D. Garelick

Production of charm mesons at high transverse momentum in 515-GeV/c pi- nucleon collisions

We present results on the production of high transverse momentum charm mesons in collisions of 515 GeV/c negative pions with beryllium and copper targets. The experiment recorded a large sample of events containing high transverse momentum showers detected in an electromagnetic calorimeter. From these data, a sample of charm mesons has been reconstructed via their decay into the fully charged K pi pi mode. A measurement of the single inclusive transverse momentum distribution of charged D mesons from 1 to 8 GeV/c is presented. An extrapolation of the measured differential cross section yields an integrated charged D cross section of 11.4+-2.7(stat)+-3.3(syst) microbarns per nucleon for charged D mesons with Feynman x greater than zero. The data are compared with expectations based upon next-to-leading order perturbative QCD, as well as with results from PYTHIA. We also compare our integrated charged D cross section with measurements from other experiments.

Dimuon production by protons in Tungsten

The mass spectrum of dimuons produced by 400 GeV/c protons in Tungsten has been measured for masses greater than 7 GeV. A clear resonant signal of 2700 upsilons has been seen. The dependence of dimuon production on xF and pT has been determined for dimuon masses in the range 7.0 to 8.25 GeV as well as for masses in the upsilon region 8.25 to 9.75 GeV.

Measurements of Missing Mass (MM) Spectra from π−p ⇒ (MM)−p at 8, 11, 13.5, and 16 GeV

Measurements of missing mass (MM) spectra from π − p ⇒ ( MM ) − p at 8, 11, 13.5, and 16 GeV are reported. The MM mass range examined is 0 ≤ M 2 ≤ 7.3 GeV 2 with t (the proton four momentum transfer squared) in the interval 0.2 ≤ ∣ t ∣ ≤ 0.3 GeV 2 . Narrow resonances (R1, R2, R3, S, T, and U) with cross sections and widths reported by the CERN missing mass group are ruled out by the data. The cross sections d 2 σ/ dtdM 2 show evidence for triple factorizability of the form d 2 σ dtdM 2 ≃ D ( P B ) A ( M 2 ) G ( P ⊥ 2 ) where P B is the incident beam momentum,and P ⊥ 2 is the perpendicular component of the detected protons momentum with respect to the beam direction.

Missing-mass search for negative-charge bosons with masses between 2 and 12. 5 GeV

A missing-mass search has been made for negatively charged boson resonances B/sup -/ produced in the reaction ..pi../sup -/p ..-->.. B/sup -/p at beam momenta of 40, 100, 200, and 240 GeV. Approximately 600 000 events were included in the final mass spectra. In the mass region 2 < or = M/sub B/ < or = 12.5 GeV no statistically significant enhancements were observed. The 5-standard-deviation upper limit on the production of narrow resonances is of the order of 10 ..mu..b for 2 < or = M/sub B/ < or = 10.5 GeV.

Search for forward production of massive states which decay with muon emission

In a search for charmed particles the reactions ..pi../sup -/+p..-->..p/sub r/+..mu..+X and p+p..-->..p/sub r/+..mu..+X have been studied at beam energies of 200 and 240 GeV, respectively. Measurements of the beam particle and the slow recoil proton, p/sub r/, were used to reconstruct the mass (M) of the ..mu..+X system. Model-dependent upper limits, sensitive to threshold behavior, are presented for the forward production cross section times the muon branching ratio for high-mass states (6

DIMUON PRODUCTION BY PIONS AND PROTONS IN IRON AND A SEARCH FOR THE PRODUCTION IN HYDROGEN OF NEW PARTICLES WHICH DECAY INTO MUONS

Dimuon production cross sections were measured with a 200 GeV ..pi../sup -/ beam and a 240 GeV proton (p) beam. The dimuon mass spectra produced by ..pi.. and p have essentially the same shape. The dimuon transverse momentum behavior is essentially the same for vector mesons produced by ..pi.. or by p. For (rho + ..omega..) or psi production the x (Feynman) behavior is approximately independent of the mass of the dimuon produced. The dimuon ..pi.. production cross section is approximately 6 times greater than that of the p for x greater than .5. Using a missing mass (M/sub m/) technique, the same pion and proton beams were used to search for the production in hydrogen of new particles which decay with muon emission. Model dependent upper limits (50 to 7000 nanobarns) for the production of such objects with 2.5 less than M/sub m/ less than 7. GeV are given (for charmed meson pair production M/sub m/ is the mass of the D anti D system).

Measurements of Missing Mass (MM) Spectra from π−p ⇒ (MM)−pat 8, 11, 13.5, and 16 GeV

Measurements of missing mass (MM) spectra from π − p ⇒ ( MM ) − p at 8, 11, 13.5, and 16 GeV are reported. The MM mass range examined is 0 ≤ M 2 ≤ 7.3 GeV 2 with t (the proton four momentum transfer squared) in the interval 0.2 ≤ ∣ t ∣ ≤ 0.3 GeV 2 . Narrow resonances (R1, R2, R3, S, T, and U) with cross sections and widths reported by the CERN missing mass group are ruled out by the data. The cross sections d 2 σ/ dtdM 2 show evidence for triple factorizability of the form d 2 σ dtdM 2 ≃ D ( P B ) A ( M 2 ) G ( P ⊥ 2 ) where P B is the incident beam momentum,and P ⊥ 2 is the perpendicular component of the detected protons momentum with respect to the beam direction.

Measurements of Missing Mass (MM) Spectra from

Measurements of missing mass (MM) spectra from π − p ⇒ ( MM ) − p at 8, 11, 13.5, and 16 GeV are reported. The MM mass range examined is 0 ≤ M 2 ≤ 7.3 GeV 2 with t (the proton four momentum transfer squared) in the interval 0.2 ≤ ∣ t ∣ ≤ 0.3 GeV 2 . Narrow resonances (R1, R2, R3, S, T, and U) with cross sections and widths reported by the CERN missing mass group are ruled out by the data. The cross sections d 2 σ/ dtdM 2 show evidence for triple factorizability of the form d 2 σ dtdM 2 ≃ D ( P B ) A ( M 2 ) G ( P ⊥ 2 ) where P B is the incident beam momentum,and P ⊥ 2 is the perpendicular component of the detected protons momentum with respect to the beam direction.

Proposal to study multiparticle-peripheral hadron physics at NAL

We propose to build a large wire chamber magnetic spectrometer at NAL to measure multi-body forward-going hadronic systems produced by {pi}s, Ks and protons up to 80 GeV/c. Specific reactions will be isolated in order to study the s and t dependencies of the cross sections for peripheral processes, search for new resonant states and attempt to measure {pi}{pi} and K{pi} inelastic scattering. We propose a physics program for the spectrometer which is initially limited to those processes easiest to measure and which nevertheless spans a large range of strong interaction problems. Technically, the proposed spectrometer is a relatively modest extension of presently operating systems in the 10-20 GeV/c region, and does not present a challenge of uncertain magnitude to construct.