94 Matching Results

Search Results

Advanced search parameters have been applied.

Observation of B0 (s) ---> K+ K- and Measurements of Branching Fractions of Charmless Two-body Decays of B0 and B0(s) Mesons in anti-p p Collisions at s**(1/2) = 1.96-TeV

Description: The authors search for decays of the type B{sub (s)}{sup 0} {yields} h{sup +}h'{sup -} (where h,h' = K or {pi}) in 180 pb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. They observe the new mode B{sub s}{sup 0} {yields} K{sup +}K{sup -} with a yield of 236 {+-} 32 events, corresponding to (f{sub s}/f{sub d}) x {Beta}(B{sub s}{sup 0} {yields} K{sup +}K{sup -})/{Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}) = 0.46 {+-} 0.08(stat.) {+-} 0.07(syst.), where f{sub s}/f{sub d} is the ratio of production fractions of B{sub s}{sup 0} and B{sup 0}. They find results in agreement with world averages for the modes B{sup 0} {yields} {pi}{sup +}{pi}{sup -} and B{sup 0} {yields} K{sup +}{pi}{sup -}, and set the following upper limits at 90% CL: {Beta}(B{sup 0} {yields} K{sup +}K{sup -}) < 1.8 x 10{sup -6}, {Beta}(B{sub s}{sup 0} {yields} K{sup -}{pi}{sup +}) < 5.6 x 10{sup -6}, and {Beta}(B{sub s}{sup 0} {yields} {pi}{sup +}{pi}{sup -}) < 1.7 x 10{sup -6}.
Date: July 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Diboson physics at CDF

Description: At the Fermilab Tevatron, the CDF detector is used to study diboson production in p{bar p} collisions at {radical}s = 1.96 TeV. We report recent diboson production measurements, limits on anomalous triple gauge couplings and latest results from semi-leptonic diboson searches.
Date: September 1, 2009
Creator: Annovi, Alberto
Partner: UNT Libraries Government Documents Department

Diboson Production at D0

Description: We present recent diboson production measurements from the D0 experiment at Fermilab's Tevatron collider. The production of ZZ was observed using leptonic final states. Z{gamma} {yields} vv{gamma} was observed and used to set the most stringent limits from a hadron collider on anomalous Z{gamma}{gamma} and ZZ{gamma} trilinear gauge couplings (TGCs). WW events with leptonic final states and WW + WZ events with semi-leptonic final states were used to set limits on anomalous WWZ and WW{gamma} TGCs. Finally, limits on anomalous WWZ and WW{gamma} TGCs were obtained from a combination of the fully-leptonic W{gamma}, WW, and WZ channels and the semi-leptonic WW and WZ channels, giving the most stringent limits from a hadron collider.
Date: October 1, 2009
Creator: Haley, Joseph
Partner: UNT Libraries Government Documents Department

CDF Run II Monte-Carlo tunes

Description: Several CDF Run 2 PYTHIA 6.2 tunes (with multiple parton interactions) are presented and compared with HERWIG (without multiple parton interactions) and with the ATLAS PYTHIA tune (with multiple parton interactions). Predictions are made for the ''underlying event'' in high p{sub T} jet production and in Drell-Yan lepton-pair production at the Tevatron and the LHC.
Date: November 1, 2006
Creator: Field, Rick & U., /Florida
Partner: UNT Libraries Government Documents Department

Producao d Dijatos por Dupla Troca de Pomeron Exclusiva no Experimento D0

Description: The first search for exclusive diffractive dijet production with invariant mass {approx}> 100 GeV in Run II of the Fermilab Tevatron Collider is performed. The set of data used is the Run IIa, corresponding to an integrated luminosity of 30 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV taken with the D0 detector. At 95% CL, an upper limit for the ratio between the number of diffractive exclusive events and the number of non diffractive events is set to be 7.5 x 10{sup -6}, excluding two of the three models proposed to explain this production.
Date: October 1, 2008
Creator: Rangel, Murilo, Santana & /Rio de Janeiro, CBPF
Partner: UNT Libraries Government Documents Department

