We present first data on event-by-event fluctuations in the average transverse momentum of charged particles produced in Pb+Pb collisions at the CERN SPS. This measurement provides previously ...unavailable information allowing sensitive tests of microscopic and thermodynamic collision models and to search for fluctuations expected to occur in the vicinity of the predicted QCD phase transition. We find that the observed variance of the event-by-event average transverse momentum is consistent with independent particle production modified by the known two-particle correlations due to quantum statistics and final state interactions and folded with the resolution of the NA49 apparatus. For two specific models of non-statistical fluctuations in transverse momentum limits are derived in terms of fluctuation amplitude. We show that a significant part of the parameter space for a model of isospin fluctuations predicted as a consequence of chiral symmetry restoration in a non-equilibrium scenario is excluded by our measurement.
Evaporative cooling of mixed atomic fermions Geist, W.; Kennedy, T. A. B.
Physical review. A, Atomic, molecular, and optical physics,
06/2002, Letnik:
65, Številka:
6
Journal Article
We report the observation of the doubly strange b baryon Omega_b- in the decay channel Omega_b- to J/psi Omega-, with J/psi to mu+ mu- and Omega- to Lambda K-, in $p\bar{p}$ collisions at ...$\sqrt{s}=1.96$ TeV. Using approximately 1.3 fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8 +/- 4.9 (stat) +/- 0.8 (syst) Omega_b- signal events at a mass of 6.165 +/- 0.010 (stat) +/- 0.013(syst.) GeV. The significance of the observed signal is 5.4 sigma, corresponding to a probability of 6.7 x 10^{-8} of it arising from a background fluctuation.
We report on a measurement of the inclusive jet cross section in p (p) over bar collisions at a center-of-mass energy root s = 1.96 TeV using data collected by the D0 experiment at the Fermilab ...Tevatron Collider corresponding to an integrated luminosity of 0: 70 fb(-1). The data cover jet transverse momenta from 50 to 600 GeV and jet rapidities in the range -2.4 to 2.4. Detailed studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented, and the cross section measurements are found to be in good agreement with next-to-leading order QCD calculations.
To determine a reference range for prostate-specific antigen (PSA) in patients who have had external beam radiation therapy for adenocarcinoma of the prostate.
Serum PSA levels were serially measured ...with the Hybritech Tandem-R assay in 35 patients who had completed radiation therapy for a mean of 51 ± 32 months (range, 10 to 133).
Serum PSA levels that were greater than 2.0 ng/mL (n = 20) continued to rise at a rate of more than 1 ng/mL per year, whereas levels between 0.0 and 2.0 ng/mL (n = 15) remained stable for an average of 71 ± 32 months (range, 22 to 133). One of these latter 15 patients had a false-negative PSA level when he experienced a biopsypositive prostate nodule and positive bone scan 43 months after therapy.
Prostate cancer control after radiation therapy was indicated in most men by a PSA reference range of 0.0 to 2.0 ng/mL. Cancer activity was indicated in all men with levels above this range.
Search for the rare decay Bs0→μ+μ Adams, M.; Alexeev, G.D.; Alton, A. ...
Physics letters. B,
10/2010, Letnik:
693, Številka:
5
Journal Article
Recenzirano
Odprti dostop
We present the results of a search for the flavor changing neutral current decay Bs0→μ+μ− using 6.1 fb−1 of pp¯ collisions at s=1.96 TeV collected by the D0 experiment at the Fermilab Tevatron ...Collider. The observed number of Bs0 candidates is consistent with background expectations. The resulting upper limit on the branching fraction is B(Bs0→μ+μ−)<5.1×10−8 at the 95% C.L. This limit is a factor of 2.4 better than that of the previous D0 analysis and the best limit to date.
We measure the correlation between the spin of the top quark and the spin of the anti-top quark in tt¯→W+bW−b¯→ℓ+νbℓ−ν¯b¯ final states produced in pp¯ collisions at a center of mass energy s=1.96 ...TeV, where ℓ is an electron or muon. The data correspond to an integrated luminosity of 5.4 fb−1 and were collected with the D0 detector at the Fermilab Tevatron collider. The correlation is extracted from the angles of the two leptons in the t and t¯ rest frames, yielding a correlation strength C=0.10−0.45+0.45, in agreement with the NLO QCD prediction within two standard deviations, but also in agreement with the no correlation hypothesis.
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