucl.Phys.B659:3,2003 O.Buchmueller et al. Eur.Phys.J.C64:391-415,2009 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  45. B0s→μμ: Motivation • Branching Ratio very sensitive to NP models • BR strongly enhanced in MSSM at large tanβ:  tan6/mA4 • Example: 10x higher BR for tan=50(20), mH+=800(200) GeV A.Buras, G.Isidori, P.Paradisi Phys.Lett.B694:402-409,2011 1-CL tanβ=50 mH+=200 GeV 2x10-8 1x10-8 Mt1=500 GeV, Mt2=850 GeV 5x10-9 10x SM 10x SM SM-like → tan  → MH+ (GeV) A.Buras et al., Nucl.Phys.B659:3,2003 Curves obtained through SuperIso, (eg. F.Mahmoudi, arXiv:0906.0369) Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  46. B0s→μμ: at LHCb Analysis based on Mass Kinematic / geometrical (lifetime, IPB, IPSμ, DOCA, isolation) > Compare observed to expectation Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  47. B0s→μμ: mass LHCb preliminary 2011 √s = 7 TeV L ~ 150 pb-1 B0s→μμ? 5.4 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  48. B0s→μμ: mass LHCb preliminary 2011 √s = 7 TeV L ~ 150 pb-1 B0s→μμ? 5.4 Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  49. B0s→μμ: mass • Mass resolution at mBs expected around 22 MeV σ(M) = 16 MeV σ(M) = 40 MeV J/ψ(1S) (1S,2S,3S) Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

  50. B0s→μμ: mass σ(M)mB = 24 MeV J/ψ(1S) σ(m) (MeV) (1S,2S,3S) mμμ (MeV) Niels Tuning - Precision Measurements at LHCb - Nikhef Coloquium

More Related