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Short-lived resonances with TOF. S.Kiselev, ITEP 22.01.08 Bologna. Short-lived resonances. channel B.R.(%) c (fm) RHIC data Δ m (MeV) ALICE studies. a 1 (1260) π ~0.5 0.5 ρ 0 (770) π + π - ~100 1.3 p+p/d+A/Au+Au -70 p+p/Au+Au
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Short-lived resonances with TOF S.Kiselev, ITEP 22.01.08 Bologna
Short-lived resonances channel B.R.(%) c (fm)RHIC dataΔm (MeV)ALICE studies a1(1260) π ~0.5 0.5 ρ0(770)π+ π-~100 1.3 p+p/d+A/Au+Au -70 p+p/Au+Au Δ++(1232) p π+ ~100 1.6 p+p/d+Au -40 f0(980) π+ π- 66 2.6 K*(892) πK ~100 4 p+p/d+Au/Au+Au -10 p+p/Au+Au Σ*(1385) Λπ 88 5.5 p+p/d+Au/Au+A 0 Λ*(1520) p K45 12.6 p+p/d+Au/Au+Au 0p+p/Au+Au Ξ*(1530) Ξπ~100 21 p+p/d+Au/Au+Au 0 ω(782) π+ π- π089 23 p+p/d+Au 0 ω(782) π0 9 23 p+p/d+Au/Au+Au 0 ω(782) π+ π- 2 23 ω(782) e+e-7 10-223 p+p/d+Au/Au+Au in prog. Φ(1020) K+ K-49 44 p+p/d+Au/Au+Au 0 p+p/Au+Au Φ(1020) e+e-3 10-244 p+p/d+Au/Au+Au in prog. Life Time
a1(1260) πγ • Volker Koch, workshop on dileptons at CBM, GSI, 2007: • in the case of afull restoration of the symmetry the spectral functions oftheρmeson and its chiral partner the a1 meson becomedegenerate. • it has been proposed to measure the a1 mass spectrumin a hot and dense medium and compare it to the massspectrum of the ρmeson • If the degeneracy wouldbe observed it is expected to serve as an unambigiousexperimental signal for the detection of chiral symmetryrestoration in the hot and dense medium. • But: width 250 to 600 MeV
Nuclear Modification Ratios (RCP) for resonances f0(980) RHIC results have shown as, in the intermediate pt region, nuclear modification factors depend on the constituent quarks rather than on particle mass. Recent suggestion by Maiani et al. (Phys. Lett. B645(2007)138) to use this observable to solve the problem of the real quark composition of some resonances as the fo(980)( or ?) A. Badalà- SQM07- Levoča – 24/06/-29/06/07
f0 (980) π+π-, ω(782) π+π- STAR Preliminary STAR Preliminary 20-40% dAu 0.6 ≤ pT < 0.8 GeV/c 40-100% dAu 0.6 ≤ pT < 0.8 GeV/c √sNN = 200 GeV √sNN = 200 GeV STAR Preliminary STAR Preliminary 40-80% Au+Au 0.6 ≤ pT < 0.8 GeV/c 0-20% dAu 0.6 ≤ pT < 0.8 GeV/c √sNN = 62 GeV √sNN = 200 GeV
ω(782) π+π- π0 • One arm PHOS: only high pt π0
Summary • Can be added to the ALICE list of short-lived resonance studies: a1, Δ++/ Δ--, ω