Microsoft PowerPoint - HP2006.ppt 1 PIETRO FACCIOLI, for the HERA-B Collaboration Università di Bologna and INFN PPIETROIETRO FFACCIOLIACCIOLI, , for the for the HERAHERA--B B CollaborationCollaboration Università di Bologna and INFNUniversità di Bologna and INFN Charmonium, open charm and beauty production at HERA-B Charmonium, open charm and beauty Charmonium, open charm and beauty production at HERAproduction at HERA--BB June 14, 2006 Asilomar Conference Grounds, Pacific Grove, California June 14, 2006 Asilomar Conference Grounds, Pacific Grove, California 2 HERA-B detector and physics topics results and comparison with previous experiments outlineoutline heavier states and heavier states and feeddownfeeddown to J/to J/ψψ ψ′/ψ and kinematics fraction of J/ψ’s from χc J/J/ψψ productionproduction pT and xF distributions, A-dependence newnew: : decaydecay angularangular distributionsdistributions fraction of J/ψ’s from b decays charmcharm inclusive D0, D+, D*+ and ratios A-dependence highest energy among fixed-target experiments often unclear experimental picture, especially for p-A collisions test production models (pQCD + initial/final state interactions in nuclei) largest χc statistics analyzed in hadron collisions largest χc statistics analyzed in hadron collisions first data at negative xFfirst data at negative xF observation of low-pT /|xF| effects observation of low-pT /|xF| effects 3 10 m 0 m20 m target wires (C, Ti, W) target wires (C, Ti, W)MagnetMagnet TrackingTracking good PID good PID (e±, μ±, π, K, p) √s = 41.6 GeV A = 12 ÷ 184 large acceptancelarge acceptance (15-220 mrad) high resolutionhigh resolution (top view) electrons fixed nuclear fixed nuclear targettarget the HERAthe HERA--B detectorB detector + photon reconstruction ECALECAL MUONMUON RICHRICH 920 GeV/c protons 920 GeV/c protons Vertex Detector Vertex Detector 4 mμμ [GeV/c2] 0.4 0.6 0.8 1.0 1.2 800 600 400 200 0 e n tr ie s (a .u .) mμμ [GeV/c2] 6 7 8 9 10 11 12 102 10 1 10-1 mee [GeV/c2] 2.5 3.0 3.5 4.0 4.5 103 102 104 •• J/J/ψψ, , χχcc, , ψψ′′, with A-dependence •• DDoo →→ μμ++μμ−− (FCNC) •• inclusive inclusive bb production •• ϒϒ, , φφ, , ρρ//ωω dilepton trigger: ~ 150·106 eventsdilepton trigger: ~ 150·106 events ψψ′′ J/J/ψψ ρρ//ωω φφ ϒϒ(1S)(1S) ϒϒ(2(2--3S)3S) two independent channels (e+e− + μ+μ−)two independent channels (e+e− + μ+μ−) physics at HERAphysics at HERA--BB ~50k φφ → KK 1 1.02 1.04 1.06 1.08 mKK [GeV/c2] 4000 3000 2000 1000 0 e n tr ie s (a .u .) •• KKss,, KK **,, ΛΛ,, φφ,, ΞΞ++-- • pentaquarks •• DDoo,, DD++,, DD*+*+,, DDss •• J/J/ψψ ~ 210·106 minimum bias events~ 210·106 minimum bias events ‘hard photon’ trigger: ~ 35·106 events ‘hard photon’ trigger: ~ 35·106 events E d 3 σ /d p 3 [a .u .] MinBias data, run 20478 HP trigger, run 20595 ET [GeV] 0 1 2 3 4 5 6 7 8 pC → γγX 107 105 10 10-3 10-1 103 directdirect γγ,, ππ oo, , ηη production with four different nuclei e+e− μ+μ−μ+μ− 5 J/J/ψψ and and ψ′ψ′ signalssignals e n tr ie s /( 2 5 M e V /c 2 ) m(μ+μ−) [GeV/c2] 103 104 2.8 