BEACH 218 Penihe, June 17-23, 218 Studies of b-hadron prodution and CKM matrix elements using semileptoni deays Olaf Steinkamp on behalf of the LHCb ollaboration Physik-Institut der Universität Zürih Winterthurerstrasse 19 CH-857 Zürih olafs@physik.uzh.h
LHCb [JINST 3(28)S85] Vertex loator p RICH detetors p B Traking system Muon system Calorimeters BEACH 218 Semileptoni deays @ LHCb (2) 2<η<5
LHCb [JINST 3(28)S85] Vertex loator RICH detetors Muon system Optimized for beauty and harm deays: p Low-pT trigger thresholds p B Exellent momentum and mass resolution Unique partile-identifiation apabilities Unique forward overage Traking system Calorimeters BEACH 218 Semileptoni deays @ LHCb (3) 2<η<5
Semileptoni Deays A deay aused by the weak fore in whih one lepton (and the orresponding neutrino) is produed in addition to one or more hadrons [https://en.wikipedia.org/wiki/semileptoni_deay] ℓ+ W Hb + νℓ b q q BEACH 218 Semileptoni deays @ LHCb (4)
Semileptoni Deays A deay aused by the weak fore in whih one lepton (and the orresponding neutrino) is produed in addition to one or more hadrons [https://en.wikipedia.org/wiki/semileptoni_deay] ℓ+ W Hb + νℓ b q q Ideal lab for, e.g., tests of Lepton Flavour Universality BEACH 218 Semileptoni deays @ LHCb (5)
Semileptoni Deays A deay aused by the weak fore in whih one lepton (and the orresponding neutrino) is produed in addition to one or more hadrons [https://en.wikipedia.org/wiki/semileptoni_deay] ℓ+ W Hb + νℓ b q q Ideal lab for, e.g., tests of Lepton Flavour Universality and measurements of CKM matrix elements BEACH 218 Semileptoni deays @ LHCb (6)
Semileptoni Deays Expet almost 1 million reonstruted semileptoni b deays from Run 1 + Run 2 All b flavours (B, B+, Bs, B+, Λb) Clean signatures for muoni modes low bakgrounds from non-semileptoni deays CP violating asymmetry assl in Bs - Bs mixing Tests of τ μ Flavour Universality [PRL 117(216)6183] [PRL 115(215)11183] BEACH 218 Semileptoni deays @ LHCb (7)
Semileptoni Deays Expet almost 1 million reonstruted semileptoni b deays from Run 1 + Run 2 All b flavours (B, B+, Bs, B+, Λb) Clean signatures for muoni modes low bakgrounds from non-semileptoni deays talk by Mark Smith yesterday morning CP violating asymmetry assl in Bs - Bs mixing Tests of τ μ Flavour Universality [PRL 117(216)6183] [PRL 115(215)11183] BEACH 218 Semileptoni deays @ LHCb (8)
Semileptoni Deays Preision measurements require good understanding of the hadroni part of the interation W+ ℓ+ νℓ b Hb q hadroni form fator q BEACH 218 Semileptoni deays @ LHCb (9)
Outline CKM matrix elements Vub Prodution of b hadrons Λb Λ+ form fator Fration of D, D*, D** in B D X μ νμ Flavour-speifi Bs lifetime Ω lifetime BEACH 218 Semileptoni deays @ LHCb (1)
Vub
Vub [Nature Phys 1(215)138] One side of the CKM Unitarity Triangle Can be determined from branhing frations of b u ℓ + νℓ transitions Long-standing disrepany between determinations from inlusive and exlusive deays LHCb measurement of νℓ 2 BF ( Λ b p μ ν μ ) V ub = R FF 2 V b BF (Λ b Λ μ ν μ ) b Vu()b ℓ u () Λb u u d d BEACH 218 Semileptoni deays @ LHCb (12)
Vub [Nature Phys 1(215)138] One side of the CKM Unitarity Triangle Can be determined from branhing frations of b u ℓ + νℓ transitions Long-standing disrepany between determinations from inlusive and exlusive deays LHCb measurement of 2 BF ( Λ b p μ ν μ ) V ub = R FF 2 V b BF (Λ b Λ μ ν μ ) Disriminating variable 2 2 m orr m p μ + p + p BEACH 218 Semileptoni deays @ LHCb (13)
Vub [Nature Phys 1(215)138] One side of the CKM Unitarity Triangle Can be determined from branhing frations of b u ℓ + νℓ transitions Long-standing disrepany between determinations from inlusive and exlusive deays LHCb measurement of 2 BF ( Λ b p μ ν μ ) V ub = R FF 2 V b BF (Λ b Λ μ ν μ ) Disriminating variable 2 2 m orr m p μ + p + p BEACH 218 Semileptoni deays @ LHCb (14)
