CP Violation at BaBar: sin2β

Transcription

1 Violation at aar: in2β Soeren Prell Iowa State Univerity -Factory Sympoium Stanfor, 27 October 28

2 Violation until 2 Firt obervation of V in kaon ecay by Cronin, Fitch et al. (1964) Unitarity Triangle in 2 Kobayahi an Makawa provie mechanim for V (1973) Large aymmetrie in ecay preicte by igi an Sana (198) Inirect in2β meaurement from unitarity contraint an irect meaurement ha poor preciion Early in2β meaurement (2) Large CLEO ample of 1M CLEO ha meaure many R, but no V meaurement Sin2β wa aar opportunity to provie an important new meaurement with early ata October 27, 28 aar Sympoium 2

3 Senitivity to in2β mixing b t V / V e t t b * i2β t b ecay W + mixing A VV * cb c A A c c f K mixing q K / p K A VV VV λ = e = e = e * * i 2i2 β i2β cb c c c 2iβ η * * A VcbV c VV c c S 2Im( λ ) 1 λ S= = 2 = η in 2 C β 2 C = λ 1 + λ Δ Δ t / t / τ e τ Γ = e Δ Δ 44 τ τ Δ Δ t / e t / τ τ Γ e + 44 τ τ ( ( Γ J / ψkf )) S = [ 1[ 1 in2 S βin( ΔmmΔt) t+ )] C co( ΔmΔt) ] ( ( Γ J / ψkf )) S = = [ 1[ 1+ in S 2 βin( ΔmΔmΔtΔ) t ) ] C co( ΔmΔt) ] October 27, 28 aar Sympoium 3

4 The in2β Meaurement ϒ(4S) prouce coherent pair: Δ t =Δz/ βγ c ϒ( 4S ) e z e + βγ ϒ (4 S ) =.56 tag Proper time Δz ~26μm ψ K Excluive meon an vertex recontruction μ K S μ + π π + tag flavor an vertex recontruction Many novel technique were neceary to meaure in2β K L recontruction, Δt meaurement, flavor tagging, multi-parameter likelihoo fit, blin analyi metho October 27, 28 aar Sympoium 4

5 The Golen in2β Moe Theoretically clean in the Stanar Moel S J/ψK in2β ~ O(1-3 ) Groman, Kagan, Ligeti, PL 538, 327 (22) oo, Reuter, Mannel, PRD 7, 366 (24) Ciuchini, Pierini, Silvetrini, PRL 95, (25) Li, Mihima, JHEP 73, 9 (27) η even Relatively large branching ratio an clean experimental ignature Small backgroun level Now ~25 recontructe an flavortagge (cc)k ecay per 1 6 event η o aar, arxiv: October 27, 28 aar Sympoium 5

6 Δt Meaurement an Reolution Function New proper time meaurement technique prouction point (in z) i unknown at aar We on t meaure t, but Δt (which i itribute a a two-ie exponential ) Nee to ientangle reolution function from Δt itribution aar, PRL 87, 2183 (21) Δt reolution much more important for lifetime meaurement than for in2β Δt meaurement ominate by z reolution of tag ecay vertex (σ Δt ~ 1.1 p) τ ~ 1.5 p, λ -mixing = 2π / Δm ~ 12 p Sin2β only looely correlate with reolution function Demontrate unertaning of reolution function with preciion meaurement of lifetime (2% error) Ue much larger ample of fully-reco e ecay to flavor final tate ( flav ) Mot precie + / lifetime ratio meaurement at that time τ τ = ±.32 ±.22 p, τ + = ±.32 ±.23 p, / τ = 1.82 ±.26 ±.12 + October 27, 28 aar Sympoium 6

7 Flavor Tagging from Mixing Flavor of tag unambiguouly efine flavor of at prouction Determine flavor of tag from it charge ecay prouct (l, K, high-p track an oft π) Starte out with conervative cut-bae approach an lowly move towar multivariate etimator Effective tagging efficiency Σ ε(1-2w) 2 ~ 3% aar, PRL 88, (21) or Meaure mi-tag rate w with flav ample Mitag rate cannot be etermine from ample, but i not want to rely on MC Mitag rate in flav ample ame a in ample, with known mixing amplitue (=1) Demontrate tagging performance with preciion meaurement of mixing frequency (3.7%) Together with aar Δm from i-lepton analyi bet meaurement of Δm at that time (*) (*) (*) flav D ± π, D ± ρ, D ± a1 Δ =.516 ±.16 ±.1 p October 27, 28 aar Sympoium 7 m 1