3.2 3.6 4.0 m(e+e−) [GeV/c2] e n tr ie s /( 3 0 M e V /c 2 ) 103 104 2.5 3.0 3.5 4.0 ~ 120 000 J/ψ ~ 2 200 ψ′ σJ/ψ ~ 64 MeV ~ 120 000 J/ψ ~ 2 200 ψ′ σJ/ψ ~ 64 MeV e+e− full dilepton data sample (3 target materials) J/ψJ/J/ψψ ψ′ψ′ψ′ μ+μ− J/ψJ/J/ψψ ψ′ψ′ψ′ ~ 170 000 J/ψ ~ 3 000 ψ′ σJ/ψ ~ 44 MeV ~ 170 000 J/ψ ~ 3 000 ψ′ σJ/ψ ~ 44 MeV 6 J/J/ψψ productionproduction kinematics: pkinematics: pTT distributiondistribution preliminary data (di-electron channel). Compatible results from the di-muon data, not shown here. comparison with p-A results at similar energy (√s = 38.8 GeV) [a . u .] pT [GeV/c] 2 T d dp σ A 197 184 48 28 12 9 E789 (Au) E789 (Au) E789 (Au) CCC E672/E706 (Be) E672/E706 (Be) E672/E706 (Be) TiTiTi WWW E771 (Si) E771 ( E771 (SiSi)) HERA-BHERAHERA--BB < p T > [G eV /c ] A increase of with A increase of with A C Si Ti Au W Be 7 xxFF distributiondistribution Preliminary data (e+e−), compared with p-A results at 38.8 GeV first data centred at negative xF E789 (Be, Cu) E789E789 (Be, Cu)(Be, Cu) E672/706 (Be) E672/706E672/706 (Be)(Be) E771 (Si)E771E771 ((SiSi)) E789 (Au)E789E789 (Au)(Au) HERA-B (C)HERA-B (C) CC TiTi WW 8AA--dependencedependence xF E866 38.8 GeV Be/Fe/W E789 38.8 GeV Be/C/Cu/W E772 38.8 GeV H2/C/Ca/Fe/W NA50 29.1 GeV Be/Al/Cu/Ag/W NA3 22.9 GeV H2/Pt E866 38.8 GeV Be/Fe/W E789 38.8 GeV Be/C/Cu/W E772 38.8 GeV H2/C/Ca/Fe/W NA50 29.1 GeV Be/Al/Cu/Ag/W NA3 22.9 GeV H2/Pt α - RR. . Vogt, PRC 61 (2000) 035203, NP A700 (2002) 539Vogt, PRC 61 (2000) 035203, NP A700 (2002) 539 -- K.GK.G. . BoreskovBoreskov && A.B. A.B. Kaidalov, Kaidalov, JETPL JETPL 77 77 (2003) 599(2003) 599 B&KB&K B&K Vogt: final state absorptionVogt: final state absorption Models (with variants): 1.0 0.9 0.8 0.7 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 1.0 0.9 0.8 0.7 HERA-B preliminary (di-muon channel, carbon+tungsten double-wire runs) errors statistical only 9 decaydecay angularangular distributiondistribution: : polarizationpolarization framesframes J/ψ direction in the hadron (p-n) CM frame beam direction in the J/ψ rest frame direction of e +(μ+) as seen in the J/ ψ rest frame θ polarization axis bisector between beam and (–)target directions in the J/ψ rest frame Collins-Soper (“CS”)Gottfried-Jackson (“GJ”) “BEAM” helicity “HCM” E615, E672-706 , E771, E537, etc. E866, NA3, etc. CDF, NA60, etc. Il Nuovo Cimento Vol. XXXIII, N. 2 (1964) Phys. Rev. D16, 2219 (1977) target direction in the J/ψ rest frame = (-)J/ψ direction in the lab frame refor mula ted as 1) 2) 3) 10 0 /4π 3 /4π 5 /4π 7 /4π 2π −1/2 1/2 1−1 0 2 1 cos2 3 dN d θλ +∝ + ϕλ ϕ ϕ ϕ cosθ 2 ) 1 ( dN d ∝ + cos cos θ λ θ θ example: 0>ϕλ ( ) dN d d ∝ cos ϕθ 2 21 sin2 sin cos2sincos+ + +θ ϕθϕ θθ θϕ ϕλλλ (x axis reaction plane)⊥ example: 0<θλ parametrizationparametrization =0θϕλ =0θϕλ 11 λλ φφ ~ ~ 00 BEAMBEAMBEAM CSCSCS HB 41.6 GeV p-C/Ti/W NA3 22.9 GeV p-Pt/p-H2 E615 21.8 GeV π±-W p−-W/π−W E537 15.4 GeV p−-Be/π−Be p−-Cu/π−Cu HB 41.6 GeV p-C/Ti/W NA3 22.9 GeV p-Pt/p-H2 E615 21.8 GeV π±-W p−-W/π−W E537 15.4 GeV