Vub [Nature Phys 1(215)138] One side of the CKM Unitarity Triangle Can be determined from branhing frations of b u ℓ + νℓ transitions Long-standing disrepany between determinations from inlusive and exlusive deays LHCb measurement of 2 BF ( Λ b p μ ν μ ) V ub = R FF 2 V b BF (Λ b Λ μ ν μ ) Vb from exlusive measurements Form-fators from Lattie QCD BEACH 218 Semileptoni deays @ LHCb (15)
Vub [Nature Phys 1(215)138] One side of the CKM Unitarity Triangle Can be determined from branhing frations of b u ℓ + νℓ transitions Long-standing disrepany between determinations from inlusive and exlusive deays LHCb measurement of 2 BF ( Λ b p μ ν μ ) V ub = R FF 2 V b BF (Λ b Λ μ ν μ ) Vb from exlusive measurements Form-fators from Lattie QCD BEACH 218 Semileptoni deays @ LHCb (16)
Λ Λ form fator b +
Λb Λ+ form fator Chek preise preditions from Lattie QCD Showase the potential for form-fator measurements in LHCb Detmold, Lehner, Meinel [PRD92(215)3453] Heavy Quark limit form fators redue to one Isgur-Wise funtion Perform a Taylor expansion and fit the first two terms ξ B (w ) = 1 ρ 2 (w 1) + 1 2 σ 2 (w 1)2 + with w m 2Λ + m 2Λ q 2 b + 2 mλ mλ b + BEACH 218 Semileptoni deays @ LHCb (18)
Λb Λ+ form fator [PRD96(217)1125] Analysis based on Run-1 data sample: 3 fb-1 at 7 and 8 TeV Clean event sample of 2.7 million Λ+ μ andidates with Λ+ p K π+ Bakground from prompt Λ+ found to be negligible Bakgrounds from exited Λ+ resonanes estimated from Λ b Λ π + π μ νμ Λ(2625)+ Λ(2595)+ Λ(2765)+ Λ(288)+ BEACH 218 Semileptoni deays @ LHCb (19)
Λb Λ+ form fator [PRD96(217)1125] Two-fold ambiguity in determination of w due to missing neutrino: Use solution with smaller value of Λb momentum (orret in 5-6 % of ases) Determine resolution and bias on w from simulation Unfold measured distribution using Single Value Deomposition BEACH 218 Semileptoni deays @ LHCb (2) Hoeker and Kartvelishvili [NIM A372(1996)469]
Λb Λ+ form fator [PRD96(217)1125] Extrat ρ2 and σ2/2 from χ2 fits to d N orr /d w K (w ) = onst ξ B (w ) ( K(w): kinematial fator ) Results ompatible with expetation from theory 2 ρ = 1.63 ±.7 (stat ) ±.8 (syst ) [PLB 629(25)27] [PRD 57(1998)6948] [PRD 73(26)942] BEACH 218 Semileptoni deays @ LHCb (21)
f (D,D*,D** ) in B D X μ νμ
f (D,D*,D**) in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) Frations of D, D*, D** produed in semileptoni b deays not yet well known Relevant, sine higher resonanes onstitute bakground for exlusive deays B D ℓ ν and B D* ℓ ν, e.g. in measurements of R(D) or R(D*) Use B andidates from Bs2* B K+ Reonstrut B momentum vetor from known Bs2*, B and K+ masses, B prodution and deay verties, K momentum and flight diretion preliminary BEACH 218 Semileptoni deays @ LHCb (23)
f (D,D*,D**) in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) Frations of D, D*, D** produed in semileptoni b deays not yet well known Relevant, sine higher resonanes onstitute bakground for exlusive deays B D ℓ ν and B D* ℓ ν, e.g. in measurements of R(D) or R(D*) Use B andidates from Bs2* B K+ Reonstrut B momentum vetor from known Bs2*, B and K+ masses, B prodution and deay verties, K momentum and flight diretion Reonstrut D K π+ and alulate preliminary 2 m miss p B2 p D2 μ to distinguish between D, D*,D** BEACH 218 Semileptoni deays @ LHCb (24)
f (D,D*,D**) in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) Frations of D, D*, D** produed in semileptoni b deays not yet well known Relevant, sine higher resonanes onstitute bakground for exlusive deays B D ℓ ν and B D* ℓ ν, e.g. in measurements of R(D) or R(D*) Use B andidates from Bs2* B K+ Reonstrut B momentum vetor from known Bs2*, B and K+ masses, B prodution and deay verties, K momentum and flight diretion preliminary Reonstrut D K π+ and alulate 2 m miss p B2 p D2 μ to distinguish between D, D*,D** BEACH 218 Semileptoni deays @ LHCb (25)
