Luminosity-driven channeling extraction has been observed for the first time in a 900 GeV study at the Fermilab Tevatron. This experiment, Fermilab E853, demonstrated that useful TeV level beams can be extracted from a superconducting accelerator during high luminosity collider operations without unduly affecting the background at the collider detectors. Multi-turn extraction was found to increase significantly the efficiency of the process. The beam extraction efficiency was about 25%. Studies of time dependent effects found that the turn-to-turn structure was governed mainly by accelerator beam dynamics. An investigation of a pre-scatterer using the accelerator flying wire system showed that a fiber could produce a significant extracted flux, consistent with expectations. Based on these results, it is feasible to construct a parasitic 5-10 MHz proton beam from the Tevatron collider.

We report on a search for the decay KL → πee carried out by the KTeV/E799 experiment at Fermilab. This decay is expected to have a significant CP violating contribution and the measurement of its branching ratio could support the CKM mechanism for CP violation or could point to new physics. Two events were observed in the 1997 data with an expected background of 1.06 ± 0.41 events, and we set an upper limit B(KL → πee)< 5.1 × 10 at the 90% confidence level. 13.20.Eb, 11.30.Er, 14.40.A Typeset using REVTEX

The cross section for b (b) over bar production in 800 GeV/c pN interactions has been measured in Fermilab, experiment E771 to be 43(-17)(+27)(stat)(-7)(+7)(syst) nb per nucleon from the observation of events in which both the b and the (b) over bar decay semimuonically or a B decays into a J/psi followed by J/psi --> mu(+)mu(-). [S0031-9007(98)07987-3].

Author(s): Alavi-Harati, A; Albuquerque, IF; Alexopoulos, T; Arenton, M; Arisaka, K; Averitte, S; Barker, AR; Bellantoni, L; Bellavance, A; Belz, J; Ben David, R; Bergman, DR; Blucher, E; Bock, GJ; Bown, C; Bright, S; Cheu, E; Childress, S; Coleman, R; Corcoran, MD; Corti, G; Cox, B; Crisler, MB; Erwin, AR; Ford, R; Glazov, A; Golossanov, A; Graham, G; Graham, J; Hagan, K; Halkiadakis, E; Hanagaki, K; Hidaka, S; Hsiung, YB; Jejer, V; Jennings, J; Jensen, DA; Kessler, R; Kobrak, HGE; La Due, J; Lath, A; Ledovskoy, A; Mc Bride, PL; Mc Manus, AP; Mikelsons, P; Monnier, E; Nakaya, T; Nauenberg, U; Nelson, KS; Nguyen, H; O’dell, V; Pang, M; Pordes, R; Prasad, V; Qiao, C; Quinn, B; Ramberg, EJ; Ray, RE; Roodman, A; Sadamoto, M; Schnetzer, S; Senyo, K; Shanahan, P; Shawhan, PS; Slater, W; Solomey, N; Somalwar, SV; Stone, RL; Suzuki, I; Swallow, EC; Swanson, RA; Taegar, SA; Tesarek, RJ; Thomson, GB; Toale, PA; Tripathi, A; Tschirhart, R; Wah, YW; Wang, J; White, HB; Whitmore, J; Winstein, B; Winston, R; Wu, JY; Yamanaka, T | Abstract: We have compared the decay rates of KL and KS toΠ+ Π- Π0Π0 final states using a subset of the data from the KTeV experiment (E832) at Fermilab. We find that the direct-CP-violation parameter Re (μ’/μ) is equal to [28.0±3.0(stat)±2.8(syst)]×10-4. This result definitively establishes the existence of CP violation in a decay process. © 1999 The American Physical Society.

We present the first observation of Xi(0) beta decay, using the KTeV beam line and detector at Fermilab. We have identified 176 beta decay events after subtracting a 7 event background. Normalization to 41024 simultaneously collected Xi(0) --> Lambda(0)pi(0) decays yields a branching ratio of Gamma(Xi(0) --> Sigma(+) e(-)<(nu)over bar>(e))/Gamma(total) = (2.71 +/- 0.22(statistical) +/- 0.31(systematic)) X 10(-4). The flavor symmetric quark model calculation agrees with this result.

The cross section for b{bar b} production in 800 GeV/c pN interactions has been measured in Fermilab experiment E771 to be 43{sup +27}{sub {minus}17}(stat){sup +7}{sub {minus}7}(syst) nb per nucleon from the observation of events in which both the b and the {bar b} decay semimuonically or a B decays into a J/{psi} followed by J/{psi}{r_arrow}{mu}{sup +}{mu}{sup {minus}} . {copyright} {ital 1998} {ital The American Physical Society}

We have searched for the flavor changing neutral current decay Do + p-l+p”in the dimuon data obtained by the E771 experiment conducted at Fermilab. No evidence is found. A branching ratio of (-1.0 ‘A:,’ f 0.2) x 10v6 is obtained, corresponding to a 90% confidence level upper limit of 3.3 x 10m6. This new upper limit is about three times more sensitive than the best published limit. (Submitted to Physical Review Letters)