p−-Be/π−Be p−-Cu/π−Cu / / / / / / // λφ HCMHCMHCM 12 meaningmeaning ofof λλθφθφ The “natural” polarization frame has λλ θφ equal to zero: in such frame the decay distribution is symmetric and is described by only two parameters. polar axisproduction plane 0=θϕλ 0<θλ 0>θλ 0>ϕλ 0>ϕλ λλ θφ ≠ 0 means that the axes of the current frame are not principal axes of symmetry for the angular distribution. But it is always possible to define a reference frame with this property: the angular distribution can always be diagonalized to a form with λλ θφ = 0 0=θϕλ 0<θϕλ 0<θϕλ 13 λλθφθφ in in thethe threethree framesframes [GeV/c] λθφ BEAM CS HCMBEAM BEAM CS CS HCMHCM μ μ+ − + −+e e ,<∼ θϕ θϕϕθ λλ λ,<∼ θϕ θϕϕθ λλ λ preliminary, ⇒ The three frames actually see the decay kinematics from different perspectives CS the best frame? (statistically ~100% correlated) 14 dN d(cosθ) cosθ 1 N μ μ+ − + −e e cosθ λλθθ andand thethe hierarchyhierarchy ofof framesframes BEAM (arb. norm.) BEAM BEAM ((arbarb. norm.). norm.) HCM (arb. norm.) HCMHCM ((arbarb. norm.). norm.) CSCSCS preliminarydN/d(cosθ) ∝ 1 + λθ cos2θdN/d(cosθ) ∝ 1 + λθ cos 2θ |λθ| |λθ| |λθ| > > μ μ+ − + −+e e preliminary μ μ+ − + −+e e [GeV/c] HCM BEAM CSHCM HCM BEAM BEAM CSCSλθ 15 [GeV/c] The data are consistent (for example) with a polarization generated in the CS frame interpretationinterpretation polarization generated polarization generated in the CS framein the CS frame …… and translated into and translated into the HCM framethe HCM frame λθ points = data, lines = Toy MC [GeV/c] generation in generation in the HCM framethe HCM frame CSCS exp CM/1 (2GeV/ )J cψ ⎡ ⎤=− ⋅ −⎢ ⎥⎣ ⎦θλ p HCM CS HCM HCM CSCS λθ The CS frame is the best approximation of the “natural” polarization frame → physics: origin of J/ψ polarization No hypothesis of generation in the HCM fr. can reproduce the data in the CS fr. case 1 case 2 16 experimental situation: CS frameexperimental situation: CS frame J/ψ significantly polarized at low momentum (low pT and |xF|) λθ E866 38.8 GeV p-Cu E444 20.6 GeV π±-C/Cu/W NA3 22.9 GeV p-H2 NA3 22.9 GeV p-Pt HB 41.6 GeV p-C/Ti/W E866 38.8 GeV p-Cu E444 20.6 GeV π±-C/Cu/W NA3 22.9 GeV p-H2 NA3 22.9 GeV p-Pt HB 41.6 GeV p-C/Ti/W 17 BEAM frameBEAM frame λθ WA11 16.8 GeV π−-Be 31.1 GeV π−-Be 31.6 GeV p-Be 38.8 GeV p-Be E771 38.8 GeV p-Si E615 21.8 GeV π±-W HB 41.6 GeV p-C/Ti/W WA11 16.8 GeV π−-Be 31.1 GeV π−-Be 31.6 GeV p-Be 38.8 GeV p-Be E771 38.8 GeV p-Si E615 21.8 GeV π±-W HB 41.6 GeV p-C/Ti/W E672 /706 E672 /706 p−-W/π−W / p−-Be/π−Be / p−-Cu/π−Cu / p−-W/π−W / p−-Be/π−Be / p−-Cu/π−Cu / E537 15.4 GeV E537 15.4 GeV 18 HCM frameHCM frame polarization almost completely smeared out, except for pT very close to zero λθ E444 20.6 GeV π±-C/Cu/W CDF 1800 GeV p−-p Run II WA92 25.7 GeV π±-W/Cu/Si NA60 17.3A GeV In-In HB 41.6 GeV p-C/Ti/W E444 20.6 GeV π±-C/Cu/W CDF 1800 GeV p−-p Run II WA92 25.7 GeV π±-W/Cu/Si NA60 17.3A GeV In-In HB 41.6 GeV p-C/Ti/W 19 ψ′ψ′--toto--JJ//ψψ production ratioproduction ratio p-A results consistent within a 