f (D,D*,D**) in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) Signal: B D X μ νμ with B from Bs2* B K+ preliminary Dominant bakground from deays of B and B not from Bs2* Modeled using same-sign Kaon andidates Bakground from B D X D and B D X τ ντ modeled using simulation preliminary Bakground from Bs and Λb deays and mis-reonstruted deays modeled using data-driven methods BEACH 218 Semileptoni deays @ LHCb (26)
f (D,D*,D**) in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) Signal: B D X μ νμ with B from Bs2* B K+ preliminary Dominant bakground from deays of B and B not from Bs2* Modeled using same-sign Kaon NEW: shown here andidates for the first time Bakground from B D X D and B D X τ ντ modeled using simulation preliminary Bakground from Bs and Λb deays and mis-reonstruted deays modeled using data-driven methods BEACH 218 Semileptoni deays @ LHCb (27)
f (D,D*,D**) in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) preliminary f (D ) =.27 ±.6 ry a n i m i rel f (D ) =.14 ±.7 p f (D ) 1 f (D ) f (D ) BEACH 218 Semileptoni deays @ LHCb (28)
Flavour-speifi B lifetime s
Flavour-speifi Bs lifetime [PRL119(217)1181] D Measure flavour-speifi Bs lifetime in ( ) Bs Ds Ds + μ νμ Sensitive to deay-width differene between heavy and light eigenstates in the Bs Bs system Large yields, but systematis from missing neutrino Perform measurement relative to B D ( ) + μ νμ reonstruting Ds(*) and D(*) in deay to K+ K π D (s ) π + veto BEACH 218 Semileptoni deays @ LHCb (3)
Flavour-speifi Bs lifetime [PRL119(217)1181] Analysis based on Run-1 data sample: 3 fb-1 at 7 and 8 TeV Event samples of 468 k Ds μ+ and 141 k D μ+ andidates 1 Δ Γ B =.115 ±.53 (stat) ±.41 (syst) ps fs τ B = 1.547 ±.13 (stat) ±.1 (syst) ±.1 ( τ B ) ps s BEACH 218 Semileptoni deays @ LHCb (31)
Flavour-speifi Bs lifetime [PRL119(217)1181] By-produt: measurement of Ds lifetime 1 Δ Γ D = 1.131 ±.117 (stat) ±.65 (syst) ps τ D =.546 ±.3 ( stat) ±.17 (syst) ±.17 ( τ D ) ps s BEACH 218 Semileptoni deays @ LHCb (32)
Ω lifetime
Ω lifetime [LHCb-PAPER-218-28] (in preparation) Ω lifetime so far known only to 17 % preision More preise measurement interesting, e.g. to test hierarhy expeted from Pauli interferene: τξ > τλ > τξ > τω e.g. Browder, Honsheid, Pedrini [arxiv:hep-ph/966354] Measurement uses sample of Ω b Ω μ ν μ X with Ω p K K π To minimize systematis, measure lifetime relative to D+ lifetime from B D + μ ν μ X with D+ K π π BEACH 218 Semileptoni deays @ LHCb (34)
Ω lifetime [LHCb-PAPER-218-28] (in preparation) Ω lifetime so far known only to 17 % preision More preise measurement interesting, e.g. to test hierarhy expeted from Pauli interferene: τξ > τλ > τξ > τω e.g. Browder, Honsheid, Pedrini [arxiv:hep-ph/966354] NEW: first shown at LHCP two weeks ago Measurement uses sample of Ω b Ω μ ν μ X with Ω p K K π To minimize systematis, measure lifetime relative to D+ lifetime from B D + μ ν μ X with D+ K π π BEACH 218 Semileptoni deays @ LHCb (35)
Ω lifetime [LHCb-PAPER-218-28] (in preparation) Ω lifetime so far known only to 17 % preision More preise measurement interesting, e.g. to test hierarhy expeted from Pauli interferene: τξ > τλ > τξ > τω e.g. Browder, Honsheid, Pedrini [arxiv:hep-ph/966354] From analysis of Run-1 data sample: 3 fb-1 at 7 and 8 TeV τω τ D =.258 ±.23 (stat ) ±.1 (syst) + τ Ω = 268 ± 24 (stat) ± 1 (syst ) ± 2 ( τ D ) fs + ry a n i m i prel BEACH 218 Semileptoni deays @ LHCb (36)