Measurement of N* Production in p p ---> p N* between 9-GeV/c and 300-GeV/c

Description: The authors have measured the missing-mass spectrum of p + p {yields} p + MM in the region 1.5 < MM < 7.0 GeV using the acceleration ramp of the NAL machine between 9 and 300 GeV/c and the H{sub 2} jet target. They observe strong N*(1690) and N*(2190) production and are continuing the search for heavier mass resonances.
Date: August 1, 1973
Creator: Abe, K.; Alspector, J.; Bomberowitz, R.; Cohen, K.J.; Colleraine, A.P.; De Lillo, T. et al.
Partner: UNT Libraries Government Documents Department

Measurements of the Trilinear Gauge Boson Couplings from Diboson Production at D0

Description: The most recent measurements of the trilinear gauge boson couplings from the diboson production at the D0 experiment has been presented. The analyzed final states are Z{gamma} {yields} {nu}{nu}{gamma}, WW {yields} l{nu}l{prime}{nu}, and WW+WZ {yields} l{nu}jj. We also present results obtained combining all final states involving the W boson. These results represent the most stringent limits set to date at the hadron collider.
Date: October 1, 2009
Creator: Sekaric, Jadranka
Partner: UNT Libraries Government Documents Department

Search for the Production of Narrow t anti-b Resonances in 1.9 fb-1 of p anti-p Collisions at s**(1/2) = 1.96-TeV

Description: We present new limits on resonant tb production in ppbar collisions at sqrt(s) = 1.96 TeV, using 1.9 fb{sup -1} of data recorded with the CDF II detector at the Fermilab Tevatron. We reconstruct a putative tb mass in events with a lepton, neutrino candidate, and two or three jets, and search for anomalous tb production as modeled by W{prime} {yields} tb. We set a new limit on a right-handed W{prime} with standard model-like coupling, excluding any mass below 800 GeV at 95% C.L. For any narrow W{prime}-like state with mass above 800 GeV, the cross-section is found to be less than 0.28 pb at 95% C.L. We also present an exclusion of the W{prime} coupling strength versus W{prime} mass.
Date: February 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Partner: UNT Libraries Government Documents Department

A Search for the Production of Technicolor Particles at the D-Zero Detector

Description: A search for the Technicolor processes p{bar p} {yields} {rho}{sub T}{sup {+-}} {yields} W{sup {+-}}{pi}{sub T}{sup 0} {yields} {mu}{nu}b{bar b} and p{bar p} {yields} {rho}{sub T}{sup 0} {yields} W{sup {+-}}{pi}{sub T}{sup {+-}} {yields} {mu}{nu}b{bar c} is conducted at the D0 detector. Selection requirements are individually optimized for each of twenty mass hypotheses by means of a random grid search. No excess is seen in a 291 pb{sup -1} data set and 95% confidence level upper limits are set on the Technicolor production cross section. The mass combinations M{sub {rho}} = 195 GeV/c{sup 2}, M{sub {pi}} = 100 GeV/c{sup 2} and M{sub {rho}} = 200 GeV/c{sup 2}, M{sub {pi}} = 105 GeV/c{sup 2} are excluded for the choice of the Technicolor scale parameter M{sub V} = 500 GeV.
Date: July 1, 2006
Creator: Desai, Satish Vijay & /SUNY, Stony Brook
Partner: UNT Libraries Government Documents Department

A search for charmed particles in pi- d at 200 GeV/c

Description: The authors have searched for evidence of charmed production in {pi}{sup -}d interactions by examining a sample of pictures from the FNAL 30-inch bubble chamber. A downstream muon detector was used to tag events in which a muon emerged. Results of the search is presented.
Date: April 1, 1975
Creator: Hayes, K.; Klems, J.H.; Ko, W.; Lander, R.L.; Pellett, D.; Yager, P. et al.
Partner: UNT Libraries Government Documents Department

Single Pion Measurement Capabilities at SciBooNE

Description: The precise knowledge of the single pion production cross-section of neutrino around the {approx}1 GeV energy region is an essential ingredient in the interpretation of neutrino oscillation experiments. The unique opportunities and prospects of single pion measurements at SciBooNE are described.
Date: December 1, 2007
Creator: Nakajima, Y. & U., /Kyoto
Partner: UNT Libraries Government Documents Department