4% variation: no apparent dependence on production energy and kinematics (different xF/y, cosθ windows) slight dependence on the target nucleus: NA38/50/51 (+ E866) J/J/ ( (W) (Ti) )% % C % B B 1.63±0.08 1.99 ±0.26 1.62±0.11 ψψ ψ ψψ σ σ ρ + − + − ′′→ ′ → + − ⎧⎪⎪⎪= =⎨⎪⎪⎪⎩ e e Analysis finished. Combined results (e+e- + μ+μ-): 238 184 28 197 12 184 12 1 2 9 27 64 108 184 HERA-BHERAHERA--BB HERA-BHERAHERA--BB E771E771E771 E789E789E789E705E705E705 NA38, NA50 & NA51 NA38, NA38, NA50 & NA50 & NA51NA51 [GeV]s 6 12 9 E331E331E331 E444E444E444 E288E288E288 B ′σ (ψ ′) /B σ (J /ψ ) (% ) 12 NA38NA38NA38 p-A 48 HERA-BHERAHERA--BB )(= 7.0 ± 0.2 ± .4 %0 BRs 0 0 0 J/ J/ J/ J/ J/ + −⎧⎪⎪⎪⎪⎪⎨⎪⎪⎪⎪⎪⎩ + − + − → ′→′ ′→ = × ⋅′ B B B R ψπ πψπ π ψ η ψπ ψ ψψ ψ ψ ρ 20 ψ′ψ′ kinematicskinematics measured relative to the J/ψ distributions: B′σ(ψ′)/Bσ(J/ψ) as a function of xF. pT , cosθ HERA-B (full stat, e+e-/μ+μ- avg.)HERAHERA--B B (full stat, (full stat, ee++ee--//μμ++μμ-- avg.)avg.) E771 (38.8 GeV)E771 (38.8 GeV) NA50 (29.1 GeV)NA50 NA50 (29.1 GeV) E789 (38.8 GeV)E789 (38.8 GeV) xF pT [GeV/c] ( ) ( / ) 0.23 0.17′ − = ±Jθ θλ ψ λ ψ B ′σ (ψ ′) /B σ (J /ψ ) cosθ B ′σ (ψ ′) /B σ (J /ψ ) 21 measurement: fraction of J/ψ’s from χc: kinematical distributions A-dependence χχcc productionproduction ( ) INCL ( J/ ) (J/ ) c iRχ σ χ ψγ σ ψc → = ∑ selection: J/χ γψc {e eμ μ + − + − e n tr ie s /( 10 M e V /c 2 ) m(μ+μ−γ)-m(μ+μ−) [GeV/c2] background: mixed events after background subtraction from the 2000 data, with 370 ± 74 χc’s (μ +μ− + e+e−): R(χc) = 0.32 ± 0.06 ± 0.04 [Phys. Lett. B 561, 61 (2003)] new data: 40× bigger χc statistics (the largest analyzed in a hadronic experiment) preliminary 2002/2003 data (di-muon sample) 22 RR((χχcc)) preliminary evaluation (2002/2003 data): based on 1300 χc’s reconstructed in the di-muon channel (less than 10% of the total statistics) (21 ± 5)% of the produced J/ψ’s come from χc decays [GeV]s (%) ( )cR χ expected final precision CDF CDF ((pp--pp)) ISR ISR ((pp--pp)) E771 E771 ((pp--SiSi)) E705 E705 ((pp--LiLi)) E369/ E369/ 610/ 610/ 673 673 ((pp--BeBe)) 2002/3 2002/3 prelim.prelim. ππ--AA HERAHERA--BB 20002000 23 J/J/ψψ’s from b decays’s from b decays pA → bb X b → J/ψ Y → e+e-/μ+μ- Y detached J/ψ’s mμμ 46.2 ± 8.246.2 ± 8.2 36.9 ± 8.136.9 ± 8.1 μ μ+ − + −e e TOT ( ) (J/ ) (0.065 0.011) J % / b N N bR ± ← = = ψ ψ - extrapolation to full xF range - normalization by total J/ψ cross sect. - correction by BR of b → J/ψ σ(bb) = 14.9 ± 2.2stat±2.4syst nb/nucleon [Phys. Rev. D 73, 052005] σ (b b ) (n b /n u c le o n ) proton energy (GeV) N. Kidonakis et al.HERA-BHERA-B E789E789 E771E771 R. Bonciani et al. 400 500 600 700 800 900 1000 1 10 102 mee 24 E771E771 E789E789 ISRISR E 6 72 /70 6 E 6 72 /70 6 N A 5 0 N A 5 0 E 5 9 5 E 2 8 8 E 5 9 5 E 2 8 8 E705E705 UA6UA6E444E444 E331E331 NA3NA3 NA3NA3 E331E331 / / 1 R R R ⎡ ⎤ ⎢ ⎥= − − − −⎢ ⎥⎣ ⎦ J DIR J INCL … ψ ψσ σ indirect and direct J/ψ productionindirect and direct J/ψ production (21 ± 5)% χc J/ψ ψ′ J/ψ b J/ψ (7.0±0.4)% (0.065±0.011)%(to