Ω lifetime [LHCb-PAPER-218-28] (in preparation) Ω lifetime so far known only to 17 % preision More preise measurement interesting, e.g. to test hierarhy expeted from Pauli interferene: τξ > τλ > τξ > τω e.g. Browder, Honsheid, Pedrini [arxiv:hep-ph/966354] Four times larger than urrent PDG average BEACH 218 Semileptoni deays @ LHCb (37)
Ω lifetime [LHCb-PAPER-218-28] (in preparation) Ω lifetime so far known only to 17 % preision More preise measurement interesting, e.g. to test hierarhy expeted from Pauli interferene: τξ > τλ > τξ > τω e.g. Browder, Honsheid, Pedrini [arxiv:hep-ph/966354] Four times larger than urrent PDG average τξ > τω > τ Λ > τξ Learn something about the dynamis of the ss quark pair? BEACH 218 Semileptoni deays @ LHCb (38)
Summary No news from LHCb (yet) on Vub Analyses in progress, see bakup slides New measurements on Λb Λ+ form fator Fration of D, D*, D** in B D X μ νμ Preliminary Presented here for the first time Flavour-speifi Bs lifetime Ω lifetime BEACH 218 Semileptoni deays @ LHCb (39) Preliminary
Summary No news from LHCb (yet) on Vub Analyses in progress, see bakup slides New measurements on Λb Λ+ form fator [PRD96(217)1125] Fration of D, D*, D** in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) Flavour-speifi Bs lifetime [PRL119(217)1181] Ω lifetime [LHCb-PAPER-218-28] (in preparation) ( Ds± prodution asymmetry ) [arxiv:185.9869] BEACH 218 Semileptoni deays @ LHCb (4)
Thank You
Ds± prodution asymmetry [arxiv:185.9869] By-produt of the assl analysis [PRL 117(216)6183] Reonstrut prompt Ds± ϕ π± with ϕ K+ K Measure raw asymmetry + Araw N (D s ) N (D s ) N (D +s )+N (D s ) in bins of pt and rapidity Corret for Ds-from-B bakground and detetion asymmetries AP = 1 1 f bkg ( Araw AD f bkg AP (B) ) Bakground fration and asymmetries from simulation and literature Detetion asymmetries from data-driven methods BEACH 218 Semileptoni deays @ LHCb (42)
Ds± prodution asymmetry [arxiv:185.9869] Analysis based on Run-1 data sample: 3 fb-1 at 7 and 8 TeV (2.9 + 9.1) million D andidates with 97 % purity ± s 8.5 < pt < 25 GeV/ 3.5 < y < 4.5 Mag down BEACH 218 Semileptoni deays @ LHCb (43)
Ds± prodution asymmetry [arxiv:185.9869] Analysis based on Run-1 data sample: 3 fb-1 at 7 and 8 TeV (2.9 + 9.1) million Ds± andidates with 97 % purity Compatible results for the two field orientations of spetrometer magnet BEACH 218 Semileptoni deays @ LHCb (44)
Ds± prodution asymmetry [arxiv:185.9869] Analysis based on Run-1 data sample: 3 fb-1 at 7 and 8 TeV (2.9 + 9.1) million Ds± andidates with 97 % purity Compatible results for the two field orientations of spetrometer magnet Find no signifiant dependene on rapidity or pt In ontrast to expetation from Pythia BEACH 218 Semileptoni deays @ LHCb (45)
Ds± prodution asymmetry Learn something about the s-quark ontent of the proton? BEACH 218 Semileptoni deays @ LHCb (46)
Vub BEACH 218 Semileptoni deays @ LHCb (47)
Vub νℓ Work ongoing towards a measurement of 2 s s + BF (B K μ ν μ ) V ub = R FF 2 + BF (B D s μ ν μ ) V b b Vu()b s ℓ u () s preliminary BEACH 218 Semileptoni deays @ LHCb (48)
Vub Working on a searh for + + + B μ μ μ νμ Branhing fration sensitive to Vub Extra μ+ μ pair breaks heliity suppression provides deay vertex Deay not yet observed, expet + + + 7 BF(B μ μ μ ν μ ) 1 [EPJ Web Conf 158(217)35] Analysis uses full Run-1 data set + 1.7 fb-1 from Run-2 Expet to be able to exlude signal down to few 1-8 BEACH 218 Semileptoni deays @ LHCb (49)
Vub BEACH 218 Semileptoni deays @ LHCb (5) [Nature Phys 1(215)138]
Λb Λ+ form fator BEACH 218 Semileptoni deays @ LHCb (51) [PRD96(217)1125]
f (D,D*,D**) in B D X μ νμ [LHCb-PAPER-218-24] (in preparation) ary n i m i l p re BEACH 218 Semileptoni deays @ LHCb (52)
Flavour-speifi Bs lifetime [PRL119(217)1181] BEACH 218 Semileptoni deays @ LHCb (53)
Ω lifetime [LHCb-PAPER-218-28] (in preparation) ry a n i m i prel BEACH 218 Semileptoni deays @ LHCb (54)