Charmless B decays at CDF Mauro Doneg Universit

Charmless B decays at CDF Mauro Donegà Université de Genève on behalf of the CDF collaboration Mauro Donega – WIN 05

Outline Lot of Charmless B results… …in this talk: • B hh’ (B PP) • BR and Acp: Bd Kπ • BR: Bd π π Bs KK • B VV • BR first evidence: Bs • B PV • BR and Acp B± K ± Mauro Donega – WIN 05

CDF TIME OF FLIGHT B =1. 4 T TOF: ~100 ps resolution, 2 sigma. K/ separation for tracks below 1. 6 Ge. V/c (significant improvement of Bs flavor tag effectiveness) COT: large radius (1. 4 m) Drift C. • • 96 layers, 200 ns drift time Precise PT above 400 Me. V/c • Precise 3 D tracking in | |<1 (1/PT) ~ 0. 1%Ge. V – 1; (hit)~150 m • d. E/dx info provides >1. 4 sigma K/ separation above 2 Ge. V SVX-II + ISL: 5 + 1 (2) layers of double-side silicon (3 cm < R < 30 cm) • Standalone 3 D tracking up to | |= 2 • Very good I. P. resolution: ~30 m (~20 m with Layer 00) LAYER 00: 1 layer of radiation-hard silicon at very small radius (1. 5 cm) (expected 50 fs proper time resolution in Bs Ds ) Mauro Donega – WIN 05

Silicon Vertex Trigger B physics @ hadron collider : • 2 leptons (rare decays, charmonium decays) • 1 lepton + 1 displaced track (semileptonic decays) • 2 displaced tracks : (two-body decays, multibody decays) Silicon Vertex Trigger Secondary Vertex Decay Length Lxy Pt(trk) >2 Ge. V/c Primary Pt >5. 5 Ge. V/c Vertex 100 m<IP(trk)<1 mmd = | | <1 B 35 m 33 m = 47 m (resolution beam) impact parameter Mauro Donega – WIN 05

B hh’ at CDF Te. Vatron all b-hadrons (Bd, Bs, b…) Both Bs hh’ processes and Bd hh’ Physics opportunities: Counting experiments: CDF is the first experiment to be sensitive to Bs hh’ decays Contributions from both: tree Bd K+ – Branching Ratio – Direct CP asymmetry • With higher statistics Bs K- + – Branching Ratio – Direct CP asymmetry Mauro Donega – WIN 05 penguin

B hh’ at CDF More than counting: • Bs K+K- : • Lifetime measurement • sample sensitive to ΓL • Combined with other lifetime measurements →ΔΓs … in the future • Bd + - → • Bd K+ - → Time dependent CP asymmetry requires b-flavor tagging and more statistics ! Mauro Donega – WIN 05

B hh’ in 180 Bd k pb-1 Bs kk Bd Bs k Selection cuts Bd Bs The only significant cut not already present in the trigger Invariant mass hp (Ge. V/c 2) Mauro Donega – WIN 05 893± 47 B hh’ events

Unbinned Maximum Likelihood Fit Sum over the 4 channels BKG Likelihood BKG fraction (float) Likelihood variables: Mauro Donega – WIN 05

Likelihood in detail j Signal likelihood j fraction of events of the jth mode j = Kinematics Particle Identification Unbalance Momentum P(A|B)P(B) Background likelihood same structure as the signal Mauro Donega – WIN 05

Kinematics Invariant mass ( hypothesis) vs unbalance Def: =[1–p 1/p 2] q 1 Helps to disentangle the Bd K+ - from Bs K- + M Bd K- + Bd + Bd K+ M Bs K+ - Bs K+ K Mauro Donega – WIN 05 Bs K- +

Particle Identification Helps to disentangle Bd + - from Bs K+K • K/ separation: 1. 4 @PT>2 Ge. V/c e p …no ev/ev PID separation k • This PID performance implies statistical separation of K-pi with resolution 60% of a “perfect” PID • Background composition: (ad-hoc study) kaons & pions (muons)& protons electrons Mauro Donega – WIN 05 &

Fit Projections Mauro Donega – WIN 05

B hh’ results BR and Acp Analyzed Luminosity =180 pb-1 Mauro Donega – WIN 05

Systematic uncertainties 0. 01272 will decrease with statistics 0. 0033 0. 04755 0. 0464 ± 0. 063 ± 0. 012 ± 0. 019 ± 0. 054 Mauro Donega – WIN 05

Upper Limits • ΔΓs/Γs = 0. 12 (Standard Model) • Bs KK = 100% short eigenstate • (HFAG 2005) BR(Bd K ) = 18. 2 x 10 -6 • (PDG 2004) fs = 0. 107 fd = 0. 397 Mauro Donega – WIN 05

