Biomedical subjects

M Convery

Publications and source records attributed to M Convery.

27 records · Page 2Linked to original sources

PubMed2003

Search for long-lived charged massive particles in pp collisions at square root s = 1.8 TeV.

We report a search for the production of long-lived charged massive particles in a data sample of 90 pb(-1) of square root[s]=1.8 TeV pp collisions recorded by the Collider Detector at Fermilab. The search uses the muonlike penetration and anomalously high ionization energy loss signature expected for such a particle to discriminate it from backgrounds. The data are found to agree with background expectations, and cross section limits of O(1) pb are derived using two reference models, a stable quark and a stable scalar lepton.

Journal Article↗

PubMed2003

Search for a W' boson decaying to a top and bottom quark pair in 1.8 TeV pp collisions.

We report the results of a search for a W' boson produced in pp; collisions at a center-of-mass energy of 1.8 TeV using a 106 pb(-1) data sample recorded by the Collider Detector at Fermilab. We observe no significant excess of events above background for a W' boson decaying to a top and bottom quark pair. In a model where this boson would mediate interactions involving a massive right-handed neutrino (nu(R)) and have standard model strength couplings, we use these data to exclude a W' boson with mass between 225 and 536 GeV/c(2) at 95% confidence level for M(W')>>M(nu(R)) and between 225 and 566 GeV/c(2) at 95% confidence level for M(W')<M(nu(R)).

Journal Article↗

PubMed2002

Limits on extra dimensions and new particle production in the exclusive photon and missing energy signature in pp collisions at square root [s]=1.8 TeV.

The exclusive gammaE(T) signal has a small standard model cross section and is thus a channel sensitive to new physics. This signature is predicted by models with a superlight gravitino or with large extra spatial dimensions. We search for such signals at the Collider Detector at Fermilab, using 87 pb(-1) of data at square root [s]=1.8 TeV, and extract 95% C.L. limits on these processes. A limit of 221 GeV is set on the scale |F|(1/2) in supersymmetric models. For 4, 6, and 8 extra dimensions, model-dependent limits on the fundamental mass scale M(D) of 0.55, 0.58, and 0.60 TeV, respectively, are found. We also specify a "pseudo-model-independent" method of comparing the results to theoretical predictions.

Journal Article↗

PubMed2002

Search for new physics in photon-lepton events in pp collisions at sqrt[s] = 1.8 TeV.

We present the results of a search in pp collisions at sqrt[s] = 1.8 TeV for anomalous production of events containing a photon and a lepton (e or mu), both with large transverse energy, using 86 pb(-1) of data collected with the Collider Detector at Fermilab during the 1994-1995 collider run at the Fermilab Tevatron. The presence of large missing transverse energy (E(T)), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large E(T), for which the observed total is 16 events and the expected mean total is 7.6+/-0.7 events.

Journal Article↗

PubMed2002

Upsilon production and polarization in p p macro collisions at square root of s = 1.8 TeV.

We report on measurements of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential cross sections (d(2)sigma/dp(T)dy)(/y/<0.4), as well as on the Upsilon(1S) polarization in p p macro collisions at square root of s = 1.8 TeV using a sample of 77+/-3 pb(-1) collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay Upsilon-->mu(+)mu(-). The measured angular distribution of the muons in the Upsilon(1S) rest frame is consistent with unpolarized meson production.

Journal Article↗

PubMed2002

Measurement of the strong coupling constant from inclusive jet production at the Tevatron pp collider.

We report a measurement of the strong coupling constant, alpha(s)(MZ), extracted from inclusive jet production in pp collisions at square root[s] = 1800 GeV. The QCD prediction for the evolution of alpha(s) with jet transverse energy ET is tested over the range 40<ET<450 GeV using ET for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. The value of alpha(s) at the mass of the Z0 boson averaged over the range 40<ET<250 GeV is found to be alpha(s)(MZ) = 0.1178+/-0.0001(stat)+0.0081(-0.0095)(expt. syst). The associated theoretical uncertainties are mainly due to the choice of renormalization scale ((+6%)(-4%)) and input parton distribution functions (5%).

Journal Article↗

PubMed2001

Double diffraction dissociation at the Fermilab Tevatron collider.

We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.

Journal Article↗

PubMed1991

Thecal and interstitial cells in polycystic ovaries (PCO) in the rat.

Two different types of experimentally-induced polycystic ovaries (PCO) have been examined. A macrocystic ovarian condition is induced by estradiol valerate (EV) injection, whereas a microcystic ovarian condition is engendered with subcutaneous estradiol implants. In both of these models thecal and secondary interstitial cells were characterized using three functionally significant indices. Expression of alkaline phosphatase was evaluated immunohistochemically, hCG/LH-binding capacity was assessed by means of EM radioautography, and the size and percent cytoplasmic area of intracytoplasmic lipid were determined, in the same cells, by morphometry. In both types of ovary, thecal cells of healthy and atretic follicles stained heavily for alkaline phosphatase whereas cystic theca exhibited little or no staining. Intermittent faintly stained patches of secondary interstitial cells, as well as intensely stained spheroidal cell clusters, were most numerous in the microcystic ovary and occurred less frequently in the macrocystic ovary. Cystic thecal cells in both conditions exhibited large lipid droplets and minimal hCG binding. Lipid droplet area was minimal and hCG binding maximal in secondary interstitial cells of both types of ovary. It is concluded that specific clusters of secondary interstitial cells are important steroidogenic elements in PCO, whereas cystic theca is relatively inert.

Alkaline Phosphatase↗

PubMed1990

Remission of the polycystic ovarian condition (PCO) in the rat following hemiovariectomy.

The estradiol valerate-induced polycystic ovarian condition in the rat represents a normal ovarian response to aberrant endocrine stimuli. Although we have shown that removal of one polycystic ovary (hemiovariectomy) results in restoration of cyclicity and normal morphology in the remaining ovary by 1 week, nothing is known about the process of recovery or about the role of the hypothalamo-pituitary unit in initiating recovery. We have therefore examined ovaries at 3, 12, 24, 48, and 120 hours following removal of the contralateral polycystic ovaries. The ovarian content and size distribution of healthy and atretic follicles was determined, as well as the occurrence of follicular cysts, type III large follicular structures, and corpora lutea. The plasma LH pattern was also examined at a short postoperative interval. At 3 hours, there was a significant increase in mean ovarian weight that coincided with the emergence of healthy large secondary follicles. By 12 hours, there was a significant sustained diminution in the number of atretic follicles of all sizes, but the total number of healthy follicles did not increase significantly until 120 hours. The cystic follicles had all but disappeared by 120 hours because of mechanical compression by newly developing ovarian tissue. Ovarian recovery is, therefore, biphasic, consisting of a very early diminution in atresia coincident with, and perhaps caused by, a major alteration in the plasma LH pattern. The second phase is characterized by a wave of follicular recruitment and development.

Animals↗