J. Bofill

Two-jet invariant-mass distribution at sqrt s =1.8 TeV.

We present the dijet invariant-mass distribution in the region between 60 and 500 GeV, measured in 1.8-TeV {ital {bar p}p} collisions in the Collider Detector at Fermilab. Jets are restricted to the pseudorapidity interval {vert bar}{eta}{vert bar}{lt}0.7. Data are compared with QCD calculations; axigluons are excluded with 95% confidence in the region 120{lt}{ital M}{sub {ital A}}{lt}210 GeV for axigluon width {Gamma}{sub {ital A}}={ital N}{alpha}{sub s}{ital M}{sub {ital A}}/6, with {ital N}=5.

Hadron showers in a low-density fine-grained flash chamber calorimeter

Abstract Hadronic showers at six incident particle energies from 33.8 to 415.4 GeV have been studied using the low-density fine-grained flash chamber calorimeter of the Lab C neutrino detector at Fermilab. Transverse distributions of unprecedented fine granularity have been obtained for a range of depths in the shower. Longitudinal energy distributions have been compared with those from iron-scintillator detectors. Some differences are observed which may be attributable to the different relative sensitivity of the two detector types to electromagnetic and hadronic shower components. Both longitudinal and transverse distributions have been parametrized. Fluctuations in energy deposition have been studied. The relative size of the fluctuations is largest near the starting vertex and in the tail of the shower, and falls slowly with increasing beam energy. Correlations between energy deposition in neighboring parts of the shower are observed, and anticorrelation is seen between energy deposition in the peak and in the tail of the shower. Containment lengths and widths have also been measured and parametrized.

Measurement of D /emph> production in jets from p̅p collisions at √s =1.8 TeV

The production rate of charged {ital D}{sup *} mesons in jets has been measured in 1.8-TeV {ital {bar p}p} collisions at the Fermilab Tevatron with the Collider Detector at Fermilab. In a sample of approximately 32 300 jets with a mean transverse energy of 47 GeV obtained from an exposure of 21.1 nb{sup {minus}1}, a signal corresponding to 25.0{plus minus}7.5(stat){plus minus}2.0(syst) {ital D}{sup *{plus minus}}{r arrow}K{sup {minus plus}}{pi}{sup {plus minus}}{pi}{sup {plus minus}} events is seen above background. This corresponds to a ratio {ital N}({ital D}{sup *+}+D{sup *{minus}})/N(jet) =0.10{plus minus}0.03{plus minus}0.03 for {ital D}{sup *} mesons with fractional momentum {ital z} greater than 0.1.

Erratum to “hadron showers in a low-density fine-grained flash chamber calorimeter”☆

Abstract Our recent paper ∗ described an analysis of the energy deposition in hadronic showers at six incident particle energies from 33.8 to 415.4 GeV using the low-density fine-grained flash chamber calorimeter of the Lab C neutrino detector at Fermilab. More recent work on the subject has led us to revise some of the results presented for energies above 200 GeV. We present here revised results for the longitudinal and transverse energy deposition, and new coefficients for the parametrization of these curves.

Measurement of D sup * production in jets from p p collisions at radical s =1. 8 TeV

The production rate of charged {ital D}{sup *} mesons in jets has been measured in 1.8-TeV {ital {bar p}p} collisions at the Fermilab Tevatron with the Collider Detector at Fermilab. In a sample of approximately 32 300 jets with a mean transverse energy of 47 GeV obtained from an exposure of 21.1 nb{sup {minus}1}, a signal corresponding to 25.0{plus minus}7.5(stat){plus minus}2.0(syst) {ital D}{sup *{plus minus}}{r arrow}K{sup {minus plus}}{pi}{sup {plus minus}}{pi}{sup {plus minus}} events is seen above background. This corresponds to a ratio {ital N}({ital D}{sup *+}+D{sup *{minus}})/N(jet) =0.10{plus minus}0.03{plus minus}0.03 for {ital D}{sup *} mesons with fractional momentum {ital z} greater than 0.1.

Jet-fragmentation properties in p-barp collisions at sqrt s =1.8 TeV.

The charged-particle fractional momentum distribution within jets, {ital D}({ital z}), has been measured in dijet events from 1.8-TeV {ital {bar p}p} collisions in the Collider Detector at Fermilab. As expected from scale breaking in quantum chromodynamics, the fragmentation function {ital D}({ital z}) falls more steeply as dijet invariant mass increases from 60 to 200 GeV/{ital c}{sup 2}. The average fraction of the jet momentum carried by charged particles is 0.65{plus minus}0.02(stat){plus minus}0.08(syst).

Jet-fragmentation properties in p p collisions at radical s =1. 8 TeV

The charged-particle fractional momentum distribution within jets, {ital D}({ital z}), has been measured in dijet events from 1.8-TeV {ital {bar p}p} collisions in the Collider Detector at Fermilab. As expected from scale breaking in quantum chromodynamics, the fragmentation function {ital D}({ital z}) falls more steeply as dijet invariant mass increases from 60 to 200 GeV/{ital c}{sup 2}. The average fraction of the jet momentum carried by charged particles is 0.65{plus minus}0.02(stat){plus minus}0.08(syst).

Two-jet invariant-mass distribution at radical s =1. 8 TeV

We present the dijet invariant-mass distribution in the region between 60 and 500 GeV, measured in 1.8-TeV {ital {bar p}p} collisions in the Collider Detector at Fermilab. Jets are restricted to the pseudorapidity interval {vert bar}{eta}{vert bar}{lt}0.7. Data are compared with QCD calculations; axigluons are excluded with 95% confidence in the region 120{lt}{ital M}{sub {ital A}}{lt}210 GeV for axigluon width {Gamma}{sub {ital A}}={ital N}{alpha}{sub s}{ital M}{sub {ital A}}/6, with {ital N}=5.

Dijet angular distributions from p-barp collisions at sqrt s=1.8 TeV.

We have measured dijet angular distributions at ..sqrt../ital s/ =1.8 TeV with the Collider Detector at Fermilab and the Tevatron /ital p/bar /p/ Collider and find agreement with leading-order QCD. By comparing the distribution for the highest dijet invariant masses with the prediction of a model of quark compositeness, we set a lower limit on the associated scale parameter ..lambda../sub /ital c// at 330 GeV (95% C.L.).