B VV B PV _ • b->sss pure penguin amplitude Bs B± K ± • New Physics has a chance to compete! ( B K*: “B K* polarization discrepancy Bs is the Bs counterpart of Bd K* Unexpected result (3 effect) from sin(2 b) measure from penguin dominated modes) Bs g or W u, c, t • Measuring angular distribution of decay products determine polarization amplitudes and their relative phases through interference effects: • CP violation • ΔΓs Mauro Donega – WIN 05 • … B+ K+

A blind analysis was performed in anticipation of a small signal rate. Normalize rate using another Bs VV decay: Bs J/ : • NO production ratio of Bs vs Bd (fs/fd) • one K+K- in the final state • some systematic on efficiency cancel • sizeable rate M(kk) Ge. V/c 2 Bs M(kk ) Ge. V/c 2 Separate optimization for Signal and Normalization sample Cuts optimized checking which of The tracks fired the trigger Mauro Donega – WIN 05 M(kk) Ge. V/c 2

Bs signal Bs n o i at v r e t s r i F s b o From Data From PDG * From MC BR = (14 +6 -5 (stat) ± 2(syst) ± 5 (BR)) 10 -5 Mauro Donega – WIN 05 * BR( ) needs to be rescaled for fs/fd

Yield and ACP (B± K±) Extended unbinned maximum likelihood fit to : • MKKK • M B± f 0 K± B± K*0 Bu, d X mass comb • helicity angle Measure at the same time: N(B± K±) kaons pions • d. E/dx from COT ID Helicity angle ACP(B± K±) + disentangle signal from B± f 0 K±, B± K*0 , Bu, d X and combinatorial background Normalization: B± J/ K± Extended unbinned maximum L Mauro Donega – WIN 05 M M k

B± K± Results +PDG BR(B± J/ K±) PDG 2004 NB B± J/ K± B± K ± 439 ± 22 47. 0 ± 8. 4 Babar/Belle results with ~100 fb-1 -1 Analyzed L –=180 Mauro Donega WIN 05 pb

B hh’ perspectives CDF “the present”: • Next round with ~360 pb-1 • Better tracking • Improved PID 180 pb-1 B hh’ the future: • Higher precision BR(Bs KK) • Bs KK lifetime: ΔΓs • Precision Acp(Bd Kπ) (eventually 1%) • Bs Kπ BR and direct Acp • Tagged time-dependent measurements further ahead: Acp parameters for Bd and Bs Mauro Donega – WIN 05 360 pb-1

B VV perspective With dataset now on tape new Bs modes should be visible (Bs K*0 K*0 , Bs r): Need significantly more statistics to perform CP measurements (…full Run II) Measure “untagged” quantities with Bs and Bd K*events: And other charmless decays are currently under study: • Bd(s) K*+ -(K-) • V 0 (as b 0 ) Mauro Donega – WIN 05

Conclusions • CDF is giving important contribution in the field of the charmless B decays and remains the only player in the Bs fully hadronic decays • New analysis with improved tracking and PID are already in the pipeline • Significant improvement of the Te. Vatron performance Mon, 23 May 2005 first fb-1 was exceeded (delivered luminosity ~600 pb-1 on tape) • Higher level of precision is at the door ! Mauro Donega – WIN 05

Mauro Donega – WIN 05

Te. Vatron 1 fb-1 delivered Mauro Donega – WIN 05

Imbalance - Momentum Monte Carlo p Binned ML fit p Signal BCKG Mauro Donega – WIN 05

Systematics a) Mass resolution: the mass resolution is input from MC. It is rescaled to match the D 0 resolution on data, vary the rescale factor of ± 10% and repeat the fit. b) d. E/dx correlation: repeat the fit using the correlation shape extracted in the sample of kaons and pions from “mixed-events”: e. g. one meson from an event, the other from the subsequent event. Quote the difference wrt the central value. c) d. E/dx shapes for e and p: repeat the fit assigning to the electrons and protons all 4 combinations of d. E/dx shapes (ep)= ( / K/KK/K ). Quote the maximum difference wrt the central fit. Mauro Donega – WIN 05

Systematics (cont’d) d) input masses: the fit is done on data in which the recipe used for mass measurement at CDF II was applied. Input masses in the kinematics pdf are those measured by CDF II. Repeat the fit varying M(Bd) and M(Bs) within their statistical uncertainties (0. 92 and 1. 29 Me. V/c 2). Quote the differences wrt the central fit e) Background model: the fit assumes mass spectrum of bckg = exp + C. Repeat the fit with p 1, p 2, p 3 and quote the difference wrt central value Mauro Donega – WIN 05

Systematics (cont’d) f) Different p-spectra for bckg components: central fit assumes the same momentum distribution for e/pi/K/p of background. Reweight each term of the bckg p. d. f. according to linear fits of populations vs momentum plots. Mauro Donega – WIN 05

