W. DeSoi

EVIDENCE FOR PARTON KT EFFECTS IN HIGH-PT PARTICLE PRODUCTION

Inclusive pizero and direct-photon cross sections in the kinematic range 3.5 < pT < 12 GeV/c with central rapidities are presented for 530 and 800 GeV/c proton beams and a 515 GeV/c pi- beam incident on beryllium targets. Current Next-to-Leading-Order perturbative QCD calculations fail to adequately describe the data for conventional choices of scales. Kinematic distributions from these hard scattering events provide evidence that the interacting partons carry significant initial-state parton transverse momentum (kT). Incorporating these kT effects phenomenologically greatly improves the agreement between calculations and the measured cross sections.

Measurement of direct-photon production at the Fermilab Tevatron fixed target energies

Measurements of the production of high transverse momentum direct photons by a 515 GeV/c {pi}{sup -} beam and 530 and 800 GeV/c proton beams in interactions with beryllium and hydrogen targets are presented. The data span the kinematic ranges of 3.5<p{sub T}<12 GeV/c in transverse momentum and 1.5 units in rapidity. The inclusive direct-photon cross sections are compared with next-to-leading-order perturbative QCD calculations and expectations based on a phenomenological parton-k{sub T} model.

Direct photon production at high p-transverse in pi- Be and p Be collisions at 500-GeV/c

We report new measurements of inclusive direct photon production at high transverse momenta (pT) for π - and p interactions on Be at 500 Gev/r. The yields as a function of pT and rapidity (y) are in good agreement with expectations from next-to-leading-log QCD calculations employing recently extracted quark and gluon structure functions

A large liquid argon photon/hadron calorimeter for FNAL

Abstract This paper describes a new liguid argon photon/hadron detector currently under construction for Experiment E706 at the Fermi National Accelerator Laboratory.

Calibration and performance of the E706 lead and liquid-argon electromagnetic calorimeter

Abstract We report on the calibration and performance of a large lead liquid-argon electromagnetic calorimeter used by experiment E706 at Fermilab. The reconstructed π 0 mass was used to calibrate the energy response of the calorimeter. The systematic uncertainty in the linearity and uniformity of the mean-energy response of the calorimeter after calibration was found to be less than ±0.5% for the sample of data analyzed. Detector characteristics, including sampling fluctuations and position resolution, are discussed.

Silicon position sensitive detectors for the Helios (NA 34) experiment

Abstract Silicon detectors having both “pad” and strip position sensitive configurations have been fabricated for the Helios experiment which requires an elaborate pulse height-dependent trigger as well as one dimensional silicon strip position sensing. The trigger detector is a 400 element, 30 mm diameter detector with readout connections from a ceramic overlay board. Tests with full prototype detectors have shown essentially 100% detection efficiency and excellent pulse height resolution well capable of delineating 0, 1 or 2 hits per pad. Strip detectors with 25 μm pitch and a varying readout pitch have been tested, which utilize both capacitive and resistive charge division. Techniques for realization of required interstrip resistors will be discussed and results which may compare these readout methods will be reported.

Evidence for parton

Inclusive pizero and direct-photon cross sections in the kinematic range 3.5 < pT < 12 GeV/c with central rapidities are presented for 530 and 800 GeV/c proton beams and a 515 GeV/c pi- beam incident on beryllium targets. Current Next-to-Leading-Order perturbative QCD calculations fail to adequately describe the data for conventional choices of scales. Kinematic distributions from these hard scattering events provide evidence that the interacting partons carry significant initial-state parton transverse momentum (kT). Incorporating these kT effects phenomenologically greatly improves the agreement between calculations and the measured cross sections.

k_{T}

Abstract A charged particle spectrometer containing a 7120-channel silicon microstrip detector system, one component of Fermilab experiment E706 to study direct photon production in hadron-hadron collisions, was utilized in a run in which 6 million events were recorded. We describe the silicon system, provide early results of track and vertex reconstruction, and present data on the radiation damage to the silicon wafers resulting from the narrow high intensity beam.

effects in high

We present results on the production of direct photons, {pi}{sup 0}, and {eta} mesons on nuclear targets at large transverse momenta (p{sub T}). The data are from 530 and 800 GeV/c proton beams and 515 GeV/c {pi}{sup -} beams incident upon copper and beryllium targets that span the kinematic range of 1.0<p{sub T} < or approx. 10 GeV/c at central rapidities.

p_{T}

We present results on the production of high transverse momentum pizero and eta mesons in pi-p and pi-Be interactions at 515 GeV/c. The data span the kinematic ranges 1 < p_T < 11 GeV/c in transverse momentum and -0.75 < y < 0.75 in rapidity. The inclusive pizero cross sections are compared with next-to-leading order QCD calculations and to expectations based on a phenomenological parton-k_T model.