S. V. Greene

Analysis of three D → Kππ Dalitz plots

Abstract Analysis of three D → Kππ Dalitz plots is presented using data collected by the Fermilab high energy photoproduction experiment E687. Our data are fit to a model consisting of a sum of Breit-Wigner amplitudes for the intermediate two-body resonant decay modes and a constant term for the nonresonant contribution. We extract branching fractions and relative phases and compare them to the results obtained in other experiments. Although this model qualitatively reproduces many features of our data, statistically significant discrepancies are observed in some of our fits.

Analysis of the decay mode D+ → K∗0μ+ν

Abstract Fermilab high-energy photoproduction experiment E687 provides a high statistics sample of the decay mode D + → K ∗0 μ + ν (charge conjugates are implied). Our analysis yields a branching ratio of Γ (D + → K ∗0 μ + ν) Γ (D + → K − π + π + ) = 0.56±0.04±0.06 . The ratios of the form factors governing the decay are measured to be R ν = 1.74 ±0.27±0.28 and R 2 = 0.78±0.18±0.10, implying a polarization of Γ l Γ t = 1.20±0.13 ±0.13 for the electron decay. Finally, we report new limits on the decay modes D + → K − π + μ + ν (nonresonent) and D + → K ∗0 π 0 μ + ν .

First evidence of

Abstract We report evidence of a narrow resonance at a mass of 2705.9 ± 3.3 ± 2.0 MeV/c2 in the final state Ω−π+ and the charge conjugate. The mass and width support the interpretation of a weakly decaying doubly strange charmed baryon, the Ω c 0 . Limits on the relative branching ratios for Ω c 0 →Ω − K − π + π + and Ω c 0 →Ω − π − π + π + are also presented.

Measurement of pion enhancement at low transverse momentum and of the Δ resonance abundance in Si-nucleus collisions at AGS energy

Abstract We present measurements of pion transverse momentum ( p t ) spectra in central Si-nucleus collisions in the rapidity range 2.0 y p t down to and including p t = 0. The data exhibit an enhanced pion yield at low p t compared to what is expected for a purely thermal spectral shape. This enhancement is used to determine the Δ resonance abundance at freeze-out. The results are consistent with a direct measurement of the Δ resonance yield by reconstruction of proton-pion pairs and imply a temperature of the system at freeze-out close to 140 MeV.We present measurements of the pion transverse momentum (p_t) spectra in central Si-nucleus collisions in the rapidity range 2.0<y<5.0 for p_t down to and including p_t=0. The data exhibit an enhanced pion yield at low p_t compared to what is expected for a purely thermal spectral shape. This enhancement is used to determine the Delta-resonance abundance at freeze-out. The results are consistent with a direct measurement of the Delta-resonance yield by reconstruction of proton-pion pairs and imply a temperature of the system at freeze-out close to 140 MeV.

Analysis of the D+, Ds + → K+K-π+ Dalitz plots

Abstract Amplitude analyses of the D + and D s + → K + K − π + Dalitz plots are presented using data collected by the Fermilab high energy photoproduction experiment E687. Our data are fit to a model consisting of a sum of Breit-Wigner amplitudes for the intermediate two-body resonant decay modes. We extract decay fractions and relative phases. These results are used to infer new branching ratios for D + → K + K − π + inclusive as well as the Φπ + and K ∗ (892) 0 K + channels.

Analysis of the decay mode D+ ---> anti-K*0 mu+ neutrino

Abstract Fermilab high-energy photoproduction experiment E687 provides a high statistics sample of the decay mode D + → K ∗0 μ + ν (charge conjugates are implied). Our analysis yields a branching ratio of Γ (D + → K ∗0 μ + ν) Γ (D + → K − π + π + ) = 0.56±0.04±0.06 . The ratios of the form factors governing the decay are measured to be R ν = 1.74 ±0.27±0.28 and R 2 = 0.78±0.18±0.10, implying a polarization of Γ l Γ t = 1.20±0.13 ±0.13 for the electron decay. Finally, we report new limits on the decay modes D + → K − π + μ + ν (nonresonent) and D + → K ∗0 π 0 μ + ν .

Search for strange quark matter in high-energy heavy-ion collisions

Abstract We have initiated a search for strange quark matter in the products of 14.6 GeV/ c per nucleon 28 Si collisions with nuclei, utilizing the apparatus of E-814 at Brookhaven National Laboratorys AGS. We report the first results of this search, which is sensitive to particles with charge-to-mass ratios between 0.1 and 0.3 (GeV/ c 2 ) −1 that are produced within approximately ±0.5 units of the center of mass rapidity.

First evidence of Ωc0→Ω−π+

Abstract We report evidence of a narrow resonance at a mass of 2705.9 ± 3.3 ± 2.0 MeV/c2 in the final state Ω−π+ and the charge conjugate. The mass and width support the interpretation of a weakly decaying doubly strange charmed baryon, the Ω c 0 . Limits on the relative branching ratios for Ω c 0 →Ω − K − π + π + and Ω c 0 →Ω − π − π + π + are also presented.

First measurement of the lifetime of the omega(c)0.

Abstract We present the first measurement of the lifetime of the Ω c 0 baryon. The data were collected in the Fermilab high energy photoproduction experiment E687. The measured lifetime is τ = 86−20+27(stat.) ± 28(syst.) fr. Thus the Ω c 0 has one of the shorter lifetimes among the weakly decaying singly charmed baryons.

Evidence for expansion of a hot fireball from two-pion correlations for Si + Pb collisions at AGS energy

Abstract The two-pion correlation function has been measured for charged pions produced in central 14.6 A GeV/ c Si + Pb collisions at the AGS. Data for like-sign pions show a clear quantum interference effect as expected for identical bosons. The experimental correlation function agrees well with that obtained for events generated by a cascade code (RQMD). The present data are consistent with a time-averaged rms freeze-out radius of 8.3 fm and a mean duration of pion emission of 9 fm/ c . The system has expanded considerably before freeze-out.