Systematics (cont’d) g) B lifetimes: relative kinematics efficiencies depend on the lifetime assumed in MC. Re-evaluate efficiencies after simultaneous shift of Bs lifetime (+1 ) and Bd (-1 ) and viceversa. is the PDG 2004 uncertainty. Quote difference wrt central value h) Isolation efficiency: has a ~ 10% from measurement on data. Re-evaluate the efficiency at +/- 1 and quote difference wrt central value i) MC statistics: kinematics efficiencies have statistical error. Re-evaluate them at +/- 1 and quote difference wrt the central fit. Mauro Donega – WIN 05

Systematics (cont’d) l) Charge asymmetry: assess +/-25% of the 10% chargeasymmetry effect studied in the published D 0 analysis m) XFT bias correction: the correction function have uncertainties. Stretch (push) K/ discrepancy shifting simultaneously the correction coefficients by 1 , reevaluate the correction, and quote differences wrt the central fit n) p. T(B) spectrum: Bs and Bd spectra are different, in principle, but use MC with an “average” spectrum. Created an additional “shrunk” spectrum by shifting by – 1% each entry in the p. T(B) histogram used in central fit. Extract weights from the ratio of the two spectra, apply to MC events; re-evaluate the relative efficiencies. Mauro Donega – WIN 05

Systematics (cont’d) o) ΔΓs/Γs : Standard Model predicts ~ 0. 12± 0. 06 and Bs →K+K- to be dominated by the short-lived component. We derive the systematic uncertainties from these assumptions by varying ΔΓs/Γs from 0. 06 to 0. 18 , reevaluating the relative efficiencies and quoting the differences wrt the central fit. Mauro Donega – WIN 05

Systematic uncertainties will decrease with statistics Mauro Donega – WIN 05

• Measure sin(2 b) using golden charmonium modes (i. e. Bd J/ KS 0)from mixing induced time dependent CP asymmetry • Unexpected result (3 effect) when measuring sin(2 b) from penguin dominated modes Mauro Donega – WIN 05 B 0 th eo K 0 re th and ica B lly 0 cle an ’K 0 ! Hint of discrepancy with SM in b s penguin decays

B background Due to the large width of K* and to its value close to mφ we get in our Bs signal window a reflection from Bd J/ψ K* for Bs J/ψ φ and from Bd φ K* for Bs φφ We get an estimate of this contribution by evaluating from MC the efficiency of reconstructing a Bd J/ψ K* event as Bs J/ψ φ and from the measured BRs and fs/fd. As a cross-check we can evaluate the contribution from the sidebands subtracted mass spectrum of the φ meson, in which the only remaining source of background comes from the Bd J/ψ K* reflection that doesn’t enter the Bs sidebands region Mauro Donega – WIN 05

BR(Bs ) systematics • Systematic error dominated by normalization mode BR uncertainty and already similar in size to the statistical error • Theory uncertainty on polarization very conservative (vary longitudinal fraction in 20 % to 80% range as suggested by A. Kagan) • DGs uncertainty based on the preferred theory value of: DGs/Gs = 0. 12 ± 0. 06 • BR is rather on the low side respect to QCDF (2. 5 ) 1. 4 vs 3. 7 E-5 Source Relative error on BR Trigger efficiency 3. 3 % J/ yield and efficiency 8. 4% Background subtraction 5. 4% Bs polarization 3. 8% Bs J/ polarization 1. 4% DGs uncertainty 0. 6% J/ and BR 2. 1% Sub Total 11 % BR(J/ ) 35% Total 37% Mauro Donega – WIN 05

BR(B± K±) systematics • Systematic error on BR dominated by fit uncertainty and acceptance correction, largely below statistical uncertainty • ACP systematic is largely statistical in nature, intrinsic systematic below 0. 01 • Comparable to B-factory experiments Source Relative error on BR Trigger efficiency 3. 3 % J/ K yield and eff. 4. 0% Efficiency Ratio 3. 6% B± K± fit syst. 3. 0% J/ and BR 2. 1% B± K± BR 0. 4% Total 7. 4 % Source error on Acp B± K± fit syst. +0. 034 -0. 020 Charge asymmetry ± 0. 005 Mauro Donega – WIN 05

Further Bs modes Decay • Rich harvest of interesting Bs VV decays – K*+K*-/K*0 anti-K*0 untagged angular analysis gives (with SU(2) assumptions) (Fleisher, Duniets) – r 0 dominated by Electro Weak Penguin (insight in to the B K puzzle!) b d • Only the shown in the table here • Measure them all! b s 0 -less BR/BR( ) (including daugher BR) Pure penguin (Li, Lu, Yang hep-ph/0309136) BR(10 -6) K*0 r 0 0. 53 0. 11 K*+K*- 1. 94 0. 008 r 0 1. 03 0. 16 K*0 anti-K*0 2. 61 0. 35 K*0 0. 14 0. 014 13. 1 1 Trigger efficiency not included (but expected very similar) Mauro Donega – WIN 05