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ϕ and K masses/widths in p+p at 7/0.9 TeV

ϕ and K masses/widths in p+p at 7/0.9 TeV. Sergey Kiselev, ITEP Moscow Motivation Input info ϕ  K + K - K *0 /anti-K *0  K π Δ ++  p π - , ρ 0  π + π - Summary and next steps Results for pass2 at 7 and 0.9 TeV Summary and recommendations. Δ ++ JPG35(2008)0412019.

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ϕ and K masses/widths in p+p at 7/0.9 TeV

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  1. ϕ and K masses/widths in p+p at 7/0.9 TeV • Sergey Kiselev, ITEP Moscow • Motivation • Input info • ϕ  K+ K- • K*0/anti-K*0 K π • Δ++  p π-, ρ0 π+π- • Summary and next steps • Results for pass2 at 7 and 0.9 TeV • Summary and recommendations ALICE week, PWG2, CERN S.Kiselev

  2. Δ++ JPG35(2008)0412019 Motivation RHIC data channel B.R.(%) c (fm)Δm (MeV) a1(1260) π  ~0.5 0.5 ρ0(770)π+ π-~100 1.3 -40 Δ++(1232)  p π+~100 1.6 -40 f0(980) π+ π- 66 2.6 - K*(892) πK ~100 4 -10 Σ*(1385)  Λπ 88 5.5 0 Λ*(1520) p K45 12.6 0 Ξ*(1530) Ξπ~100 21 0 ω(782)  π+ π- π089 23 0 ω(782) π0 9 23 0 ω(782) e+e-7 10-223 in prog. ϕ(1020) K+ K-49 44 0 ϕ(1020) e+e-3 10-244 in prog. K*0 PRC71(2005)064902 ρ0PRL92(2004)0307023 - mass shift for very short-lived resonances (cτ< 5 fm) was observed even in p+p. - Possible explanations: re-scattering effects, Bose-Einstein correlations, … - there are theoretical speculations that at LHC energies “medium”/”collective state” can be created even in p+p ALICE week, PWG2, CERN S.Kiselev

  3. input info the AliRsn package, test macros for analysis on CAF/SKAF (thanks to Alberto): … const char *inputSource = "/ALICE/pp007000/LHC10b_000115XXX", … I-AliRsnAnalysisSE::Terminate: Number Of Events Processed : 2450000 I-AliRsnAnalysisSE::Terminate: Number Of Events Accepted : 1536647 … gProof->EnablePackage("VO_ALICE@AliRoot::v4-19-05-AN",kTRUE); … // -- Set prior probabilities … kElectron, 0.02 … kMuon, 0.02 … kPion, 0.83 … kKaon, 0.07 … kProton, 0.06 … AliRsnPair::EPairType pidType = AliRsnPair::kRealisticPID; … cutESDPrimary->GetCuts()->SetMaxCovDiagonalElements(2.0, 2.0, 0.5, 0.5, 2.0); cutESDPrimary->GetCuts()->SetRequireSigmaToVertex(kTRUE); cutESDPrimary->GetCuts()->SetMaxNsigmaToVertex(4.0); cutESDPrimary->GetCuts()->SetMinNClustersTPC(80); cutESDPrimary->GetCuts()->SetMaxChi2PerClusterTPC(3.5); … // --> add axes … axisIM … axisPt … axisEta // -- pairs --> window in eta … kEta, -0.9, 0.9 ALICE week, PWG2, CERN S.Kiselev

  4. ϕ  K+ K- : unlike/like-sign pairs will fit US - LSN ALICE week, PWG2, CERN S.Kiselev

  5. ϕ  K+ K- : signal fit E917/AGS Phys.Rev.C69(2004)054901 Relativistic Breit-Wigner (RBW) convolved with a Gaussian resolution function (RF). σm = 1 MeV has been used by STAR ALICE week, PWG2, CERN S.Kiselev

  6. ϕ  K+ K- : pT dependence RBW&RF(σm=1 MeV) fit ϕ mass and width agree with the PDG values ALICE week, PWG2, CERN S.Kiselev

  7. K*0/anti-K*0 K π : unlike/like-sign pairs The LS shape in not ~ the shape of US bkg. Will fit US - LS ALICE week, PWG2, CERN S.Kiselev

  8. K*0/anti-K*0 K π : signal fit STAR/RHIC Phys.Rev.C71(2005)064902 Relativistic Breit-Wigner (RBW) times the Boltzmann factor to account for phase space (PS) plus residual background (RBG) : RBW x PS + RBG RBW = for p+p Tfo = 160 MeV has been used by STAR ALICE week, PWG2, CERN S.Kiselev