be improved!) extracted from MB data [ ] ( )± ±stat syst J/ nb/nucl41.6 GeV = 663 74 46ψσ pN (72 ± 5)% of the J/ψ’s are produced directly Using partial/preliminary HERA-B results: curve: NLO NRQCD fit of all data (Maltoni et al., hep-ph/0601203) p-p p-A 25 Kππ inv. mass [GeV/c2] e n tr ie s /( 10 M e V /c 2 ) e n tr ie s /( 10 M e V /c 2 ) Kπ inv. mass [GeV/c2] open charm: reconstructedopen charm: reconstructed signalssignals 194 ± 20 preliminarypreliminary p r e li m in a r y p r e li m in a r y p r e li m in a r y p r e li m in a r y 92 ± 11 D± D*±D0+D0 m(Kππ)-m(Kπ) [GeV/c2] e n tr ie s /( 0 .5 M e V /c 2 ) 49 ± 10 | ( ) ( )| 50 MeVm K mπ − <0D | ( ) ( )| 50 MeVm K mπ − >0D p N D+ K − π+ π+ 0D K− π+ p N p N 0D K− π+ π+ +*D 26D cross sectionsD cross sections D0: unclear situation at high √s E789 result clearly disfavoured energy dependence well described in each case by the function reflecting the behaviour of proton PDFs (Lourenço & Wöhri) 0.35 12[1 1.2 /( ) ]D sσ ∝ − without E789: with E789: D0+D0 √ HERA-B prel. D± √ HERA-B prel. D*± √ HERA-B prel. comparison with pwith p--p/pp/p--A resultsA results 27 σ σ σ+ ∗= =0DIR DIR 1 3 ( ) ( ) ( )D D D cross section ratios: experiments vs. isospin symmetrycross section ratios: experiments vs. isospin symmetry u ↔ d 3 polar. states 0 INCL INCL( ) / ( 0.326 ) 0.003 D Dσ σ± ±= 0 INCL INCL( ) / ( 0.497 0.001 )D Dσ σ∗± ±= PDG averages for D*0, D*± → D0, D± feeddown BRs violated by a factor of 1.87 ± 0.25 is o s p in s y m m e tr y e x p e r im e n ts u ↔ d D*±/D0 √ 0.43 0.09.avg ±= HERA-B prel. u ↔ d D±/D0 √ 0.61 0.08.avg ±= HERA-B prel. 28 AA--dependencedependence ααAVG.AVG.((xxFF~0) =~0) = 1.01 ± 0.031.01 ± 0.03 experimental situation (p-A): mass spectra by target material (e.g. for D0): e n tr ie s /( 10 M e V /c 2 ) Kπ inv. mass (GeV/c2) C Ti W 70 ± 11 19 ± 6 103 ± 14 (prel. D-meson average) C Ti W curves: σpA = σpN·A α consistent with no suppression αα((DD00)= 0.92±0.08)= 0.92±0.08 αα((DD±±)= 1.02±0.09)= 1.02±0.09 αα((DD**±±)= 1.05±0.14)= 1.05±0.14 29 summarysummary J/J/ψψ production production in in pp--AA collisions at √collisions at √ss = 41.6 = 41.6 GeVGeV …… …… and its components:and its components: high statistics, clean signals, two decay channels wide kinematical coverage pT up to 5.5 GeV/c negative xF A-dependence: flat suppression down to xF ~ -0.35 ψ′-to-J/ψ ratio fraction of J/ψ’s from χc fraction of J/ψ’s from b 300000 J/ψ’s300000 J/300000 J/ψψ’s’s 15000 χc’s 15000 15000 χχcc’s’s 5000 ψ′’s50005000 ψψ′′’s’s 80 J/ψ’s from b80 80 J/J/ψψ’’s from bs from bJ/J/ψψ decay decay angular distributionsangular distributions D0, D±, D*± inclusive production cross sections and ratios A-dependence consistent with α = 1 open charmopen charm longitudinal polarization rapidly increasing in magnitude with decreasing pT and |xF| strong hierarchy of frames: the direction of the original interaction (CS frame) is better than the J/ψ “flight” direction (HCM) as a reference for the observation of the “true” decay distribution