8 Extract in2β with imultaneou unbinne likelihoo fit to Δt pectra of an flav ample 35 fit parameter for firt paper Determination of common parameter (mitag rate, Δt reolution) ominate by much larger flav ample Only in2β ominate by ample Very mall total correlation between in2β an other parameter (<1%) The Likelihoo Fit "I remember my frien Johnny von Neumann ue to ay, with four parameter I can fit an elephant, an with five I can make him wiggle hi trunk." Enrico Fermi (1953) Nee at leat 3 parameter to fit omething that reemble an elephant! flav (provie mitag rate an Δt reolution) (etermine in2β) Wel, J., Leat quare fitting of an aar, PRD 66, 323 (22) elephant, Chemtech February (1975) October 27, 28 aar Sympoium 8

9 lin Analyi Avoi poible experimenter bia e.g. towar the tanar moel preiction The firt look at bline in2β ata (July 1, 2) -tag -tag Sin2β meaurement well uite for blin analyi Value an ign of in2β in fit are hien Apparent aymmetry in Δt itribution for an -tagge event are hien Sytematic uncertaintie are etimate before unblining aar etablihe a culture of removing experimenter bia whenever poible aar aymmetry, mixing an lifetime analye have been bline in a imilar way ranching ratio meaurement ue hien ignal box, etc. in2 β ( blin) = 1.22 ±.37 October 27, 28 aar Sympoium 9

10 Towar the Firt Reult Firt public in2β reult targete for ICHEP 2 conference in Oaka (July 27- Aug 2) Elba aar meeting (May 28-31) Define the Elba flavor tagger Hybri tagger with 4 categorie (lepton, kaon + 2 NN) Firt meaurement of mitag rate with flav ample preente on 3.7/fb SLAC aar meeting (July 1-13) Tagging performance meaure in ata, Δm competitive with worl bet meaurement Firt bline fit on 8/fb (tatitical error larger than expecte, 5% probability) Lat 2 week Lat 1/fb ae on July 15 Unblining of in2β on July 17 Final Oaka paper (AD 44) on July 25 Sin2β reult preente at ICHEP on July 31 October 27, 28 aar Sympoium 1

11 Valiation, Valiation, Valiation, Monte Carlo Stuie Parametrize MC an full imulation with variou in2β value Null-tet for aymmetrie in flav an + control ample 1 alternative vertex fit configuration 3 inepenent fitting package Alternative extraction of mitag rate time-integrate metho in optimize Δt interval (Single-in metho) Kin in 2β = i i K K i 2 i Alternative extraction of in2β with Kin Κ ~ η in( ΔmΔt) Full meaurement of τ an Δm October 27, 28 aar Sympoium 11

12 ICHEP 2 (Oaka) aar 12 tagge J/ψ K S an ψ(2s) K S event in 9 fb -1 give in2β =.12 ±.37 ±.9 tag tag Theoretically intereting central value, but ba tarting point for oberving violation elle reult with 6.2 fb -1 alreay inclue J/ψ π, J/ψ K L an χ c1 K S +1 σ 1 σ in2β =.45 ± aar, hep-ex/848 October 27, 28 aar Sympoium 12

13 aar Firt Paper aar in2β reult publihe on March 19, 21 in PRL 86, 2518 (21) ack-to-back with elle in2β paper J / ψk, ψ(2 S) K S S Improvement to analyi ince ICHEP Rebline after ICHEP Double the ata ample to 23M Ae J/ψ K L moe Combine likelihoo fit to an flav ample with 35 free parameter in 2β =.25 ± tagge event total J K / ψ L Sin2β i lowly going up in 2β =.34 ±.2 ±.5 λ conitent with 1 in 2β =.87 ±.51 October 27, 28 aar Sympoium 13

14 Submitte to PRL on July 5, 21 elle ubmitte 14 ay later, publihe back-to-back Analyi improvement ouble enitivity 4% more ata ae Improve track an K S recontruction Ae J/ψ K * an X c1 K S moe etter SVT alignment an vertex recontruction in 2β =.56 ±.15 2 n mot cite aar phyic paper in2β =.59 ±.14 ±.5 (4.1 σ ) λ =.93 ±.9 ±.3 in 2β =.82 ± 1. aar, PRL 87, 9181 (21) October 27, 28 aar Sympoium 14

