φ and ω decay modes ratios

φ and ωdecay modes ratios Possible rescattering of hadronic daughters  Reconstruction probability decrease for hadronic mode ω(782) π+ π-π0B.R. 0.89 (c = 23 fm) ω(782) π+ π-B.R. 0.017 ω(782) π0B.R. 0.089 ω(782) e+e-B.R. 0.000072 φ(1020) K+ K-B.R. 0.49 (c = 44 fm) φ(1020) ηB.R. 0.013 φ(1020) e+e-B.R. 0.000297 Stavinskiy,13.09.08

Decay modes ratios- new source of information t hadrons with &without QGP quarks&gluons

Model l0~cτβ/√(1-β2) ~ ~(β=1/3 for this estimate)~ ~15fm(for φ)&8fm(for ω) li~2fm for any hadron & 1fm for any pair of hadrons li l0 η η φ  l hadronization Kinetic freeze-out

Results • Upper line – lepton mode Splitting – two hadron and hadron-photon modes l -decay products trajectory length within matter φ β= 1/3 ω Stavinskiy,13.09.08 l,fm

PHENIX STAR Au+Au √sNN = 200 GeV ω π0 f e+e- Is it really possible measurements?

Extended f  K+K- analysis Consistency between f  K+K- and f e+e- f Double ID analysis K+ K- f candidates d+Au no ID analysis 0-20% h+ h- f candidates No ID Single ID Double ID No ID Single ID Double ID e+e- Single ID analysis M.B. p+p K+ or K- h+ or h- f candidates f d+Au 0-20% M.B. p+p • fK+K- measurements have been extended to both higher and lower pT using new methods, i.e. no kaon ID and single kaon ID methods. • The three independent kaon analyses are consistent with each other. In p+p, spectra of e+e- and K+K- show reasonable agreement!

Low pT mesons tend to decay inside the hot/dense matter f f Low pT High pT Thus, pT-dependent information is essential for comparison.

Spectra comparison between fe+e- and f K+K- f e+e- AuAu MB f e+e-20-40% x 10-3 fe+e- 40-92% x 10-1 f K+K- AuAu MB (no PID) f K+K- AuAu MB (double PID) fK+K- AuAu MB (PRC72 014903) f K+K- 20-40% x 10-3 (double PID) f K+K- 40-92% x 10-1 (double PID) fK+K-40-92% x 10-1 (PRC72 014903) Au+Au M.B. 40-92% 20-40% Errors are too large to make any clear statement about the comparison of spectra for f  e+e- and f  K+K-.

Φ information early stages of the collision • Φ  different production for hadronic and leptonic channels • K*  time between chemical and kinetic freeze-out π K* K K* measured π K* K*lost K π K* π π K* K K K K* measured S. Pal et al., Nucl.Phys. A707 (2002) 525-539 • If resonance decays before kinetic freeze-out  not reconstructed due to rescattering of daughters • K*0(c = 4 fm)survival probability timebetween chemical and kinetic freeze-out, source size and pT of K*0 • Chemical freeze-out elastic interactionsπK  K*0 πKregenerate K*0(892)until kinetic freeze-out • K*0/K may reveal time between chemical and kinetic freeze-out Chemical freeze-out Kinetic freeze-out P. Fachini BNL,SQM2007

STAR K*  Ratios Chemical freeze-out Kinetic freeze-out Chemical = Kinetic freeze-out • K*/K- p+p ratio reproduced by thermal model at chemical freeze-out  Au+Aureproduced by thermal model at kinetic freeze-out

Y. Nakamiya Hiroshima University, Japan for the PHENIX collaboration QM 2008, India Branching ratio between e+e- and K+K- may be sensitive to mass modification, since Mphi is approximately 2  MK. -> Compare yields of fe+e- and f K+K-

ΦProduction K+K- and e+e- e+e- K+K- • The leptonic channel yield is a little higher than hadronic channel • More accurate measurement is required to confirm whether there is branch ratio modification

What is the difference? • Modes absorbtion vs Mass modification • Standard mesons vs modified mesons • φ→KK & φ→η • Modes absorbtion vs K/K* ratio • Reference- Lepton modes vs thermal model • Hadronization stage vs equilibrium stage • Modes absorbtion vs both other approaches • Internal cross-check - 3 modes Stavinskiy,ITEP,13.09.08

Real σMN in matter can differ from that in free space • ω photoproducton on nuclear targets (ELSA) M.Kotulla et al., ArXiv: nucl-ex/08020980 σωN ≈ 70 mb (in nuclear medium, 0.5 < P <1.6 GeV/c) σωN ≈ 25 mb (in free space - the model calculations) •  photoproducton on nuclear targets T.Ishikawa et al., Phys.Lett.B608,215,(2005) σφN= 35 ± 14 mb (in nuclear medium) σφN ≈ 10 mb (in free space) “φ-puzzle” photoproducton on nuclear targets

To Do • To make calculationsfor the effect of interest within realistic model • To create algorithm for photonic modes identification in AA interactions • To check this algorithm for ALICE&CBM conditions with realistic simulations Stavinskiy,ITEP,13.09.08

Extra slides

Formulas Stavinskiy,ITEP,10.06.08

e+ e- f,w Momentum Electron ID gEnergy g p0 g p0 g g K+ p+ w f K- p- g Hadron ID Momentum Momentum Hadron ID Electron, hadron and photon in PHENIX f/w  e+e- • PHENIX acceptance -0.35 < η < 0.35 2 x 90°in azimuthal angle for two arms • Event selection BBC • Electron ID RICH EMCal • photon ID EMCal • Hadron ID TOF EMCal-TOF w p+p-p0, p0g f  K+K-

Why  ?(common part) Themeson was proposed in the middle of 80’(Koch,Muller,Rafelski PR142,ShorPRL54) as one of the most promising QGP messengers because of the following reasons: • an enhancement of –meson, as well as other strange hadrons in QGP phase • interaction cross section is small and will keep information about the early hot and dense phase • meson spectrum is not distorted by feeddown from resonance decays • strangeness local conservation for  Stavinskiy,ITEP,9.04.08

φ and ω decay modes ratios