Search for associated production of z and Higgs bosons in proton-antiproton collisions at 1.96 TeV

Description: We present a search for associated production of Z and Higgs bosons in 4.2 fb{sup -1} of {bar p}p collisions at {radical}s = 1.96 TeV, produced in RunII of the Tevatron and recorded by the D0 detector. The search is performed in events containing at least two muons and at least two jets. The ZH signal is distinguished from the expected backgrounds by means of multivariate classifiers known as random forests. Binned random forest output distributions are used in comparing the data to background-only and signal+background hypotheses. No excess is observed in the data, so we set upper limits on ZH production with a 95% confidence level.
Date: December 1, 2010
Creator: BackusMayes, John Alexander & /Washington U., Seattle
Partner: UNT Libraries Government Documents Department

WW production cross section measurement and limits on anomalous trilinear gauge couplings at sqrt(s) = 1.96-TeV

Description: The cross section for WW production is measured and limits on anomalous WW{gamma} and WWZ trilinear gauge couplings are set using WW {yields} ee/e{mu}/{mu}{mu} events collected by the Run II D0 detector at the Fermilab Tevatron Collider corresponding to 1 fb{sup -1} of integrated luminosity at {radical}s = 1.96 TeV. Across the three final states, 108 candidate events are observed with 40.8 {+-} 3.8 total background expected, consistent with {sigma}(p{bar p} {yields} WW) = 11.6 {+-} 1.8(stat) {+-} 0.7(syst) {+-} 0.7(lumi) pb. Using a set of SU(2){sub L} {direct_product} U(1){sub Y} conserving constraints, the one-dimensional 95% C.L. limits on trilinear gauge couplings are -0.63 < {Delta}{kappa}{sub {gamma}} < 0.99, -0.15 < {lambda}{sub {gamma}} < 0.19, and -0.14 < {Delta}g{sub 1}{sup Z} < 0.34.
Date: April 1, 2008
Creator: Cooke, Michael P. & U., /Rice
Partner: UNT Libraries Government Documents Department

Measurement of the production fraction times branching fraction $\boldsymbol{ f(b\to\Lambda_{b})\cdot \mathcal{B}(\Lambda_{b}\to J/\psi \Lambda)}$

Description: The {Lambda}{sub b}(udb) baryon is observed in the decay {Lambda}{sub b} {yields} J/{psi}{Lambda} using 6.1 fb{sup -1} of p{bar p} collisions collected with the D0 detector at {radical}s = 1.96 TeV. The production fraction multiplied by the branching fraction for this decay relative to that for the decay B{sup 0} {yields} J/{psi}K{sub s}{sup 0} is measured to be 0.345 {+-} 0.034 (stat.) {+-} 0.033 (syst.) {+-} 0.003 (PDG). Using the world average value of f(b {yields} B{sup 0}) {center_dot} {Beta}(B{sup 0} {yields} J/{psi}K{sub s}{sup 0}) = (1.74 {+-} 0.08) x 10{sup -5}, they obtain f(b {yields} {Lambda}{sub b}) {center_dot} {Beta}({Lambda}{sub b} {yields} J/{psi}{Lambda}) = (6.01 {+-} 0.60 (stat.) {+-} 0.58 (syst.) {+-} 0.28 (PDG)) x 10{sup -5}. This measurement represents an improvement in precision by about a factor of three with respect to the current world average.
Date: May 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Partner: UNT Libraries Government Documents Department

Measurement of Double Charmonium Production in$e^+e^-$ Annihilations at $\sqrt{s}=10.6$ GeV