Luminosity-driven channeling extraction has been observed for the first time using a 900 GeV circulating proton beam at the superconducting Fermilab Tevatron. The extraction efficiency was found to be about 30%. A 150 kHz beam was obtained during luminosity-driven extraction with a tolerable background rate at the collider experiments. A 900 kHz beam was obtained when the background limits were doubled. This is the highest energy at which channeling has been observed. [S1098-4402(98)00003-2]

We present the x(F) and p(T) differential cross sections of J/psi, and psi', respectively, in the ranges -0.05<x(F)<0.25 and p(T)<3.5 GeV/c. The data samples are constituted by about 12000 J/psi and 200 psi' produced in proton-silicon interactions at 800 GeV/c and decaying into opposite sign muons. The x, and p, distributions are compared with recent results from experiments E789 at the same energy and to leading order QCD predictions using the MRS DO parametrization for the parton structure function. The measured shapes of the differential cross sections, except for the d sigma/dx(F) at small x(F), agree very well with the prediction, even though their value is quite a bit larger than the prediction. We also present the cos theta differential cross section of the J/psi which indicates unpolarized production in contrast with color octet models predictions.

We have searched for the flavor changing neutral current decay D-0 --> mu(+)mu(-) in the dimuon data obtained by the E771 experiment conducted at Fermilab. No evidence is found. A 90% confidence level upper limit of 4.2 x 10(-6) is obtained for the branching ratio. This new upper limit is about two times lower than the best published result.

The central region of the silicon microstrip detector used in Fermilab experiment E771 was subjected to a peak fluence of 9.5 × 1013 p/cm2 induced by 800 GeV protons over a two-month period. Fourteen 300 μm thick planes manufactured by Micron Semiconductor were operated at bias voltages ranging from 84 to 109 V. Analysis of data from low intensity beam triggers taken near the end of the run shows that the mean pulse height from our amplifiers began to decline at a fluence of approximately 2 × 1013 p/cm2 and fell to near zero by 6 × 1013 p/cm2. We show that the use of fast amplifiers contributed to this early loss of signal.

A silicon strip detector (SSD) system for use in very high rate experiments has been operated in Experiment E771 (Cox, 1989) at the Fermi National Accelerator laboratory. The detector electronics were designed (Swoboda, 1990; Bowden, 1990; Zimmerman, 1989; Christian, 1991) to meet the specific needs of Fermilab experiment E771 using ASIC chip sets where commercial circuits were not suitable. The electronics for the SSD were designed to operate at rates up to 60 Mhz and were operated at interaction rates up to 107 interaction/sec (beam rates of 2 × 108 proton/sec). In addition to being very fast, the detector for the 1991 run was very compact with 10000 channels of active detector in a volume fo 5cm × 5cm × 10cm. An expansion of the system to 16000 channels is planned for the next Fermilab fixed target run. The strip pitch ranged from 25 μm in the center of the detector near the target to 100 μm pitch at the most downstream, outer edges of the detector. The readout is a latch design with pipelined readout and appears to have single strip efficiencies of ≈ 75% even in the presence of a high radiation dose (∽ 1014 protons/cm2) and high leakage currents(≈ 1 nA/strip). The detector and associated amplifier electronics has presently been operated at 17° C and is designed to operate as low as 8° C.

The production properties of lambdas (LAMBDA0, LAMBDA0BAR) and cascades (XI-,XI-BAR) in the central region in ppBAR collisions at square-root s = 1.8 TeV at the Fermilab collider are reported. The transverse-momentum spectra of lambdas are measured as a function of multiplicity and the ratios of lambdas to protons (p,pBAR) and to all charged particles are studied as a function of transverse momentum and multiplicity. Moreover the average transverse momentum of cascades and the ratio of cascades to lambdas are presented.

A silicon microstrip detector (SSD) system for use in very high rate experiments has been designed for Experiment E771 at Fermi National Accelerator Laboratory. The detector electronics were designed from the ground up using application-specific integrated circuit chip sets where commercial circuits were not suitable. The electronics for the SSD were designed to operate with interaction rates up to 10/sup 7/ interactions/s (beam rates of 2*10/sup 8/ protons/s). In addition to speed, the detector for the current run is very compact, with 10000 channels of active detector in a volume of 5 cm*5 cm*10 cm. The system will be expanded to 16000 channels in the next Fermilab fixed target run. The strip pitch ranges from 25 mu m in the center of the detector near the target to 100 mu m pitch at the most downstream, outer edge of the detector. The readout is a latch design with efficiencies of approximately 95% even in the presence of radiation damage and high leakage currents. The detector and associated amplifier electronics have been operated at 20 degrees C and are designed to operate at 8 degrees C.< >

Details of the construction of high-rate, mid-sized (1-m*2-m) pad chambers, intended for use in Fermi National Accelerator Laboratory (FNAL) experiment E-771, are described. Each gas volume module represents a chamber doublet: two identical anode wire planes, two transverse strip planes, and two pad planes. Wire signals, from 8-mm square cells, are recorded via TDCs; corresponding stripe and pad image signals are latched. Pad sizes range from 0.8 cm*3.6 cm to 3.2 cm*35 cm. In addition to facilitating pattern recognition, pad signals are also used as inputs to an online, high transverse momentum trigger processor.< >