  9. K*0/anti-K*0 K π : signal fit RBG is fitted by a polynomial of degree 3, PS(pT = 1 GeV/c) PS factor: mass 887 MeV  891 MeV, widths agree to within errors ALICE week, PWG2, CERN S.Kiselev

  10. K*0/anti-K*0 K π : pT dependence RBW PS(pT = middle of PT bin,Tfo = 160 MeV) +P3 PT < 1 GeV/c: Δm ~ -10 MeV, smaller width ? but syst.error ~ 10 MeV (STAR) ALICE week, PWG2, CERN S.Kiselev

  11. Δ++  p π- , ρ0 π+π- Δ++  p π-– unlike/like-sign pairs include Δ0 /Δ++ resonances  mixed events technique is needed Year ago there was such a possibility in the AliRsn package One can hope it will be soon again ρ0 π+π- - analysis of other resonances contributions is needed ρ0PRL92(2004)0307023 ALICE week, PWG2, CERN S.Kiselev

  12. Summary and next steps Mass/width analysis of ϕ and K*0 for 1.5 106 p+p @ 7 TeV events has been made with the AliRsn package: - ϕ mass and width agree with the PDG values - K*0 mass at PT < 1 GeV/c lower the PDG value, Δm ~ -10 MeV, as it was observed at RHIC Next steps: - p+p @ 900 GeV events - improve PID - the K*0 analysis for high multiplicity p+p events. - Δ++ (Δ0 ) mass/width with the mixed event technique in the AliRsn package. ALICE week, PWG2, CERN S.Kiselev

  13. Results for pass2 at 7 and 0.9 TeV AliEn p+p @ 7 TeV, runs with > 106 events: 115322, 115328, 115393, 117060, 117109, 117222 ~ 9 106 events at all p+p @ 900 GeV, pass2_recovery_900GeV,runs with > 106 events: 118506, 118557, 118558, 118560 ~ 7 106 events at all ALICE week, PWG2, CERN S.Kiselev

  14. 7 TeV/pass2: ϕ  K+ K- RBW&RF(σm=1 MeV) fit ϕ mass and width agree with the PDG values ALICE week, PWG2, CERN S.Kiselev

  15. 7 TeV/pass2: K*0/anti-K*0 K π, unlike/like-sign pairs will fit US - LSN ALICE week, PWG2, CERN S.Kiselev

  16. 7 TeV/pass2: K*0/anti-K*0 K π : signal fit RBG is fitted by a polynomial of degree 2, PS(pT = 1 GeV/c) PS factor: ΔmPS = + 2 -3 MeV ALICE week, PWG2, CERN S.Kiselev

  17. 7 TeV/pass2: K*0/anti-K*0 K π, pT dependence RBW PS(pT = middle of PT bin,Tfo = 160 MeV) +P2 PT < 2 GeV/c: Δm = - 6 MeV ALICE week, PWG2, CERN S.Kiselev

  18. 900 GeV/pass2: ϕ  K+ K- RBW&RF(σm=1 MeV) fit ϕ mass and width agree with the PDG values ALICE week, PWG2, CERN S.Kiselev

  19. 900 GeV/pass2: K*0/anti-K*0 K π, unlike/like-sign pairs will fit US - LSN ALICE week, PWG2, CERN S.Kiselev

  20. 900 GeV/pass2: K*0/anti-K*0 K π : signal fit RBG is fitted by a polynomial of degree 2, PS(pT = 1 GeV/c) PS factor: ΔmPS = 2 - 4 MeV ALICE week, PWG2, CERN S.Kiselev

  21. 900 GeV/pass2: K*0/anti-K*0 K π, pT dependence RBW PS(pT = middle of PT bin,Tfo = 160 MeV) +P2 PT < 2 GeV/c: Δm = - 4 MeV ALICE week, PWG2, CERN S.Kiselev

  22. Summary and recommendations Mass/width analysis of ϕ and K*0 for p+p @ 7 TeV and 900 GeV: - ϕ mass and width agree with the PDG values - K*0 width is in agreement with the PDG value mass: ΔmPS = 2 - 4 MeV at PT < 1-2 GeV/c Δm ~ - 5 MeV Hint: at LHC energies there is K*0 mass shift as it was observed at RHIC Recommendations: would like to have - the standard PID procedure for an analysis - the mixed event technique in the AliRsn package. ALICE week, PWG2, CERN S.Kiselev

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