15 Towar a preciion meaurement 3 more aar in2β PRL an 2 PRD The in2β PRD [PRD 66, 323( 1)] Longet aar paper with 54 page Run 1+2 paper [PRL 89, 2182 ( 2)] 3 r mot cite aar paper Run 1-4 paper [PRL 94, ( 5)] Run 1-5 paper [PRL 99, ( 7)] Final in2β reult on full ata et [arxiv:88.193, to be ubm. to PRD] aar in2β meaurement benefite from continuouly improving the analyi for each publication Tagging, ample, ytematic,. Each in 2 β error i cale by 1/ N ( J / ψψ, (2 S), χ, η) K c1 c S in2β =.688 ±.32 J K aar at ICHEP 8 / ψ L After ome up an own aar an elle have converge on in2β in2β =.671 ±.24 C =.5 ±.2 in2β HFAG Worl Average in2β =.698 ±.62 in2β =.691±.29 ±.14 =.26 ±.2 ±.16 October 27, 28 aar Sympoium 15 C

16 Removing the 9 o β Ambiguity The ign of co2β reolve the 9 o β ambiguity in in2β Interference term between -o an -even amplitue in ecay to three-boy or VV final tate are enitive to co2β aar, PRD 71, 325 (25) J / ψ K * fit reult co2β> (in2β contr.) co2β< (in2β contr.) * J / ψk [AAR, PRD 71, 325 (25)]: co 2β 89% C.L. D h [AAR, PRL 99, (27)]: co 2β 86% C.L. (*) + K S π π * + * D D KS + K K KS [AAR, PRD 74, 9111 (26)]: co 2β 94% C.L. [AAR, arxiv:88.7 (28)]: co 2β 4.8σ co2β < olution exclue: β = (21.1 ±.9) October 27, 28 aar Sympoium 16

17 Impact on the Stanar Moel Sin2β i now the mot precie contraint on the apex of the Unitarity Triangle Contrary to the ie in2β i till limite by tatitic Sin2β erve a a benchmark for other β meaurement from ecay enitive to New Phyic (e.g. haronic-penguin) an the ie an other angle meaurement October 27, 28 aar Sympoium 17

18 Searching for New Phyic: Sin2β in Cabibbo-uppree Tree Decay D D * + * Large icrepancie from S = -in2β in thee moe coul inicate evience for new phyic All meaurement are conitent with the Stanar Moel preiction D h (*) -o aar, arxiv , ubmitte to PRD S =.7 ±.16 ±.3 S =.62 ±.21±.3 C * + * + D D D* D * + * + D D D D* S C =+.5 ±.9 ±.2 S =.73±.23±.5 =.63±.36 ±.5 C =+.8 ±.17 ±.4 + * + D D D D =+.7 ±.23±.3 C =+. ±.17 ±.3 + * * D D D D aar, PRL 99, 8181 (27) October 27, 28 aar Sympoium 18 S C D (*) h D (*) h =.56 ±.23±.5 =.23±.16 ±.4 aar, PRL 11, 2181 (28) S C J / ψπ J / ψπ = 1.23 ±.21±.4 =.2 ±.19 ±.3

19 Searching for New Phyic: Sin2β in loop-ominate Decay Rare ecay meiate by heavy virtual particle can receive contribution from New Phyic b W + Stanar Moel uct,, g φ, η K S New Phyic (example) b b g ~ + (δ ~ b 23 R ~ R RR ) g φ, η η KK S violating amplitue of uch ecay preicte by the Stanar Moel coul iffer from actual obervation October 27, 28 aar Sympoium 19

20 Aymmetrie in Penguin Decay Meaure S in many penguinominate moe an compare to in2β meaure in (cc)k aar, arxiv: Mot ignificant ifference in naïve penguin average reache in 24 More precie meaurement have ecreae the ignificance of δs below 1σ Some meaurement come now from complicate 3-boy timeepenent Dalitz analye S in charmle penguin moe i till a goo place to look for new phyic, but no evience with aar tatitic η ' K S Mot precie in2β from a charmle moe S C η ' K η ' K 24 : δ S =.32 ±.8 (3.8 σ ) 28: δ S =.3±.4 (.7 σ ) η ' K L = +.57 ±.8 ±.2 =.8 ±.6 ±.2 October 27, 28 aar Sympoium 2

21 Concluion Sin2β meaurement by the -factorie etablihe violation in the ytem Confirme CKM mechanim a ominant ource for violation in quark mixing Sin2β analyi ha a large impact on the whole aar phyic analyi program Pioneere the time-epenent analyi technique Flavor tagging, vertex an Δt recontruction Many-parameter likelihoo fit, blin analyi technique High tanar impoe on in2β meaurement lai the founation for the quality, thoroughne an conervatim that i maintaine until toay in aar analyi program an review proce October 27, 28 aar Sympoium 21