Description: The authors study e{sup +}e{sup -} {yields} J/{psi} c{bar c} by measuring the invariant mass distribution recoiling against fully reconstructed J/{psi} decays, using 124.4 fb{sup -1} of data collected with a center-of-mass energy of 10.6 GeV with the BABAR detector. They observe signals for {eta}{sub c}(1S), {chi}{sub c0}, and {eta}{sub c}(2S) in the recoil mass distribution, thus confirming previous measurements. The authors measure {sigma}(e{sup +}e{sup -} {yields} J/{psi} + c{bar c}){Beta}(c{bar c} {yields} > 2 charged) to be 17.6 {+-} 2.8(stat){sub -2.1}{sup +1.5}(syst) fb, 10.3 {+-} 2.5(stat){sub -1.8}{sup +1.4}(syst) fb, and 16.4 {+-} 3.7(stat){sub -3.0}{sup +2.4}(syst) fb with c{bar c} = {eta}{sub c}(1S), {chi}{sub c0}, and {eta}{sub c}(2S), respectively.
Date: June 29, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Search for Resonant Pair Production of long-lived particles decaying to b anti-b in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: We report on a first search for production of Higgs bosons decaying into neutral long-lived particles (NLLP) which each decay to a b{bar b} pair, using 3.6 fb{sup -1} of data recorded with the D0 detector at the Fermilab Tevatron collider. We search for pairs of displaced vertices in the tracking detector at radii in the range 1.6-20 cm from the beam axis. No significant excess is observed above background, and upper limits are set on the production rate in a hidden-valley benchmark model for a range of Higgs boson masses and NLLP masses and lifetimes.
Date: June 1, 2009
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Partner: UNT Libraries Government Documents Department

Measurement of D* Production by Pions on Nucleons at s**(1/2) = 19-GeV/c

Description: The authors report results of an experiment to measure the cross section for the reaction {pi}{sup -} + N {yields} D*{sup {+-}} X at 200 GeV/c. They observe a 2.7 standard deviation signal corresponding to a D* production cross section d{sigma}/dy = 1.0 {+-} 0.4 {mu}b at y = 0.
Date: July 1, 1980
Creator: Fitch, L.; Montag, A.; Sherman, S.; Webb, R.; Witherell, M.; Devaux, B. et al.
Partner: UNT Libraries Government Documents Department

Pentaquark Searches And Properties of D/SJ Resonances at BaBar

Description: Preliminary results from inclusive searches for strange pentaquark production in e{sup +}e{sup -} interactions at {radical}s = 10.58 GeV using 123 fb{sup -1} of data collected with the BABAR detector are presented. In addition new mass estimates for the D*{sub sJ}(2317){sup +} and D{sub sJ}(2460){sup +} mesons are given. The mesons are studied in e{sup +}e{sup -} {yields} c{bar c} data using 125 fb{sup -1} for the decay to the D{sub s}{sup +} s meson along with one or more {pi}{sup 0}, {pi}{sup +}, or {gamma} particles. A search is also performed for neutral and doubly-charged partners.
Date: October 12, 2005
Creator: Halyo, V.
Partner: UNT Libraries Government Documents Department

Long Baseline Neutrino Oscillations

Description: There is compelling evidence for neutrino flavor change as neutrinos propagate. The evidence for this phenomenon has been provided by several experiments observing neutrinos that traverse distances of several hundred kilometers between production and detection. This review outlines the evidence for neutrino flavor change from such experiments and describes recent results in the field.
Date: October 1, 2009
Creator: Rebel, Brian
Partner: UNT Libraries Government Documents Department

Searching for New Physics through Charm at CDF

Description: We report a search for non-Standard Model physics through the measurement of CP-violating asymmetry in the Cabibbo suppressed D{sup 0} {yields} {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} K{sup +}K{sup -} decays reconstructed in about 5.94 fb{sup -1} of CDF data. We use the strong D*{sup +} {yields} D{sup 0} {pi}{sup +} decay (D* tag) to identify the flavor of the charmed meson at production time and exploit CP-conserving strong c{bar c} pair-production in p{bar p} collisions. Large samples of Cabibbo favored D{sup 0} {yields} K{sup -}{pi}{sup +} decays with and without D* tag are used to highly suppress systematic uncertainties due to detector effects. The results are the world's most precise measurements to date.
Date: May 1, 2011
Creator: Di Canto, Angelo
Partner: UNT Libraries Government Documents Department